A1 Studs, Headlift Fix and still lifted - heres why- please read

So last week I was trying to get some final numbers on my e16G kit and I got up to 595 awhp on 100 octane at 24psi and started to see some coolant push, so obviously it was time to call it a night. Head gasket was not compromised.

I have A1 Technology heads, and Ray's headlift fix on DR Stage 3 heads.

I pulled the motor apart the other night with the help from one of my engine builder buddies, and we figured out the problem. The washers that A1 comes with are smaller than stock in Diameter, so they had dug into the head slightly leaving an indentation. He had just been down this road with a Supra build and this is a common problem with them and ARP head studs. We are thinking the aluminum had yielded due to the washers digging in. Every single stud was different torque after the lift.

I had religiously followed the torque sequence provided by A1 using their moly lube, and retorqued them after head cycling on it. So torque was certainly to spec and had been checked since.


We think we need to go back to the stock size head washers so it spreads the load out. 105ft lbs may be acceptable, but do we really need to go to 125 with 30 weight?

I am not necessarily blaming the a1 washers on this, because I had ARP's in the past so its likely their washers were also the cause and I had overlooked the indentions into the head, but the A1 washers are still smaller than stock.

I don't think this is a problem that will present itself until 600 and up HP. I CANT be the only one to see this. And ironically their problems start at around 600hp.

See the Supra thread here- http://www.supraforums.com/forum/sho...-Washer-debate

Just a heads up for those who have A1's or ARP's and going for big power, check your washers! Were not helping our matters by defeating the benefit of stronger studs on a smaller surface area.

Edited- A1 Washers are fine, I did compare to stock washers same diameter, im thinking the old ARP kit from years back did this. I will post pics of the double indent from the washers Monday when I go by the machine shop.

put inserts in head. read on the 7m supra guys. their heads are soft and this was the fix. dsms are starting to do it also. especially if 1/2" studs are used.

We think a wider washer is just as good. The fact is the smaller washer caused issues, and no issues with wider washers in the Supra. I agree maybe im at the point where its yielded and now no matter what is going to lift even with bigger washers and need an insert put in which your not the first person to say that. But as we speak im having a machine shop mill off a tiny bit to make the seating surface flat again, I will talk to them about doing an insert for added safety though since your the 2nd person to mention that. Stronger cant hurt

Im surprised this has not been mentioned before, with so many people running ARP's, it CANT be only me. Im sure as usual, its been a problem with others, never really discussed or addressed.

Good info, and good catch!

-John

Do you happen to know any other factors that could be related to the peak cylinder pressure? Timing advance at peak torque? EGT's?

Can you also measure the washers so I can estimate the cylinder pressure to exceed compressive yield? Do you also know the depth of the indentation? You might also find that the bolt hole inside diameter on the cylinder head has reduced from the yielding.

Ewan

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You say 600hp and up... but wouldn't it be based off cylinder pressures? That force is what is pushing the head off... and horsepower is not directly related to that.

Also, I have the headlift fix and STOCK headbolts/washers. I wonder what cylinder pressure I should be good up to? I also have 2 68HTA's ready and waiting to go on...

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Originally Posted by chooch

Do you happen to know any other factors that could be related to the peak cylinder pressure? Timing advance at peak torque? EGT's?

Can you also measure the washers so I can estimate the cylinder pressure to exceed compressive yield? Do you also know the depth of the indentation? You might also find that the bolt hole inside diameter on the cylinder head has reduced from the yielding.

Ewan

Sent from my SM-J500FN using Tapatalk

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Timing was not too crazy..18-19 degrees it was about all the 100 octane would take though
i do agree the pressures were prob high, we backed it down a degree or too for safety. The inner side of the holes are mushroomed a little too. I will measure them tonight

Most people dont lift until 700 ish..

ARP's are known to be a waste of money. Stock is worlds better. That's ancient knowledge.

I lifted the heads around 600. Switched to A1 (I convinced them to make the 1st set), and o-ringed the heads. Never had another problem clear into the 8xxawhp/7xxawtq range. However, as the dirty Kentuckian said, power isn't the real factor here, it's cylinder pressure. I wouldn't be scared to recreate my build with stock bolts.

Jeremy