M90

[kasbatts]

Sometimes you can't see the forest for the trees!

Yesterday I was under the hood of the car an I noticed that my engine is a M90 and not a M30, I've had the car for 8 odd years now and been under the hood god now knows many times and never noticed! Must open my eyes a bit more often! Anyway, my question is, has anyone out there run a stroker M90?

I now have the option of quite a few choices for when I do my engine rebuild and have always thought the stroker M90 might be nice, What to do???.

I can do a

M30B35
M90
M90 stroker (M90 with M30 crank giving a little under 3.6ltr) they say there's no substitute for cubic inches

Thoughts??

 

[decoupe]

Steve,

I also have a M90 (Euro L) block and asked the same question here http://www.e9coupe.com/forum/showthread.php?t=9768 .

I ended up just switching to a rebuilt b35 head and intake manifold along with programable EFI but left the M90 as it is - only had 40,000miles on it since the PO had it re-done.

Do the stroker thing please with full disclosure and photos so I get it right when it's my turn.

Doug

 

[OCCoupe]

I'm currently building an m90 stroker for my coupe. I am using custom 94mm pistons, 142.5 Carillo rods, a 90mm crank out of an s38b38, and a b35 head with a Paul Burke cam. 10:1 compression. So essentially a 3.8L.

The m90 is actually a pretty cool motor because it is a short stroke motor and revs really nicely. It almost doesn't make sense to stroke an m90 since it is such a rev happy motor. I think over-boaring an m90 is really the way to go. Achieving 3.6L with just pistons and then putting a b35 head would make for a nice motor. I think this would be a less expensive route that would still make a nice fun motor for our coupes.

The m90 is basically the same block that was used for the m88 m635/euro m6 and euro m5,

quote wikipedia:
M90

"The M90 engine is a lower performance SOHC engine that was based on the M88/1. It utilizes the same block from the M88 and maintains the same bore and stroke, but borrows its head from the BMW M30 engine family. Different years of M90 engines used both Bosch Motronic and Bosch L-Jetronic engine management systems.[3] Typically identified by a white L painted on the block behind the oil filter housing."

 

[kasbatts]

Ok guys thanks for that.

But I was talking to a few guys in the weekend at a car meeting and now it may seem I might not have a 3.5 m90??

So what do I have?

My engine definitely has the protruding water passage on the side, but does not have 3.5 cast into the side of it, so I think its a M90 but maybe not a 3.5 ltr??? I was under the impression all M90's were 3.5 ltr????

 

[decoupe]

Stock should be 88mm stroke and 93.4mm bore if you have the head off.

 

[bdigel]

Stock should be 88mm stroke and 93.4mm bore if you have the head off.

84 mm stroke on that engine

 

[decoupe]

Yup - 84mm - my bad.

 

[sfdon]

Replacement engines were produced without the typical markings.
Look for an "X" above the starter.

 

[kasbatts]

Head isn't off at the moment, out to the garage to look for an X

Thanks

 

[kasbatts]

Ok, so no X, but a check on this site with the vin number above the starter motor ( http://bmwfans.info ) tells me I got a 3.0 M30 out of a euro E3.
Confused as it has the protruding water passage on the side of the block?

Any ideas?

 

[kasbatts]

Wow, just put in my vin from my chassis plate and apparently if got a 87 318i ???

 

[restart]

IIRC those online vin searches are typically confused by the short numbers. I seem to remember finding similar wrong data on my 7 digit vins. So don't worry, pretty sure I t's still a coupe:smile:

 

[sfdon]

There were two blocks with the water jacket . Long and short versions.
Look on the pass. Side of the block for the date. If it's before the m90 came out you will know what you got.

 

[Arde]

Wow, just put in my vin from my chassis plate and apparently if got a 87 318i ???

I love 318's, are you selling it?