blow by?

[nitrousED]

400 miles on the build ,i have 120lb cyl pressure on all but one cyl,it has 80.Im assuming i have a ring seating issue.Also have a fuel smell with a little smoke coming out of vc vents at idle but when i get in on it, it smokes a good bit.Is it time to pull the motor down and put a better ring in?

didnt realize they were chromeoly

 

[HISSIN50]

id do a leakdown test first.

 

[nitrousED]

just did a test by dropping some oil in the cyl that was low,well it went from 80 to 125lb just like that,im told that is a cracked ring

 

[HISSIN50]

ok, wet compression test compared to dry does help. and your results do suggest a ring problem. that works.

 

[nitrousED]

waiting for a few more replys,then it may be time to rering

thanks

 

[87'GTstang]

Like hissin said, do a leakdown test. 10% or less is good, 5% is great. Anything higher suggests you have major ring issues. Make sure you read up on the procedure as there are a lot of things/guidlines that you go by to tell what signs mean what *rings, valves, seating, ect.).

It does however seem like, no offense, cheap piston rings - either that or poor install that lead to damage upon installation.

 

[nitrousED]

i believe they are cheap rings,i didnt do anything different than the last few times i installed rings,i guess ill see if the leakdown test fails.i have a funny feeling it will end up in a tear down

another test i ran is i took the rocker arms off on that low cyl and put about 100lb of air in the cyl and felt a good amount of air coming from the oil drain holes in the head,seemed alot less air came from the other cyl


thanks

 

[bgjohnson]

well man it sounds like you may have to bite the bullet and refresh the motor a bit, like new heads (or have the valves and seats reground on the stock ones)and rings and have the block cleaned up