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2JZ-S14A

Blew 2 Headgaskets in 2 weeks

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So a year ago my sr20 gave up and so i went ahead and rebuilt it. Forged bottom end gt3076r cometic headgasket etc. It made 240kw at 20psi and i was happy with that up until a few months ago. Took it back to a shop and had a set of poncams and type a springs put in. Was warned that the engine rebuilder reused the factory head studs.. went back to the dyno and made 292kw at 22psi when the head lifted. Engine got pulled apart and checked. Machined head new tomei head gasket and arp 2000 head studs fitted. 1 week later its back for another tune. 2nd run in it starts to miss and a few drops of water in cylinder 3.....

 

Is my block warped or what?

Edited by 2JZ-S14A

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check for fucked head gasket first. pull head off, check for warping, and check block as well...

 

should be able to determine whats going on prety easily with the head off

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check for fucked head gasket first. pull head off, check for warping, and check block as well...

 

should be able to determine whats going on prety easily with the head off

 

The head was off and a brand new headgasket fitted a week ago.

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Was the head skimmed and pressure tested?

 

I always do this when removing a head especially if it lifted

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Was the head skimmed and pressure tested?

 

I always do this when removing a head especially if it lifted

 

The following was done. Even replaced valve stem seals.

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Fair enough bud

 

I bought a 2nd hand SR22, full Brian Crower stroker. Fitted it and it was white smoking really bad. Immediately ripped the head off and got it skimmed pressure tested and new Tomei gasket. Put it all back together and started it the day before mapping and it was still the same!

 

Had to tear it back down and fully rebuild the motor as the cylinder liner was split on number 1, hopefully this isn't the case for you but its worth checking if you end up taking the head back off

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Either way the head has to come back off to replace the gasket. We went over it prior and it checked out. We will check it again when the head comes off next week.

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Either the install wasn't done correctly or you need to deck the block

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Overheating SR blocks softens the metal. A simple way to test is a ball bearing in a plastic tube. Drop the ball bearing and see if it bounces the same height at all parts of the block. If it doesn't bounce on one part - it's soft. If you put a straight edge on the block, if you can see light under it, it's warped.

 

And yes, pretty easy to warp them.

 

Noone cares, it's probably why a lot of built motors fail. A mate went through four donor engines in order to find a good block and a good head that my machinist was happy to touch.

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What would you say is a good water temp to keep around to prevent issues.

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The fact that the original engine builder used the old factory torque-to-yield head bolts speaks volume for their competence, or lack thereof. The moment you were told that the engine was running used head studs, you should have replaced them before making another power run; it's no surprise that the head lifted the first time.

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Overheating SR blocks softens the metal. A simple way to test is a ball bearing in a plastic tube. Drop the ball bearing and see if it bounces the same height at all parts of the block. If it doesn't bounce on one part - it's soft. If you put a straight edge on the block, if you can see light under it, it's warped.

 

And yes, pretty easy to warp them.

 

Noone cares, it's probably why a lot of built motors fail. A mate went through four donor engines in order to find a good block and a good head that my machinist was happy to touch.

 

 

 

I will try this. The engine has never overheated in its life.

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The fact that the original engine builder used the old factory torque-to-yield head bolts speaks volume for their competence, or lack thereof. The moment you were told that the engine was running used head studs, you should have replaced them before making another power run; it's no surprise that the head lifted the first time.

 

You're right and i learnt the hard way. I now deal with one of the best workshops around. Im just gathering information because he wants to pull the motor out, get the block decked and install a girdle. All up around $4000

Edited by 2JZ-S14A

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Either the install wasn't done correctly or you need to deck the block

 

We are pulling the head off again on monday and will check to see where the headgasket failed. Then we will thoroughly go over the block again and have it decked if need be...

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The fact that the original engine builder used the old factory torque-to-yield head bolts speaks volume for their competence, or lack thereof. The moment you were told that the engine was running used head studs, you should have replaced them before making another power run; it's no surprise that the head lifted the first time.

 

You're right and i learnt the hard way. I now deal with one of the best workshops around. Im just gathering information because he wants to pull the motor out, get the block decked and install a girdle. All up around $4000

 

If you're installing ARP main studs to go with the girdle, be sure to have the bearings line-honed, as the studs will make bearing channel go slightly oval. A good shop will know to do that, but it doesn't hurt to mention it to the customer. That was the reason I sold my ARP main studs and changed to OEM TTY bolts when I rebuilt my SR, as I cbf dealing with the extra machining for an overkill upgrade.

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So the last gasket to blow was a tomei 87x1.2

 

Ive got 87mm pistons. Shouldn't i use an 88x1.2 gasket?

 

Could that have caused the leak?

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Gasket should be .5 to 1mm bigger than poiston/bore size.

 

Look at the blown gasket and see if you can work out where the leak occured. Is the fire ring marked?

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Gasket should be .5 to 1mm bigger than poiston/bore size.

 

Look at the blown gasket and see if you can work out where the leak occured. Is the fire ring marked?

 

Il find out on monday when we pull the head off. Im guessing the tiny section between the water jacket between cylinders 3 and 4 gave up.

Edited by 2JZ-S14A

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or maybe there was so much timing in the motor the cylinder pressure was through the roof and lifted the head enough to destroy the head gasket

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