1JZGTE Stock headgasket...how much boost?

[MR 1JZ]

Im in a bit of a pickle of a situation at the moment...I have been waiting for nearly 2 months for my cometic 1.6mm metal headgasket to arrive and its really the last thing that I need to finish my motor to get the car running again with the new turbo, and I really cant afford to wait any longer, the head has been fully rebuilt and faced with new valve stem seals as well, I have been offered a brand new stock headgasket from a mate of mine which is also a 3 layer metal as thats what the 1J's came with stock, im going to be running a T04E Ball bearing turbo charger and im curious as too how much boost im going to be able to run through the stock hg, essentially my quesiton is: Do I need to wait for the cometic 1.6mm if I want to run around 24 pounds of boost or will the stock item suffice?

Cheers

Matt

[lumpy]

There was a jza70 supra in zoom a number of years ago running 30 pounds of boost for drag runs from a big single (and clocking in the 10s). Apparently the head had never been off - although it had 272 cams, aftermarket ecu etc etc.

I guess there's only 1 way to find out, but with all the big Hp 1jz running around I'd be surprised if 24 pound would be a problem.

Will your newly faced head be compatible with the stock 1jz HG material?

How long will you be satisfied with 24lbs??

[MR 1JZ]

good points lumpy but the thing that worries me is, most of the big HP 1JZ's are being used for drag racing and while its still a harsh sport on a motor vehicle they dont have to sustain 30 laps of constant caning each outing...but then again I am more than confident with my cooling system so I suppose it should be ok

they only took 4 thou off the head as it was barely warped at all, so im confident it shouldnt have an issue bonding as the new gasket I am going for is still a metal jobbie like the 1J item

cheers for the help anyway

[jeffro ra28]

yer but the surface finish of ur head has a big deal to do with sealing for ur HG.

Generallly when i surface a head or block at work, the engines that will use a copper HG have a very fine surface finish on the block and head, the composite gasket need a courser finish on the block and head.

Wat did the guys surface ur head for? a Copper gasket or composite?

[BlackSupra]

Factory HG is metal anyway.

[MR 1JZ]

just rang the machine shop then and their comment was "becuase its an alloy head it will suit either just fine"

they seem to think 25 psi through the stock gasket might be a bit much tho...

[BlackSupra]

Hypo77 358rwkw @ 1.58 bar
1JZ 747 334rwkw @ 1.51bar

Read into that what you like.

[MR 1JZ]

stock one looks the go then

[jeffro ra28]

just rang the machine shop then and their comment was "becuase its an alloy head it will suit either just fine"

Seems a bit sus to me. Surface finish is still important no-matter wat head type.

Wats the exact composition of the stock HG if its no trouble to find out?

[MR 1JZ]

Seems a bit sus to me. Surface finish is still important no-matter wat head type.

Wats the exact composition of the stock HG if its no trouble to find out?

Steel, I thought it was that and then dong boy confirmed this...

[jeffro ra28]

I have been offered a brand new stock headgasket from a mate of mine which is also a 3 layer metal as thats what the 1J's came with stock,
Cheers

hmm kewl didnt know 1jz's came stock with one