Stronger / bigger head and main studs than ARP

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Speeedy

Member
Messages
207
Location
Oldenburg, Germany
Hey guys!

Some of you know my 1UZ twin turbo Supra MK3 build a few years ago.
Now I'm searching for some stronger head studs.
But a little story advanced...

I upgraded the mains with ARP studs and the head studs was 10mm ARP in the first build, too.
After a head gasket problem (Cometic MLS) I decided to upgrade to 12mm ARP head studs for a Ford Pinto and used a modified Cometic MLS HG with Garlock O-rings. Cometic sold these type of gaskets called "Phuzion" for some engines like SR20DET etc.
I thought it should be bullet proof now.
The engine runs good with no issues and I turned up the boost to 1,8bar with two GT2871R turbos where the engine makes about 840 hp at the crank and about 1100Nm of torque.
I'm driving around this setup for a while.
But after a WOT half mile run I had a head gasket problem again. It could be, that the tune was to close to the limit and the engine was knocking a little bit. The head gasket failed on both sides and four or five cylinders had a leakage. Maybe the head gasket "Phuzion" style is bad or the heads lifted or both? Who knows it exactly...

I think about it for a while and came to the point, that the 12mm head studs should be strong enough, but after talking to ARP they told me that these 12mm studs for the Ford Pinto are from 8740 material only.
I asked ARP for some similar studs from ARP2000 material or better, but there are no available. When talking to ARP they asked for the block material and they told me, that these Ford Pinto studs are made for a steel block and have 1 inch of thread on the block side only. But if they used in an aluminum block thread length should be twice this and should be about 2 inches or more. If I'm right, the 10mm ARP head studs for the 1UZ have 1" of thread on the block side too. So thread length is too short too.

So if using 10mm or 12mm studs, thread length is critical. That's logical.
You can use a very strong stud (10 or 12mm maybe L19 material) but if the thread on the block side is not long enough, it can't hold the heads down when pushing up cylinder pressure.
The biggest possible washer should be used too.

Maybe I'm wrong but I'm looking around for some other studs. I don't want to build the engine with these studs again because I want to upgrade the turbos and looking for 1000-1200 HP.

Here in Germany there is a manufacturer (Pro-Series) building head, main and other studs and bolts which should be stronger than ARP CA625+ material.
Here is a link to the shop selling the products

https://www.tuningteile.de/toyota-supra-mk4-2jz-gte-pro-series-18-8-zylinderkopf-stehbolzen-set

Or

http://pro-series.gmbh

I'm in contact with them, asking for head studs (10 and 12mm) and main studs too.
All these studs with maximum thread length for the 1UZ aluminum block. I'm waiting for prices now.

Is there somebody else having head gasket problems and looking for stronger studs (especially head studs)?
If they make a lot more sets a time the price will drop.

Please give me a feedback, comments or something else...

Thanks
Alex
 
Hey Speeedy, it's great to see you here again, and that's good news about your 1UZ monster Supra!

I think you may have the honor of having the highest HP, street driven 1UZ. I'll bet it's a LOT of fun.

I've had problems with the heads lifting on my 1UZ's and others have too, so perhaps you've found a good solution with these stronger head studs. I was going to try the Phuzion head gaskets as well, but I think Cometic have discontinued them now?

At any rate, if you're looking for another buyer for a set of head studs, I'm in with you.
 
Hey John!

Nice to hear from you!

Yes you are right, this monster is so much fun to drive. I had a smile on my face every time I pushed the throttle down. Hahaaaa.
And I'm very sad the HG failed again. I hope we are on the right way to make some big numbers with other head studs now.

Do you want 10 or 12mm studs, John?
I need M12x1.75 for my machined block.
I think M12x1.50 or M12x1.25 would be a bit better but the Ford Pinto studs have M12x1.75 on the block side.

I would like to test Fel-Pro MLS HG instead of the Cometic too
Any experience with Fel-Pro?

Alex
 
I ran 21.5psi and had a head lift due to detonation.

The second time around it ran well and didn't give any trouble and 6 years later is, to my knowledge, still running.
 
I was talking to a 1uz drag car engine builder over here. Around 1400hp from memory. Stock steel head gaskets on 24psi. Didn't discuss head studs sorry.

It would be very interesting which fasteners he use in this race engines.
Maybe he used some ARP L19 custom studs. And 1400 HP from 24 PSI on a 4 liter engine is awesome. Respect to his head work.
Cam specs, head porting, intake Turbos etc would be interesting too.
 
I ran 21.5psi and had a head lift due to detonation.

The second time around it ran well and didn't give any trouble and 6 years later is, to my knowledge, still running.


My first HG failure was at 21.75Psi (1.5 bar) too with 10mm ARP studs.

In my opinion these 10mm ARP studs are okay for a safe tune and conservative boost level.
But it's on a knife edge build. A little bit too much cylinder pressure, and the heads are lifting and burned HG are the result.
Look at some other awesome engines like the JZ family. With ARP2000 head studs there is a lot more room for misstuning or some detonation peaks before it comes to a HG failure. They use 11mm studs in an iron block.

My goal is to have a bit more safety in my build. That's why I'm looking for some different parts, optimized for our aluminum UZ engines.
 
Hey,

Has anyone come with any solutions here? I am trying to search a solution for a 1200hp street car build now. I am trying to get some studs with the same pitch as standard in L19 and 11mm instead of 10mm so they can easily be drilled out.
 


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