Early euro 2.7l questions

[cb750r]

Hi folks. New owner of a euro imported 4/85 build date with a 6KA stamped block. From what I read this should be an 11:1 compression motor

I have read a few posts on this forum here and one had a chart with the different piston configurations.

Car runs and drives great right now but I can see wanting to head swap and raise the RPM and have more fun while keeping the “stock” m20 motor.

Am I correct in assuming this would make an “easy” swap as I wouldn’t drop too low CR using an 885 head? Very little info on the early euro 2.7s that I can find so far.

I’m a motorcycle guy and have a done a lot of my own work so I’m fairly mechanically inclined.

[82eye]

you might wanna check the uk forums like e30 net as they have piles more experience with that motor. there are other euro forums as well but you generally need to be fluent in other languages.

[cb750r]

you might wanna check the uk forums like e30 net as they have piles more experience with that motor. there are other euro forums as well but you generally need to be fluent in other languages.

Ah good point will join up on that one as well. Cheers.

[cb750r]

Continuing work on the car, getting great compression test numbers which would indicate I have a high compression ratio engine averaging 195psi across the 6 cylinders. One was a bit lower than the rest so I have put some penetrating oil in the hole, see if I have a sticky ring as that hole shit up to 210psi with a wet comp test. Plug wasn’t oily so I think it’s minor blow by at this stage not really concerning at the moment especially considering Bentley manual calls 156psi good…

[Northern]

Personally I don't trust the numbers on compression testers.
If you have a cheap borescope (like the $20 variety that plug into a cellphone), you could sneak a peak at the pistons and maybe be able to verify.

If it feels good, I'd run it.

[cb750r]

I did have a peak. I have one of those cheap borescopes. I can still see crosshatch in the bore and couldn’t find any evidence of scoring. Definitely no dish in the piston, couldn’t clearly see the small dome section as indicated in the far right of the chart due to carbon on the piston face, and a cheap scope. I have used this gauge on a variety of engines and have found it to be reliable. I have 8 bikes in the shop now and I’ve been wrenching on my projects for a long time now.

Personally I don't trust the numbers on compression testers.
If you have a cheap borescope (like the $20 variety that plug into a cellphone), you could sneak a peak at the pistons and maybe be able to verify.

If it feels good, I'd run it.