Speeedy
Member
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
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