Head gasket (copper head gasket, who has done it?)
05-19-2002, 02:11 AM
#1
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Head gasket (copper head gasket, who has done it?)
As to the copper head gaskets ive heard about now and then, who sells them? how much? is it better than the widefire headgasket or the same? which one lasts longer and holds more boost? assuming a smooth head surface and good head studs, thanks for any info
05-19-2002, 05:49 AM
#2
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Copper headgaskets are available from numerous sources. If you don't know them, then you don't need a copper headgasket, or it would not be in your best interest.
I've used them on motorcycles and previous hot-rod Celicas and Supra. They require a precision fit between the head and block as well as a special gasket sealant/adhesive. When installed and used properly, they can easily withstand heat & pressure 10x better than a widefire headgasket.
HOWEVER.... going back to my original assertion... if you are blowing headgaskets with the standard or widefire headgasket, using a copper headgasket will only make matters worse. IMO, copper headgaskets should only be used for high-boost (30psi+) applications where incredible combusion pressure lifts your head and/or blows your headgasket apart.
HOWEVER, all of the headgasket failures I've seen on 951s are due to being burnt by the intense heat of knock/detonation caused by improper air-fuel ratios and ignition timing. Combustion pressures are well within the capabilities of the widefire headgasket. If you use a copper headgasket in hopes of preventing a burned widefire headgasket, you're just masking the problem and shifting the burden elsewhere, such as the pistons and rods:
I would only go to a copper headgasket once you've done enough dyno-testing to confirm that your air-fuel ratio is flat at 12.5:1 across the board and that your ignition is spot on. And only if you can confirm that it is only combustion pressure that is actually blowing your headgasket (instead of burning it), then... it would be a good time for a copper headgasket.
For the price of a head-rebuild seal kit ($200, headgasket and all top-end seals), blowing the headgasket is relatively cheap insurance compared to the cost of melted piston and valves, bent con-rods, warped heads & blocks, etc...
I've used them on motorcycles and previous hot-rod Celicas and Supra. They require a precision fit between the head and block as well as a special gasket sealant/adhesive. When installed and used properly, they can easily withstand heat & pressure 10x better than a widefire headgasket.
HOWEVER.... going back to my original assertion... if you are blowing headgaskets with the standard or widefire headgasket, using a copper headgasket will only make matters worse. IMO, copper headgaskets should only be used for high-boost (30psi+) applications where incredible combusion pressure lifts your head and/or blows your headgasket apart.
HOWEVER, all of the headgasket failures I've seen on 951s are due to being burnt by the intense heat of knock/detonation caused by improper air-fuel ratios and ignition timing. Combustion pressures are well within the capabilities of the widefire headgasket. If you use a copper headgasket in hopes of preventing a burned widefire headgasket, you're just masking the problem and shifting the burden elsewhere, such as the pistons and rods:
I would only go to a copper headgasket once you've done enough dyno-testing to confirm that your air-fuel ratio is flat at 12.5:1 across the board and that your ignition is spot on. And only if you can confirm that it is only combustion pressure that is actually blowing your headgasket (instead of burning it), then... it would be a good time for a copper headgasket.
For the price of a head-rebuild seal kit ($200, headgasket and all top-end seals), blowing the headgasket is relatively cheap insurance compared to the cost of melted piston and valves, bent con-rods, warped heads & blocks, etc...
05-19-2002, 08:03 AM
#3
Hey Danno,
That brings me to a question I've been wondering. As you may or may not remember, I'm still using APE Stg2.7 chips in my car. My a/f ratios are perfect, and have been dialled in using a combo of bigger injectors, afpr, and the ARC2. I've never checked my ignition curves though, and I have no idea if they are appropriate for me running 16-18psi of boost. I do recall you mentioning once that the APE chips had ignition maps that are very conservative, and were designed for much higher levels of boost than the APE system (banjo bolt) provides. I also asked Mike at Lindsey Racing about this awhile back, and he said the chips would work fine, as long as I was controlling fuel properly. Even the guy at APE told me the ignition maps on those chips are "probably pretty close" to where I want to be.
So my question is, how does one check this out? Put the car back on the dyno, and have someone read an advance timing light while I'm accelerating away? Any easier ways, or should I just take everyone's word for it and leave well enough alone? Thanks!!
That brings me to a question I've been wondering. As you may or may not remember, I'm still using APE Stg2.7 chips in my car. My a/f ratios are perfect, and have been dialled in using a combo of bigger injectors, afpr, and the ARC2. I've never checked my ignition curves though, and I have no idea if they are appropriate for me running 16-18psi of boost. I do recall you mentioning once that the APE chips had ignition maps that are very conservative, and were designed for much higher levels of boost than the APE system (banjo bolt) provides. I also asked Mike at Lindsey Racing about this awhile back, and he said the chips would work fine, as long as I was controlling fuel properly. Even the guy at APE told me the ignition maps on those chips are "probably pretty close" to where I want to be.
So my question is, how does one check this out? Put the car back on the dyno, and have someone read an advance timing light while I'm accelerating away? Any easier ways, or should I just take everyone's word for it and leave well enough alone? Thanks!!
