new 7m installed, having problems with head gasket.

[lukebaumstark]

hey guys ive been searching around and i still cant find the answers im looking for.

i replaced a hg on my 7m with an hks 1.2mm with arps and all that.
it leaked. i had everything prepped properly and torqued right.

im going with a felpro oem replacement gasket and arp studs.


can you guys please help me out with the following questions.

1. does the gasket need a sealer (last time i used copper spray and all it did was clog the cooling ports on the head, also ive heard the flepro gaskets do not need a sealer)

2. with the arp studs and a OEM gasket, what should they be torqued to ( the stud and the nut itself)

3. do the studs NEED moly lube? and why?

4. is there anything else i should be aware of while im doing this?

thank you all in advance for your help.

-luke

 

[nerfkhat]

Usually you only spray copper stuff when you are reusing a hg(usually a metal hg).

Torque specs are diff if you use moly lube or oil. Moly lube is at 82lbs and if you use oil its 102lbs.

The only thing I would suggest is to follow torque specs. Start in middle and go out to sides in x pattern, in 3 different sets. (i.e. 30lbs,60lbs, 82lbs). Did you ever find out what happen with the hks hg?

 

[SRZMK3]

yes the studs NEED moly lube because without it the studs will just get stuck and not even turn to actual torque specs. i torqued my head studs to 90ft lbs of torque.

before you put the full metal headgasket on did you clean the block off of any old gasket residue.

did you resurface the head at a reputible machine shop? YOU HAVE TO resurface the head no matter what.

 

[lukebaumstark]

Usually you only spray copper stuff when you are reusing a hg(usually a metal hg).

Torque specs are diff if you use moly lube or oil. Moly lube is at 82lbs and if you use oil its 102lbs.

The only thing I would suggest is to follow torque specs. Start in middle and go out to sides in x pattern, in 3 different sets. (i.e. 30lbs,60lbs, 82lbs). Did you ever find out what happen with the hks hg?

okay so no spray on the gasket.
and yes i always do the x pattern.
and i havent got a clue about the hks gasket, very upset about that.

yes the studs NEED moly lube because without it the studs will just get stuck and not even turn to actual torque specs. i torqued my head studs to 90ft lbs of torque.

before you put the full metal headgasket on did you clean the block off of any old gasket residue.

did you resurface the head at a reputible machine shop? YOU HAVE TO resurface the head no matter what.

can any type of moly lube be used?
yes i cleaned the block for several hours first.
and yes i took the head to a good machine shop.

 

[ben1984j]

So I gather you didn't get the block machined, only the head? Cleaning up the block with a sharp scraper is usually enough when using a composite HG, but if you put on a metal headgasket without machining both the block and the head you are really taking a gamble as to whether or not it will seal. Honestly, that is most likely the reason why yours failed, the same thing has happened to many others on here as well.

And it's not unheard of to use copper spray with an OEM style HG...the idea is that it will help to fill in the little imperfections in the block surface, if you don't get the block machined. Just a little bit of extra insurance...but it's equally correct to not use the copper spray; the OEM HG doesn't require as smooth a surface to seal as an MHG does.

Since you're not machining the block this time around either, you are right to go with a composite headgasket. Without the proper prep work, an MHG is arguably less reliable than a stock headgasket....

 

[lukebaumstark]

So I gather you didn't get the block machined, only the head? Cleaning up the block with a sharp scraper is usually enough when using a composite HG, but if you put on a metal headgasket without machining both the block and the head you are really taking a gamble as to whether or not it will seal. Honestly, that is most likely the reason why yours failed, the same thing has happened to many others on here as well.

And it's not unheard of to use copper spray with an OEM style HG...the idea is that it will help to fill in the little imperfections in the block surface, if you don't get the block machined. Just a little bit of extra insurance...but it's equally correct to not use the copper spray; the OEM HG doesn't require as smooth a surface to seal as an MHG does.

Since you're not machining the block this time around either, you are right to go with a composite headgasket. Without the proper prep work, an MHG is arguably less reliable than a stock headgasket....

yes exactly my thoughts aswell =/


i am using an OEM gasket, so your saying the copper spray is NOT needed at all right?

and can i use any type of moly lube for the head studs?

 

[Supraflymk3]

yes any moly lube should work. they sell moly engine assembly lube at most autoparts stores. and ARP specifys that you should torque thier stud nuts down to 90 ft/lbs. they also say to just thread the studs in by hand, but on mine for a little extra insurance I tightened them a smidgeon with a 1/4 drive ratchet.

 

[lukebaumstark]

i took a close look at the gasket last night and it appears to have the aluminum sealer on it already so thats perfect.

im having the head rechecked again and milled today just incase.. a secone time wont hurt

and im on the run to find a tap for the block, i cant find the right size anywhere...

 

[Supraflymk3]

Go to a hardware store its a pretty common size. Otherwise go to a tool supplier if you have any around.

 

[lukebaumstark]

^^ found the tap and cleaned them out, they were pretty filthy, good thing i found a tap.

new studs came in today, and im picking up the head in a few.


anything else i should be aware of?



where do i apply the moly lube?

 

[lukebaumstark]

what should the final torque be on a FELPRO OEM style gasket with arps??

 

[Supraflymk3]

Apply a descent coat of moly lube on the threads going into the block and where the nut will go on. When I did my headgasket I found it easiest to place the head on first before the studs. Then drop each washer into the head holes, after that thread the nuts on part way on each stud then drop them in and thread them in finger tight. After that torque them down to 90 ft/lbs. Doesn't matter what kind of headgasket you use the nuts still get torqued to the same torque.

 

[lukebaumstark]

^^^ thats exactly what i did. i have a good feeling on this one, thanks to everyone for all the help and advice, it is extremely appreciated!

-luke