Hey guys, first post here. Normally hang out on the Domestic Performance website's since that is what my performance shop specializes in. However, my Brother has an '89 Turbo Supra, and the head gasket let go. History so you guys do not think you have to go into the small details:
Dad worked at Toyota since I was born (MANY YEARS AGO!), a friend of mine (have not spoke to him in a couple years) has been the Parts Mgr. at Mike Calvert Toyota for @ 30 years. My Step Dad (who passed away) owned (yes owned) Gulf Freeway Toyota in the early-mid 80's (is now Jay Marks Toyota I believe) I was a tech @ Don Davis Toyota back in '94-'95. I have had my own performance shop since @ '01. We build race cars, restorations, motors, etc....So, I am a newb to the site, but now new to 'Yota's or cars
So, I took on my brother's head gasket issue. Before I tear it down, what are the things we need to be most concerned with/prepared for? We know that the head gasket is a HUGE issue with this motor (as in VERY common) so figured you guys would know best on what to expect. Cracked head? Block warped? Is there a CURE, and not just a band aid fix? Maybe a new MLS Head gasket that is out? ARP head bolts? Or studs? You guys maybe have a link to some of the questions I have?
You should know to always expect the worst and smile when you get something less . That said, block cracks and warp are rare, though the fire rings often left fairly deep marks. The head is much the same, except it will warp somewhat. Heat straightening often fixes it. That said, The block and head need to visit a machinist in order to get prepped, like new performance engines, for a multi-layered steel gasket. Several make them, from HKS to Cometic. I'm partial to either of these brands as they have proven track records. Technically, you could follow the recommendations below on a stock composite gasket (I've done it with good results...got 8 years out of the last one before I took it down of my own desire for a performance build and went metal, and there were no signs of deterioration at all) and as long as nobody plans to turn up the boost, it should be fine. For higher power applications though, the metal gasket is a must.
Since it is apart, new bolts are in order. Many choose ARP studs or bolts, and suggest they are good for a torque up to 80ft/lbs. IMO, and from metallurgical testing several years back by a guy named Reg Reimer (well known Toyota and TTE tuner and factory team consultant), the factory bolts are designed for use at 70-72ft/lbs, and that will secure the head for the very long term. 56ft/lbs as they were set to from the factory was just not enough to keep the head on through years of heat cycles, and was deemed to be far too low (by everyone except Toyota, who still insist the 56 is right, even when shown otherwise from scientific testing and observation of the patterns). The bolts would back out on the exhaust side first, and then the gasket failed.
OK, thanks for the reply and info! Really helps out. Looks like we are gonna go ARP bolts with the Cometic MLS. Boost levels are stock, car is stock. Been a 1 owner car (Brother is 2nd) all recods, window sticker type of thing, but we want to do this one time and one time only sense my Brother wants to keep the car for a long time. Again, thanks!
If anyone else has any info they want to share, please do so.
The solution I've seen work time and time again has rarely changed. Machine the block and head (Only recently had I heard 30RA smoothness as a defined number...). Pick up a metal head gasket of your choosing (I've heard great things of cometic, greddy (backorders though) and a few other big names, pick up ARP studs to go with them use their moly lube, put it all together and torque it to your preference >80ft/lbs but not more than 90. Follow the torque sequence and make many multiple passes. Add boost and enjoy.
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1988 Mk3 Turbo Targa - 17.5psi, 486hp, 494tq.
[img]http://www.**********s.com/supra/rsw_sig_stupidTN.jpg[/img]
Who came up with this 500px wide BS?
The solution I've seen work time and time again has rarely changed. Machine the block and head (Only recently had I heard 30RA smoothness as a defined number...). Pick up a metal head gasket of your choosing (I've heard great things of cometic, greddy (backorders though) and a few other big names, pick up ARP studs to go with them use their moly lube, put it all together and torque it to your preference >80ft/lbs but not more than 90. Follow the torque sequence and make many multiple passes. Add boost and enjoy.
haha, thanks! That is what we plan on doing (we were still thinking Bolts over studs though). I have not looked close, but CAN you remove teh head in the Supra with the studs installed? I mean, I hope that once it is back together, it is the last time, BUT, out of curiosity, can you remove the head, in the car, with studs installed? I know on a few cars that I have doen studs with, you can't (well, without removing a bunch of stuff anyways) but those were all "V" engines. But since I am not looking at the car (still at my Brothers garage) was wondering if the motor is up under the cowl any?
Thanks guys! Oh yeah....how much more are the studs over bolts, ARP?
The studs will not allow it to be done easily. That said, some have luck tilting the engine forward (lift the tranny off the mount), and other place the head on the locating dowels and then install the studs through the head. As I recall, the studs have a provision for a small torx type socket on them (or was it an allen head...can't remember). I see no downside to the bolts however, and they are a little easier to install and remove.
The studs will not allow it to be done easily. That said, some have luck tilting the engine forward (lift the tranny off the mount), and other place the head on the locating dowels and then install the studs through the head. As I recall, the studs have a provision for a small torx type socket on them (or was it an allen head...can't remember). I see no downside to the bolts however, and they are a little easier to install and remove.
OK, gotcha. Thanks! Yeah, we will probaly go bolts than. I just want it to go as smooth as silk, and while I know the stud provides the ultimate in clamping power, with his stock boost level, I know that a good ARP Bolt wil be more than sufficient (with the proper Tq applied to them) I can't believe Yota calls for, what was it...56 Ft/lbs? Wow. On a Forced Induction motor especially. AND, with all of the KNOWN head gasket failures, yo uwould think they would go....OK, we were wrong on that one Oh well. Thanks guys. Will let you guys know how it turns out (and of course if I have any more questions/concerns, will let ya know!)
IIRC in the later TSRMs they uppped the number to 72ft-lbs. But even then, many regarded that as too low.
OK thanks. I was planning on @ 82 ft-lbs. If we were gonna add boost, would probaly go studs and closer to 90. Finally got car today. Gonna yank head off on Monday....will keep you guys updated.
Thanks for the info
OK guys, update. I was working on the Supra and another car at teh same time, so sorry for the delay in teh update. The Supra is done. Got it back together on Friday, and @ 250 miles have been put on it since, and so far so good. Thanks to everyone that chimed in, I used your advice and help. So, thanks guys!
Edit:It appears a member read this thread, and got ahold of me and now I am doing his head gasket as well. Funny how that worked out. Anyways, again guys, THANKS!
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. That said, block cracks and warp are rare, though the fire rings often left fairly deep marks. The head is much the same, except it will warp somewhat. Heat straightening often fixes it. That said, The block and head need to visit a machinist in order to get prepped, like new performance engines, for a multi-layered steel gasket. Several make them, from HKS to Cometic. I'm partial to either of these brands as they have proven track records. Technically, you could follow the recommendations below on a stock composite gasket (I've done it with good results...got 8 years out of the last one before I took it down of my own desire for a performance build and went metal, and there were no signs of deterioration at all) and as long as nobody plans to turn up the boost, it should be fine. For higher power applications though, the metal gasket is a must.
Wow. On a Forced Induction motor especially. AND, with all of the KNOWN head gasket failures, yo uwould think they would go....OK, we were wrong on that one 
Oh well. Thanks guys. Will let you guys know how it turns out (and of course if I have any more questions/concerns, will let ya know!)
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