Compression Test Results. Alternate Cylinder Loss

[rochie 1]

My tuned 8v engine is filling the oil catch tank rather quickly so trying to diagnose it with a compression test. I would say the tank fills about 50ml per 30mins of spirited driving. It also produces a small amount of white smoke from the breather pipes especially when idling (running rich?)

 

Results:

Dry:

cylinder 1: 7.2bar

Cylinder 2: 13.9bar

Cylinder 3: 7.9bar

Cylinder 4: 13.2bar.

 

Wet:

cylinder 1: 7.5bar

Cylinder 2: 14bar

Cylinder 3: 8bar

Cylinder 4: 12.9bar

 

Wet test didnt change anything much so doesn't look like the piston rings? Maybe valves as they are low on alternate cylinders?

 

The engine is the following spec:

1.9 8v rebuilt 4 years ago. Rehoned etc.

1.6 pistons (to up cr)

Twin 45 webers

Lightly ported head which had valves relapped 4 years ago.

Piper race/rally cam

It has been propperly built to a very high standard and set up on a rr to 175bhp.

 

Performance isn't noticeably down when driving.

 

The head gasket was replaced by previous owner (who is a friend) 150 miles ago. He said the bores still had their honing marks!

 

Could the head gasket have something to do with it?

 

Any help greatly appreciated!

[welshpug 1,626]

Check the valve clearances and cam for wear.

[rochie 1]

Check the valve clearances and cam for wear.

Thanks for the tips! The cam is fine for wear as I had the cover off the other day. I will check the clearances, cheers. Would that alone cause such a large change?

Edited June 29, 2013 by rochie

[rochie 1]

I've been unable to work on the car the past month due to work. But I'm planning on working on it this weekend!

 

Does anybody else have any opinions or suggestions on these results?

[rochie 1]

Here's a video showing the white smoke which happens only at low rpm. I'm thinking the problem may just be at lower rpm hence not feeling the lack of power, so again does this point to the valve timing?

 

Cheers

trim.F4Z3dL.MOV

Edited July 22, 2013 by rochie