FirstFives.org™

2.8L to 3.5L Engine Conversion

Courtesy of Sean and Peter

Background:

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 www.firstfives.org 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.

Consideration

L-Jet

Motronic

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

Tuning

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

Performance

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.

Aesthetics

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.

PC........

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.

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.

1	Remove Hood	Removal	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.
	Remove Battery	Removal	Disconnect the battery, remove it, and store it.
	Drain Coolant Remove radiator	Removal	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).
	Label Injection Wiring Harness Points	Removal	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.
	Label Chassis Wiring Harness Points	Removal	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	Removal	Remove air cleaner assembly, AFM multi plug , and AFM. Take the rubber bellows off the throttle body.
	Undo Throttle Linkage	Removal	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	Removal	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.
	Remove Injection Wire Harness	Removal	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.
	Remove Chassis Wire Harness	Removal	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	Removal	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	Removal	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!
	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).
	Remove All Coolant Hoses	Removal	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	Removal	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	Removal	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	Removal	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	Removal	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.
	Undo Engine Mounts	Removal	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.
	Under the car ...	Removal	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	Removal	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.
	Undo all rear tranny Connections	Removal	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.
	Remove the Tranny	Removal	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.
	Undo the Bellhousing	Removal	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.
	Extract Engine from Bimmer	Removal	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 1^st time around.
	Position 2.8 for ease of Access	Removal	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.