Head re-TQ?

[WJM]

The FSM states, as well as other sources, that you must re TQ the heads on the EA82 (T and NA) after you "warm up the engine, and then let the heads cool down"

 

something about oil, loosening and tighening things in certin orders...

 

I wonder if that is truly nessisary....as us EA82T people keep blowing headgaskets here lately.

[Ratty2Austin]

I dont know about that one... I havent retorqed my heads on my XT turbo, and it still hasnt done anything bad yet! (and I drive it hard!)

 

[WJM]

See, thats just the thing....my wagon, I never Re-TQ'd on the 9.5:1, and they held fine. Rings and a valve went before anything else.

 

The last one was on NAPA head gasket...so i expected it to go at any time.

 

The RX so far is going great. *knock on wood*

[Subarutex]

Unfortunately, I've decided to retorque mine once I get the engine back together. Its goign to be PITA, but I need to stop cutting corners and try and ensure this next round with the engine lasts more than a couple hundred or even a thousand miles.

[Vanislru]

They suggest this for the older VW,s too, I did it on a couple of engines but only managed to ever find one bolt that "needed" it. I'm not sure how this poses a benefit cause aluminum expands with heat at a higher rate than steel bolts do. :-\

[NorthWet]

As far as I am concerned, if the gasket maker says retorque, then you should definitely retorque; if the engine manufacturer says retorque, then you should retorque. (BTW, there was another thread within the last week talking about this.)

 

A little history lesson from one who lived through it for those graced with the youth to not have. Up until the 70's, IIRC, virtually all head gaskets specified that they needed to be retorqued after running the engine to temperature. Around the 70's, several gasket manufacturers came out with HGs that they claimed did not need to be retorqued. BTW, in my experience there were more failures amongst these that hadn't gotten retorqued than with those that had.

 

Later, in the 80's(?), cars started coming out with stress-to-yield head bolts. With these you torqued them down to a specific setting, then turned them a certain angle more, which stretched the bolt past its limit of elasticity: The bolt couldn't stretch more without failing. This allowed a consistant clamping force without the bolt being able to "give" a little and release the force. It also made the headbolts use-once items.

 

The reason for retorquing is pretty much for the same reason that to properly bore/hone a cylinder you need to use a torque-plate: Static/cold/unstressed conditions do not let the bolts "see" what operating conditions will be like. You can't tell during a retorque which ones really needed it (unless one was obviously loose, which indicates a problem with how the bolt was originally installed/torqued). You are just ensuring that the clamping force is as equal as you can get with bolts or studs that still can "give" a little.

 

Retorquing is a good thing. PITA, but good. And just because an unretorqued HG didn't fail doesn't imply that it was done properly. Sort of like just because you didn't get caught while speeding doesn't mean that speeding is a good idea or legal.

 

Happy retorquing!

 

Pat

[Petersubaru]

if you are useing the newer style (better technology) headgaskets then no re-torqueing is necessary...just re-check the torque on each bolt again before continueing with the assembly...I think the best gaskets can be found at...http://www.corteco-usa.com/