Leak Down Test Help

[DDink]

Ok, here's the deal. I have stroked a 383 to 431 cu in. During the race season as I would lift out of the throttle at the end of a run the car would smoke a lot. The only other time the car smokes it at the top end right before my shift point. So this winter I did a compression test and the average for the cylinders was 112. So I then did a leak down test on a couple of cylinders. The leakage on average was 60%. The air is not escaping via the carburetor, the exhaust, the radiator, the pcv valve or the dipsitck tube. The air is coming up from the center of the block and escaping around the push rods. My obvious thought is that the rings are bad. Am i right? This motor was put together last year. The rings I used are a Childs and Albert ring file fit. They were file fit by the machine shop I used. I wonder if I installed the rings incorrectly? Is that possible? I could use any help that you may be willing to share. If you need more information to make a judgement just let me know. Thanks for the help.

[451Mopar]

The oil burning problem could be valve stem seals or rings or even a head or intake manifold gasket, but the leak down test seems to point towards the rings or head gasket. try squarting some oil in the cylinder and re-check the compression ratio and leak down. If it gets better, then it's probbably the rings.

[perfmachst]

hello, if you have 60 % leakage, you have problems!! plus, why run a PVC in a race motor? all they do is suck oil through the motor.when you lifted off the throttle, motor creates a lot of vacuum, draws oil. if your racing ,just use breathers only. just food for thought

[Crank]

sounds like head gaskets to me could be valve guids but wear the leek is the only thing that is their is a gasket.

[Crank]

after rereading your post are you saying its leaking into the crankcase or under the manifold? if crankcase the rings are not sealing ,like 451 mopar said squirt some oil in it and recheck it.

[DDink]

Guys thanks for the responses, tonight I am going to re-do the leak down test after getting some oil into the cylinder. I will update then.

[DDink]

A further update, I squirted some oil into the cylinders and the leak down test went from an average of 60% loss to 25% loss. So must be the rings are bad or I installed them wrong. So i will dig in and see what happened. I will let you know after i get the pistons out.

[DDink]

The motor came out today and finally pulled out a piston, the top ring was put on upside down. That sucks. Anyway at least I know the problem. So who out there would just turn the ring the correct way and keep going versus, who would re-hone the cylinders and put on new rings. The cylinders look fine and my logic says what is the differnce in one ring being flipped. I would appreciate any input, and I would like to thank everyone for their help so far.

[charger_dan]

re-ring and hone time.
you know if you don't it'll bother you.

[JLM440]

Originally Posted by charger_dan

re-ring and hone time.
you know if you don't it'll bother you.

I Agree, don't take short cuts, do it right for piece of mind, you already have it torn down.

[oldguyalso]

Remember, there's never enough time to do it right but there's always enough time to do it over! LOL Yeah, you'll feel better if you re-ring and hone. Even if it is a pain the .....

[DDink]

Everyone thanks for the responses and yes it is time to hone and re-ring. I appreciate everyones help.