NA-T Build Head Gasket Options

[86.5ny]

[skip to the last 2 paragraphs if you do not feel like reading :icon_bigg]

I am currently moving piece by piece to try to lower the amount spent on absolute necessity parts for my conversion. My top end spending cap is at ~$2,000 and at the moment, I am at ~$1,491 using local supra friends as well as Driftmotion/Toyota/Summitracing for other parts. This total is not including aftermarket intercooler/piping, full flow oil system, CT-26 rebuild kit, and LC-1 + gauge. This price total does include all stock parts needed, BIC DDP, HKS Turbo cat-back, Warlboro 255 inline, ARP studs, HKS MHG, boost gauge and controller.

As said I'm looking to shave some cash off my current total and was wondering if I can safely substitute HKS MHG w/ Toyota HG and ARP studs w/ Toyota bolts torqued to spec. This would save me close to $200 at the cost of having a non-metal head gasket and not having the most reliable seal on an boosted N/A block.

Now, I plan on running a stock CT-26 w/ 8-10psi attaining roughly (280-300hp)hp/(280-310ft-lb)tq. The block is a newer JDM Cressida 7M-GE, which I replaced all seals, gaskets and o-rings approx 2 years ago when I bought it. I used a OEM Toyota Head Gasket and OEM Toyota bolts at the time and have put approx 10,000 miles on the motor. I ran compression tests on all cylinders this morning and all numbers were on target with TSRM specs. The motor does not leak or burn any fluids and does not make any noises besides vrmmm vrmmm :naughty:. It pulls as strong as an N/A possibly could.

I do not plan on cranking power up in the near future (1-1 1/2 years) and at that point I will use a MHG if I do not use one now. But for now, will it be safe enough to run a OEM Toyota HG torqued properly on: 9.1:1 N/A running ~10psi boost attaining in the range of 280-305 hp/tq? Thanks Folks.

 

[shaeff]

Absolutely. Headgasket failure that's NOT due to the crap stock torque specs can usually be attributed to user error. Overheating will kill it, (even a MHG) and a bad tune will kill it quickly. If you tune the car properly, a stock headgasket will be perfectly fine for the 300rwhp range.

With the higher static CR, it wouldn't be a bad idea to at least try to get a more efficient intercooler, though. Keep the detonation threshold that much further away with cooler air.

 

[IJ.]

All it takes is one bad rattle/detonation to destroy the composite HG so personally with the higher comp inadequate engine controls (assuming some sort of piggyback) I'd go for a 2mm Cometic installed correctly.

 

[ValgeKotkas]

Ajusa semi-metal?

 

[shaeff]

He's not having the block machined, which is why I suggested staying with the composite. If he were pulling the motor and rebuilding, I'd recommend a Cometic.

For what it's worth, make the decision when you pull the head. My block was very, very smooth and true, so I opted to try a Cometic with stripped Viton coating, and re-coated it in Permatex Brake Quiet. Block was stock JDM imported, head had work and machining done. Do I recommend doing it that way? No. Did it work for me even with a wicked overboost situation (faulty EBC solenoid), absolutely. Still had great compression #'s before I pulled it for a full restoration of the car.