compression test

[daz the plumber]

my engine was tested today , i got around 145 psi, does that sound healthy .

[GreenV8S]

That's a reasonable figure, although it wouldn't be surprising to see it a bit higher. Consistency between the cylinders is more important than the actual value.

[daz the plumber]

the figures were about the same with in 5 psi , what would you get from a new engine ?

[dwgriffith]

Engine hot or cold?

[GreenV8S]

daz the plumber said:

the figures were about the same with in 5 psi , what would you get from a new engine ?

Depends on the cam and compression ratio, and whether the bores have got any oil in them, but for example mine at around 10.5:1 was typically around 165 psi. You engine may be a slightly lower compression ratio so will produce a slightly lower figure.

[daz the plumber]

so do the 4l cars have different compression ratios .mine is a 96 or do you think tvr fitted what they had at the time !

[GreenV8S]

daz the plumber said:

so do the 4l cars have different compression ratios .mine is a 96 or do you think tvr fitted what they had at the time !

There's no such thing as a standard where TVR is concerned but the original 9.35:1 seems to be most common.

[Chimjunkie]

Just to add to this thread. I have just tested my engine cold and measured a consistent 250psi (17 bar). This is a lot higher than that posted earlier in this thread. The engine is a 500 with a V8D stealth cam. Does this seem too high and could i have set the cam timing wrong?

[Chimjunkie]

Just thought it may be an idea to try another gauge. Thinking about it, not sure timing will affect compression....?