ok ive priced up a metal head gasket but the thing is i dont wanna rip the engine out and pretty much dismantle everything to get the block done because aapparently u have to have a real flat surface on the block aswell as the head.....so i was just wondering if i torqued the standard toyota head gasket to the correct revised torque specs will it still blow or will it be ok..even if i up the boost more will it still be ok? o and its a 7mgte and yes i have searched but cant really find anything that answers my specific question..cheers..
metal HG vs normal HG
- Thread starter sketchy_89
- Start date
G'day mate, just a quick heads up you need flat surfaces regardless of what type of head gasket you use. Dont think just because your going to use a standard type of head gasket you can cut corners. If you do the job properly you will be ok to turn up the boost, I dont have time to search for you (its your head gasket not mine ) but I remember reading on this forum that if the head gasket is replaced properly it will hold 18psi no trouble, it's all in the tune 
Good luck
Good luck
Yes, you need to have flat surfaces regardless of the gasket used.
If your local machine shop can't get that nice mirror finish for you (needed for a metal head gasket) then just snag a FelPro and go to town.
If your local machine shop can't get that nice mirror finish for you (needed for a metal head gasket) then just snag a FelPro and go to town.
Though the stock HG can handle more warpage than the metal ones, the maximum it can take is .002. anymore than that, replace, or refinish. It's definitely in your best interest to do the machine work. The different heat profiles of a cast iron block, and an aluminum head, demand the job be done the best way possible. I don't have any money, so I've had to do my own decking, with straight edges, sandpaper, and a homemade lapping block. It's been excruciating work, but it had to be done.
so does that mean i pretty much have to pull the whole engine out to do it if i send it to the shop..litke pistons n shit to
probably wouldnt be a bad idea. you should just do it right the first time so you dont have to keep going back and doin it again and again
sketchy_89;1301946 said:
NO.
first you have to pull the head off and check it with a straight edge(not a rule. its a machinist to. perfectlyl flat bar stock). then check your block. like mentioned above anything under .002" will be fine. even thought the tsrm says .004 iirc i feel thats sorta pushing it. and unless you got it really hot you block should be fine. the head might even be fine to, but if you have to you can machine just the head if the block is under .002". i went with a felpro hg/arp bolts and its been holding 12psi since. DAILY.
here is the thread when i did mine.
http://www.supraforums.com/forum/showthread.php?t=477428
black89t;1302005 said:
I say yes, because of the inevitable damage from the old gasket. I've seen pitting over .004, and that would be enough to put it beyond spec. The surest way is to get it machined, and eliminate any potential for problems. P.S. I'm going to have to double check, but as I remember it, my 92 tsrm states .002 max. I will check when I go work on the engine.
Look at the attached pics. would you rather put your HG on example 1, or example 2? P.S. these were the easiest to get to pics, and I forgot to take pictures of the block until after I had removed most of the damage, so the block shots wouldn't be a good example.
Attachments
i just want him to know his options. i think its funny how everybody acts like a mhg is the only way. anything under 400whp and i say your wasting your money. and yeah. .0039"
that is unless he was planning to tear the block down for a build then obviously the mhg is the way to go.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=42
that is unless he was planning to tear the block down for a build then obviously the mhg is the way to go.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=42
black89t;1302043 said:
This is not MHG specific, it goes for all types. It's better to have a good clean deck to seal, than a beat up damaged one.
black89t;1302043 said:
Also, I just checked the tsrm. You are correct about .0039. But, thats for the head only. Understandable, as being aluminum, it will flex quite a lot. I was refering to the block spec, which is indeed .002 as I stated, because the block does not flex as much.
black89t;1302005 said:
Sorry, mate, but that's the hard way to do things. Just pulling the head alone is as much work as pulling the entire motor. If this repair is not done right, it WILL blow again, and maybe even get RK. So why waste time, lots of efforts and money half-assing the job? Nobody said owning a Supra is cheap. So my advice is pull the motor, disassemble and have the block and head professionally checked. I say "do it right, do it once".
black89t;1302043 said:
As far as I know, you can't get the oem gasket in anything but the stock thickness. If any significant machining has been done, it would require a thicker HG, which are readily available in all MHG lines. Also, though this is only my belief, A thicker oem style gasket, if available, might prove weaker, and less likely to survive in a boosted environment, due to it's material being softer.
gtsfirefighter
SM Expert on White trash
GotBoost?;1302090 said:
I had a bhg, had the head machined and used an OEM gasket, ARP bolts and torqued accordingly. That was 10k miles ago and I'm daily driving it. Did I do it right or did I just half ass it? If so when WILL it blow again? :sarcasm:
I didn't see it stated anywhere that he has a BHG. :sarcasm:
There's more required than a flat mirror finish for an MHG. There are RA specs that have to be met. If you go with an MHG, find out what their RA spec is and have things machined accordingly.
I have personally been involved with removing OEM HG's and installing MHG's with ARP's on three different cars. All three were 'In-Car' jobs. The engines were not removed.
While we DID NOT reach the manufacturer's RA specs, and while I DO NOT recommend this, all three cars are boosting over 12 psi daily and have been for quite some time.
There's more required than a flat mirror finish for an MHG. There are RA specs that have to be met. If you go with an MHG, find out what their RA spec is and have things machined accordingly.
I have personally been involved with removing OEM HG's and installing MHG's with ARP's on three different cars. All three were 'In-Car' jobs. The engines were not removed.
While we DID NOT reach the manufacturer's RA specs, and while I DO NOT recommend this, all three cars are boosting over 12 psi daily and have been for quite some time.
GotBoost?;1302090 said:
This is definitely not good information... Doing it the right way involves checking everything to make sure they are within acceptable specs, not doing useless and unnecessary work. BTW pulling the motor isnt the difficult/time consuming part. Explain to me how pulling the entire engine apart and disassembling the entire bottom end/reassembling the entire bottom end is less work/ more cost effective than pulling the head off in the car and checking everything.