Toyota Supra Forums! Join the Supra forum!

Toyota Supra Forums! Join the Supra forum! (http://www.toyota-supra.info/forums/)

- MKIII Supra (http://www.toyota-supra.info/forums/mkiii-supra/)

- - Head gasket leak (http://www.toyota-supra.info/forums/mkiii-supra/20509-head-gasket-leak.html)

Head gasket leak

So it seems I have a small head gasket leak and I am debating on whether or not I should torque it down until I can get it changed with ARP studs. What are the pros and cons of torquing it down at this stage vs not torquing it down?

I know this has been beaten to death but I haven't be able to find a thread with an issue like mine. Thanks in advance.

tourqing it down will ensure you car lives untill you can get the studs and new HG. if there is any leaks torquing them might hide and prevent damadge ( remind you this is only a band aid not a solution) i would buy a good quality meatal head gasket whith the arp studs and torqu them down to proper setting useing the proper lubs for this application and use the proper sequence to take the head off and on . also clean the deck and heads while also making shure the head has not become warped,

this is all covered in the mk3 FAQ'S there would be a good place to look for further help

I am debating on going for a metal gasket since I don't plan on going for high power, maybe 400hp tops, also there is the cost issue with the gasket itself and machining the head and block, etc. I planned on getting an OEM gasket and my shop will machine the head anyway to ensure a good contact. Yea I will replace the head gasket I just don't want the coolant to keep getting into the motor or getting pushed into the overflow tank. I plan on doing it tomorrow in the proper sequence, torque it down to 72ft/lb right?

I thought that 72 was the original specification, I believe people do them an extra 20ftlbs no?

let me check the FAQ's and ill get back to ya

i checked the FAQ's and it says 72 i havent been on the fourm THAT long to have heard about going 20ftlbs over, i think useing the proper moly lube the 72 should be just fine( the arp studs should tell you what lube to use and what torue settings, only if there specific to your car tho) heres a link of the FAQ'S which explanes just about everything

http://www.supras.nl/index.php?optio...d=26&Itemid=42

P.S in my opinion if you got the heads out and putting a new head gasket might as well go whith MHg just because your there and that little extra will give you peace of mind down the road and if you want to go a bit higher on the HP level you dont have to worry about it

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.

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)

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.

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).

Quote:

Originally Posted by cre (Post 77288)

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).

Quote:

Originally Posted by oregonjoe (Post 77285)

I have wondered if you can torque down a composite gasket too much? to a point that the crush rings expand too much into the coolant and oil passages? Don't think metal head gaskets have the same issue.

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.

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

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.