Could Someone Explain How These Valve Stem Seals Are Supposed to work

Poorman · Jul 22, 2024

I just received new stem seals for my 6.9 idi. I'm confused, the intake (not shown) look like the originals but the exhaust are way different. Will these work? how do they work? The picture shows the old brown one and the new white nylon one. Is this just a short version of the old one? it fits over the stem nice and snug. The large end is much smaller than the guide, so my only guess is that they just ride on the stem and keep oil from running down the stem to the guide? and why are there 16 pc. in the package? does it take two per stem? I'd really appreciate some help!

You must be registered for see images attach

TahoeTom · Jul 22, 2024

The white seal called an umbrella seal snaps into the upper spring retainer. They only go on exhaust valves. I think if used with the larger intake seal it will interfere with that seal. No idea why there are 16. Classic Diesel Design sells a set 16 seals like the intake seals so I assume you could use that type on all the valves. I wonder if that is a better idea? I watched a video of Justin at R&D IDI performance assembling a head and he used the same positive seals on all valves. I may go that route myself unless someone can tell me why it is a bad idea.

Poorman · Jul 22, 2024

I didn't force it but it does feel like it's sized to snap into the bottom of the retainer, but what good would that do? it's an inch and a half away from where the sealing needs to be. The old ones, shown in the pic were not snapped into the retainer, although they were all riding high up the stem. You can see the out of round wear on the top of it so it's possible if they were snapped in and they just fell off.

TahoeTom · Jul 22, 2024

They just divert oil away from the guide like the name umbrella. I looked at CDD store and he said the positive seal on all valves reduces blowby and carbon buildup. I wonder if the guide needs some lubrication so the umbrella was the answer the engineers at IH came up with.

Kevin 007 · Jul 23, 2024

I don't run positives on the exhaust. Minimal oil consumption. These guides need all the lube they can get

Could Someone Explain How These Valve Stem Seals Are Supposed to work

Poorman

Registered User

TahoeTom

Supporting Member

Poorman

Registered User

TahoeTom

Supporting Member

Kevin 007

Full-floater

Similar threads

Latest posts

Forum statistics

Members online

Share this page