oil consumption

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tekslk

tekslk

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Well lets see I have a 360 that uses a lot of oil did compression check today every thing was 160 to 165 plugs looked great I installed a new intake about a month ago that didnt help. Could it be the heads? New valve seals about a month ago also, didnt help. cam has 494 lift,automatic, How about some ideas.
 
sucking oil out of the lifter valley into the intake ports....
 
Do you have a PCV valve? Where is it plugged in to? What was done to the heads during the last rebuild? How many miles since the rebuild of the engine?
 
moper said:
Do you have a PCV valve? Where is it plugged in to? What was done to the heads during the last rebuild? How many miles since the rebuild of the engine?
Click to expand...

That's what I was going to ask.
(What kind of crank case venting does it have?)
 
pcv valve in drivers side valve cover, vent to air cleaner in the other side, Just before rebuilt heads were taken to machine shop springs replaved with new valve seals. How does oil get in the valley? aproxximately 3500 miles since rebuild used oil the whole time.
 
because you have good compression does not rule out oil scraper and oil control ring. in fact stuck or gunked up oil control rings will help with a compression test. i would guess this thing is smoking just a bit. if it is the rings, it will smoke after coasting and or any hi vacuum situation and then you pick up the throttle. ive seen the lifter valley thing before. and stem seals damaged when the springs were installed. is the pcv valve baffled
 
do you know what your ring gaps were and are your valve cover baffled at your pcv valve?
 
valve covers baffled, total seal ring but I dont remember end gap, Spark plugs look great also.
 
tekslk said:
How does oil get in the valley?
Click to expand...

Oil is always in the valley. That's where it gathers before return to the bottom end. The problem arises when that oil makes it past the side rail intake gaskets into ports due to intake port vacuum.

One cause can be milling of the heads to raise compression along with the required milling of the intake side of the intake manifold (or intake side of the head). This can cause the front and rear rail of the intake manifold to bottom out on the block even when gaskets are not used ( I can't use gaskets on each end, only silicone sealant). With this situation, the intake will not seal on the heads causing oil from the valley to get sucked into the intake ports.

It happened to me, so much so, I could see blue smoke from the exhaust immediately after firing a new motor.

If you suspect rings may be at fault, I would run a leakdown test on each cylinder as opposed to a compression test. A lot more can be learned about cylinder health from a leakdown test.
 
Just to let you guys know, i have been talking with tekslk about this issue also. I have the intake that recently came off his engine and the plenum is overly oily. I went out tonight and inspected it and the gasket surfaces look very evenly compressed so i don't believe it's a fitment problem. I too came to the conclusion that the PCV was close to a rocker and picking up excess oil splash. If it is baffled properly then my only conclusion is too much crankcase pressure. It sounds ugly, but as some of you have brought up the rings, my next thought would be that the gaps are lined up or the 2nd ring could be upside down. The later would still allow a decent comp test, but will actually scrape oil toward the top ring......... I hope "T" by posting here i didn't offend you. I just found this thread and wanted everybody to know what i knew so we can come up with a solution for you. Afterall i love your Cuda :grin:.
 
Your the greatest Rick and thanks alot for all you help, Now Im getting my second wind Im going out to garage to see if that valve cover is baffled for sure.
 
Well so much for that both valve covers are baffled. What should we check next or how do we do a leak down check?
 
Oil consumption can also be due to a leak. Given your motor rebuild 3500 miles ago, nothing on the garage floor after running that motor? I'm just saying... : )
 
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