Valve Seals
Valve Seals 2001 LS1 application.
I've read about two different GM/OEM Valve Stem Seals that are available.
"1st Design" & "2nd Design."
Both the Intake & Exhaust sides have both part numbers.
Intake: 12533586 (1st) & 12482063 (2nd)
Exhaust: 12457652 (1st) & 12482062 (2nd)
Doing a cam/header/convertor swap one of these days & am in process of gathering the parts necessary.
1) Does anyone have any details on what would be the preferred for the application noted above?
2) Should I NOT use the stock GM Valve Stem Seals with the 918 Springs? (The GM seals have this 'shim seat design', whereas the aftermarket type do not. Would using the stock GM type with the shim seat design create coil bind on the 918's? Yes, I already have the 918's, TiRetainers, & Locks.)
I've read about two different GM/OEM Valve Stem Seals that are available.
"1st Design" & "2nd Design."
Both the Intake & Exhaust sides have both part numbers.
Intake: 12533586 (1st) & 12482063 (2nd)
Exhaust: 12457652 (1st) & 12482062 (2nd)
Doing a cam/header/convertor swap one of these days & am in process of gathering the parts necessary.
1) Does anyone have any details on what would be the preferred for the application noted above?
2) Should I NOT use the stock GM Valve Stem Seals with the 918 Springs? (The GM seals have this 'shim seat design', whereas the aftermarket type do not. Would using the stock GM type with the shim seat design create coil bind on the 918's? Yes, I already have the 918's, TiRetainers, & Locks.)
Last edited by PontiacFan; Dec 13, 2009 at 10:20 AM.
Joined: Nov 2001
Posts: 3,043
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From: Texas and Qatar
Both designs require a spring seat, the older seal-only design uses a separate spring seat while the newer design is the integral seat/seal combo. Your 2001 probably has the newer design.
For 918's, which is a beehive design like the stock springs, use the later design as that is what is in the car. With duals, which require a new special spring seat, you have to go to the older design.
So why does the stock GM seal have the seats built into the 2nd design, yet the Comp Cams design shown above does not?
Will I be okay using the OE/GM 2nd design with the spring seats, when using the 918 springs?
Why would Comp Cams make the seals without the seats?
Or if someone were to use the Comp Cams design seals, would you have to purchase spring seats seperately?
Will I be okay using the OE/GM 2nd design with the spring seats, when using the 918 springs?
Why would Comp Cams make the seals without the seats?
Or if someone were to use the Comp Cams design seals, would you have to purchase spring seats seperately?
So why does the stock GM seal have the seats built into the 2nd design, yet the Comp Cams design shown above does not?
Likely an assembly/cost savings move. Also, these will not come off the guide and I have had the others pop off the guide and move with the valve.
Will I be okay using the OE/GM 2nd design with the spring seats, when using the 918 springs?
Yes. GM and the Comps are both beehive designs. If you shim with these seals then the shims go on top of the seal not under it. See photo below.
Why would Comp Cams make the seals without the seats?
Likely because their seal fits many motors including non-GM.
Or if someone were to use the Comp Cams design seals, would you have to purchase spring seats seperately?
Yes, you would need seats. You cannot place the spring directly against the aluminum head or you will destroy the head very quickly.
Likely an assembly/cost savings move. Also, these will not come off the guide and I have had the others pop off the guide and move with the valve.
Will I be okay using the OE/GM 2nd design with the spring seats, when using the 918 springs?
Yes. GM and the Comps are both beehive designs. If you shim with these seals then the shims go on top of the seal not under it. See photo below.
Why would Comp Cams make the seals without the seats?
Likely because their seal fits many motors including non-GM.
Or if someone were to use the Comp Cams design seals, would you have to purchase spring seats seperately?
Yes, you would need seats. You cannot place the spring directly against the aluminum head or you will destroy the head very quickly.
