Understanding Compression Values

[Guest toby7]

am I right in concluding my compression rings are worn with age and use. my compression on an xu9ja D6b engine is 110 to 120 psi across all cylinders. The engine uses no oil and does not make any smoke or loose coolant and still revs to 6000rpm. During a leakdown test air could be heard coming out of the oil filler pipe. 100psi was pressurised into the spark plug and apparently gave a poor reading.What compression values in psi should a healthy engine give (D6B) and more importantly if I've only 110 psi to 120 on each cylinder how much power would I be loosing compared to a healthy engine. Hope I've worded this correctly. I don't want to rebuild just for the sake of doing a rebuild.

 

Regards

Peter

[Jonmurgie 2]

Different compression test tools give different readings so it's hard to compare, the important thing is that your readings are all around the same level, so list them off fully and let's see...

[Grim.Badger 15]

I wouldn't worry about them being low, mine gets over 200psi across all cylinders and is still a terribly weak engine that burns quite a lot of oil

[ALEX 98 1 Cars]

Pour a cap full of oil down each bore and do the compression test again.

The reading will be higher but If they're much higher its a sign of worn rings.

[Guest ashnicholls]

And make sure you battery is full.

 

I did compression test and got 110 across them all.

 

I left it for abit on charge and went and did it again and got 190. With battery not being completly full.