difference in compression....

[mavis cruet]

would a difference of approx 7 psi (0.5 bar) between cylinders effect the performance and give a vibey engine? the readings are around the 9/9.5 bar scale. cheers in advance..... karl.

 

[Arch]

Good question I wouldn't have a clue

 

[(RIP) Proff]

7 psi is very negligible, could be just a spot on the valve seat.....
Mine [Gertie] has around 10 psi more on left hand side till she warms up, then it balances out to around 4 psi but it's bloody dangerous doing comp test on hot fecking airhead Check valve clearances, if one seems to be abnormally large you might be experiencing a cam followers hardening breaking down ...

 

[cookie]

i'd have thought out of balance carbs are far more likely to be the cause.

tolerance on compression difference is normally about 5/10%, and i've seen way more than that on engines that seem to run perfectly.

 

[Shep]

7 psi, no, you're very unlikely to notice that.

More likely its a cracked con rod or piston, perhaps even a dodgy crank


Shep