I have researched a lot of old posts on the forum about valve stem seals but have not been able to draw a conclusion on what type of seals I should use on my 1989 L98 with 113 heads. I have pulled and replaced heads on other engines and adjusted valves before but I have never been under a valve spring. My engine has about 113k on it and puffs oil smoke at startup and randomly during idle. Compression is good and all evidence points to valve stem seals. Did this car come with umbrella seals or are those for worn engines that need sealing help due to worn parts? Should I use intake seals all around or the factory setup? I have all Felpro seals ready to install. Umbrella all around, intake all around, and a set for the exhaust stems. Should I put in the factory setup with umbrellas on top or all intake with umbrellas on top or just add umbrellas? You see, I just don't have experience in this area and could use guidance for the least course of regret as this is somewhat labor intensive on the car. probably going to use the rope method although I am was prepared to use the air method, just a little spooked about a dropped valve possibility and having to pull that intake to get a head off. Any thoughts on the seals I should use?

 

Anthony, a good set of Viton (rubber) umbrella seals on both the intakes and exhaust will last a very long time. I would give either JEG's or Summit tech line a call to be sure you get the correct ones for your heads.

Ford used umbrella seals on both intake and exhaust valves from 1962 on the SBF and I've only ever replaced them when doing a complete overhaul. This was even before Viton seals (which last even longer) were widely available.

I've used Sealed Power or Fel Pro seals for many years with no issues at all.

Good luck... GUSTO

 

use the felpro intake vss on both intake and exhaust.

push the seals all the way on.

easy peezy.

use the feeler gauge method for adjusting the lash

 

Umbrella seals are considered a "upgrade". If you already purchased umbrellas then use them. I always remove the oem seal clean everything and put on the umbrellas. I'm not sure if you can just put the umbrellas over the oem seals, since your already their I would pull the oem seals.

 

Thanks for the replies. I have all of the seals. Should I try to replace all the oem seals and add the umbrellas? Any reason not to use intake seals on exhaust valves?

 

no reason.

 

There are three types of seals O-ring, bonnet and positive.

O-ring seals seal between the valve and the valve spring retainer and rout oil down the outside of the retainer and spring. There is no real seal at the guide.

Bonnet (umbrella) seals do the same thing at a different point, just above the guide. There no real seal, oil just runs down the valve stem over the bonnet and down the outside of the guide.

Positive seals are just that. There is a positive seal between the seal and guide and also between the seal and the valve.

There is positive pressure in the the exhaust port under the exhaust guide which tends to blow oil out of the exhaust guide into the rocker side of the head. The intake guide has a negative pressure that tends to suck oil out of the rocker (valve) cover into the guide and then combustion chamber. This is why a better seal was used on the intake side plus the exhaust valve runs hotter and needs more lubrication.

Late model GM used positive seals on intake and exhaust I guess because gas and oil additives and maybe valve guide and stem materials are good enough now the extra lube is not needed.

I have had no trouble running positive (intake) seals on intake and exhaust. I also use the o-ring also as they direct more oil to the rotators and maybe act as a cushion between valve and retainer.

 

There are three types of seals O-ring, bonnet and positive.

O-ring seals seal between the valve and the valve spring retainer and rout oil down the outside of the retainer and spring. There is no real seal at the guide.

Bonnet seals do the same thing at a different point, just above the guide. There no real seal oil just runs down the valve stem over the bonnet and down the outside of the guide.

Positive seals are just that. There is a positive seal between the seal and guide and also between the seal and the valve.

There is positive pressure in the the exhaust port under the exhaust guide which tends to blow oil out of the exhaust guide into the rocker side of the head. The intake guide has a negative pressure that tends to suck oil out of the rocker (valve) cover into the guide and then combustion chamber. This is why a better seal was used on the intake side plus the exhaust valve runs hotter and needs more lubrication.

Late model GM used positive seals on intake and exhaust I guess because gas and oil additives and maybe valve guide and stem materials are good enough now the extra lube is not needed.

I use the o-ring also as they direct more oil to the rotators and maybe act as a cushion between valve and retainer.

 

Thanks. This is very good and helpful information.