F Block M 90

OZCSi

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Okay, this has gone unanswered for long enough, I need the engine gurus to step forward on this one.

I have an M90 engine that has a very clear F painted in white on it, not an L. It is above the starter that it is painted near the 3.5 casting number

I have asked and asked and got no response..........a free thank you to the correct answer.

It is driving me nuts as I want to freshen it up, but dont want to start until I identify it correctly. It is from a 635csi i believe around 1979/1980 .It is attached to a 5 speed manual with speedo drive and is sitting in my garage in good order with all electrics etc.

Help

OZ
 

OZCSi

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Just to answer my own question, is it possible that the F is mark for factory rebuilt or similar???


If no one answers this, I am willing to cop a blast of logic from jranman to put me out of my misery.
 

Arde

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Here is my logic. Anything that is painted rather than stamped is not an attribute of the block, but rather something determined after the manufacturing process. Is the letter professionally etched or appears like some fellow with a Sharpie drew it?

In my field (integrated circuits) when we test prototypes in the lab we use a letter F to mark the ones that fail and P (or a swoosh) to mark the good ones. So that is a bad omen right there.

On the other hand if it was marked in Germany it probably means Fahrvergnugen...
 

OZCSi

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It is a very clear F, that is in the same font as the L that I have seen on other M90's.

So that is my position.....
 

x_atlas0

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I guess the only thing to do is remove the head and oil pan, then grab a pair of calipers. That way, you will be sure as to the state of the engine.
 

OZCSi

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Thanks,

On a big coupe forum, I thought i saw double , a guy was asking the same question about his euro 1980ish bmw 635csi.............so they do exist. he was asking anyone as he also knew what an L block was but has an F block and had a great angle.......suggesting it may be a remanufactured or a block for outsourcing companies with some special bore finish etc or parent bore .......for a tuning company etc to finish to their requirements.

Anyway, it does interest me and thanks for responses.

Thanks for the Fail possibility( kidding).............my take is that maybe L stands for Loser?? LOL I need some help with this. Can the real gurus that have seen everything please stand up?
 

Arde

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I can contact an acquaintance that works for BMW factory service in Munich, if you post a picture I am sure he can solve the puzzle.

I can visualize a nice southern wine arriving at my doorstep at the end of this saga...
 

OZCSi

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I will take some pics.............southern wine.............mexican ?? Or just plain oztralian vino perhaps.

Forget any thoughts of sipping a nice Silver oak cab sav!!! Arde I am eternally grateful if that helps....

Cheers
 
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