2.8L to 3.5L Engine Conversion

Back to Frequently Asked Questions

Courtesy of Sean and Peter


According to Peter:  This is hot rodding made easy.  The M30 engine has the same basic block from 1972 to 1993.  Virtually any big six will bolt right into the E12 engine bay.  Some, particularly the '89-'93 blocks, require adaptation.  When you get ready to buy your engine, post a message on so we can give you the particulars.

The L Jet and Motronic Injection systems are unitized so they can be transplanted easily from car to car.  The entire process is strictly bolt up, there are no special brackets, no welding, no one off pieces.  You can do this in California and still pass smog.

Why a 3.5?   The larger engine makes the E12 A TRUE EUROPEAN AUTOBAHN cruiser.   The car just feels great. Its the engine that Gunther and Ugo always had in mind for the E 12.

Grassroots magazine has several great articles including performance results on their E12 with a 3.5.  (Since sold)

According to Sean: Faced with a pretty much perfect E12, original owner car, I had to decide if a 2.8 cylinder head (needed valve seals, but was still very strong), was worth the $800 or so to replace (labor not included). It was consuming oil at the rate of 1 quart per fill-up. So was I to spend the $800 or should I go a bit extra (turned into around $2500) and replace the motor with a 3.5ltr? I chose the latter… A few reasons to go this route were evident: MORE Horsepower with the same weight, Save the newer catalytic converter from being loaded up with oil, and MORE Horsepower!

DunRite's Disease: Sean has this aversion to making sure things are DONE RIGHT! It may be a bit on the anal side, but it proves to be effective in the long run. Hence: DUNRITE’s  disease…. Reminds me of an old advertisement: “you can pay me now…. OR you can pay me later”. 

Our directions include Mr. Dun-Rite editorials for perfectionists who have lots of time.

OK Now the FAQ’s:


L Jet vs Motronic

First off, this covers converting from a 2.8 with L-Jet FI to a 3.5 using the same L-Jet setup. Peter included a nice comparison chart for L-Jet vs. Motronic. Motronic is a definite consideration and will surely add MORE Horsepower, but also introduces a number of other items/considerations that need to be added to the conversion. This will also drive the price up and time to build it out.




















Donor Parts required


Long Block only


Re use injection system, flywheel, ECU and AFM.


Long Block, Manifolds, Wire Harness,

AFM, Computer, flywheel w/ timing devices, 1985(only) bell housing to mate to your Gertrag 265, or automatic tranny with timing devices.


87’s read off Harmonic balancer



Other Parts


Reuse engine mounts, AC, alt, PS brackets, pulleys, water pump, fan,

Radiator, thermostat housings.

Reuse E12 oil pan, use E28 damper


Reuse E12 AC,  pulleys, water pump, fan, ,  use E28 thermostat housings,

Reuse E12 oil pan, E12 PS, E12 alt, use E 28 damper




Relative Labor


Lots more R & R from old engine to new 3.5 for the injection system.


Majority of the labor is in removal and replacement of engine.


Have to change over PS, alt brackets, engine mounts, oil pan


Better have all the Motronic pieces.



Relative Cost


Dismantlers – Long Block $1000 to $1500 depending on condition


E Bay, Local - $300 & up


U Pull It - $ 100 & up


Dismantlers – Long Block $1000 to $1500 depending on condition

$100 – 300 computer

$100 – 300 AFM

$75 Flywheel

$??  85 bellhousing


Best deal – wrecked car







Have to mess with mixture, idle, and possibly fuel pressure.

(You can mess w/ mixture, idle and pressure, and timing)


Plug and play

85 and later are “Chip-able”


Avoid 83 & 84 w/ idle computer





Works pretty well. 

Flat spots at 4000 RPM.

Need 320i intake runners for better

Breathing.  Need 3.5 exhaust system for even better breathing.


212 HP if from 85 or later car

Manifold is more highly tuned.  Smoother power delivery.





Love those long runners and that

log manifold !


Still has that jet turbine whine from the AFM


Less hoses and US smog afterthoughts


Seamless power




Finding an Engine & Components


There are numerous avenues to your 3.5 (or 3.3 engine). 


The easiest (and most expensive)

Peter went to a BMW dismantler, Double 02 Salvage for his engine.  They had 7 to choose from at the time. Sean  originally found an engine (long block with motronic intake) in Texas from an 88 735i. The great thing about this particular engine is that it has the triggering for a possible motronic install on the front Harmonic balancer. Turns out this motor was damaged in the valve train and went back to the vendor. Sean located a second engine, an 85 3.5 in CA.  The California dismantlers sell the complete engine less the transmission, AFM and ECU.  They will usually record the pressure for each cylinder.  PC got one with 165psi in all 6 cylinders.  Sean’s were all above 160 psi.  There are numerous national dismantlers on the web. 


The best (and most challenging)

Find a 535i, or better, a 735i wreck with an automatic and low freeway miles driven by a little old lady whose son is a perfectionist BMW mechanic who changed the oil every 1500 miles.  Pay $1,500 for the miserable wreck, sell the seats, instruments, and wheels and voila!  A free engine.  Even better would be an 87 to 92 model with the 212 hp engine and “chipable” motronic.


If you have the time

Surf eBay relentlessly.  Surf First Fives relentlessly.  Surf E28 Boards relentlessly.  Read the local Auto Trader religiously.  Make friends with all the local insurance agents to see if they are totaling out any donor BMW’s.  Get friendly with your local BMW dealer parts man.  They are a gossip center for BMW stuff.


Stay away from

Advertised rebuilders that note in the fine print that parts are replaced only where required.  Any engine over 150,000 miles.  Any engine from a car fire. Engine recently rebuilt by college dropout to pay for drug rehab.  Any engine advertised that needs work.



Once you see one - what do you look at?

(We need help here from the experts)


Pull the sparkplugs.       Are they all the same in appearance.  Do the ceramic tips have a tan color.


Pull the cam cover.       What is the general color and texture.  Golden glow. Even coating. No deposits.

                                    (Slimy, gunky, dark brown, dark black are signs of poor oil maintenance)


Feel the cam lobes.       With your trusty fingernail, scratch across the high part of a lobe, especially number one cylinder.  You should not feel any ridges.  If you do the cam is shot.


Look in the intakes       They should be spanky clean and free from oil.  The aluminum should gleam.

Look at the exhausts     Should be an even dull flat black.  No white powder look.  No oil.  All even.


Look in the water ports They should be grunge free.  Light white deposits indicate regularly changed antifreeze.  There should be no traces of oil.


Check head gasket       There should be no oil oozing from it.  Look over starter area.


Check oil pan               Leakage should be minimal.  Check residue at drain plug.


Overall appearance       The engine should be relatively clean and free from tons of grunge.  If not keep looking.  BMW’s are being wrecked every day.



