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head bolt TQ....

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factory is....43? 45? 47? one of those. (ft-lbs that is)

 

when i put my 9.5:1 engine together...it lasted 24k miles and I TQ'd it down to like 60 or so....it burned a valve and destroyed the rings. the HG's were PERFECT...and OE at that.

 

the last engine in the wagon was NAPA HGs...lasted 17k miles, also TQ'd at ~60.

 

The other wagon engine got ~60 as well, and OE HG's....but something internally let go...only 2k miles on it at that point. :-\

 

This RX engine....factory specs to the letter/number. ~20k miles on it...

 

 

So....Im thinking Im going to TQ the heads down somewheres between 65~75.

 

 

What do you other experts think? I'll be using OE again, as the Cometics are not ready, CU wont be ready in time...and unless I oring, the CU's are worthless...I had and extended talk with Tom at TWE today as well.

why do you say that coppers are useless?? why are they any worse than the Cometics??

 

either way you need to have the block and heads machined....

 

explain?

  • Author

the cometics wont be READY in time for this weekend. They are multi-layer metal gaskets much like the newer style EJ HGs. They are the BEST ones to use.

 

Tom and I talked about Copper...he said on closed deck engines, they are fine to use as long as you are not going crazy with combustion chamber presures. Open deck and semi closed are a no no...as you still get some minor deck walk...and CU HGs dont like that. Also, they dont like to seal....you need to be careful with a proper sealant for the coolant. I too have realized this when I had CU HGs for a while.

 

So we came to the general consensus that the CUHG's are not for me....the OE's would be ok for now, and the Cometics would be best.

 

 

the only ones that are junk are the ones that are NOT OE...good ones=OE and beyond.

 

When i do build an engine, I'll have studs and a completely reworked block and heads.

I believe I did mine to 55 when I put my engine together, with no retorque. Been doing great for about 10k so far (it's an n/a motor so might not be a fair comparison). I do think I would have witnessed any problems that overtorquing would cause by now, such as distorting the block or pulling threads out, which hasn't happened.

so when the cometics gonna be ready??

 

i think we'd prolly buy 3 sets....atleast.

 

i'm either going with Coppers, or Cometics for the rally car...just saving some dough for it.

  • Author

thats a good question....whenever Tom gets around to needing them for his twin turbo 25 PSI EA engine...

the cometics wont be READY in time for this weekend. They are multi-layer metal gaskets much like the newer style EJ HGs. They are the BEST ones to use.

 

Tom and I talked about Copper...he said on closed deck engines, they are fine to use as long as you are not going crazy with combustion chamber presures. Open deck and semi closed are a no no...as you still get some minor deck walk...and CU HGs dont like that. Also, they dont like to seal....you need to be careful with a proper sealant for the coolant. I too have realized this when I had CU HGs for a while.

 

So we came to the general consensus that the CUHG's are not for me....the OE's would be ok for now, and the Cometics would be best.

 

 

the only ones that are junk are the ones that are NOT OE...good ones=OE and beyond.

 

When i do build an engine, I'll have studs and a completely reworked block and heads.

Gee, it seems that for all the reasons that you are saying copper gaskets are bad are the reasons why you should use copper gaskets. With copper being a softer metal, it tends to mold itself to any imperfection in the head. Sealing is the whole reason to go with copper, because of it's softness. There is another plus, they are reuseable, but the trick there is that you have to anneal them before you re-use them, and that is easy to do. One of the major causes of head gasket failure on Subarus is that after the engine is rebuilt, people don't go back and retorque that heads after about 500 miles. With copper head gaskets, you wouldn't have to do that (but you should just to be safe).

i was thinking of using coppers. for the rally car...

 

but ofcourse sending the block and heads out to be machined perfectly flat, with a good surface finish. using cometic specs....they ask for perfectly flat, and specify a surface finish.

 

That an coppers are cheap...they were telling me like 75 bucks USD for the pair...that's cheaper than OE subaru ones

  • Author

putting CU and Cometics aside...

 

what should I TQ the heads down to?

i say torque the heades down to factory spec, and re-torque them, thats what ive been told to do with alum. block/head motors. remember, even though the heads and block are both aluminum, doesnt meen that they will expand and contract at the same time, no two pieces of aluminum are the same. hope this helps.

 

 

 

 

~Josh~

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