Valve stem seals

[jessesandy]

So the head gasket set doesn't have different valve stem seals for intake and exhaust.
All 16 seals are "intake" (with the white/silver spring band).
The package says they are Viton seals. Does the advanced rubber material make them interchangeable for intake and exhaust ?
Has anyone seen this ?
Thanks.

 

[Prozon]

I didn't think it mattered. They are all the same aren't they?

 

[dc2GS-R]

Sorry, I didn't realize that I overlooked this question in your previous thread.

The valve stem seals are not interchangeable between exhaust and intake valves. The stem diameter of the intake valves is larger than that of the exhaust. The stem seals should be different as well, to match the valve stem diameters.

 

[Prozon]

Probably a good thing I haven't touched my head yet.

So it isn't even possible to interchange them right?

 

[jessesandy]

Thanks. Fortunately, a set of stem seals is only around $20 (?).
I hope the rest of the Fail-Pro (Fel-pro) gasket set works good for me.

 

[jessesandy]

The repair manuals definately say intake and exhaust seals are NOT compatible.

All the parts stores I have asked (decent local stores, not chain) say the replacents are just a bag of 16 seals.
On-line they're are plenty of places that show a replacement set with 8 intake and 8 exhaust.

Fel-pro tech support not answering (on holiday ?)

 

[dc2GS-R]

Probably a good thing I haven't touched my head yet.

So it isn't even possible to interchange them right?

It is possible to interchange them. But putting the larger intake stem seal on the smaller exhaust valve will cause it to leak. Putting the smaller ID exhaust stem seal on the intake valve will cause it to wear out quickly.

 

[mirrorimg]

On my old head, I got a pack of generic stem seals and had the machine shop put them in when they sprung the head up. I didnt notice any ill-effects of them, and they were all uniform. (I had noticed the same thing you are experiencing). Since OEM seals were about $50, I went ahead and used them.

I made it a point when building my new head to use OEM. I didnt want to risk the longevity of the head by using generic stem seals.

 

[Prozon]

I will have to take a look at my valve seals.. i'm pretty sure they're all just jumbled into one bag. I don't know if they're actually different or if they are all the same..

 

[jessesandy]

I just measured my new "generic" seals and the hole for the valve stem is about 0.219".
The specs for the valve stems are 0.259 and 0.258 (intake and exhaust).
So, the rubber has to stretch 40 or 39 thousandths to get around the valve anyway.
I wonder, could the 0.001 difference between valves really make a difference in the tiny amount of oil allowed past the seal to lubricate the valve guide ?!?

 

[emd513]

look at the ones in the bag a lot closer. i bought some in a gasket kit from auto zone and if you look harder one is white and one is more of a darker white almost a light gray

 

[jessesandy]

All the springs looked silver. (They're installed now so I can't get a good look anymore.)

Another note on identifying the seals:
the originals had a very tiny IN or EX moulded into the rubber around the top, along with NGK 21. The replacements in the Fel-pro head gasket set had nothing.