Make sure your donor includes the following:

                                    Harmonic Balancer & pulley set

                                    Flywheel (if manual tranny)

                                    Water pump and pulley (even though you’ll be replacing the pump).



Advance Preparation


A majority of time will be pre prep. Getting ALL the needed gaskets, seals, fluids, cleaning solutions, gloves, tools, parts, etc. in advance is the way to go. You don’t want to be chasing down things while you are working. It wastes A LOT of time!  We can’t stress the need to get all NEW gaskets/seals for the engine. Changing them while the motor is out is easy and will save you considerable work after the motor is in (DunRite raises his head here…). BWM doesn’t sell engine gasket/seal sets, so you’ll need to get them individually. The list is long, but most all of the gaskets are the same for all the years up to 88 (We think) for both the 2.8 and the 3.5. They are the same block. The Mobile Traditions CD is VERY useful here. It not only lists part #’s but also list bolt sizes and lengths.  (Sean is working on a parts listing)


Okay…. So now you’ve got all the goods, engine, gaskets, hoist, etc…. We used two cement blocks under the front tires to get the car high enough to get under it. It’s pretty stable, jack stands are also recommended as an additional safety item. Chock the rear wheels. A lift would be nice, but hey….. a driveway works too… 



The Ongoing Saga ..................


Sean ......

The next thing I would tackle, and it is a bit disputed by Peter and others, is to remove the transmission. In my case it’s a five speed. I won’t venture Auto trans models here. If your hoist has a tilter cradle, then tranny removal may not be required. Every engine swap I’ve done, I have removed the tranny first.



This issue ended up being the most controversial issue of all during each of our transplants.  We will walk you through the highlights of yanking that nasty engine out of that teeny space and shoe horning it back in. 


PC, possessing greater in depth BMW experience than Sean… Thought he had the engine removal scheme all figured out ! Not ! 


When PC did his engine swap he decided to keep the tranny on the engine, disconnect the driveline and pull the whole engine/tranny assembly out.   PC had a conventional engine hoist with chain bridging the water pump bracket and the bellhousing point.  The car was jacked up on jack stands approximately 16” behind the front wheel wells.  He also had the rear on jackstands at 12”.  Even with engine at an extreme upward tilt it was a struggle to get the tranny to clear the transmission hump at the firewall whilst keeping the pulleys from decimating the AC Condenser.  As a result PC tore up the foil covered black rubber acoustics at the firewall.


For Sean’s car,  PC was convinced that we should leave the tranny in place, undo the 4 – 19mm transmission bolts, and pull the engine/bell-housing out.  Enhancing this wonderful labor saving method was the discovery of the magic “C” box wrench for ease of tranny top left bolt removal.  However, due to limited clearances fore and aft, we could not slip the engine free from the tranny input shaft.  Thus our extraction angle was limited and the pulleys jammed the top of the radiator bulkhead.  As a last ditch effort Sean unbolted the pulleys and the harmonic balancer and we just barely lifted the engine free.   We also tore Sean’s black rubber acoustics up.  Sean was not at all impressed with Peter’s in depth knowledge.



The optimum but most labor intense method is to undo the tranny at the driveshaft, undo the shift linkage, undo the 4 – 19mm  tranny bolts, drop the cross member, and slide the tranny out.  Then, undo the bolts securing the bellhousing to the engine and pull the bellhousing out.  At that point you should be able to lift the engine straight up and out of the car.  By the way, your chain and hoist need to hooked up throughout this procedure.

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A variation on this method is to leave the bellhousing on, without the input shaft it should be easier to get a decent upward angle on the engine.


If you have a high garage, tall jackstands, and a decent hoist, the  engine/tranny combo is still workable.  Unfortunately most of the time consuming labor is in disconnecting the drive shaft, the gear shift, and the tranny crossmember.


Humbled,  PC did not argue with Sean on dropping the engine in.  Engine only, no bellhousing, no tranny,  virtually a straight drop into the engine bay.   Even with this simplicity, you have to wrestle the AC pump and the engine mounts into exact position, a difficult task.  With the engine in position, bolting up the spanky clean bellhousing was a breeze.  The tranny is heavy and difficult to maneuver into position.  The secret is to rotate the drive flange while pushing the input shaft into the pilot bearing.   Secure the 4 nuts and connect the rear of the tranny.


When PC did his car, He installed the engine/tranny as one unit.  The time and energy spent jockeying and repositioning the engine to get it to fit in just right (3 times) was far greater than the Sean approved method described above.


We note that some bulletin posters claim that they can undo the bellhousing bolts while leaving the tranny in place.  This  greatly reduces the labor required to pull the engine free.  We tried several combinations of universals, extenders and 12” flex drives with poor results.  Hence the above recommendations for fellow swappers with limited tool collections and minimal transmission R & R experience.



* Here we’d like to drop in a note on hardware storage… A box of Ziplocks comes in handy here. And some type of tagging. Paper tags, printed labels, etc. This will make the re-assembly process much easier. Take the time to do it, If not you’ll be referring to the Parts CD later to find the right size nuts/bolts.




Remove Hood







Remove the 4 bolts that secure the brackets to the car.  (Not hood)  Undo the 2 bolts that hold the elbow limit braces.  Disconnect the window washer hoses.  


Remove the hood and store it in a safe place. You don’t want it falling over.


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Remove Battery


Disconnect the battery, remove it, and store it.


Drain Coolant

Remove radiator


Drain the coolant. There is no petcock on these radiators so it can be   messy.  Remove a temp sensor at the lower hose to drain radiator.  Undo 19mm bolt at passenger side of block beneath #6 sparkplug to drain block.


The plastic fan shroud has 2 sheet metal screws at top and tabs at the bottom.  Undo screws.  There is a 10mm screw at passenger side bracket.  Remove bracket.  Undo top and bottom hoses.  Undo wire spade connectors at thermo sensors near lower hose.  Radiator should pull upward with some jiggling.  Remove shroud. Place a piece of masonite where the radiator was to protect the condenser from being hit (if you have A/C).

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Label Injection Wiring Harness Points


Here is where you really want to pay attention and label whenever you can.

There are really not too many connections on the motor. The biggest problem is that all the wires are the SAME COLOR for the injection harness.!!! We snapped some pics before doing this… Might be useful later?


Be sure to label all of the thermo sensor wires.


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Label Chassis Wiring Harness Points


Oil Pressure sender, starter, alternator, ground at thermostat cover, ignition wire at distributor, transistor box multi-plug, coil, AC connector.  For 79 the front and rear runners had to be removed to undo the wire harness.


Chart Manifold hoses


Make a diagram of all manifold vacuum hoses and cold start connections.  (Aux air valve)  Even better, label the hoses.

Remove them.  Check them for age and cracks.

Mr.  Dun Rite: Take pictures of them before disassembly. You will REPLACE them later.


