Valve Stem Seals

tblake · #1 11-21-2009, 10:58 PM

Ok, so I replaced my spark plugs yesterday and one was covered in oil buildup almost closing the electrode gap, another had some starting, and a few others had some oily wet spots on the cereamic center insulator.

Anyone ever replace the valve stem seals on a 96-98 vortec 350 V8? I have done it once on an older TBI 350. I am sure it is not much different.

I guess the only thing I am really wondering is if I can use an unbrella type seal in conjunction with the stock o-ring seal.

And if I remember right, on the tbi 350 I replaced the valve seals in, the owner provided a fel-pro set of valve seals that included the intake and exhaust umbrella seals along with the o-rings.

Does anyone have the fel-pro part number for this set?

Thanks!

MT-2500 · #2 11-22-2009, 09:54 AM

Quote:

Originally Posted by tblake

Ok, so I replaced my spark plugs yesterday and one was covered in oil buildup almost closing the electrode gap, another had some starting, and a few others had some oily wet spots on the cereamic center insulator.

Anyone ever replace the valve stem seals on a 96-98 vortec 350 V8? I have done it once on an older TBI 350. I am sure it is not much different.

I guess the only thing I am really wondering is if I can use an unbrella type seal in conjunction with the stock o-ring seal.

And if I remember right, on the tbi 350 I replaced the valve seals in, the owner provided a fel-pro set of valve seals that included the intake and exhaust umbrella seals along with the o-rings.

Does anyone have the fel-pro part number for this set?

Thanks!

Parts places that sell fel-pro gaskets should have a book with the correct applaction.

If you replace them check valve guides for excessive wear.

jdmccright · #3 11-23-2009, 11:18 AM

I can't say you will have the same issues as I did (mine is pre-Vortec), but the part numbers for the umbrella seals given me did not match for the exhaust valves I had. I had to measure the diameter, then go through the different packs at the parts store to find the right ones, after having them special ordered. If you can have the diameter info before you go the buy new ones you can verify their diameter at the store to avoid multiple trips. Good luck.

Here is my thread with the parts numbers I used...again, these are for the non-Vortec heads.

http://www.automotiveforums.com/vbul...d.php?t=966407

danielsatur · #4 11-23-2009, 12:16 PM

Are you doing a ''In The car Valve stem seal'' replacement?

iroc343 · #5 11-23-2009, 01:18 PM

Based upon my experience, replacing the oil seals will not fix the problem you are experiencing. Unfortunately, The only real fix is removing the heads and replacing the guides. This can be done by boring the guide and installing bronze sleeves by any competent automotive machine service. Don't waste your time and money replacing the seals.

danielsatur · #6 11-23-2009, 01:20 PM

It's seems to work good on Fords 4.6L, because the OEM's seem to wear out like a bad condom.

iroc343 · #7 11-23-2009, 06:13 PM

I don't doubt there are some applications that the seals do fail, but on the gen I chevy small blocks this never seems to work. We replaced the o-ring types and added umbrellas to try to stop the notorious blue cloud on start up, and it never did the trick like resizing the guides did. Don't let anyone talk you into knurling the guides either, this is also just a band-aid.

danielsatur · #8 11-23-2009, 06:20 PM

I have noticed, that neglected oil services can cook these seals.

tblake · #9 11-23-2009, 09:14 PM

Thanks for the info guys. The truck has just over 100,000 miles, so the guides could be culprit, but I don't think so yet. BTW, no noticible oil loss on the dipstick, and there is no blue exhuast. The only indication I had was the bad plug (which I possibly could get a picture of). So, I don't really know how long the plug has been in there, or how long its been running on it. In fact, it missed at idle once in a while, but nothing serious. So I don't know. I think I'll just throw a set of valve guide seals in there and see what happens.

j cAT · #10 11-23-2009, 09:21 PM

Quote:

Originally Posted by tblake

Thanks for the info guys. The truck has just over 100,000 miles, so the guides could be culprit, but I don't think so yet. BTW, no noticible oil loss on the dipstick, and there is no blue exhuast. The only indication I had was the bad plug (which I possibly could get a picture of). So, I don't really know how long the plug has been in there, or how long its been running on it. In fact, it missed at idle once in a while, but nothing serious. So I don't know. I think I'll just throw a set of valve guide seals in there and see what happens.

plug fouling could be bad wire,injector,low compression...cracked plug.with no smoking oil use and only 100,ooomi ..valve guides worn , would be odd

danielsatur · #11 11-23-2009, 09:35 PM

How much oil is being consumed in between oil changes?

tblake · #12 11-24-2009, 10:43 AM

I don't see any oil consumption on the dipstick yet. So I don't know.

Yeah, the plugs were cheapo champion that were dang near rusted in (only God knows how long they were in there) and to tell you the truth, the two plugs with the buildup on them were both on the drivers side that are blocked by the steering shaft. So, maybe whoever shanged the plugs from stock to champion didn't have a 3/8's swivel to get those two out and just left them. Either way, I replaced all 8 with ac-delco 41-993's and also replaced the wires, cap and rotor, which were all original also. The cap had a lot of corrosion inside. So, at the next oil change I will pull the bad two plugs out and see what they look like. The truck has definatly gotten more HP and seems snappier than it was before changing all the ignition components. So I guess I'll see.

tblake · #13 11-24-2009, 10:45 AM

I will try and get some pictures of the plugs that came out and you guys can help with diagnosis. It wouldn't suprize me if the MPI unit has some issues (as a lot of them do).

tblake · #14 11-24-2009, 11:18 AM

Ok guys, here is about the best picture I could get. I didn't resize it so you can click on it to open it in a new window full size and see that I am talking about.

I dont know if #3 and #5 are originals which is why they have so much build up on them, or if they were replaced because the champions fouled out (possible).

All I know is a few of them seem oily, and all of them smell like gas.

What is your diagnosis?

j cAT · #15 11-24-2009, 12:42 PM

the pictures aren't the greatest to view but the plugs appear to have normal build up. the color at the tips look good..

replacing those ignition parts over time the engine/combustion chamber should get better performance as the deposits get blown out..

I would put 2-3oz of marvel mystrey oil in the fuel tank..for a few tank fulls to help clean/lubricate the valves/compression rings..

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