1972 CS M90 Conversion

Deano1

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Hi Everyone.

I joined this forum a couple of years ago, and on occasion have been reading through the threads building up my knowledge on the E9. Predominantly my experience is with E30's, and more recently E32's.

I bought my E9 a couple of years ago. It had been in dry storage about 25-years. Originally an Inka orange car, fitted with the original blue velour type interior. It's fitted with the carburetted 3-litre engine and automatic transmission. The car had been partially disassembled when I bought it, however I managed to get the engine running fairly quickly despite the extensively gummed up/seized carburettors. The car also came with an M90 engine. I have two 1990 735i parts cars, one of which is complete with engine. This X-Mas I plan to start work on an engine. I'd like to go down the M90 route, using the M90 intake, with Motronic 1.3 conversion as I have a lot of the parts and carburettor rebuild services in New Zealand are very expensive. I have no practical experience with carburettors and have no interest in rebuilding them.

My initial problem is accurately determining what gaskets and seals I need for the M90 engine (Manufactured March 1980). From what I can determine M30 gaskets and seals will suffice with the exception of the head gasket, perhaps the sump gasket, and perhaps the gasket between the oil filter housing and the engine block. I'm aware of the limited options for suitable head gaskets from reading threads here. I won't know until I remove the M90 cylinder head and get it checked as to whether the head and associated hardware will require machining.

Can someone guide me as to how I can obtain, and maybe where I can source, the correct gaskets and seals?

I plan to use the car for occasional street use and short out of district trips. The camshaft in the spare M30/B35 head I had lying around, and was hoping to use, has wear so I will need to look at options to repair/replace. I've read good things about the standard cam. Is there a better alternative for my use?

I will only be undertaking a sympathetic return to the road restoration at this time. I bet you that comment raised a few eyebrows and you're thinking wait until you find the rust. I've had the car on the hoist and checked the areas identified on this forum which are common for rust, and so far, I can only see surface rust so I will focus on the mechanical aspects.

Future considerations..... I have a Getrag 265/6 gearbox, manual pedal box, and 3.64 ratio LSD.


Regards, and thanks in advance.

Dean.
 

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Hi Deano, only BMW for the M90 head gasket they use Elring. Other aftermarket aren't all up to scratch. The standard cam is ok, Schrick do a 282, for either motronic or distributor drive which works well, others will know better whether 1.3 ecu works with the motor, I used a Haltech.
 
Hi Deano, only BMW for the M90 head gasket they use Elring. Other aftermarket aren't all up to scratch. The standard cam is ok, Schrick do a 282, for either motronic or distributor drive which works well, others will know better whether 1.3 ecu works with the motor, I used a Haltech.
Thanks Ian. It will be interesting to see what I find when I disassemble the engine. I'm hoping the M90 is good. It sounds like a fun motor.
 
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