Remove AFM


Remove air cleaner assembly, AFM multi plug , and AFM.  Take the rubber bellows off the throttle body.


Undo Throttle Linkage


Undo pop-on connectors at fire wall and from bell-crank to throttle body.  Note the position and orientation of the rods.


Remove Throttle Body


Undo 4 nuts 10mm.  Cut the 2 small water hoses and undo crankcase vent hose from cam cover.  Doing so allows easy access for disconnecting the plastic injector  plugs.  Disconnect the throttle position plug connectors.  Be sure to label them.  Idle & WOT.


Remove the accelerator rod.


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Remove Injection Wire Harness


Remove the plastic thermo and injector  plugs.  We found that a “pick” type tool works well for this. Be prepared to catch the clips as they fly… (spring steel)  Cut wire ties at firewall. Work your way from the front of the motor to the rear.

Disconnect and label the wiring from the engine main harness along the valve cover. This includes the injector wires, WOT (already disconnected from previous step), cold start injector sensor, coolant temp sensor, oil pressure switch, etc. The locations of some of the sensors vary depending on the model year you are starting with. Drape harness on windshield, secure with wipers.


Pull computer plug from glove box if installing Motronic.  PC tried for fun and could not figure how it pulls out - so good luck.

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Remove Chassis Wire Harness


Undo starter wires, undo alternator wires, undo dipstick wire holder, undo wire stays at intake runners.  Secure out of the way on the wheel well.


The wire harness from the distributor/ignition module can be routed onto the top of the radiator support and out of the way. You may want to tuck it behind the masonite protecting the condenser.




Remove Fuel Lines







Remove the fuel lines from the pressure regulator and the rear of the fuel rail.  Label them for re-installation.

Remove and label the vacuum lines from the pressure regulator.

Remove the fuel line from the cold start injector.



Remove Brake Booster Hose


We had to cut this hose near where it attaches to the log manifold.  Be careful to preserve this hose.  It is difficult to find a replacement.


This is special “anti collapse” hose so don’t skimp on replacement! We’re talkin’ brakes here!

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Map Coolant Hoses


Coolant hoses vary from year to year.  Pay special attention to the heater formed hoses and connections.


This is especially important if you have the “Jules Verne” plumbing under the intake pipes like Sean’s car has(1979).

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Remove All Coolant Hoses


Remove the heater hoses that go to the heater unit.

Remove the coolant hose from the filler (expansion) tank.

If stuck, cut them off especially at the firewall and the smaller hoses. 

Save all hoses and label for the hunting and gathering of new replacement hoses.


Power Steering Pump


AC Pump


Remove with 3 -17mm bolts.  It stays on the chassis.  Wire out of the way.


Remove top adjuster bolt and 2 bottom 17 MM bolts.  It stays with the chassis.  Disconnect the wire if you have not done so.


Remove the belts. A/C, P/S, Alt. You may want to mark them so you know which ones are for what later. (Of course you’ll want to put on new ones! Mr. DunRite)


Remove Cooling  Fan


With radiator out, remove fan from water pump. 4 -10mm bolt. Remove the cooling fan and fan clutch. There are two different styles here. Sean had the older style pump with 1 – 10mm  bolt thru the fan clutch. (This will determine which way you may want to go when you replace the water pump.  More on this later.)



Remove Distributor







Set engine at Cylinder #1 TDC (See Timing Marks on Damper).  Release 10mm clamp bolt.  Distributor spins counterclockwise up and out.


Now would also be a good time to remove the cap, Ignition wires, and the distributor.  Take notice on the position of the vacuum advance on the distributor and also observe the rotation of the rotor as you remove the distributor. This will help on reinstall. Tape over the dist. hole with duct tape. Don’t want any “smeg” going in there.


(“smeg”- besides the biological stuff, it is also the stuff that is covering your engine at this point. Grease/Grime/Dirt = ”SMEG”)


Chain Engine to Hoist


Using the front hoist tab and the hole in the engine block above the starter, hook or (better) bolt a chain.   If these locations aren’t accessible, you’ll need to find suitable locations to connect to the motor. Be sure you are not bending or rubbing any crucial parts when you lift.  Set chain so it does not press against the fuel rail.


Once you get the chain attached, you should be able to get the hoist to lift it almost straight out of the engine bay. You may want to have a slight tilt UP at the front of the motor. You should have enough space to get the motor out with the clutch still on, but with the bellhousing still on you’ll have a VERY tight squeeze (See memo on tranny or not). Another thing to think about, make sure your hoist can be fully extended as you’ll need to lift the motor very high to get it over the front of the car without lowering it off the blocks.

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Undo Engine Mounts


Undo 4 - 17 MM nuts top and bottom.


Double Check


Take a minute, maybe stop and have a beer, and check that all wires, hoses, etc. are disconnected, labeled and out of the way.

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Under the car ...



There are several different tranny/engine removal sequences available for your home mechanic pleasure.  We will go with the most labor intense/ easiest engine yank.  (In Sean’s own words)


 (By the Sean feels very strongly about PULLING the TRANNY FIRST!)


Exhaust Downpipe


Undo 3 nuts from rusty manifold studs from under the car.  Be gentle so you do not damage the studs.  Use liberal amounts of Liquid Wrench starting a week prior to removal.  Undo the hanger above the fuel pump and the rubber donuts at the rear.


Remove Oxygen Sensor. Remove the Heat Shield.


On Sean’s car the Exhaust system came out in one piece. It was pretty simple to remove but a bit cumbersome to move around.

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Undo all rear tranny Connections


Remove the 3 Guibo (Rubber Donut) nuts and bolts.  Disconnect the shift levers and remove the shifter. There is a 10mm bolt up high.  Remove speedometer cable.  Remove the clutch slave cylinder 2 – 13mm nuts and the clutch hydraulic line keeper at the bellhousing.   One 17mm bolt.  Remove the reverse sender wires above the clutch slave.

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Remove the Tranny


Undo the 4 - 17mm nuts at the tranny to bellhousing.  You need a special “C” or “S” shaped box wrench to get this bitch of a nut loose. Tilt engine up on hoist.  Tranny should slide out from bellhousing.  The tranny is heavy, so be carefully of your body and fingers.


The drivers top left nut may be a candidate for a weeks worth of liquid wrench prior to removal.

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Undo the Bellhousing


With the tranny out, you now have access to the bolts securing the bellhousing to the engine.  Starting at the oil pan, there are 3 - 10mm bolts that secure the bottom cover plate.  More than likely they are covered with crud, smeg, and slime.  There are 17mm bolts at 4 locations and 13mm bolts at 3 locations holding the bellhousing to the engine.  The aluminum bell housing slides right off. 

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Extract Engine from Bimmer


With a slight upward tilt, whilst wrestling the AC pump out of the way, you should be able to lift the engine up and out of the bay without interference from the top of the radiator bulkhead.


Boy wasn’t that easy !


