New head gasket

[Jack Daniels]

Ok one quick question. Last season i replaced my head gasket on the motor in my signature. Since it was a great day today in indy, i fired her up on muffs. After some huffing and puffing and a little backfire she fired up. I was really happy because i thought i also had spark trouble. Anyway back to my question. I let her idle for about 5 min, i remember someone saying after you replace a head gasket you should re torque your head bolts. Was 5 minutes in the driveway enough time to re torque, or should i drop her in a lake and let it run under load before re torqueing? Thanks for the help.

 

[pnwboat]

Re: New head gasket

I don't think it's a requirement. The manual for my 125HP doesn't specifically say to re-torque the head bolts. It's probably doesn't hurt to check the head bolt torque after changing the head gasket, but you want to put the gasket/head through at least one cycle of heating up and cooling off before re-torquing. Running it on the lake to get the engine up to operating temp. for a while is probably better than running it on muffs in the driveway.

Maybe some of the other folks on this forum will chime in with their thoughts and experiences. There's a lot of guys out there that certainly have "boat loads" of experience.

 

[Frank Acampora]

Re: New head gasket

I don't know if 5 minutes will do it. The trick is to heat the engine block and head to normal operating temperature so the aluminum expands. This further compresses the head gasket and you will probably take up another 1/4 turn to again reach standard torque.

Think about it this way: After torqueing the head bolts, the first time you heat the engine, the aluminum expands more than the steel head bolts lengthen due to heat. Something has to give so the head gasket compresses. After the gasket is fully compressed, under heat, the aluminum "gives" and the head bolts stretch a bit.

I always wondered about factory procedures: They never re-torque the heads or anything else for that matter.

I don't know if it is absolutely required but way back I have seen it recommended in repair manuals.

I re-use head gaskets and since they have been heated and torqued a couple of times, it is not necessary to re-torque bolts with the used ones.