how does oil get into the engine combustion chambers?

[custom89stang]

Besides the O-rings what other ways can oil get in? is that the only way? can they get in through the head seals? valve stem seals? any other way? Alrigh thanks a lot.

 

[Daggar]

Has to come in either through the top or the bottom I imagine. So your post pretty much covers it. The only other way I can think of is on cars with mechanical fuel pumps. If the diaphram is bad you can get oil in the gas and vise versa.

 

[custom89stang]

so it can come through the heads into the combustion chamber? through the valve seals, valve stems, etc? Or is there only ONE WAY? (through the o rings)

 

[stang2841]

this is the kinda quesiton that seperates the men from the boys , and the noobs from the rookies

im curious as well , how else?

 

[TT91]

oil can be coming past the piston rings if they are shot, or down through the valve seals/guides. Also, if you have a pcv valve issue and were sucking in through your intake.

 

[custom89stang]

alright thank you, i just had some heads rebuilt because my mechanic said that was the problem, i also know one of the spark plugs gets oily so it could be the piston ring, my dad said get a compression test so i can find out whether its the ring or the heads, thanks!

 

[dvs bullet]

check to make sure that the little basket under the pcv isn't plugged as well, it could be as easy as that.

 

[00 Red SS]

Today when i regapped my plugs to .35 for nitrous i noticed my #4 and 8 plugs had oil on them. I have a new pcv valve, how do isee if its the pistons rings or valve seals?

 

[HISSIN50]

a leak down test is best for checking the source of a leak. dry and then wet compression tests can help a bit too (though not nearly as much).

 

[Michael Yount]

Sirsureshot, your dad, and hissin have you covered on this one. Leak down will tell you if it's rings, or a bad valve/seat seal. Unfortunately, it won't tell you if it's a guide or valve stem seal. The actual symptoms will nail those down. Guides will usually make noise, and blue smoke will be seen on start up (and go away after the engine warms a bit). Guides and/or stem seals may show blue smoke upon deceleration - as heavy vacuum in the cylinder can pull oil from the head past the seals or a loose guide. So, if your leakdown test tells you the rings are sealing, and you've got the smoking symptoms above, it's likely guides and/or seals.

Oh - if you've got problems with valve to seat sealing (like a burnt exhaust valve for instance or bent valve stem), the leak down test won't tell you anything about the rings in that cylinder. The pressure will find the path of least resistance (usually past the bad valve seat) and you won't get an effective ring test cause the valves won't hold the pressure in.

 

[custom89stang]

how much is a leakdown test? and will a compression test tell me if its the rings or the valves?

 

[HISSIN50]

dont know about the prices. you can make a leakdown tester. i think Jrichker has a link to make one on his site.

dry compression tests check baseline/relative compression - the wet component checks rings by comparison to the dry numbers (and thus can be used as a crude elimination device).
good luck.