It only took three of us, 4 hours to get to this point on Sean’s car. PC’s took 8 as he was “on his own” and it was his 1st time around.

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Position 2.8 for ease of Access


You will now be removing many more parts from the 2.8 for transfer to the 3.5  than you thought.

Remove the alt. And store.

Remove the brackets for the steering pump, alt, and a/c.

Remove the clutch and discard.

Remove the flywheel. You may need to improvise here to get the bolts out. An air impact wrench will help here.

Remove the exhaust manifold(s). These nuts may need to be soaked with “liquid wrench” in advance.

You’ll probably need to replace these on the 3.5 motor, so don’t worry to much about breaking the studs.

Remove the motor mount flanges from the engine block.

Remove the cold start injector and spacer

Remove the 6 “C” intake runners.

Remove the “log” from the top of the intake.

Remove the injector holddowns. (remember to “bag and tag” the bolts, spacers, washers, etc!)

Remove the injectors, the fuel rail and injector manifold as one unit. Remove all of the coolant hoses. On the 79 engine we removed this, which also led us to the removal of the coolant jacket for the Aux. Air Valve. See the pic as this one looks like a spider web. This housing also has the temp-time switch and coolant temp sensor. On the 80 and newer models the Aux. Air valve/sensors are located on the valve cover and thermostat housing respectively. The coolant piping is different between these years as well. We used the stock setup on re-assembly(for Sean’s 79) so piping here may need some improvisation.

Remove the dipstick.

Remove the oil filter housing from the block.

Remove the oil pan. Lots of bolt here…

Remove the thermostat

Remove the water inlet housing.

Remove the starter


If  you are doing a Motronic conversion, you can skip several of these steps but you still need to move a lot of parts.

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Front Timing Cases


Upper and Lower






Engine R&R

UPPER - Remove the large nut in the side of the lower timing case. It is spring loaded to holds the timing chain damper.  Remove the 6 front bolts from the Upper Timing cover. There are also 2 smaller bolts connecting the upper cover to the lower, remove these as well. The cover may need a bit of coaxing to get it off (rubber mallet works well here). The Distributor drive gear is housed in this cover, it should come out of the front of the cam pretty easily. There may be a bit of tension on this as there is a rubber O-Ring on the drive gear shaft (inside the cam).

LOWER  - (Optional) This means you’ll have to remove the harmonic balancer/pulley assembly from the engine. 8 – 13mm bolts.  You will have to undo the 325 Ft LB crankshaft “mother” nut.  We used an air impact wrench to get this nut off.  There are other ways to remove it, but we think it puts too much unneeded stress on the crankshaft. Use a gear puller to remove the hub. 

Install a new front seal.

Remove the old seal from the lower case. This may require a hammer and punch. Be careful not to “nick” the case. Using wood blocks to hold the case will help. Insert the new seal, DRY. Use a large socket around the edges of the seal to hammer it in (tap it in per PC).


Use gasket sealant and place the new timing case gaskets onto the case. Coat both sides, but not the top (where the upper case meets it) and not the bottom (where it meets the oil pan). Insert and tighten the bolts that don’t have brackets to be included (this is the reason to LABEL everything…)

Install hub and retighten crankshaft bolt to 325 FtLbs with air impact gun. Don’t forget to wipe a bit of oil on the rubber part of the seal before putting the case on.


Mr, Dun-Rite

The L Jet & Motronic are very sensitive to engine vacuum which includes the entire sump and head volumes of the engine.  Replacement of the crank seals is an easy procedure to insure 100’s of K miles of vacuum tightness.

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Rear Crank Seal

Engine R&R

The seal is held by a cast aluminum housing.  The seal can be removed with a pick.  Check the crank for grooves.  If present, try to locate the new seal wiper on unworn surface.  Apply a finger of oil to the seal part touching the crank.  Lightly tap into place incrementally using a piece of wood and small hammer. Try not to deform it. There is also a spacer ring that may be in there. According to the BMW parts guy we spoke to, that part has been omitted. we didn’t use it… but that will be your call. You’ll want to remove the oil pan bolts here too. Cut away the old gasket.


Mr, Dun-Rite

If you go the housing route, apply “form a gasket” to all mating surfaces of the aluminum housing to the cast iron block to insure a vacuum tight installation.

Dunrite! Sean also changed the gasket on the oil seal holder as well. ( This is one part he forgot to get in advance. Had to run out and get it or we were done for the day. Wasted 3 hours.)


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(L jet specific)

Engine R&R

Surfacing .....

You need to get your flywheel surfaced at a machine shop(remember we are using manual trannys…).  They will take approx. 20 thousandths off.  Sean’s required surfacing at the shoulders, thus the 3 pressure plate locating pins had to be removed.  PITA.  Replace the pins when done.  You may need new ones since you may ruin the existing ones extracting them.


Installation ...

There is a locating tube at one of the 8 holes.  Thread in all 8 -19 mm bolts coated with Loctite.  Torque to 73 Ft Lbs in stages of 10 lbs..  The bolts had a nice feel as we did the last round of torque to73 FT Lbs.

To hold the flywheel when tightening use a flywheel holder (time for a new tool anyway).


Mr. Dun_Rite

Purchase new bolts from the dealer for this critical application.

The Loctite is an important step toward eliminating vacuum leaks in addition to holding the flywheel to the car at higher RPM’s. (Loctite is an epoxy that cures in the absence of oxygen)

*** Make sure you use both sealant and thread locker on the flywheel bolts. This is a crucial step as if you don’t use sealant, you will have an oil leak, and think it’s the rear seal. The bolts WILL leak. 

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Pilot Bearing

Engine R&R

Apply Loctite to outer surface of the Pilot Bearing.  Gently tap it into position using some wood and a hammer.  We could not determine the optimum depth to set the bearing at.


Note:  We both had donor engines with automatics, hence no existing pilot bearings.  Here are three techniques for removing a pilot bearing that refuses to come out ....

1)      rent a removal tool, it looks like a slide hammer, or lock extractor.

2)      Fill the space behind the pilot w/ Black Cats, light the fuses and voila! (Wear goggles for this method! And KEEP YOUR MOUTH CLOSED!)

3)      Fill the volume behind the bearing with packing grease.  Find a wood dowel that matches the pilot hole take a hammer and?… (hydraulics)

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Clutch, Pressure Plate

Engine R&R

Using the nifty plastic clutch tool, set the clutch plate and the pressure plate on to the flywheel.  There are 3 locating pins for the pressure plate.  Thread the 6 – 13mm or (6 mm allen) bolts.  Tighten evenly in 4 or 5 sequences till the pressure plate is snug to the flywheel.  Torque to 17 FtLbs.  Slide the clutch tool in and out during this sequence to insure that the clutch disc is evenly centered on the pilot bearing.


