elanman999 wrote:I have used Ajusa gaskets and I still have the data sheet provided with the gasket (about 10 years ago) and it says to retorque the gasket. It also says to use 69lbs/ft. However for the Ajusa gasket that I have just fitted to my Elan there was no mention of retorqueing.
Cheers
John
All gaskets take a set with heat cycles and retorque is done to compensate for this set. The head cycles compress the gasket further than when cold due to the expansion of the alloy head compared to the bolts and the gasket needs to be compressed to a point where it fully recovers from hot to cold after a heat cycle.
If you dont retorque it your head gasket will fail sooner rather than never. How critical it is depends on the gasket type. The composite fibre style gasket takes the greatest set, the original copper / set the next and an MLS gasket the least. ( which is why they may be more reusable than the other types but also why they are hardest to seal in the first place) Thus most critical on the composite fibre, less on the original and less again on the MLS
I normally retorque 3 times when using a composite gasket.
1. after the intial startup and running head cycle while checking for leaks and setting the carbs
2. After the initial run in or around 100km
3. After the first 500km of normal driving.
When I have checked a 4th time after around 1000km I don't find the head bolts move on a road engine and maybe move a fraction on a race engine
cheers
Rohan