Valve stem seals AND O-rings?
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Car: GTA 89
Engine: 350 TPI
Transmission: TH700
Valve stem seals AND O-rings?
Maybe this question sounds a bit stupid...
I will start to replace the old valve stem seals with new ones:
FELPRO SS 72527 for the intake valves
FELPRO SS 72877 for the exhaust valves
In the seal sets I've found the seals and a set of the O-rings.
Now my question is:
Do I only have to replace the valve stem seals or the valve stem seals AND the O-rings too???
Where do I have to install the O-rings?
I will start to replace the old valve stem seals with new ones:
FELPRO SS 72527 for the intake valves
FELPRO SS 72877 for the exhaust valves
In the seal sets I've found the seals and a set of the O-rings.
Now my question is:
Do I only have to replace the valve stem seals or the valve stem seals AND the O-rings too???
Where do I have to install the O-rings?
#2
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Car: GTA 89
Engine: 350 TPI
Transmission: TH700
By searching Google I found the following:
"The o-ring valve stem seal goes on the SECOND grooved notch of the stem"
I think this answers my question.
"The o-ring valve stem seal goes on the SECOND grooved notch of the stem"
I think this answers my question.
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Car: 83 Z28
Engine: 305 (LG4)
Transmission: THM700R4
Axle/Gears: 10 bolt, 3.23 non-LS
I used the Positive type 72527 for both intake and exhaust. The 72877's are umbrella type and not Positive type. And yes you change both the o-ring and the valve seal.
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Car: 89 Formula Firebird
Engine: 305 - Demon 525
Transmission: 700R4
Originally posted by phess11
I used the Positive type 72527 for both intake and exhaust. The 72877's are umbrella type and not Positive type. And yes you change both the o-ring and the valve seal.
I used the Positive type 72527 for both intake and exhaust. The 72877's are umbrella type and not Positive type. And yes you change both the o-ring and the valve seal.
#7
Re: Valve stem seals AND O-rings?
I know this is an old thread, but I am doing the same job on a 1990 350 TBI. I have SS72527 and SS72877. The SS72527 is the intake positive seal, which came with BIG rubber o rings; SS72877 is the exhaust umbrella seal which came with small square o rings.
The problem is the big o rings that came in SS72527 with the positive seals are loose in the second groove of the stem and they're way to big to install with the spring cap/retainer on and compressed... I don't get it, the exhaust was straight forward. I put on the umbrella, then the spring and retainer, compressed them, installed the little square o ring in the second groove, then the keepers, relaxed the compressor - done. But, the intake side is not working out like that... The o ring is enormous. What the hell? Did they give me the wrong o rings? lol
The problem is the big o rings that came in SS72527 with the positive seals are loose in the second groove of the stem and they're way to big to install with the spring cap/retainer on and compressed... I don't get it, the exhaust was straight forward. I put on the umbrella, then the spring and retainer, compressed them, installed the little square o ring in the second groove, then the keepers, relaxed the compressor - done. But, the intake side is not working out like that... The o ring is enormous. What the hell? Did they give me the wrong o rings? lol
Last edited by 69GTOby; 03-06-2016 at 01:57 PM. Reason: spelling error
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#8
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Re: Valve stem seals AND O-rings?
Forget the o-ring on the intake side. Not needed. Today's positive seals are viton which is miles ahead of the old rubber seals used by the factory back in the 80s. FYI- you can also use them on the exhaust side by themselves if you want (no o-ring), but getting the intake side sealed up tight is 10X more important than the exhaust side. Some engines (endurance/road race applications) I don't even put a seal on the exhaust. I figure the exhaust valve is getting the snot beat out of it for hours on end it can use as much lubrication as it can get to keep the guides alive.
#9
Re: Valve stem seals AND O-rings?
I omitted the o ring on the intakes like you said. I did put the proper-looking squared o rings on the exhaust since they came with the exhaust umbrellas anyway. Honestly, I am not sure I got them all in correctly in the groove, but I am not too worried about it. It turns out it didn't have any seal besides old rotten o rings on the exhaust, so it should be much better off with the umbrellas on there at least.
I used compressed air to hold the valves shut. I heard air escaping and the compressor would keep turning on for all the cylinders. Then I got to the last cylinder and it was so bad it wouldn't even hold the valves up. All the air was escaping out the intake port. My heart sank. I thought I had a bad valve. But, it ran so well... I put a piece of wood atop the valve and hit it with a hammer several times. Then it sealed, much better anyway. I don't know if it was carbon or gasket pieces holding it open or what...
I used compressed air to hold the valves shut. I heard air escaping and the compressor would keep turning on for all the cylinders. Then I got to the last cylinder and it was so bad it wouldn't even hold the valves up. All the air was escaping out the intake port. My heart sank. I thought I had a bad valve. But, it ran so well... I put a piece of wood atop the valve and hit it with a hammer several times. Then it sealed, much better anyway. I don't know if it was carbon or gasket pieces holding it open or what...
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