Sean and I both used the Sachs “Super Set” clutch kit which comes with everything you need to do a complete clutch job..  We paid $180.


There may be a 3.5 pressure plate that is a little stronger than the 2.8.  Sean is using the 2.8 and it works just fine for everyday driving.


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Timing Marks on


Engine R&R

Mr, Dun-Rite

Apply white and yellow paint 2 inches beyond the stainless balls and between the stainless timing balls.  This will make it very easy to find the marks through the bell-housing view port.

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Engine Mounts

Engine R&R

Bolt up your 2.8 steel mounts to the cast iron block bosses. 17mm bolts.


Based on uniformed opinions, all M30 blocks have bolt bosses that will take the E 12 engine mounts.  At least thru 1987 engines.

 Eng_mnts1.jpg (19536 bytes)


Oil Pan





Engine R&R

The oil pan has to fit the E12 chassis and cross bar.  Most later E28s do not fit.  Some earlier 733, 633 etc. May fit.  The E28 & E24 oil pans are approx. ½” or 10mm deeper than the E12, they also have better baffles.  If your new pan looks like it might fit, chain new engine on engine hoist and do a trial fit.  Replacing the oil pan gasket is infinitely easier with the pan out of the car...  clean it spanky clean.

(this pan is why you want to do a conversion!)

 pan1.jpg (57184 bytes)

Oil Pick Up

Engine R&R

If using your E12 pan, the oil pick up needs to be transferred from the 2.8 engine.  The E12 pick up is approx. ½” less deep than the 3.5 pick up. The tabs holding it are different from the E12 so you may need to improvise a bit. There are 3 -10mm bolts that secure it to the oil pump.  There is a thin metal gasket that fits between the pump and pick up.  All 10mm bolts.

You will need to remove the 3.5 oil pick up. It is held by 4 bolts on the pump and 2 on a support bracket. Don’t remove the end cap to take off this support bracket. It is easily bent out of the way to remove the pickup.

 Oil_PUs1.jpg (33285 bytes)

Oil Pan Install

Engine R&R

Lightly screw all of the 10 mm bolts back in.  Starting at the middle (Cylinders 3 & 4) tighten the bolts in a pattern working outward in both directions to avoid creating any weird stresses in your beautiful aluminum casting. Use Sealant/gasket cement on the pan gasket. Put the pan back on. Tighten the bolts evenly, and don’t over tighten. If you crush the gasket too much you may have leaks.



There are different schools of thought for gasket sealing.  We both went with coating both sides of the oil pan gasket.  I used copper RTV, Sean used liquid “form a gasket”, we will see whose is better.  Avoid applying too much sealer as it might get stuck in an oil passage. It appears that trying to replace the gasket with the engine in the car is next to impossible so why worry if a one sided application facilitates future servicing.


Harmonic Balancer

Engine R&R

Before installing harmonic balancer...


The Alternator, AC Bracket, Power Steering brackets all have bolts thru the lower timing case.  The 3.5 balancer blocks access to the bolts.  Secure the bolt for each bracket.  Be sure to keep track of the correct bolts.  The bolts through the timing case are all special lengths. 13mm bolts.


The balancer has a locating pin to reference it to the crankshaft TDC.  The pulley holes are eccentric (not evenly spaced).  Rotate the pulley until all of the holes align.  Install and evenly torque  the 8 - 13mm bolts.


The 3.5 balancer is larger than the 2.8.  Be sure your engine monger includes it in the deal.  We could not get an opinion it is important to use the 3.5 balancer or not.



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AC Bracket

Engine R&R

Install the AC bracket.  2 -17mm bolts to the block and 2 -13mm bolts thru the timing case.

 ACBracket1JPG.jpg (25363 bytes)

Engine Diagnostic Sensor

Engine R&R

You need the sensor bracket off of the 3.5(due to the larger balancer).  One of the bolts also secures the AC Pump adjusting bracket.  One of the bolts is extremely long.  13mm x 45 mm


 sensor.jpg (15823 bytes)


Water Pump




Fan Pully

Engine R&R

Install  with new gasket and 4 - 10 mm bolts.  We strongly recommend a new water pump. $50


There is a Catch 22  ....

(There two types of fan clutch mounting systems which affect the model of pump that you use.  The E12’s have a single 10mm bolt to secure the fan clutch to the pump.  That old style fan clutch costs $125 for replacement.  A newer style fan clutch has a large gland nut that spins onto a large thread on a newer style water pump.  New style fan clutch $75.  You will also need a newer style fan pulley, the hole spacing is different.  It is vastly easier to remove & replace when radiator is installed)




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Special Conversion Nut

(L Jet required)

Engine R&R

There is a special nut that threads onto the end of the 3.5 camshaft with a slot milled to accept the spade end of the distributor drive. Put the “giant” nut onto the cam. Use a bit of  thread lock.  Torque to the end of the cam.

32 or 36 mm.  It is big. (Cannot remember)  We paid $45.

You can use channel locks to grip the bolt.  Or go to Sears and get a $20 socket (PC) or a $20 open end (Sean).

 Cam_magicbolt1.jpg (96149 bytes)

Upper Timing Case     (L Jet required)

Engine R&R

Install the nut, spring, ball and piston for the timing chain damper. Use a good amount of oil on these during assembly.


If L-jet, you need to re-use upper timing cover from the 2.8 for  the distributor drive. . Put the NEW O-ring onto the distributor drive and coat with a bit of oil. This O-ring is important for engine oiling (don’t skimp here get a new O ring!). Insert the drive gear into the cam end. Oil  the 2.8 distributor driver shaft and insert into cover.  Install cover with new gaskets at sides and the bottom.  Loosely install the 6 – 10 mm side bolts then thread  the 2 – 10 mm bottom bolts.  The bottoms were difficult to get threaded.  Evenly tighten with a very light torque. 


(Note;  the L Jet timing cover requires re-use of the 2.8 cam-cover.  The front bolt holes are different.  The gasket  is different from the Motronic cam -cover.)

 LE12timingR735a.jpg (39709 bytes)








Engine R&R

Clean up the 2 - 17 mm nuts.  Apply oil or graphite.  Do not overly tighten the top bolt. (a)  Apply dielectric grease to the electrical connections.


(When you go back to change your starter with the engine in the car you will appreciate this instruction.)

 starterbolts.jpg (24475 bytes)

Accessory Bracket

Engine R&R

Bolts to block, timing case and bottom of oil sump.  Use the 2.8 bracket to insure that all of your 2.8 accessories (alternator & PS Pump) will fit correctly.

  AltBracket1.jpg (73815 bytes)


Engine R&R

Replace the rubber sleeve if it is worn.  Someone  mentioned using a polyurethane sleeve that would never wear out.  Secure alternator loosely to the adjusting bracket which you installed prior to the balancer.


