I bought this car a few weeks ago and it smokes on deceleration. I was thinking it needed a valve job but today I did a compression test with the following results:

330 2 barrel

#1 - 150
#2 - 160
#3 - 160
#4 - 160
#5 - 145
#6 - 150
#7 - 150
#8 - 80/130 wet

#8 is low and goes up with a wet test. I tested several times and still get the same results.

Does this mean I have bad piston rings for sure or could it still be just valves? Before I did the compression test I was either going to replace the valve seals or pull the heads and have them rebuilt but now I'm thinking I need to do more than that.

 

When you say wet, do you mean you puy oil in the cylinder, and tryed again, and it when up? If so, I agree it is a ring problem. Also do you have a leak down gage? That would help determin where it is leaking.

 

Yes, I put oil in the cylinder and it went up. I do not have a leak down guage but may know someone that does. So does that mean that valves are defintely are out as the culprit? What else could it be if it isn't the rings?

I'm prepared to pull the engine and get it rebuilt if needed...I just didn't expect to have to do it so soon.

 

When compression increases wet over dry, it's rings.

 

So what would I gain by doing a leak down test?

 

At this point, nothing. If the compression had not come up wet, a leak-down test would have told you which valve was leaking, or if you had a head gasket problem. If the cylinder is worn enough (especially if it's gouged), oil on a wet test may not seal the leak. A leak down would tell you if the compression was going to the crankcase and not out one of the items mentioned above.

 

Thanks for the explanation. Unfortunately I know just enough to be dangerous.

Guess I will start looking into pulling the engine and getting it rebuilt. Hopefully I can be on the road again next summer or sooner.