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411 HP GSXR / 203 HP Vrod
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1,947 Posts
Discussion Starter #1 (Edited)
I have had my Cylinder Head milled two times since I've had it due to excessive heat/warpage over the last year. The first time when my motor had 118K miles and the second time when my new shortblock recently let loose. My question is what is the minimum thickness for safety in terms of the Cylinder Head measurement? Ryan Woon has my shortblock and told me that he had to mill .006 off of it to get it true again and my machine shop just milled .004 off the Cylinder Head. How much was milled off the Cylinder Head the first time I don't know. The Cylinder Head now measures 4.748" from Valve Cover surface to head, then one must calculate that .006 was taken off the Block. Am I in unsafe waters with this? Is there a thicker head gasket that could be used? I'm probably going to just have my installer test the clearances either with clay or by installing weaker springs which would enable him to pust the valve down by hand to test. Here's the real kicker: According to the spreadsheet provided by the Engine Builders Association for the 2JZ-GTE, the stock Cylinder Head Thickness is 4.570. How in the hell can that be when mine has been milled twice and is still thicker? If the new thickness according to spec is 4.570' (116.078mm) and the minimum thickness is 4.560 (115.824mm) then that leaves me with about .010 safety barrier? Oh shit!
 

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Gary,

But isn't the greddy head gasket 88mm Bore and with JE Pistons you'll be at only 86.5mm. right?

So what head gasket will you use?

valT.
 

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411 HP GSXR / 203 HP Vrod
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1,947 Posts
Discussion Starter #4
I believe Ryan Woon told me that Greddy offers the 1.6mm headgasket with the 86.5 bore. He also told me that they are on a nationwide backorder so I'm scrambling trying to get my hands on either the Greddy or HKS headgasket...
 

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411 HP GSXR / 203 HP Vrod
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1,947 Posts
Discussion Starter #5
You're right, the Greddy Headgasket is universal and is good on any cylinder bore up to 88mm. It also has a thickness of 1.6mm and has a price of $296 at MVP Motorsports. It IS INDEED on a nationwide backorder with no time of estimation as to when it will be available. Dusty says that the HKS 1.6mm is about all he has sold for the MKIV with barely ever selling a Greddy HG unless it was for a 300ZX, etc... I ordered a HKS Headgasket from Dusty a minute ago for $309...
 
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