The alternator can go in after the engine is in the car.  It is easier out of the car.  Make sure you use a new bolt of the correct length because once in the car, adjustment of the alt. position is strictly by braille.  The PS pump limits your access to the adjusting bolt.


Mr.  Dun Rite: Replace your alternator with a Bosch rebuild.

  alt.jpg (28856 bytes)

Oil Filter Boss

Engine R&R

You may need to move your E12 boss over depending on the oil filter set up from your donor engine’s previous set up.


 (There has been considerable discussion on this subject, depending on the donor engine used. Up to 1987, you should be able to use the 2.8 mount directly. After 1988 we’re not sure. If you see any additional oil ports on the block, write to list and discuss it there).

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Intake Manifolds

L Jet Specific

Engine R&R

Install the Injector manifolds and the injector assembly. 


Install the runners. Use new paper gaskets at all connections.  (We used the single gaskets per port.)  Leave all of the bolts loose so that you can evenly snug down all of the joints (12 in all) evenly with everything aligned.  Again you are preventing vacuum leaks.  PC’s has a combo of 13mm nuts and 12mm nuts, Sean’s had all 13mm nuts.  


Install the "log" manifold. Do not forget the 2 triangular brackets that keep the log manifold supported. You may need to bend the supports a bit to get the log into position (see the pic ).


We did not do the Motronic manifold but it bolts right up.

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320i Runners

L Jet Specific





Engine R&R

The runners come with stiffeners and with out.  The stiffeners interfere with the fuel rail and need to be notched.  In either event, you need to come up with a custom bracket(s) to hold the fuel rail semi rigidly in place.


As noted in GRM the hot set up is to replace the 528 intake runners with runners from a 320i.  The longer runners definitely make a positive difference in the 2000 to 3000 RPM range.  Not to mention they look way cooler.

Intake&FuelRail1.jpg (71101 bytes)


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Water Inlet Cluster

Engine R&R

This puppy has to go on after the intake manifolds. Clean the port of gasket material. We used the 3.5 housing as the one from the 2.8 was kind of beat up. It also has all the same sensors in it that are located near the Aux. Air valve. If I ever decide to change the plumbing on the side of the engine from the 79 version to an 80-81, the wiring can be moved easily to the sensors in the thermostat housing.


Use a new paper gasket.  3 - 13mm nuts.  Note: the top nut secures the diagnostics plug bracket.


Secondary Hoses

Engine R&R

It is way easier to install the secondary hoses that mount beneath the manifold and the heater hoses with the engine out of the car.  Leave the heater hoses loose and be careful how you orient the clamps since access in the car is cramped.


Mr.  Dun-Rite

We replaced all of our hoses with new through out.  BMP is the hot set up with a set of all new correct hoses for less than $100.

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Hot Water Plumbing

L Jet Specific

Engine R&R

The L Jet has a hot water loop at the bottom of the throttle body to warm idle air.  Most likely this is a smog related item.  The 3.5 blocks do not have a water supply port above the starter like the 2.8 block.  The simple solution is get a plastic “T” from NAPA and cut into the heater supply hose.


Mr. Dun Wrong: This is not an essential fix.  PC’s car runs fine at Lake Tahoe in 15 degree weather without the idle warmer hoses.

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Aux. Air Valve Plumbing

Engine R&R

Pre 80, the L Jet uses a water temp sensor located beneath the intake manifold runners cobbled into the heater/reservoir return piping for cold start operation.  80/81 uses an electrically operated idle air control for cold running that is a much cleaner install.  If possible, get the parts off of a wreck.


See The FAQs For Aux Air Valve Descriptions.


Exhaust Manifolds

Engine R&R

Clean the threaded studs with a wire brush.  Use new gaskets.  Use a graphite anti seize compound on the studs.  (For when you install those new “ extrude honed” ported E28 manifolds later on).   Snuggle manifolds onto studs and secure with bolts.


Sean and I re-used our 2.8 manifolds since we were reusing our 2.8 exhaust systems (and need to meet CA smog laws).  According to all of the bulletins, there are countless horses waiting to be unleashed with a proper 3.5 manifolds or headers, and a free flow exhaust setup.


Mr. Dun Rite: Buy new copper bolts (12 mm)  from the dealer.  Throw the old ones away.  Mr. Dun to the Max, sweeten up the stud threads with your handy tap & die set before assembly.

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Water Drain Plug

Engine R&R

19mm – Bolt into place using a new washer or RTV. 



Mr. Dun RiteL: This one is easy to forget.


Heater supply port

Engine R&R

At rear of head beneath Rear Cam Cover.  Use E12 unit to be compatible with the preformed E12 heater supply hose.  New gasket and RTV, 3- 10mm bolts.  Loosely install supply hose.  Orient clamp so you can get a screw driver on it when engine is in car.


This part is impossible to get at with engine in the car.  Advanced Braille is required for R&R.

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Rear Cam Cover

Engine R&R

There is a stamped metal plate with a gasket and a fiber washer on one 10MM bolt that will leak sooner or later.  Replace the gasket and install the fiber washer on the bolt gasket closest  to the exhaust side of the head. This is also refered to as the “duck” gasket.


Mr. Dun Rite

With engine installed this cover can only be R&R’d by braille.  Due to its immediate proximity to the firewall.

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Damper TDC






Engine R&R

There are 2 lines in the Damper for showing TDC.  Paint them white or red.  This is a good time to turn the engine to TDC cylinder one for your eventual distributor installation. (After the engine is in the car)


Fan belt

Engine R&R

Install alt. / water pump fan belt.  Record it’s size.  Make sure you have an adequate range of adjustment for the alternator.  Fan belt sizes vary.


The power steering and AC belts go on once the engine is reinstalled.


Mr. Dun Rite: Keep your old fan belts, (or buy new), in your spare tire bay for that one time you wished you had one.


Cam Cover

Engine R&R

Install to protect valve train.


As noted previously, the L Jet and the Motronic camcovers are not interchangeable.  The front bolt hole is located differently.  The 2.8 & 3.5 gaskets are different.


Spark Plug Holes

Engine R&R

While easy to get at, check that the spark plug threads are clean,  are not cross threaded,  and are operating easily.


If not, now is the time to clean them with a tap or heli coil.


Engine Out of Car


Since the engine is out of the car, you might want to clean the engine compartment. Use some type of “gunk”. Protect the wiring as best as you can from water saturation. Clean and paint any surface rust with rust inhibiting paint. Clean out the A/C condensor (if the car has a/c of course). Fix any insulation on the firewall that is ripped.


 Eng_Bay1.jpg (79801 bytes)

Engine / Transmission

Installation techniques


See Notes on your options for engine / tranny combinations for reinstallation.  Each has its advantages / disadvantages.  

(See Pics Below at "hoist mounting")


AC Condenser


Place a piece of plywood to protect the delicate aluminum fins while reinstalling the engine.


