Head gasket leak

[Doat91]

The car comes with 52ftlbs stock that is how it came from the factory and that is the reason why 7m motors have this issue lol. I hear people torque them to 72ftlbs from 52ftlbs. I'll think about going with a MHG just right now I want to temporarily fix this small leak so I am not so nervous when I have no choice but to take the car out somewhere.

[pandrade]

yah 72 will fix the mk3 legandary head gasket( i thought you meant people put an extra 20 ontop of thr 72 my mistake), if your only pushin factory power at the moment and its not giving any issues then torque them to the proper setting of 72 and you shouldnt have any issues for a while( maby band aid wasent the right analondgy, more like a bandage it'll fix you up but not permanently, but just long enough for you to get the right stuff together for a proper fix) just get um to72 and you should be fine if your not abusing your motor and are at factory power levels

my supra is still on the new OE head gasket which to torqued to 72 whith moly lube and iv never had any issues ( origonal owner did this i just checked the torue specs to make shure everything is up to par)

[Doat91]

Yea I don't abuse the car and it is stock other than a better intake filter for the turbo. I just need to rent a torque wrench from an auto parts store and the 10mm hex allen socket if they allow me to rent one lol.

[cre]

I posted this some time ago about ARP or Toyota head bolts (not studs). Newer ARP head bolts come spec'd for 90ft lbs... refer to the manufacturer's specs for your bolts of studs (if Toyota, 75ft lbs is within spec for that size fastener and materials).

Originally Posted by cre

Stock is 58 ft lbs. The recommended torque for our size head bolts with aluminum heads is 72 or 75 ft lbs. Studs are torqued to about 90, IIRC. BOTH values vary depending on what lubricant is used for the install. I only remember some of the reasons for the differences so I'm not going to try to get in depth with this as I'd just be guessing at the end.

A retorque is good medicine for any new fasteners or gaskets (especially composite gaskets). You need to back off the fastener anywhere from one quarter of a turn to up to a full turn... you don't want to over do it though, just enough to free up the fastener. Then retorque to spec. If striction is encountered back the fastener off a little more than the first time and then torque again. When torquing ANY type of fastener you want the fastener to move smoothly and steadily the whole way... striction can cause big variances in torque readings. Also, when backing them off it isn't a bad idea to back them all off and then retorque uniformly.

As long as you properly tend to the threads in the block, lubricate with a high grade lubricant (not just one that claims to be good ) and retorque PROPERLY either type will contribute to a seal which may very well out live the car; Depends on how well everything else was tended to.

Studs do allow for a higher clamping force (accuracy is more to do with the installer IMO) and definitely gives you a better piece of mind (especially with certain types of head gasket construction).

Not really, no; Not at this level of torque. I've gotten that answer from people much smarter than I. It is possible to compromise an old composite head gasket with too much pressure after a retorque, but whether that's what the cause of a BHG after a retorque or if the gasket was already blown prior is too difficult to say.

EDIT: You can compromise an old HG by torquing As for how often it happens... hard to say. The persons HG may have already been on the way out and the retorque made it worse or earned them another 5000mi OR the retorque may have been entirely to blame.

[Joefishizzle]

Thank you cre. That is why Im afraid to do this procedure. My car has about 200k and i think it's the original HG. I have no issues with my HG (knock on wood) so im afraid doing so would compromise the gasket. Im just gonna wait for the rebuild

[cre]

I'm against re-torquing on old setups for a couple reasons but the biggest is that if you've ever dismantled any number of engines and checked the breakaway torque while removing fasteners you'll know that you will NEVER get an accurate and consistent torque across all the bolts without removing them all, chasing threads and properly lubricating them. You cannot do this without most assuredly compromising the HG. Also a quarter turn doesn't equal a flat 10 lbs of axial load and even getting the bolt to budge that little amount will be hell with some of the bolts and too easy with others, so there goes the concept of just giving each a 1/2 turn. If the torque is already inconsistent, increasing the disparity in clamping pressure across the head is not going to help.