Your Pontiac heads apparently are designed to use umbrella type valve seals. In order to use the preferred positive stop seals, you must machine the valve guides with a special tool. The tool reduces the diameter and height of the valve guide so the positive stop seals will fit. Unfortunately, the heads must come off to machine the guides.

 

"After removing the spring set there was only a o-ring on exhaust and intake but that can't work it must be anything else!"

Amazing! GM got that system to work since the mid fifties.. Chevies and Pontiacs used that system until emission controls got tight. Works good on stock engines with the shields in place. The O-ring seals the retainer to the valve stem and the oil just drips off the retainer/shield onto the head. Oil mist in the engine lubes the valve stems..:thumbup:

 

Amazing! GM got that system to work since the mid fifties.. Chevies and Pontiacs used that system until emission controls got tight. Works good on stock engines with the shields in place. The O-ring seals the retainer to the valve stem and the oil just drips off the retainer/shield onto the head. Oil mist in the engine lubes the valve stems..:thumbup:

Ok with the retainer/shield it must be good but they are missing!

 

Ok, I ordered a Engintech S2882 set. If picture is right that's umbrella style

 

The umbrella seals require the shields to work with the O-rings in order to keep oil from running down the valve stems and being drawn into the intake valve guides. Umbrella seals ride up and down on the valve stem because they do not have a tensioner band to positively hold the seal to the valve guide. It is a waste of time to install umbrella seals on the exhaust valve stems.

The PC (Positive Control aka Perfect Circle) teflon seals or Viton seals should be installed after K-line Bronze Bullet valve guide liners are installed. The PC type seals require the guide bosses to be machined from .690" OD to .530" OD. Then valves seats should be ground after the guide liners are installed. The valve seats, valve guides and PC type seal must be concentric in order to work properly. The K-line Bronze Bullet guide liners perform six functions. 1. They positively eliminate oil from entering the valve guides. 2. They make the valve seats concentric with the valve stems. 3. They make the valve stems concentric with the valve seals. 4. The phosphor bronze guide liners self lubricate the valve stems since virtually no oil gets past the PC valve seals. 5. They permit the use of tighter than normal valve guide clearances without seizing for better oil control. 6. The tight and concentric seats and valve guides provide accurate valve seating.

My engine buider / machinist uses PC teflon seals and K-line phosphor bronze guide liners exclusively. He also uses Viton seals on some heads. Viton seals are more forgiving if the valve stem clearances are stock.

 

Finally I have to machine the guide because my enginetech umbrella style are to large to fit in the inner spring.

That's anyway the best choice!

Need just to take measurement to order right tool and right seal.

MouseFink, you said .530 so if it's right I need this tool Manley Valve Guide Seal Cutters 41711 - Free Shipping on Orders Over $99 at Summit Racing

I will see tomorow, it's 9 PM and my engine is not at home!

 

That is the correct tool and it includes the arbor. The Comp Cams 4726 cutter and 4732 arbor is the same but you must purchase the Comp Cams tools separately. Those tools cut the guide to .530" OD so you can use Comp Cams 503-16 seals or equal.

I would be concerned about using the Comp Cams 503 seals without K-line Bronze Bullet guide liners. No oil gets past those seals and I would be afraid the valves may seize in the stock cast iron valve guides. The CC 503 seals do not flex and conform to the valve stems in loose valve guides and cast iron guides need at least .0025" intake and .0035" exhaust guide clearance.

Pontiacs always used loose valve guide clearances for "upper cylinder lubricant" and the is why you see a puff of smoke when a stock Pontiac engine starts up. I prefer to think it was because of sloppy engine assembly and taking short cuts during assembly. It takes extra time to install K-line valve guide liners and fit the valves with tight stem clearances.

 

One more question for the seal : Viton or Teflon (on original valve guide)?

Can teflon be so bad on stock guide?

 

Viton, unless it has bronze valveguides or bronze guide liners.

Teflon is not very flexible, so on a loose guide clearance they quickly get "egged" out and pass too much oil(the issue you are trying to fix!).....that's if they don't seize a valve in the stock guide at the beginning when they are still sealed up tight.

 

The original Pontiac valve guides use umbrella seals along with the O-ring and metal valve spring shields. The umbrella seals are made of neoprene rubber and fit in the lower groove on the valve stem. Stainless steel valves usually do not have the O-ring groove and the valve guides must be machined for teflon or Viton positive stop valve guide seals.

Viton and PTFE (teflon) positive stop valve seals will not fit a original valve guide. The original valve guides must be machined to .530" OD with the above mentioned valve guide cutting tools. Then you can discard the metal shields if you want to enlarge the spring pockets and use larger diameter valve springs. That is usually done when converting to a roller camshaft.

 

the blue Viton on a properly machined guide is the way to go. Many pontiacs require the valve guide to be machined down (lower) anyway to use aftermarket cams with more than about .500 lift. Otherwise the spring retainer hits the guide at max lift and "crash". Most machine shops (that know what they're doing) will cut down the guide height AND machine the OD for the Viton seal at the same time. Many aftermarket springs set up at 1.7" IH, so the pockets will often get cut too. There's a lot of mods that can be done to a performance pontiac head...

When installing the vitons, be sure to cover the valve stem with a soda straw to prevent tearing the new seal on the valve lock grooves during installation.