Rubber Engine Mounts


Place loosely bolted on the frame mounts. Do not tighten. You will need to be able to move them around during your engine docking procedures.


Mr. Dun Rite 

Install new OEM rubber mounts.  I f yours are over 100k miles old, they are most likely shot. (See the Pic above to compare new to used mounts).


Chain Hoist


Secure chain to water pump lifting steel tab and to hole in flywheel casing above starter motor.  Make sure the rear is easy to undo with the engine in the car, hand access is limited.



Hoist Mounting







The angle at which you set the engine at depends on tranny or no tranny and how high you have the car jacked up off the ground.  You may have to do 2 or 3 trial attempts to get a successful insertion.  The clearances are very tight.


Lower the engine SLOWLY! The tricky part is to get the Motor Mount flanges lined up with the mounts themselves. The A/C compressor and P/S pump may need to be moved a bit to get the engine all the way down.


Once it’s down correctly, make sure to put the nuts onto the mounts. You don’t want the engine lifting off of the mounts when working on the tranny reinstall.



Mr. Dun Rite: Cut up a piece of plastic garbage can or similar that matches the profile of the tranny hump.  Use it to protect the foil and rubber shielding while cramming the engine back into place.

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If you left the bellhousing off now is the time to install it while the engine is at an angle and in the car.  (Don’t worry about the engine resting on the pan, it is very strong and appears to have been designed to do this function.) It has 4 – 17mm bolts and 3 – 13 MM bolts all special lengths.  Do not forget the clutch lever and the throw out bearing.


There is a stamped metal crescent moon piece at the bottom of the bellhousing.  3 - 10 mm bolts.  Secure before the engine is in final position for ease of access.  The cross member makes access to these bolts difficult.


We made a custom bracket that bolted into the clutch slave location with a long 10 mm bolt that pressed against the clutch lever bar to keep it tight against the pressure plate.  Just some 1 x 1 alum angle drilled and tapped.  Otherwise it flops around and is a real PITA.

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Tranny  Options


a)      In theory you can leave the tranny in position and gently drop the engine so that it slides onto the input shaft.  There is not enough fore and aft clearance to accomplish this easily.

b)      If you pulled the tranny, now is a good time to slide the input shaft home while the engine is still at an angle. 

c)      The tranny is secured with 4 – 17mm bolts.  The dreaded bear of tranny world is the driver side top left bolt.  Gertrag threw too many casting fins for any access.  The remedy is the magic "S" or "C" wrench(es). (See Pics above in "Remove the Tranny Section).



tranny_under_car.jpg (61624 bytes)

Temp. Tranny Support


You will need to support the rear of the tranny. Reposition your jack to hold it until you are ready to install the cross member.


AC Pump


Before dropping the engine to the mounts, position the AC pump in the correct position.  Ease the engine down until you can set the 2 - 17mm bolts that secure the bottom of the pump.  Install the electric clutch wire.


This step is so easy to write about!  Wrestling with the heavy AC pump is a definite PITA.


Engine Mounts ***


With the above done, lower the engine onto the mounts, you may have to jiggle the rubber engine mount studs to engage. 

(You did leave them loose?)


Check the engine and tranny for clearances and alignments before dropping all the way onto the mounts. 17mm nuts.  4 total.


Rubber Donut (Guibo)


Set the three 17mm bolts that secure the Guibo to the tranny output flange.


If they will not go together, you have not dropped the engine correctly or you need to loosen the spline gland nut near the driveshaft center bearing.

Mr. Dun Rite: The manual says to use new bolts and aircraft style nuts. Get from dealer.

Replace your Guibo with a new OEM unit if it is over 75k miles old.  Don't remove the strap (if new) until it has been bolted to the driveshaft and tranny. If used, use 2- 6” PVC hose clamps to compress the Guibo. (Giant "WaterPump" pliers work too).


Gearshift & “poopdeck”


While the tranny is slightly dropped, bolt the sheetmetal gearshift “poopdeck” to the rear of the tranny 2 – 10 mm bolts and install the gear shift levers.  There is a rubber bumper at the rear of the “poopdeck” that bolts up to the transmission hump.  Do not forget the molded foam insert for noise control.


Reverse Light Sensors



Secure to top of transmission while slightly dropped.

Install speedometer cable fitting.  Secure with special 10 mm bolt.



Transmission Crossmember







Install at sliding rails flanking the transmission hump.  2 – 10mm special bolts and nuts.  Leave loose.  Secure rubber tranny mount w/ 17mm bolt.  Check that tranny and driveshaft look aligned.  Tighten rail nuts.


Mr. Dun Rite: How do you know if things are aligned when you upside down on a creeper under the car with a greasy nose?


Install clutch slave


Install with 2 – 10mm nuts to studs on the bellhousing.  Secure hydraulic line to tab on the bellhousing.  15mm bolt.  PITA.


Mr. Dun Rite: If your clutch slave is over 100k miles old, it is time to replace it.

ClutchSlave1.jpg (21453 bytes)

Exhaust Downpipe


Using a new gasket(s) install downpipe to headers.  3 nuts onto rusty studs.

Use a die to sweeten up the stud threads.  Use graphite thread compound.  Secure exhaust pipe at transmission hanger.


Mr. Dun Rite: Get 3 new copper nuts from your dealer or parts monger .They do not rust.


Oxygen Sensor


Install at downpipe.  Use gloves, do not touch the white ceramic tip.  Install a new unit to simplify tuning.


Power Steering Pump


Install pump to accessory brackets.  3 – 13mm bolts.  Install belt.  Adjust tension and tighten adjusting bolt.


AC Pump


Install adjusting bolt and nut to sliding arm from timing case.  13mm.  Install fan belt and adjust tension.  You can use your handy 18” ratchet bar to lever the pump / fan belt tension. 


Install fan

(If old E12 style)


Needs to go on before radiator is installed.


Chassis Wiring Harness


Install the wiring that feeds from the drivers side.  It connects the oil pressure sensor, the alternator wiring, engine coolant sensor and ground, it wraps around the front of the engine, distributor wire, ignition and coil wiring.  It secures to the dip stick & the distributor.  Use plastic wire ties at the distributor splash plate.


Mr.  Dun Rite:

Use dielectric grease at all connections.


Ground Strap

Alternator Ground


Secure to driver side engine mount bolt.

Secure to engine.  Check for condition of wire and connections.  If disreputable, replace for future electrical happiness.


Mr. Dun Rite:

Use dielectric grease at all connections.



Starter Wiring







Connect the starter wires 2 spade connections and 1 - 13mm bolt.





Use dielectric grease at all connections.


Heater Supply / Return



Secure to firewall plastic hose nipples.  Orient hose clamps so you can get an extra long screwdriver on them parallel to the fire wall.


