S2a 2.25 Petrol Compression Test Results

Hi All,

I performed a Comp Test today and came up with the following results:

1: 138 psi
2: 145 psi
3: 145 psi
4: 138 psi

Do these sound ok?

After consulting the Haynes book of lies, I found the following info:

7:1 Motor
145 psi

8:1 Motor
160 - 170 psi

How do I know if I have a 7:1 or 8:1 compression ratio engine please?

Cheers,
B

its stamped on passenger side of head nr rocker box in the middle ,i would have thought that your readings were not too bad as near each other in less than 10% depends on starter speed etc ,you can add oil if it improves compression shows ring wear but i wouldnt worry unless you have excess smoke especially blue

Great! Thanks James. I should also point out that these readings were taken cold, I assume they will be lower when hot? I had a quick look at the head with a totch in the dark but it has been painted so it is difficult to see. I don't suppose you (or anyone else) has a picture of the compression markings so I know where to start scraping off the paint?

Cheers,
B

piston will fit bore better when hot

Interesting, so compression may actually be higher warm!
Thanks again James, much appreciated.
B