How does oil get to valve stems ?

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Many modern cars have valve stem seals. Their valve guides are solid cylinders without oiling holes and don't have a direct connection to the pressurized oil galleries. So then how are the valve stems lubricated? What am I missing?
 
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JTK

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All engines have some kind of stem seal AFAIK. Oil laying on the top surface of the cylinder head trickles down the valve stems. The area under the cam (valve) covers gets fed with oil from pushrods on cam in block engines or jets and chain sling on OHC engines. Joel
 
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Kestas

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The engineers at our place that design valve stem seals tell me that the seals are designed to bleed a specific amount of oil necessary to lubricate the valve stems.
 
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 Originally Posted By: berniedd
Ok but I thought the valve stem seal kept all oil from entering the valve stem area, that's why it's called a seal.
On some seals, like a front or rear main, you ideally want no oil to pass through. On a valve seal you want a very small amount to get past to lubricate the valve/valve guide area. If there was no lubrication in this area, you could get a stuck valve.
 
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Shall I put the Lubriplate Motor Assembly Lube on all these valvetrain components too? Basically, is there anywhere I SHOULDN'T put the lubriplate, or somewhere it's a waste of grease?
 
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 Originally Posted By: 1993_VG30E_GXE
Shall I put the Lubriplate Motor Assembly Lube on all these valvetrain components too? Basically, is there anywhere I SHOULDN'T put the lubriplate, or somewhere it's a waste of grease?
Yes. I've never used that brand, but assembly lube should be used about everywhere. Just don't over do it, but any excess will burn off. Out of curiosity, did you grind the valves yourself? I'm just asking because if somebody else grinds the valves, they will assemble the valves, springs, keepers and locks for you.
 

JT1

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valve stems are designed to run virtually dry in there guide.Oil leaking past the seal will burn and cause a carbon build up on the stem leading to a stuck valve. The cylinder head usually expands at the same rate or faster then the valve stem when exposed to heat, so a stuck valve from overheating isn't likely.
 
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 Originally Posted By: tom slick
Some study materials
Thanks for posting those. A lot of people don't know the importance of a valve seal or exactly how they are supposed to work.
 
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 Originally Posted By: Kruse
Out of curiosity, did you grind the valves yourself? I'm just asking because if somebody else grinds the valves, they will assemble the valves, springs, keepers and locks for you.
Thanks K. I didn't grind the valves. I'm in the midst of transfering it to the stand by mid week, it's taken me long today to get the exhaust out, plenum off, and all the hoses out, and some other stuff out. But, I'm going to do all the inspections myself, I bought most of the tools. If it does need a valve job (which is probably will right? 500K clicks) I may get a friend to do it who WAS a rebuilder...he claims he'll give me a deal. I'd like to do as much of the overhaul as I can, and get the machine shop people to do just the bare minimum. Is there certain parts you recommend I ONLY get them to do? For example of course if I need it, i'll get them to mill the head and block if there's distortion. I'm concerned about the exhaust manifold ports, there was a snapped stud for years and a puttering sound, someone told me it could be warped by now. I'll check it with the machinist straight edge. Please see my next post questions.
 
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If you are going to start the engine soon and not store it long term, use engine oil on the valve stems when assembling it. I don't want flow impeding grease on the stem. BTW, gas helps cool and lube intake valve stems.
 
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