Lower Radiator Hose


The mounting of this hose is critical.  The clearance at the bottom radiator to the AC Pump pulley is very tight so the hose must be angled and positioned correctly.  Further it is bear to get it onto the thermostat housing intake, further the clamp position is important for screwdriver access, further the dealer OEM hose we got was 2” too long and had to be cut to size.  Leave hose loose until the radiator is installed.


Make sure the hose does not rub against the AC pulley. 


Radiator and fan shroud  E 12 OEM


Install your radiator on the factory rubber pads.  Slide as far to the passenger side as possible.  Check the bottom hose for clearance at the AC pump.  PC had to install a wedge under the right side of the radiator to tilt it up away from the AC (hose grinding) pulley.  Secure pass. side bracket with 2 - 10mm sheet metal bolts.  Attach lower hose.  Attach temperature sensor spade fittings near lower hose.  Slide plastic shroud into position, there are two tabs at the bottom of the radiator.  2 – sheet metal screws at top..


The E 12 brass OEM radiator is easily replaced with an E28 aluminum 535 radiator that has more cooling capacity.   It mounts in the same position however the brackets are different and require some minor sheet metal cutting and drilling.  You need to use the 535 top and bottom hoses because the radiator nipples are different.  The going price seems to be around $125 for a used unit.


Upper Hoses


Install upper hose and small diameter reservoir hoses.  Attach heater return manifold hose to reservoir.


You can use fuel hose for the radiator return.


Brake Booster Vacuum Hose


Reattach brake booster hose to manifold.  Clamp tightly.


We both had trouble with this hose.  It is stiff, un-yielding and gnarly.  We had to cut it off the manifold.  We got some hose off a wreck to replace the portions that we had cut.  It is designed for extreme vacuum pressures. The dealers have trouble getting it. Sean was able to obtain some new, but it was pricey!


Throttle Link


Grease ball joints and install.  They snap into place.  Connect at firewall and from bell crank to throttle.



PC now own a 533i with a cable linkage.   The visceral feedback from the E 12 hard rod linkage is a joy!  The cable feels mushy.


Injection Wiring Harness

L Jet Specific









Carefully reroute the harness from the firewall to run beneath the manifold log.  The wire should all have a “memory” and should fall into place.  It helps that you left the throttle body off to gain access to the #3 & #4 injector plugs.  Check to make sure that all of the connectors can reach their plugs.  Note that there are several grounding locations.  Re-plug all of the connectors.  Reinstall those little square wire clips at the injectors and sensors.  Install all of the rubberized loop wire holders.  Secure harness to firewall with plastic wire ties.


Wire harness installation looks to be similar.  The main firewall bundle is routed differently.



Mr. Dun Rite: In order to facilitate easy cam cover removal, PC re-engineered the wiring stays to hang from the triangular log supports and abandoned the stays at the upper bolts of the cam cover.



Throttle body


Secure the crankcase vent “elbow” hose to the bottom port of the throttle body.  (If you are like Sean, attach small diameter idle warming hoses at bottom of throttle body.)  Reattach with 4 - 10mm nuts.




Distributor  E12

L Jet Specific






Engine must be at Cylinder 1 TDC.  (Check the cam lobes at #1 Cylinder to verify.)  The distributor has a #1 location mark in the lip of the metal body.  That mark will end up at approx.  3:30 when looking at the engine from the passenger side.  Insert distributor with mark at 11:00 and twist clockwise into position.  The vacuum cone should almost being pointing up.  If not, twist distributor out and try 12:00.  Set clamp bolt loosely.


Install the distributor cap and ignition wires.


Mr. Dun Rite,

Get a set of high performance 7mm or 8mm ignition wires.  They seem to make a difference especially at lower RPM’s.  ALLBMW has a good deal on high performance wire sets.


L Jet Plumbing and Hoses


Install vacuum hoses, cold start and fuel hoses, cold start air hoses, AC air increase solenoid, etc.



This is all easy if you labeled them.


Fuel Hoses


Attach fuel hoses to fuel rail.  Attach hoses to charcoal canister beneath washer fluids container.



Mr. Dun Rite,

Replace all of your fuel hoses with new BMW OEM hoses.  Avoid freeway engine fires.  The new fuel additives are hard on 20 year old hoses.



Air Flow Meter


Attach meter box and secure wiring harness to multi-point plug.


Precious Fluids


Add engine OIL!!!! Don’t forget this!!! Could cause BIG problems.

Add coolant.



Final Check outs


Tie wrap all wire out of the way of moving parts.

Check and tighten ALL coolant hoses.

Install and tighten all belts.

Make sure fuel hoses are routed correctly and are tightly clamped.

RECHECK Connections, hoses, belts, etc. AGAIN!

Install freshly charged (new(DunRite!)) battery

Check the dipstick.


Spin Engine


Leave the coil wire off. You will want to crank the engine a bit before letting it fire. This is to pump up some oil pressure. It will let you see if you make oil pressure and not have to worry about shutting it off FAST!




If you get oil pressure(light goes out). Add the coil wire.


Mr. Dun Rite: Take a break, have a beer, chill out.  Go back over the list AGAIN and make sure that you have hooked everything back up correctly and that there are no loose wires or hoses. 


Fire Der 3.5er Up !


Jump into the drivers seat and turn the key.


We were lucky, the timing was pretty close, and the FI was working fine before the swap, so the motor came to life right away.


Set the timing. See the “Haynes” or  BMW manual on this…..

Bleed the coolant via the thermostat port. Top off coolant.

dutch.jpg (67662 bytes) 

Drive Der Autobahnen Muncherkin


Notice the deep surge of low RPM torque as you pull away from the stop light.  Feel a continuous surge of ever increasing power all the way to 6000 RPM.  Forget those 2.8 flat spots.  Forget to shift as much.


Let it idle.  Listen to a deep primitive rumble emanating from the pipes. 

Re- fill it with gas a lot more often.



***More to come


The followup of this FAQ will be along shortly on “tweeks” to do to get the most out of you newly installed 3.5 ltr.  We are sure we most likely have left out something in here, so let us know and we will modify it. We’re sure we missed/omitted something you will encounter.




CLEANING EVERYTHING. We practice DunRite’s to the “t”, but we also wanted minimal downtime for the car(s). Sean was ready to do all new gaskets, etc…. But cleaning all the parts wasn’t there for him… PC told Sean if he wanted his continued help “YOU HAVE TO CLEAN ALL THESE PARTS!” so Sean spent three weeks (ok not that long) cleaning parts. He is really glad he did! The car is now a pleasure to work on without getting dirty.


If you have access to a parts cleaning machine, use it! Sean ended up using a giant “rubbermaid” container and filled it with a batch of  some stuff called “oil eater”and water. Each night he dropped a piece in to soak and then the following evening he’d clean that part. Then in with the next. Old toothbrushes, household cleaning brushes, etc. all  work well. Also LOTS OF RAGS! This is “smeg” removal at it’s finest. A lot of work, but well worth it, in hindsight.

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