[lt1silverhawk]

Here is a picture of the seal itself. I am having the hardest time removing it. It just wont budge so I am leaving it alone for now until I figure out which ones to buy. Any tips on removal greatly appreciated.

[cobalt327]

That is a positive type seal, although the valve stems are set up w/the same double grooves (one for the keepers, the other lower groove for the small O-ring type seal) and there is a tin oil deflector, like has has been used since day one, pretty much.

I don't have a part number, but the seals will be the same as those used on a 1987 Camaro 305 w/TPI, for example. Some sources cite the GM factory positive seals as fitting a 0.561" SBC guide boss. Measure the guide boss OD to compare, most aftermarket type positive seals have a smaller OD (=/< 0.0530") to allow an aftermarket/double spring to fit over them. You should be able to find the seals at any parts store, just inspect them first for having similar dimensions as the ones you have.

BTW, that is an exhaust valve (you will note the spring retainer is also a valve rotator, found only on exhaust valves). The order is (from here):

SBC: front | E - I - I - E - E - I - I - E | rear

[lt1silverhawk]

Originally Posted by cobalt327

That is a positive type seal, although the valve stems are set up w/the same double grooves (one for the keepers, the other lower groove for the small O-ring type seal) and there is a tin oil deflector, like has has been used since day one, pretty much.

I don't have a part number, but the seals will be the same as those used on a 1987 Camaro 305 w/TPI, for example. Some sources cite the GM factory positive seals as fitting a 0.561" SBC guide boss. Measure the guide boss OD to compare, most aftermarket type positive seals have a smaller OD (=/< 0.0530") to allow an aftermarket/double spring to fit over them. You should be able to find the seals at any parts store, just inspect them first for having similar dimensions as the ones you have.

Got it, I will remove one and measure and compare it before buying.

Originally Posted by cobalt327

BTW, that is an exhaust valve (you will note the spring retainer is also a valve rotator, found only on exhaust valves). The order is (from here):

SBC: front | E - I - I - E - E - I - I - E | rear

Thanks for the wiki.

[lt1silverhawk]

Did a little more work on the valve stem seals today. I went back to cylinder #2 and used pliers to remove the seals from the intake and exhaust valves. Gonna head out to Autozone and see what they've got.

Originally Posted by cobalt327

I don't have a part number, but the seals will be the same as those used on a 1987 Camaro 305 w/TPI, for example. Some sources cite the GM factory positive seals as fitting a 0.561" SBC guide boss. Measure the guide boss OD to compare, most aftermarket type positive seals have a smaller OD (=/< 0.0530") to allow an aftermarket/double spring to fit over them. You should be able to find the seals at any parts store, just inspect them first for having similar dimensions as the ones you have.

I probably should've asked about the boss guide sooner, but I think I measured the correct part (circled below) and the diameter came out to be just about 0.561".







Also, I am considering doing a basic cam swap at this time as well. I want to learn how to do it and also get a bit more smog-legal oomph out of this engine. I asked for recommendations here: Chevy K20: Camshaft Recommendations for a Crate 350. All input welcome and greatly appreciated.


Will report back shortly on the seals.

[lt1silverhawk]

Just got back from my shopping trip. I asked for seals for an '87 Camaro 305 TPI and brought along one of each seals for comparison. Here's what I got:


- Autozone: Had absolutely nothing that resembled the seals that I had.


- NAPA: Informed me that the seals on the truck are actually high performance. Asked if the umbrella seals they had in stock would work and and was told yes, as long as it wasn't a high performance engine. Bought a set of Seal Power MV-1598C.






- O'Rilley's: Also had nothing that matched, but was offered positive stop intake and exhaust valve stem sets with o-rings from Felpro and was told they should work.






Will any of these work?



EDIT: Picture #6 for the Felpro exhaust seal (side view) is incorrect.

