compression test

[Turbizmo]

well my friends car is a 99 420a turbo and i did a compression test ### it was trowing to much blue smoke from the exhaust and i though 1st the turbo might of had some broken seals but it brand new so we decided to do a compression test and these where the numbers

1 cylinder = 80
2 cylinder = 150
3 cylinder = 70
4 cylinder = 160

my question is. Is the head gasket broken? also would we have gotten different results if we had the foot all the way down on the gas pedal and cranking it because we only where cranking it?

 

[rstare]

The piston rings or the headgasket are most likley.
Put some oil in the cylinders and try it agian, if the numbers change its the rings.

 

[silvreclips]

You should be doing a compression test when the motor is fully warmed up. Disconnect fuel and spark and crank at WOT until the compression no longer increases. I would be betting on broken ring lands on both of those pistons. But its prossible it could be the head gasket. When I broke the ringlands on the stock pistons I had exhaust coming out of the valve cover when I took the oil cap off so you could try that to.

 

[Locke]

Compression test with engine warm and throttle wide open, as mentioned already.

To get a better clue, perform a leak-down test.

 

[Turbizmo]

ok thanks i will do that soon and ill let you know what the numbers are