Oil in Cyliner - Compression Good All Around ?

[PHOENIX]

OK Im getting oil in my #4 cylinder.
Its seems to be enough oil to make the spark plug not fire (new plugs).

I did a compression check and found all cylinders to be damn close to even, all were about 153 psi, give or take 3-4 psi.

I am guessing valve stem seals, I dont have the tool to test the seal while the seal is in place.
1. Does anyone know what this specialty tool costs?
I do have the MityVac tool, can I just buy the adapter?
I do have the tools to keep air pressure (from compressor) in the cylinder so the valve doesnt drop, and I have the valve spring tool for removing th spring with the head on the engine.

Does this sound about right?
2. Can the valve stem seal cause enough oil to leak into the cylinder and foul the plug?
Truck idles fine, slightly rough, and runs strong to 3000rpm then gets rough and sounds like pinging. It sounds like its coming from the passenger side too (where the #4 cylinder is located). The longer I drive the truck, the worse it seems to get. I am guessing more and more oil is getting in with higher rpm and the plug isnt firing causing it to run like sh*t. It becomes sluggish at the beginning of second gear after high rpm driving, like a cylinder isnt firing.
Some guys I talked to said valve stem seal wouldnt do this, my dad (who is a great mechanic, just hates doing it out of work), said its more then likely the problem. He said because the engine has never gotten hot and has less then 80000 miles on it its probably not the piston rings. Since compression is good this sounds like the most likely cause, he also said possible the intake gasket went bad. Intake gasket isnt old, but doesnt mean its still good.
3. What do you guys think about all this?

4. Are the valve stem seals the same on a stock '83 350 and a '98 gm goodwrench 350 crate motor for use in vehicles 1970-85?

Thanks!

[NeCrOmAnCeR]

Yes a bad valve guide seal in the intake can leak enuf oil to foul a plug. It is a simple job to change them on the truck, sounds like you have the tools already to do the job. Go to the parts store and order the valve seals to do the job and give yourself an afternoon to do it.

I believe that the 83 engines did not yet use positive seals on the intakes, but I may be wrong. If they don't, then the seals from the newer engines will not work without machining the top of the valve guides. But the o-ring seals from the same engines will.

[1986Silverado]

Could also be the valve guides themselves. I had a 91 s-10 blazer that did the same thing on cylinder #2. Compression was good on all cylinders but #2 spark plug was oil fouled. I put in one of those anti-foulers and checked the oil daily. I was loosing about a quart a week. The anti-fouler is really a band-aid....but it worked.

[Bowed]

QUOTE [ Truck idles fine, slightly rough, and runs strong to 3000rpm then gets rough and sounds like pinging.]

I agree with everyone else on possible valve seal or related but I am also wondering how it runs right after you put a fresh plug in . If it is rough with a fresh plug then you have a second problem .you had mentioned in a previous post about valve clacking so I was wondering if you also had a bad cam or lifter , just a thought .

[greg0380]

I had a similar problem. Oil in cylinder and good compression. Turned out to be a broken oil control ring on the piston.

[PHOENIX]

Bowed: It is definetly possible I have a few things going wrong here. I hope to get to the seal and guide tonight or early tomorrow and see how it looks. Its does run better with new plugs, but after driving for a little while it gets sh*tty again.
Greg: I thought about the too, if the compression rings are good and the oil ring bad you should still have compression, but you would be getting oil too.

Heres another question: If I change the seal and guide and still have the oil in cylinder problem and decided to do the piston rings, can I remove the pan and pull the piston out the bottom and do it all with the engine in the truck?

[Bowed]

QUOTE [ Heres another question: If I change the seal and guide and still have the oil in cylinder problem and decided to do the piston rings, can I remove the pan and pull the piston out the bottom and do it all with the engine in the truck ]


You can pull the piston with the engine in the truck but it must come out the top after removing the head . Also I thought the valve guides on small blocks were pressed in and you you could not replace a valve guide while the head was on , am I mixed up about that ? one more thing , to me ring damage usually means bore damage , so I do not know if the time and effort you are going to put into a patch job is going to be worth the results . I have tried that a couple of times with poor results .

[greg0380]

Eddie,
I was able to pull the piston out (#1 piston) with the engine in place. However it was a 4.3L V6 and it was 2 WD. Physically, the engines (4.3L and your 350) are the same dimensions except the back two cylinders are lopped off and I'm not sure how differently the placement in the engine bay is. From what I remember when I did it was the only thing that would be in your way is the front crossmember. It should be possible, be careful with the seal around the timing chain cover, with patience and luck I was able to fit the oil pan back in without removing the cover.

[PHOENIX]

I dont know about the valve guides, does anyone know for sure?
If the heads come off theyll go to a shop for rebuild.
If I believe its the rings Ill pull the head and inspect the bore for sure.
thanks for the help, I need all I can get

Greg:
Thanks for the info, I just replace the oil pan gasket and didnt have any problems with the timing chain cover gasket leaking or anything afterwards.

If I find more things wrong with the engine and decide it needs a rebuild or replaced what do regular shops charge to rebuild (like stock). I dont have money now for anything special and cant afford to rebuild myself and risk more damage, need some sort of warranty if I invest too much. Many of my friends havent had good luck with engine rebuild shops around town, I just dont know if I can trust those people.

thanks for all the help guys!

[PHOENIX]

Called some local dealers and found kits only, nt individual.

Here is the part number they gave me: 14033547 (new number 12511890).
I know gmpartsdirect is cheaper, but I dont have time to wait for shipping.
Can anyone verify that this is the correct valve stem seal kit for a stock 350?
I called (3) dealers, (2) gave me the number (and new number) above, and (1) gave me a different #.
The (2) that gave me the number (and new number) above seemed quick and confident with the #, the (1) who had his own spent more time and didnt seem so sure.

thanks again for the help.

[swervin ervin]

Eddie,

does it smoke when you first start it? This is a tell-tell sign of bad valve stem seals. Oil will migrate down the stem. Only so much oil will go because you only have so much oil laying around the stems when you shut it off.

[PHOENIX]

If it smokes it doesnt smoke much. I havent noticed any smoke at start up, revving, or driving.

Heres something else I should have brought up.
When the truck is sitting still and I rev it up it seems to run perfectly fine.
Its only seems to run rough under load.

[TwinTurbo]

if it smokes on start up it's the stems, if it smokes when you mash the throttle and then let off it's the oil control rings.