Compression Results...I suck

[Mycarispurty]

1-125

2-100

3-95

4-100

5-155

6-160

 

Even though the car runs like a scalded dog, I guess the search is on for a good condition, great compression bottom end, preferably with a flat top set of stocker pistons (or a rebuilt short block) so I can turbocharge it. I'm pretty sure my head is fine, just need the bottom end.

[naviathan]

Those results are all over the place. Are you sure you did the test right? You're suppose to test with the engine warm, all plugs out, throttle plate open and turn the engine over for 5 seconds on each cylinder.

[savageskaterkid]

Wait, i got 150psi across, and I just tested it with the engine cold, with all spark plugs out. If I let it warm up and opened the trottle up-would the psi be even higher?

[HakosukaJD]

Wait, i got 150psi across, and I just tested it with the engine cold, with all spark plugs out. If I let it warm up and opened the trottle up-would the psi be even higher?

 

The rings often won't seal right if there's no (or little) oil on the cylinder walls and its cold.

[Thumper]

I have found that compression will go up about 5-10psi from cold to warm. And 5psi from the throttle plate is opened. It doesn't matter too much since when you are doing a compression test you are mostly looking for consistentsy.

 

Mycarispurty, Looks like you have a bad headgasket around #3 cylinder. To be more sure its the piston rings and not your valve seals you should put a teaspoon of oil down the spark plug hole and do it again. If it goes up then its your piston rings. If it doesn't then it is more likely your valve seals. Good luck.