Compression Test Advice Z3, 2.0 - M52TUB20

[Asad.C]

Hi Guys,

I have a Z3, 2.0 - M52TUB20 out of my donor car.

I did a dry compression test on a cold engine.

The figures are...

Cylinder 1 190 psi
Cylinder 2 207 psi
Cylinder 3 210 psi
Cylinder 4 180 psi
Cylinder 5 195 psi
Cylinder 6 195 psi

Are these figures normal? I can't seem to find what the standard figures for this engine should be and also cylinder 2 and 3 have thrown me off a bit. Are the rest low on compression and they should all be above 200psi? Cylinder 4 looks a bit low to me too compared to the rest.

Thanks in advance.

 

[NZ00Z3]

They all look good to me.

I think the standard is a 10% deviation, so you're about right.

 

[Nodzed]

Hi Guys,

I have a Z3, 2.0 - M52TUB20 out of my donor car.

I did a dry compression test on a cold engine.

The figures are...

Cylinder 1 190 psi
Cylinder 2 207 psi
Cylinder 3 210 psi
Cylinder 4 180 psi
Cylinder 5 195 psi
Cylinder 6 195 psi

Are these figures normal? I can't seem to find what the standard figures for this engine should be and also cylinder 2 and 3 have thrown me off a bit. Are the rest low on compression and they should all be above 200psi? Cylinder 4 looks a bit low to me too compared to the rest.

Thanks in advance.

As long as they are within 10psi of each other, it's fine, depending on your elevation compression numbers don't mean a lot, a cylinder leak down test is the real diagnostic way, where as a compression test only shows your valves are sealing.
Compression Specifications
M52 & M52 TU
10-11 bar (145-160 psi)

From Bentley Z3 (E36/7 & E36/8) service manual
Info from another forum:

 

[Asad.C]

Thanks for the responses. Appreciate the info.