[lt1silverhawk]

Based on the measurements I am seeing, the only valve stem seal that matches is this one at $1.39 each: CHEVROLET 5.7L/350 Chevy small block Gen I Valve Stem Seals - V8 Engine Type - Positive stop Valve Stem Seal Type - No Machine Work Required - 0.684 in. Valve Stem Seal Outside Diameter (in) - SummitRacing.com.


Will one of the sets I purchased earlier be fine, or should I order these instead?

[cobalt327]

Originally Posted by lt1silverhawk

Will one of the sets I purchased earlier be fine, or should I order these instead?

I prefer the FelPro type, and would use them providing they fit the boss and the 11/32" SBC valve stem OD.

I don't know your boss size, but these are what I would use if the FelPro seals didn't fit your boss and these did. The application is for '93- up LT1/Vortec engines, but that's moot if they fit your boss.

Another that may fit is here, they're intake seals; the exhaust seal p/n is given in the text. You will notice these include the small O-rings. GM used both the small O-rings and these positive seals into the '90s.

I had thought the years given earlier would have given you positive seals and not umbrella style seals. Umbrella seals will work, but there are differing opinions on using them as opposed to a positive type seal. Maybe someone else will have something to add.

[lt1silverhawk]

Thank you Cobalt.


I do have the Felpro intake set you listed, but different a exhaust set from one suggested by Summit. The LT1/Vortec seals do strongly resemble the ones I removed, but I think have a wider inner diameter. The valve stems I measured were about 0.341". I will try to get some precise measurements tomorrow. I don't want to install anything that doesn't fit and end up with a set of seals that can't be returned.


As to the pros and cons of using umbrella seals, I did find two threads on other forums which may be useful for others readers:

- let's talk valve seals - The 1947 - Present Chevrolet & GMC Truck Message Board Network

- http://www.stevesnovasite.com/forums...d.php?t=144488

[lt1silverhawk]

So I measured and remeasured the valve stems as well as the boss guides for cylinder #2.


Intake valve stem: 0.3415"

Intake boss guide: 0.560"


Exhaust valve stem: 0.3415"

Exhaust boss guide: 0.559"




I measured the ID in the Felpros using a caliper, but they seemed a little smaller than the ones removed. I wanted to stop by a Chevy dealership's parts department to see what they've got, but they were all closed today. However, I did find these viton seals on eBay:

- Metal Clad Viton Valve Stem Seals 11/32" x .562" sb Chevy Ford Chrysler sbc | eBay

- VITON VALVE SEALS 11/32 SBC SBF GT40P PONTIAC .520-.565 | eBay

[cobalt327]

The second ones have a more positive sealing area, and might be the better choice for used valve stems. But there can be too much sealing; you want there to be a slight amount of lubrication reaching the valve stem/guides. But in the case of a SBC, the guide is the head itself (cast iron) so there is always "extra" clearance.

Bottom line is I'd expect either to work. The second ones would be a good intake seal, the first ones possibly a better exhaust seal (where you need a bit more lubrication reaching them). If you were only going to get one set, the first ones in conjunction w/the small O-rings, or the second ones w/o O-rings.

[123pugsy]

Hey Hawk.

You probably read it somewhere but I thought I'd throw it out there in case you haven't.

If you don't have an installation sleeve, use scotch tape around the keeper grooves to avoid cutting the seals.

[lt1silverhawk]

Hey cobalt,

Originally Posted by cobalt327

That is a positive type seal, although the valve stems are set up w/the same double grooves (one for the keepers, the other lower groove for the small O-ring type seal) and there is a tin oil deflector, like has has been used since day one, pretty much.

I wanted to run something by. You mentioned that the picture of the valve I posted in post #136 has double grooves. I've taken a look a few times at the images I have as well as the valve stems themselves, but I am only seeing one groove for the keepers, much like the one shown on the right in this image (second one) from another forum by one of our members here: "2 groove valves: post #5. There is another view of both the intake and the exhaust stems in post #139.

