Head Flexing under boost? > Get them "Pinned"
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From: SW Florida
Head Flexing under boost? > Get them "Pinned" [QUOTE From Another Thread]>> "Last time the motor had to be rebuilt, we found the head gaskets didn't blow, and the bolts didn't stretch, but the head actually bent 0.020 in between the bolts. Damn aluminum is pretty but it bends too easy"....
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I wonder if these LS1 heads could be "Pinned"?
I had Champion Heads in FL. "pin" my 89 Turbo Trans Am heads. It envolves drilling 3 holes through the heads and the having tool steel pins pressed in. This keeps the heads from flexing at high boost levels. This work is fairly common in the Turbo Buick community, but I have not heard about it here with the LS1 guys yet.
I would bet this would be the ticket for these LS1 heads too. The head lifting problem can be traced in many instances to actual head flexing.
I see Champion's web page is under constuction, but here is there phone number. If you have any questions about head pinning, I am sure they could answer your questions: (386) 446-4488
<img src="http://www.championracingheads.com/splash.jpg" alt=" - " />
Ron,
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<small>[ November 28, 2002, 11:16 PM: Message edited by: Kimchee and Rice ]</small>
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I wonder if these LS1 heads could be "Pinned"?
I had Champion Heads in FL. "pin" my 89 Turbo Trans Am heads. It envolves drilling 3 holes through the heads and the having tool steel pins pressed in. This keeps the heads from flexing at high boost levels. This work is fairly common in the Turbo Buick community, but I have not heard about it here with the LS1 guys yet.
I would bet this would be the ticket for these LS1 heads too. The head lifting problem can be traced in many instances to actual head flexing.
I see Champion's web page is under constuction, but here is there phone number. If you have any questions about head pinning, I am sure they could answer your questions: (386) 446-4488
<img src="http://www.championracingheads.com/splash.jpg" alt=" - " />
Ron,
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<small>[ November 28, 2002, 11:16 PM: Message edited by: Kimchee and Rice ]</small>
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From: Ft. Walton Beach Florida
Re: Head Flexing under boost? > Get them "Pinned" TTT
Anyone wish to add to this, it sounds like an interesting idea.
<small>[ November 29, 2002, 11:00 PM: Message edited by: Lost & Found2 ]</small>
Anyone wish to add to this, it sounds like an interesting idea.
<small>[ November 29, 2002, 11:00 PM: Message edited by: Lost & Found2 ]</small>
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From: Centrifugal City
Re: Head Flexing under boost? > Get them "Pinned" I guess one thing to define is heads 'lifting' vs. 'flexing' and if they are the same phenomenon and address the same problem.
I think heads that are milled are more prone to have this problem. Stock TQ'd head bolts also. Head studs less so. MLS emboss ringed gaskets less so.
Who has experienced this head lifting on their LS1? How much boost? What type of gasket? Bolts/Studs? TQ procedure/specs? Which heads? Milled?
If you haven't tried high TQ specs on a head stud with stock surfaced heads and a good MLS gasket, that's where I'd begin.
Interesting idea tho!
I think heads that are milled are more prone to have this problem. Stock TQ'd head bolts also. Head studs less so. MLS emboss ringed gaskets less so.
Who has experienced this head lifting on their LS1? How much boost? What type of gasket? Bolts/Studs? TQ procedure/specs? Which heads? Milled?
If you haven't tried high TQ specs on a head stud with stock surfaced heads and a good MLS gasket, that's where I'd begin.
Interesting idea tho!
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From: Chi-Town
Re: Head Flexing under boost? > Get them "Pinned" LOL....talk to Rob Raymer
took him FOREVER to stop blowing head gaskets and lifting the heads
Then he figured out how to combat that problem...then guess what happened?
Figured out how to keep the head from lifting, but then it started warping EVERY OTHER PASS, that gets expensive
I think the problem is in the way GM designed how the head is bolted down
took him FOREVER to stop blowing head gaskets and lifting the heads
Then he figured out how to combat that problem...then guess what happened?
Figured out how to keep the head from lifting, but then it started warping EVERY OTHER PASS, that gets expensive
I think the problem is in the way GM designed how the head is bolted down
Re: Head Flexing under boost? > Get them "Pinned" I wouldn't talk to Rob Raymer at all. I'd talk to Harlan. I don't think he's lifted one head at all! He runs 16PSI of boost right now!
I think those are ported stock heads also. No pinning or anything. Unless that cam of his is keeping things together somehow by letting some of the pressure blow by.
I've run 10PSI of boost (ran it somewhat lean) on 10.5:1 CR and the cylinder seal stayed planted. However the head ended up weeping coolant to the outside. Kind of interesting.
I'll check into the pinning thing as I have some good sources on Turbo Buick engine building. They may be able to shed light on the subject.
I now use the cometic head gaskets and the ARP head studs. Course there's a new motor going in this winter. 406CI Iron block with truck heads which have more meat on the head. Hopefully keep the flexing to a minimum.
I think those are ported stock heads also. No pinning or anything. Unless that cam of his is keeping things together somehow by letting some of the pressure blow by.
I've run 10PSI of boost (ran it somewhat lean) on 10.5:1 CR and the cylinder seal stayed planted. However the head ended up weeping coolant to the outside. Kind of interesting.
I'll check into the pinning thing as I have some good sources on Turbo Buick engine building. They may be able to shed light on the subject.
I now use the cometic head gaskets and the ARP head studs. Course there's a new motor going in this winter. 406CI Iron block with truck heads which have more meat on the head. Hopefully keep the flexing to a minimum.
Re: Head Flexing under boost? > Get them "Pinned" Ok I spoke to my source. He says that many have used the pinning and feel it works. Others feel it doesn't work. His opinion was more on the it doesn't work that well. His opinion on doing it on an LS1 head was that it's never been done before. He'd be concerned about the stability of the aluminum structure while attempting it.
I didn't sign up to be the prototype on that one. It'd be VERY interesting to have someone try it and give results.
I didn't sign up to be the prototype on that one. It'd be VERY interesting to have someone try it and give results.
