Heads lifting under boost: avoid?
#1
Heads lifting under boost: avoid?
How do you guys running alot of boost (im looking to run 20-25lbs on a six liter iron block) avoid lifting the heads on "stock" LSx blocks (IE not the 6 bolt per cylinder LSx)?
Is it not as common a problem as i think? happen just every so often? ways to combat it?
Thanks
Dom
Is it not as common a problem as i think? happen just every so often? ways to combat it?
Thanks
Dom
#4
LS1Tech Co-Founder
iTrader: (34)
My 7.9:1 346 is an aluminum LS6 casting, and has seen 18-26 psi. I am running a set of GM MLS head gaskets.
I think the key would be to run aftermarket head castings that would offer the best clamping capabilities, and run a safe amount of timing with a given fuel.
I think a vastly more experienced tuner/racer like Mike Brown or Kurt Urban would talk about how a lot of timing can roach head gaskets. I think Mike Brown has push head gaskets past the limit a few times, and knows when it becomes a problem.
I think the key would be to run aftermarket head castings that would offer the best clamping capabilities, and run a safe amount of timing with a given fuel.
I think a vastly more experienced tuner/racer like Mike Brown or Kurt Urban would talk about how a lot of timing can roach head gaskets. I think Mike Brown has push head gaskets past the limit a few times, and knows when it becomes a problem.
#5
Shorty Director
iTrader: (1)
I agree with PSJ. I run GM MLS head gaskets and L19 studs. I have never had a problem with a boat load of nitrous or boost. My nitrous setup had 6.0L heads and my current setup is with AFR's.
Originally Posted by Pro Stock John
My 7.9:1 346 is an aluminum LS6 casting, and has seen 18-26 psi. I am running a set of GM MLS head gaskets.
I think the key would be to run aftermarket head castings that would offer the best clamping capabilities, and run a safe amount of timing with a given fuel.
I think a vastly more experienced tuner/racer like Mike Brown or Kurt Urban would talk about how a lot of timing can roach head gaskets. I think Mike Brown has push head gaskets past the limit a few times, and knows when it becomes a problem.
I think the key would be to run aftermarket head castings that would offer the best clamping capabilities, and run a safe amount of timing with a given fuel.
I think a vastly more experienced tuner/racer like Mike Brown or Kurt Urban would talk about how a lot of timing can roach head gaskets. I think Mike Brown has push head gaskets past the limit a few times, and knows when it becomes a problem.
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#11
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I think the LS1 head "lifting" phenomenon has more to do with detonation under load than with the amount of boost. Although, I'm sure there are some instances of extreme cyl. pressure and even 'cupping' of the head surface between studs.
#12
TECH Senior Member
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I started to push a lil water @ 20 psi with stock castings(317) and 6.oL Iron block with standard ARP head studs on GM MLS gaskets....
Lifted the heads with a lil more boost then that
20 psi was w/ 23 degree's of timing on C16...
O-Ringing the heads and copper gasketing as i type this...
New heads will be an aftermarket casting with a thicker Deck.
Kyle
Lifted the heads with a lil more boost then that
20 psi was w/ 23 degree's of timing on C16...
O-Ringing the heads and copper gasketing as i type this...
New heads will be an aftermarket casting with a thicker Deck.
Kyle
#13
Banned
iTrader: (36)
got a question guys...i understand o ringing the heads but do yall mean the block also? if not how does this keep the water from seeping under the flat surface of the ring to the block? doesnt make sense? are the rings slightly deeper than the groove your putting in the head?
#14
Dumb Ass Vette Moderator
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O-ringing the heads and block helps provide extra cylinder sealing and pressure containment. The o-ringing on the block side consists of a grove machined into the block. The o-ring in the head sits in the block groove. Doing this combo requires a special head gasket.
Mainly people, including myself, only install the o-ring in the head. This only requires a graphite composite gasket to be used. When used with head studs and good tune, it seems to hold quite well.
Keith
Mainly people, including myself, only install the o-ring in the head. This only requires a graphite composite gasket to be used. When used with head studs and good tune, it seems to hold quite well.
Keith
#15
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I haven't been to the track yet but I'm over 20 psi with a F1R, stock LS6 castings-pump gas with 1 can of Torco accelerator and a dual nozzle meth setup. Car has made over 900 rwhp and i'm still on the same head gaskets. Timing is 14 degrees up top. Car hasn't pushed a gasket yet, even with a bunch of lean outs after 5500. Knock tables are completely stock and i have yet to record any knock on my logs. Could it be the way the centri ramps up in boost why it's surviving? Fuel octane is supposed to be at 105 with the Torco and 116 with the meth? My IAT's are 90 degrees at the beggining of the pull and 65 at the end of the pull. If it does spit out a gasket I would like to o-ring the heads but what is the correct procedure and what gaskets to use?
#16
TECH Senior Member
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holding on the track is where it matters. hits on the street or dyno are way easier
i have aftermarket castings, and have conservative timing and conservative octane... i also beat on it hard at the track..
back when i didn't use to do so.. gaskets would last a long long time at higher boost levels and more timing on less octane.
i have aftermarket castings, and have conservative timing and conservative octane... i also beat on it hard at the track..
back when i didn't use to do so.. gaskets would last a long long time at higher boost levels and more timing on less octane.
#17
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Originally Posted by eb02z06
Could it be the way the centri ramps up in boost why it's surviving?
#18
LS1Tech Co-Founder
iTrader: (34)
MMouse, have you had to change hg's since you debuted the new ride?
My car went thru one set of hg's a few years ago, but that was probably due to the lack of proper timing when I first set up my old FAST system.
My car went thru one set of hg's a few years ago, but that was probably due to the lack of proper timing when I first set up my old FAST system.
#20
Originally Posted by NA$TY-TA
I started to push a lil water @ 20 psi with stock castings(317) and 6.oL Iron block with standard ARP head studs on GM MLS gaskets....
Lifted the heads with a lil more boost then that
20 psi was w/ 23 degree's of timing on C16...
O-Ringing the heads and copper gasketing as i type this...
New heads will be an aftermarket casting with a thicker Deck.
Kyle
Lifted the heads with a lil more boost then that
20 psi was w/ 23 degree's of timing on C16...
O-Ringing the heads and copper gasketing as i type this...
New heads will be an aftermarket casting with a thicker Deck.
Kyle
Ill definitely be using copper gaskets and probably just go ahead and o ring the heads, but why a thicker deck?
I was probably going to go with some ported L92 or dart heads to save a bit of cash...