Heads and Cam Interchangability??

[socalfiver]

Hi, all. First and foremost, thank you all so much for the wisdom you consistently offer. I've only been on here 3 weeks, and already feel like I've gotten years of knowledge from this site.

I believe I have a blown head gasket or possibly a cracked head. At the very least, I've got leaky valve seals. She drives fine around town, no overheating. On the freeway, the temp gets hot. Over the 3/4 mark. I slow it down, and she goes back to normal. I replaced the t-stat and fan clutch and ran some super-flush through the cooling system. Still happens. I have the air hole drilled in the top edge of my t-stat, and have bled the system as well.

At the boneyard today, I found a replacement head from an '80 633csi automatic. Took a couple of hours to strip and pull it, and lucky me, there aren't any cracks and it has an '86 casting date. The valve train is immaculate and clean with no traces of scorched oil that my current head has (all brown inside). Only $55!

Do I need to switch out the cam? what will happen if I use the 633csi cam on my 2.8 block? My car is also automatic.

Does anyone know where I can find the specs for both cams to compare?

[GripGreg]

Just where is this magical boneyard? When you're through, I might snatch the motor. Greg

[socalfiver]

I have had awesome boneyard luck since buying this car.

Pick Your Part on Alameda between Florence and Firestone has the '80 633csi and a newer 7 series. Small yard, maybe 150 cars, a large portion is MBZ.

There's another yard in the north valley that has 2 e12's, 4 e28's and an e21 as well as some 7s.

Have you been to the Pick Your Part in Wilmington? No e12's last time I was down there, but a few e28's.

[Mike W.]

Hi, all. First and foremost, thank you all so much for the wisdom you consistently offer. I've only been on here 3 weeks, and already feel like I've gotten years of knowledge from this site.

I believe I have a blown head gasket or possibly a cracked head. At the very least, I've got leaky valve seals. She drives fine around town, no overheating. On the freeway, the temp gets hot. Over the 3/4 mark. I slow it down, and she goes back to normal. I replaced the t-stat and fan clutch and ran some super-flush through the cooling system. Still happens. I have the air hole drilled in the top edge of my t-stat, and have bled the system as well.

At the boneyard today, I found a replacement head from an '80 633csi automatic. Took a couple of hours to strip and pull it, and lucky me, there aren't any cracks and it has an '86 casting date. The valve train is immaculate and clean with no traces of scorched oil that my current head has (all brown inside). Only $55!

Do I need to switch out the cam? what will happen if I use the 633csi cam on my 2.8 block? My car is also automatic.

Does anyone know where I can find the specs for both cams to compare?

An 80 633 will have the same cam as an E12 528i. Specs are in my Cylinder head FAQ. Any pre motronic M30 cam can be used though not all are the same. Even Motronic ones can be used with the cam nut adapter.

[socalfiver]

Thanks, Mike. I read the cam faq, but only saw 2500, 2800, 528I and 530I on there. I didn't see a 3.3 listed.

Will my engine retain the same displacement and compression ratio? I assume it will because the 3.3 head swap is listed as "s" on the parts interchangability faq.

Should I purchase a gasket set for a 528i or a 633? Are they identical?

Does the 633 have larger diameter pistons, or is the extra displacement a result of a longer stroke?

[GripGreg]

I haven't been to Blinn in a coupla months. Did you know there are two on Blinn? One just north of PCH & one just south of PCH. BUT, a 1/2 block so. of PCH on Blinn there's an angle street on the left. U-turn left on that street named Coil. At a park on the right. PAP is on the right. Hit PCH & you've gone too far! Sneaky, huh??
There's also an Ecology P N P close. From Blinn on PCH, go west not far to a signal. Street named Euclid; Banning Park is on the left; turn right & go til the end (Lomita), turn right & enter the second driveway on your right.
Do you recommend I get the 633 motor from looking at it? I know being an '81 everything will fit. Ohh, maybe the injection system is motronic, not L-Jet. Do you recall the injection tubes meeting in a tri-angle, or are they like our tubes, not touching each other? Thanx in Advance,,,,Greg

[socalfiver]

It's a 3.3 m30 with l-jetronic, like our cars. You'd only be getting the 3.3 block, because I took the head today. You could use your existing head, intake and injection system.

The 7 is a motronic 3.5, and appears complete. No idea on condition.

The car is in really good shape, but who knows? I was taking a gamble investing 2 hours in pulling the head. I got lucky and it's in good shape. The car was well cared for, coolant was nice and green. Little corrosion on the hose fittings. Much less than my current engine.

I don't know how much the block would cost you. I'd have loved to pull the engine whole, but I work on the street outside my apartment. Head swap is feasible, engine swap is not.

[wkohler]

The car was well cared for, coolant was nice and green.

Mike might disagree, but I see that as an oxymoron.

[socalfiver]

Why is that an oxymoron? A car with little corosion and fresh coolant, to me, indicates a relatively well cared-for car. most boneyard cars have dark, rusty coolant and corroded fittings. Also, the rest of the car is in fantastic shape. From the paperwork found inside, it looks like it was scrapped because of parking and registration fees.

[GripGreg]

Fantistic shape, interesting. What shape & color are the seats?
What is your name? Did I ask that before? Greg

[socalfiver]

The seats are, or were, black. The front seats got taken this past weekend. Backseat is still there. The 2 e12's in the valley have tan seats, one has leather in bad shape and the other has vinyl. Unfortunately, some douchebag (pardon my technical jargon) ruined the lower half of the backseat by trying to rip it out before removing the center bolt. I could've used that!! My backseat is intact but uv damaged and dried out. The front seats both have slight damage, but one complete, decent seat could be frankensteined out of the 2 there. If I had the cash, i'd do it to replace my driver seat. The back and seat of mine each have a crack.

What color seats are you looking for? I'll keep my eye out, couple more yards in the Valley that I haven't hit yet.

My name is Ted. I'm in Los Angeles, near Eagle Rock and Los Feliz.

[Mike W.]

Thanks, Mike. I read the cam faq, but only saw 2500, 2800, 528I and 530I on there. I didn't see a 3.3 listed.

80-81 3.3s used what I call the "lambda" cam which is what came in all 528i's too.

Will my engine retain the same displacement and compression ratio? I assume it will because the 3.3 head swap is listed as "s" on the parts interchangability faq.

The head is the same, period. Your engine will remain the same.

Should I purchase a gasket set for a 528i or a 633? Are they identical?

You need a headset for a 528i.

Does the 633 have larger diameter pistons, or is the extra displacement a result of a longer stroke?

Yes. Both. 2.8s are 86 bore by 80MM. 3.3s are 89 bore by 86 stroke.