Distinguishing a Euro CSi

Ohmess

Ohmess

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I looked at an e9 last year that was advertised as having an M90 engine, but one of the eagle eye car guys here noted that the compression numbers were low by 60 to 80 psi per cylinder. This told me I was likely not looking at a 10:1 compression ratio engine, and hence the car was not as advertised.

Obviously, my suspicion arises because the Euro CSi is considered by some to be more desirable, and I don't want to pay a premium for a dressed up US car.

I know the piano top pistons can be used to identify the engine, but it rather hard to check for those. My question is this: is it possible to distinguish a European engine from pictures of the engine bay? If so, what features should I be attempting to identify?
 
All Csi's are Euro cars. No fuel injected cars were officually brought into the US. There are also carb CS cars that are Euro, and all US cars have carbs.
 
There are no piano top pistons in a M90 engine. They are flat tops.
Piano tops were found in the 10:1 engine that came later.
Compression is not 10:1 in a M90 engine it is 9.3:1
You can look at the flat part of the engine above the starter for a vin number and trace that back on realoem unless it is blank or has an "X" meaning it is a factory replacement.
If you are talking about the csi in Virginia- forget it, I was there 2 weeks ago and the engine was swapped out. If you are talking about the csi in Orlando for sale- it was an original but the car was sold and shipped to my client yesterday. The csi in Vegas is not an original engine either- I was there and checked last week.
The absolute best thing to do is to do a compression check.
Then look for the "3.5" numbers cast in the side of the block drivers side.
You need to see about 180 psi.
 
No factory csi had a M90 engine.
M90 engine is 3.5 liters.
 
sfdon said:
There are no piano top pistons in a M90 engine. They are flat tops.
Piano tops were found in the 10:1 engine that came later.
Compression is not 10:1 in a M90 engine it is 9.3:1
You can look at the flat part of the engine above the starter for a vin number and trace that back on realoem unless it is blank or has an "X" meaning it is a factory replacement.
If you are talking about the csi in Virginia- forget it, I was there 2 weeks ago and the engine was swapped out. If you are talking about the csi in Orlando for sale- it was an original but the car was sold and shipped to my client yesterday. The csi in Vegas is not an original engine either- I was there and checked last week.
The absolute best thing to do is to do a compression check.
Then look for the "3.5" numbers cast in the side of the block drivers side.
You need to see about 180 psi.
Click to expand...

Wow - I was way off base.

The seller sent me a picture of the VIN on the block, which matches the VIN in the engine bay. Realoem does not recognize the VIN, however.
 
My 74 CS now has a 73 CSi motor, swapped out of the parts car I bought 20 years ago. A buddy and I found a 75 CSi Barn Find(yes in an actual barn) and he swapped the injection unit into is carbed 74 CS model. Then the chrome bumpers replaced his biggies and now, to the untrained eye, he has a euro coupe. Unless you notice the absence of a fog light on the back.

My point, a buyer really needs to know their stuff or someone who does. Take sfdon along to be sure and safe. It's worth the cost of his time and plane ticket.
 
If the numbers are matching, and it is a 3.0 csi it may also be the factory CSL block bored out 2x. This was fairly common as the factory wanted to get rid of them.
The M90 engine # will come up on realoem not the e9 #.
M90 engines are transplants not stock e9 engines.
 
sfdon said:
There are no piano top pistons in a M90 engine. They are flat tops.
Piano tops were found in the 10:1 engine that came later.
Compression is not 10:1 in a M90 engine it is 9.3:1
You can look at the flat part of the engine above the starter for a vin number and trace that back on realoem unless it is blank or has an "X" meaning it is a factory replacement.
If you are talking about the csi in Virginia- forget it, I was there 2 weeks ago and the engine was swapped out. If you are talking about the csi in Orlando for sale- it was an original but the car was sold and shipped to my client yesterday. The csi in Vegas is not an original engine either- I was there and checked last week.
The absolute best thing to do is to do a compression check.
Then look for the "3.5" numbers cast in the side of the block drivers side.
You need to see about 180 psi.
Click to expand...

sfdon's response is on the money. If you are a purist, the stamped number on a boss near the starter is probably your best indicator of originality.

High compression numbers are good but hardly determinative of engine size or originality. Heavy carbon buildup could certainly raise the compression results. Same with milling a head or installing higher compression pistons. A more aggressive cam profile might lower the compression test readings - but produce more desireable torque and hp numbers than stock. Not all compression gauges will give the same exact readings.

On any decades-old car a lot may have changed. Doubts can still remain - unless you open things up and explore with a caliper gauge.
 
When you own a Coupe there are many things that you should not do.
If the person telling you what not to do lives in Brussels then the car is a Euro, if she lives in your house then it is a US car.

Yes, you can call that a compression test if you want.
 
adawil2002 said:
Not all 3.0 CSi have a fog light on the back. Mine was originally delivered to Italy with no rear fog light.
Click to expand...

Yepp!
That's correct. Rear fog light in earlier EU was only due to individual countries regulations. I've no idea what EU countries had that import regulation at the time.
 
Last edited:
Right about the missing fog light but as usual BMW was less than consistent. My euro CS went to Italy with a fog light. And what about the Brits? I think they didn't fog lights. ????
 
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