Thanks for this!
i get asked quite often how to retorque the head bolts on 7m's to stop the gasket from blowing. this is a MUST when a new gasket is installed (bhg repair or rebuild) after 5-10 heat cycles or 500-1000km. i also do it as a maintenance item on my motors, esp 2nd hand motors i am reusing without replacing the gasket.
there are a few different opinions on how to do it, this is my way and ive not had any problems with it... of course others may do it differently.
as you can see it is literally a 5 minute job once the rocker covers are off (well 4:30 really ) and well worth the effort. thermal expansion is a bitch with iron block/alloy head engines and as we all know the 7m needs as much BHG insurance as possible!!
IMG_0729.MOV - YouTube
There is no substitute for PUBIC inches
Never late in an x8
Thanks for this!
- phoebe
"EFI? More like NFI..." - Demios, IRL
nice to be able to get access to the headbolts without removing the cams.....
Information is POWER... learn the facts!!
Yeah its a bastard with studs though, gone through a few sockets trying to find the right one... Still not quite perfect, last one broke @ 75lb
There is no substitute for PUBIC inches
Never late in an x8
Back off 1-2 turns, you'll get a better feel for the condition of it threads & remove clean inspect if it feels tight notchy or dry.
Wiggle the socket around a bit to get the residual(squirt some if there isn't) oil under the bolt head, washer & maybe even some down to the block's threads.
No chance for even capillary action with your 1/4 turn. Just because it doesn't make that same HORRIBLE nasty dry chatter sound when it's being tightened back up, doesn't mean it's happy
IMO If this helped your engine, it's better then nothing, more by luck then procedure.
Would this be worth doing on a Silvertop 4A with TRD head gasket?
Slightly less critical with a mls gasket, but still worth doing on any iron block/alloy head engine -thermal expansion is a bitch when different rates are involved.
This has helped on more 7ms than i can count on both hands, with the exact procedure used above. i do a lot of rebuilds/bhg jobs for people and everyone gets told to do this or bring it back for me to do.
The only one who didnt is the only one ive ever had come back for another gasket out of the dozens ive done.
Thats some stellar good luck, or good procedure, ill let you decide
This thread sparked lots of debate on another forum i posted it in as well, discussion and better ideas are always good though. But ill still stick with my way thanks
There is no substitute for PUBIC inches
Never late in an x8
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