Question for you guys... any advice as to what this could be... I recently had my cyinder head reconditioned due to a bad valve, and since it was still using all original valves i figured it was time to have it gone thru. So i had new valves, springs and guides installed. Now re***embled it runs great, feels stronger then ever, but... now it smokes a good size puff of bluish smoke on start up... or if i really get on the throttle hard you see some smoke then too... It never smoked before, and never used oil. I have put about 1500 miles on it since i put the reconditioned head on, and would like to solve this irritating problem. It appears on the invoice that the shop never actually replaced the valve seals, so i am hoping that could be where my problem lies... Any thoughts?
It could be a valve seal problem. Also you have added compression . however it is not uncommon for engines to start burning oil after fixing bad valves.OldWolf
Seems odd that they reconditioned the head and did not replace the valve seals I always thought that was part of reconditioning the head.
It could be rings, but all too often I see people use old style umbrella valve guide seals after a valve job when a situation really calls for some better positive-seal valve guide seals. If it smokes pretty much when you downshift and use the engine as a brake (high intake vacuum at high or mid-range RPM) to slow the car down, then it is likely to be the seals. If that condition doesn't make it smoke more, then it could be worn rings.
What type of engine is it? I'll ***ume it's a v-8 chevy. Intake gaskets, valve seals, modulator on the trans, rings, and pcv-valve covers are all common problem areas. Did you change anything else? It sure sounds like valve seals though. Jeff
That was a pretty common thing years ago when they just did a "valve job". It ups the compression to have the valves sealing good and causes more blowby and smoking.
The engine is a OHC inline 6 from a 67 firebird. I have heard one person tell me already that they think its rings... but i am just lost as to how it could be rings when the bottem end isnt old, and never used or smoked oil before this... as well compression before and after is only a couple psi different then it was with only one valve having been bad in it... i replaced all of them as why do only one when i know they are all old, may as well freshen it all up when its off you know. This may sound like a stupid question but does every valve get a seal or only intake valves?? or only exhaust valves? I can see seals on some but some of them i have looked and cant see any seal visible unless its way up in the retainer...
Better valve sealing means more vacuum, this ****s oil past rings that seemed okay before. We did a 446 IHC engine that didn't burn any oil, recon heads and it sent billowing clouds of white smoke, unbelievable! Did the bore and pistons/rings thing, cleared it right up. Now, I have done the valves on lots of older engines and had no problem, but now and then, stuff happens, I guess.
On ohc engines you really have to make sure the cam bearings are good. You get to much clearance in the cam bearings it will flood the top with oil. No valve seal will seal good if it's submerged in oil. The ohc engines are real fussy with the valve seals. Maybe some were torn when the seals were installed. Off topic. Be carefull if you ever warp the head. Never just mill it flat. You need to straighten it before you mill it. Or line bore the cam journals. The intake are most likly the leakers. You could pull the intake and look for oil in the port under the valve. Jeff
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