Re-torquing head gaskets, cometic with ARP studs

[Toby_Goodmk]

Well real life experience. After a few boost cycles and about 100 miles of run time..the heads needed a re-torque. Measured with a marker before and after and was able to turn additional 20 degrees. Goes to show, always re-torque no matter what engine builders or MFG say.

 

[flyhigh]

thanks

 

[BEATAV8]

Didn't you go through a whole torque and re-torque procedure described in a thread not too long ago? Or was that another fella?

 

[Toby_Goodmk]

it was me, trying to prove to my builder that it needed to be done...but didnt have any real life proof from my own car, only experiences from the peeps here.. Now I have truly seen the movement in degrees. Maybe a physicist could explain how something that is metal, tightened against a metal stud. 20*, that seems a bit to just be lost some where. Composite gaskets I can see crushing, but MLS...idk.

 

[turbo nasty]

Well real life experience. After a few boost cycles and about 100 miles of run time..the heads needed a re-torque. Measured with a marker before and after and was able to turn additional 20 degrees. Goes to show, always re-torque no matter what engine builders or MFG say.

Did you back them off before retorquing?

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[TT/Ameasap]

Just letting the heads sit for a few days after install will need re-torqued.

 

[Toby_Goodmk]

Did you back them off before retorquing?

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Absolutely and in reverse sequence as well.

 

[TTipe]

Gaskets relax but also have a spring co-efficient (K). Gasket preparation has to be seriously considered. The angle torque applied to a 3800 cylinder head is beneficial if rebuilding a stock 109 with irons and Victor (graphoil with a fire ring) head gaskets. Bottom tapping the cylinder head stud threads and cleaning the cylinder head nut threads prior to lube application ( to freshen the threads and allow the decks, gasket, studs and nuts ) allowing the joint to work as a system. The optimal joint will come into equilibrium (opposing forces=0). I torqued my Champions to 80 ft/lb and re-torqued to 80. Aluminum heads will grow more than irons when hot, (if they ever get there due to thermal conductivity) but the block will grow less. I would prefer to have parallel decks with a gasket that seals at a lower torque than non-parallel decks with a higher torque and a head gasket squish that varies significantly.

 

[Toby_Goodmk]

Holy tech!! That is really interesting. I'll have to Google search about 90% to get the meaning lol!!!


Thanks on the response. I guess I feel good at a 80lb tq on iron heads. I am with you on chasing threads for a positive mating surface. I bought the thread chasing kit just for this reason

 

[TurboBuRick]

Did you put them on dry?

 

[Toby_Goodmk]

Yes. No copper spray at alll