dbeachy1

Hi guys, I have a 1999 C5 with ported heads (TPIS ported heads/cam/headers installed back in 2002). Sometime after the heads were installed I noticed a puff of blue smoke on startup. It never does it unless it sits for a while, and it doesn't use much oil, so from I've researched it sounds like the valve stem seals need to be replaced. I need some advice!

1) Do I need to find new valve stem seals designed for ported heads (i.e., slightly larger diameter) so they will seal tightly? Or will replacing them with new OEM valve stem seals work OK? I'm not clear on how much material is removed around the valve stem when heads are ported.

2) Could I trust the dealer to replace the valve seals or should this only be handled by a tuner shop? From what I've read it is not necessary to remove the heads just to replace the valve seals, but I don't know how common replacing valve seals is.

3) Could anyone recommend a good tuner shop in the Northern Virginia area?

Thanks for your help!

silver408z

The valves should be stock diameter stems I would think. When they port heads they do not take anything off the valve stems. If you plan to use a shop to do the work let them figure out what parts to put back on it.

Sorry I am in Texas and have no idea about shops in Virginia but I have seen people talk well a shop called Virginia Speed. Do a search and look into them and see how far they are from you.

dbeachy1

Thanks for the info! To clarify my question, I am wondering how much material, if any, is removed from the heads at the outside of the valve seal -- i.e., if the total diameter of the valve seals will need to be increase to still seal. Or does the valve seal only seal the inside of the hole in the seal, around the valve stem? If so, then the outside diameter of the valve stem seals wouldn't matter, correct?

One other question -- what kind of labor estimate is reasonable for replacing all the valve stem seals? [I know the techs charge "book time".]

Mr. Big

If you aren't sure what seals are in there, then you need to wait to order the correct parts. You're not going to run into an issue of the size of the seal, just the type. GM uses a seat seal combo on their head, where the seat and the seal are one piece. A lot of aftermarket valve spring kits use seperate seats and seals. The diameter is not going to change.

As far as the cost, if i were doing it i would remove the heads to do it. You may not have to, but then you have to fit the seal over the valve push it down and press it on all while the valve is there. You run the risk of nicking the valve or droping the valve anyways. Both would require you to remove the head.

If you are only changing one side seal, expect pay around 1k plus parts. Both side closer to 1500 plus parts. Just a guess though

vettenuts

Seals may somewhat depend on the installed valve springs, however in most cases GM seals will work and I prefer them for the better fit.

There is no material removed that will affect valve seal fit. GM dealer may be able to do this, again depends on the valve springs. Don't let anyone use the claw type valve spring tool on your car when this is done.

JetMechZ16

HUH???? 1995 C5???

dbeachy1

LOL oops, that should be "1999 C5" -- I'll update the post.

dbeachy1

As a follow-up in case anyone else comes across this question in the future, I heard back from TPIS today and they said OEM valve seals should work fine for my TPIS heads:

racebum

gm seals come in specific colors, black for the intake and brown for the exhaust.

if someone used all blacks that could be a problem as could be excessive guide clearance

LoneStarFRC

Your '99 OEM seals are of the conventional type, i.e. non-seat seal combo design.

They can be changed without head removal using compressed air to keep the valves in place. If done carefully, the seals can be slid down over the valve stem and into position without any damage. Many machine shops/engine builders have small clear plastic sleeves they slide over the tip of the valve to assist in the installation, but if done very carefully, they are not critical to have as long as they are kept lubricated with motor oil and installed slowly.
Once the seal is in position at the valve guide boss, it can be pushed down into final position easily. I used a 1/4" dr, 12mm (IIRC) deep socket to push them down into position. It only requires a moderate amount of force. Re-install spring and retainer, etc and reassamble valve train.

Btw, the different colors of seals has to do with temperature rating. The OEM exhaust valve seals are brown to distinguish them from the intakes during engine assembly. The VITON rubber material is different than the intakes and can withstand higher temps, but the general appearance (other than color) and installation, is no different than the intake seals.

HTH

dbeachy1

Thanks for all the great information, guys! Much appreciated!