Originally Posted by cobalt327

The second ones have a more positive sealing area, and might be the better choice for used valve stems. But there can be too much sealing; you want there to be a slight amount of lubrication reaching the valve stem/guides. But in the case of a SBC, the guide is the head itself (cast iron) so there is always "extra" clearance.

Bottom line is I'd expect either to work. The second ones would be a good intake seal, the first ones possibly a better exhaust seal (where you need a bit more lubrication reaching them). If you were only going to get one set, the first ones in conjunction w/the small O-rings, or the second ones w/o O-rings.

Great! I'll consider ordering both sets. Otherwise I'll do the second set by itself. The reason I am concerned about getting the right set is because I've never replaced these before and do want to eliminate the plug-fouling issues. I definitely follow on the too much sealing, but I am not sure on how " reasonably loose" can a seal be. I imagine using a seal meant for a 0.344" valve stem is ok on a 0.341" valve stem. Any advice on this is greatly appreciated.




Hey Pugsy,

Originally Posted by 123pugsy

Hey Hawk.

You probably read it somewhere but I thought I'd throw it out there in case you haven't.

If you don't have an installation sleeve, use scotch tape around the keeper grooves to avoid cutting the seals.

Actually, one of the sets I bought from Felpro did come with a plastic sleeve. I won't be using that kit at this point, but had not come across the scotch tape method. Thanks!




Thanks!

[cobalt327]

Originally Posted by lt1silverhawk

Hey cobalt,

I wanted to run something by. You mentioned that the picture of the valve I posted in post #136 has double grooves.

Maybe I picked up on the double grooves from the linked-to video? Yours are not double.

There's no choice when it comes to the seal ID, you'll use seals for a 11/32" stem and the wear will be compensated for by the seal having a smaller ID than the valve stem. Go ahead and use the second set, no need to buy two sets.

[lt1silverhawk]

Originally Posted by cobalt327

Go ahead and use the second set, no need to buy two sets.

Thanks, I ordered them a little while ago. Hopefully they'll show up this week and I'll install 'em this weekend.




On a related subject, I was looking up information on rebuilding cylinder heads and came across ac article that mentions PC and Viton seals. Not thing major but thought it was an interesting tid bit.

"Valve-guide seals are another important consideration. While O.E.M. seals do an adequate job, JGM prefers to use Viton rubber seals available through a number of sources including Fel-Pro. These seals are positive seals, meaning that the valve guide must be machined to allow the seals to fit properly over the guide. For more information on Viton seals, refer to “Oil Control” in the October ’93 issue of Hot Rod."


"Hot Rod Magazine: Heads Up! Rebuilding Cylinder Heads The Right Way": Image 14


Read more: Cylinder Head Rebuild - How To - Hot Rod Magazine

[lt1silverhawk]

Hi All,


Just doing a quick check-in and update on the valve stem seals. The viton seals Alex's Parts came in middle around Thursday. They look quite similar to the Fel-pro blue positive stop seals but had a smaller inner diameter (approximately 0.314" vs 0.334). All the new seals can be seen below for comparison.







I first tackled the seals on cylinder #2. I used some scotch tape on the valve stems to protect the seals. Its a bit tricky to make that work because of the oil on seals. But I quickly discovered that, due to the tight inner diameter of the viton seals, the scotch tape was getting stick inside the seal and almost impossible to remove by hand. A gently pull with pliers did the trick.







After I installed the exhaust seal, I tried to install the intake seal but it was the diameter seemed to small for the guide boss. So I moved on to cylinder #4 to see if I would have the same problem and I did. The scotch tape would get stuck inside the seal and it wouldn't seat all the way. So I decided to take a gamble and try the blue Fel-pro seal and, surprisingly, it was even worse. Having already used a seal from the Fel-pro box, I went ahead used the included installation sleeve and it worked like magic. The seals fit flawlessly. I'm gonna have to contact Alex's Parts and recommend they include the installation sleeve with the set.






So, only two cylinders got done. Will get the rest finished this coming weekend.