blue smoke on newer rebuild

5

5pd

New member
Hi, new to this forum, hope you can help.I have an 81cj5, that I had the motor rebuilt on about 5000 miles ago. It has been blowing Blue smoke when I stop at a light or idle too long . I just did a compression test and all cylinders were at 185psi give or take a lb.. I thought maybe valve stem seals which were new . But I was told that they do more of a puffing when they leak. I was thinking it might have something to do with the valve cover not blocking enough splash from the pcv valve and getting sucked into the carb base. It's an omix-ada aluminum valve cover. Any thoughts? 81 cj5 258 .030 over comp.cam ported and decked head,weber,borla,tfi.
 

anyone? Friends thought it was blow by, But being the compression test came out ok and the motor runs strong i didn't think so. Am I thinking correctly? Is there something I can try to eliminate anything or prove anything ? thanks Gary
 
Valve seals will leak the most under compression braking, not at idle. Did you take the oil fill cap off and see how much blow by you have? What oil are you using? Did you do a wet and dry compression test?
 
I only did a dry compression test because the readings were so high and balanced. What should I be looking for with blow by? I had replaced the oil filler cap with an additional breather at the front. Oil is cASTROL GTX 10W/40. thANKS
 

Have someone with engine experience watch for excessive blowby. It is just too hard to describe in writing. Do you know what type of piston rings were used.
 
The machine shop went out of buisness, I'll see if i can find the build slip, to see what type of rings. If I was getting blow by would my compression be so high and equal?? Thanks for the help, I want to do more to the jeep but need to get this under control first.
 

Ok, pulled out the build ticket. Moly rings were used, bronze valve guides and teflon seals.I was told if I was getting blow by I would be getting a puffing at the oil fill on the valve cover, is that correct? Thanks Gary
 
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