M30B35 service

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Henrik

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Hi!
I have been offered a M30B35 from 1986 with a 167000km (104000 miles) history. I think it will be hard to find an engine with lower mileage, so I'm seriously considering it for my 2800CS.
The seller says it runned well before he parted the car, and I guess I just have to trust him. There is no documented service history!
I will do a compression test before I put it in my CS, but are there other checks or services I should do before I install it?

Henrik
 
If it is from a 1986 car, it is not a B35, unless they changed it later.

A leakdown test will be good, and take a look under the valve cover.
 
Early B35 Timeline

The earliest E32 models that were produced in early '86 did have B35 engines. I believe they started later in the 5 series cars. I "harvested" one from an 02/1986 produced car and, subsequently, was forced to rebuild the engine. The earliest B35 blocks still have the correct mounting points for the motor mounts--and mine were even tapped. I can attest to the potential pitfalls of buying a relatively low mileage engine with the thought that it will be a quick drop-in. I wish that was the only surprise of my restoration.

On a separate note, Henrik, I was in Oslo several years ago and saw a very nice polaris CS cruising the downtown streets near the waterfront.

Mark
 
Re: Early B35 Timeline

Mark C said:
The earliest E32 models that were produced in early '86 did have B35 engines. I believe they started later in the 5 series cars. I "harvested" one from an 02/1986 produced car and, subsequently, was forced to rebuild the engine. The earliest B35 blocks still have the correct mounting points for the motor mounts--and mine were even tapped. I can attest to the potential pitfalls of buying a relatively low mileage engine with the thought that it will be a quick drop-in. I wish that was the only surprise of my restoration.

On a separate note, Henrik, I was in Oslo several years ago and saw a very nice polaris CS cruising the downtown streets near the waterfront.

Mark
Click to expand...

Ah, those were Euro only cars. The US production didn't start until later. Dang minute differences.

I was about to rebutt, considering the engine in my coupe is a B34, despite my specifically asking for an early B35, and it came from a 1987 735.

Various older posts suggested the change occured in 02/87, but it would seem it happened for Europe a bit earlier.
 
Re: Early B35 Timeline

Just because I'm not a politician, I have to admit that . . . I was wrong in my earlier post. My E32 donor was actually produced in early 1987 and I "did not recall correctly." It was a very early production E32 that I picked up for about $1k on a business trip in LA and drove to Utah. The engine was remarkably strong for having major compression loss in a couple of pistons. I had no idea. The engine had about 120k miles.

I felt like I should get the right data out there, since I have relied on searching this site continually. I hate to think about some future schlock relying on the post to find the elusive B35 and coming up empty--so I want to set it straight.

Blame the memory lapse on my handlers, the people running from snipers in Bosnia or the small-town people clinging to religion--anything but me.[/quote]
 
Introduction of new models and engines always makes "when and where" confusions.
To be on the safe side I need some more information before I do the deal!
I guess the engine number can contribute to a clarification.
A picture of the mounting points won't hurt either.

Henrik
 
The easiest way I have foud is to look at the old fuel pump mounting point on the head:

B34:
http://www.realoem.com/bmw/showparts.do?model=DC74&mospid=47231&btnr=11_0202&hg=11&fg=15

B35:
http://www.realoem.com/bmw/showparts.do?model=GB33&mospid=47359&btnr=11_1906&hg=11&fg=15

You notice how the B34 head has a hole of sorts in the middle, where it meets with the valve cover, whereas the B35 just has a set of vertical bars? That is the key difference, based on my experience.

Although for you, Henrik, it isn't as much of an issue, as the non-kat Euro M30s had a 9.3:1 CR, whereas the US M30s had an 8:1 CR, and made much less power.
 
Thanks again!

The seller will supply me with more information and pictures in the days to come.
Most important for me is that it will fit without any maaaajor modifications.
(except for new brake booster pump, gas tank etc. etc. etc.)
As you can see from the photo I still have plenty of time to sort out the details. The car is still on high heels so to speak!
[Broken External Image]:http://i280.photobucket.com/albums/kk172/terramar-photos/rotisserie1.jpg

Henrik
 
B34 or B35, if you get an early B35, it is a literally drop-in procedure. Same motor mount plates, same everything. Just swap over the E9 oil pan to clear the subframe. No fender pounding needed. The brake booster will need changing if you use the Motronic intake manifold, though.

Oh, and re-use the CS exhaust manifolds if you plan to use stock downpipes. The B35/34 manifold's attachment flanges are rotated by about 15 degrees compared to the CS ones, making the downpipes not fit. Not a nice discovery after going through all the trouble of dropping an engine in, let me assure you.

I don't see why you'd need to change the gas tank, as all you need to do is make a return tap.
 
Agree with you! The return pipe should be an easy fix. As I can see it, it's two options. Install a tube in the existing cap, or make a new cap with suction and return like the CSI tanks.
The old exhaust was a mess so I will see what local suppliers can deliver before I decide what to do.
Henrik
 
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