2G Valve stem seals install wet vs dry

[elocneas]

Cleaning up a head for assembly and just wanted to get some opinions on if people are installing their valve stem seals with oil, dry, or a special tool?

 

[1990TSIAWDTALON]

Special tool and dry is how we did my sons, while on the car. From the machine shop, they would be dry except the valve stems would be lubed up. A stem seal is suppose to wipe the oil from the stems as its purpose.

 

[curt-s]

Special tool and dry is how we did my sons, while on the car. From the machine shop, they would be dry except the valve stems would be lubed up. A stem seal is suppose to wipe the oil from the stems as its purpose.

Bit of a revival but, does it actually matter?
Ive always added a touch of lube and pushed them on with a 10mm socket because, like most other seals that have to be "pressed" on or in, I've learned rubber(ish) being forced over/in metal should have a bit of lube.
I mean, isn't it kind of difficult to believe hot, thin oil won't get up in around the seal during its life anyway
Ie. It won't remain dry it's entire life if it was installed dry

Is there ever an instance where a lubed seal just.. popped off?

 

[Justin DuBois]

I vote dry - you want the seal to grip the sides of the valve guide and not pop off. You also don't want to press them on too far to distort the seal contact with the valve stem. It won't hurt to lube the valve stem.

Valve seals "pop off" when the valve guide is out of spec, or loose in the head. If you have oil leaking down the valve stem with good seals, then the valve guide is probably loose.

 

[curt-s]

I tried to remove one by finger, that was lubed and pressed onto the stem with a socket, and it was not having any of my attempts.

I'm just not entirely convinced (yet?) that if you popped off a seal from a motor with 10k on it, that you would find a completely dry rubber/viton-stem interface underneath. oil gets up in everything.

I do a light skim of assembly lube on the valve tip, slowly push the valve up the guide and to the seal, then remove the valve and wipe any excess off that didn't serve to lubricate the stem. Then in goes the valve again.

I have GSC bronze guides (w/ depth stoppers) and the usual supertech seals. For the seal to latch onto the guide (there's a slight step in the rubber that fits in the guide groove), you have to push them all the way down. The top of the guide then contacts the underside of the seal fully; I don't think you can push them down "too far".

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[Justin DuBois]

This is what I mean by pushed on too far- note the seal on the right side. Too many taps with the mallet

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[curt-s]

Oof, that must be related to that specific type of guide. As you can see in my (i thought 5x zoom would look better ) pic, the GSC guide sits so fat and wide under the seal it makes it basically impossible to distort. I'm sure you could if you tried, but you're more likely to damage the seal by the install tool used before anything else.

I remember installing seals back in 2009 or 2010 and it was a lot more difficult than these ones. And I do recall immediately having oil seepage on the exhaust side -- I bet I did the same thing with whatever guides I was using at the time.

 

[1990TSIAWDTALON]

Curt, as long as the guide seal stays put, like you said, it really won't matter. You just don't want the seal to "slip" off of the guide and start going up and down with the valve. When it is in place, it's job is to just "wipe" the valve stem. Not necessarily dry but not letting the oil get past the top of the seal. If you "could" pull one off, then it will more than likely come off during operation. All of mine get assembled with a special plastic tool that the stem goes into and the seal has a nice flat surface that presses it onto the guide while keeping it straight.

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[curt-s]

That there looks to be an installer meant more for when the valve is already up in the guide, isn't it? Definitely would use that if I'm changing seals when the head is still on.

When it's not, I think the socket I used was a Westward 10mm. It fit perfectly on top the seal, was the same diameter as the seal itself so it sat nice and flat on the part of the seal you want to apply pressure to when seating it, and gripped the spring just enough to not slide side-to-side. Then I just pushed them on. Mileage may vary depending on socket manufacturer, though.

 

[CanadianTalonTC]

This is what I mean by pushed on too far- note the seal on the right side. Too many taps with the mallet

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I may be blind, but can you explain exactly on the right one what the issue is? I can't seem to find the differences.

 

[1990TSIAWDTALON]

That there looks to be an installer meant more for when the valve is already up in the guide, isn't it? Definitely would use that if I'm changing seals when the head is still on.

Yes Curt and I don't even remember where I bought it at, but a vendor or freelancer.

 

[Justin DuBois]

I may be blind, but can you explain exactly on the right one what the issue is? I can't seem to find the differences.

Its subtle - there is a greater gap in the wiper seal, distorted, as it was mashed on a little too hard. It was my mistake, first one I put on in years.

 

[curt-s]

I'm interested in seeing the top of the guide because, unless it's fairly thin (like the bottom where the valve exits in the port), the top of the guide is flat should stop dead at the "shoulder" of the seal. That part is still encased in metal, so I'm not sure how it could distort enough to pucker out the top of the seal. You sure it wasn't damaged some other way, or maybe just defective from the start?

I'm just having a hard time picturing how sticking a seal on top of a guide, where the guide stops the seal from going any further than it needs to, could cause a deformation. Those two seals appear to be different colours and the lettering cast into them .. different?

 

[CanadianTalonTC]

Its subtle - there is a greater gap in the wiper seal, distorted, as it was mashed on a little too hard. It was my mistake, first one I put on in years.

Thank you very much, I see it now. Valuable information for replacement when the time comes.

 

[chrysler kid]

i used lucas assembly lube on the seal and a socket to tap on to seat them. never had a problem. the lube is to prevent the rubber from tearing when installed on the head