alright about a month ago i blew a head gasket:3d_frown: i was pretty bummed about it but i knew it was gonna happen since i bought a supra :cry: any ways. i was wondering if the stock head gasket was all that bad, is the reason the head gaskets blow on these cars is because of toyota not tourqing them down enough pounds? or is it really that bad? the reason i ask is because i can get the stock head gasket with all the other gaskets i need to do the job for the same price as a mhg without the other gaskets. Now i know that trying to do the job the cheapist way isnt the good way to go, so i am asking this question. is the stock hg really that bad?
Head Gasket question!
- Thread starter ft413
- Start date
the stock gasket really isnt all too bad for near stock performance... if you start pushing some real PSI above stock.. it might be in jeopordy. The best thing to do is just get a stock gasket, and ARPS and torque to 85 ft lbs and your good. Make sure to check the head and deck for warpage as well.. if they are warped, you will blow it again, probably instantaneously.
-R
-R
The stock HG will hold quite well all the way to 14-16 psi if properly torqued...detonation is what kills them.
Vs listening to the "well, I torqued my ARPs down to xx ft/lbs"...you will be far better off torquing to what the ARP spec sheet says for the hardware you choose. FYI - ARP bolts are limited to 75 ft/lbs on an aluminum head (like the 7M) using moly for lube. ARP studs spec 80 ft/lbs using moly...studs are the better choice.
I would not torque above those spec's and I would do a re-torque after 5 complete heat-up/cool-down cycles on the engine. Suggest you read the TSRM section on removing/installing the head several times. Pay attention to the bolt loosening sequence, the tightening torque sequence (use 10-15 ft/lb increments), and where you put dabs of RTV in the back timing cover.
Vs listening to the "well, I torqued my ARPs down to xx ft/lbs"...you will be far better off torquing to what the ARP spec sheet says for the hardware you choose. FYI - ARP bolts are limited to 75 ft/lbs on an aluminum head (like the 7M) using moly for lube. ARP studs spec 80 ft/lbs using moly...studs are the better choice.
I would not torque above those spec's and I would do a re-torque after 5 complete heat-up/cool-down cycles on the engine. Suggest you read the TSRM section on removing/installing the head several times. Pay attention to the bolt loosening sequence, the tightening torque sequence (use 10-15 ft/lb increments), and where you put dabs of RTV in the back timing cover.
^^^ Good advice jdub
ft413, I dont know where or what toyota dealership you are getting your gaskets from but you say you can get the entire top end set for less then $110!!! Wow that is a super great find since just the HG alone from toyota is normally in the $75 range.
But if you are planning on buying one of those eBay/china sets:nono:, I would recommend search here first unless you to do the HG again in the near future.
ft413, I dont know where or what toyota dealership you are getting your gaskets from but you say you can get the entire top end set for less then $110!!! Wow that is a super great find since just the HG alone from toyota is normally in the $75 range.
But if you are planning on buying one of those eBay/china sets:nono:, I would recommend search here first unless you to do the HG again in the near future.
gtsfirefighter
SM Expert on White trash
jdub;1198832 said:
I accidentally torqued my ARP bolts down to 82 ft/lbs. My dumbass misread the torque wrench due to a little slack in the handle. I can't help but be worried about it. I did everything else the way the TSRM said. I almost had the torque sequence memorized. Driven 200 miles so far with no issues. I'm keeping my fingers crossed.
I used OEM everything minus the headbolts for my HG replacement. It costs a little more but didn't want anything but.
A question for jdub.....It's who again. I swear I'm not stalking you.
In a previous thread there was a discussion about using the ARP method of 5 tightening / loosening cycles vs a re-torque after 5 heat cycles. Can you use the ARP method on the Toyota composite gasket? Or is the ARP method best saved for MHG. My question being can a composite gasket take the stress of 5 tightening / loosening cycles. Thanks.
In a previous thread there was a discussion about using the ARP method of 5 tightening / loosening cycles vs a re-torque after 5 heat cycles. Can you use the ARP method on the Toyota composite gasket? Or is the ARP method best saved for MHG. My question being can a composite gasket take the stress of 5 tightening / loosening cycles. Thanks.
gts - I wouldn't worry too much about it. Now, if you said 95 ft/lbs (which I've seen guys do)...that would be something to worry about 
who - LOL!
Yes you can use the ARP pre-load technique on a composite OEM HG...in fact, that is the preferred method. You are not exceeding the final torque the HG will be subject to.
who - LOL!
Yes you can use the ARP pre-load technique on a composite OEM HG...in fact, that is the preferred method. You are not exceeding the final torque the HG will be subject to.
gtsfirefighter;1199037 said:
my arp bolts are at 85ft/lbs with a stock hg. it's almost been a year with no problems daily driving with some hard boosting. :biglaugh:
black89t;1199172 said:
Like I said...the bolts are limited to 75 ft/lbs on an aluminum head. If you took the time to read the instruction sheet that the bolts come with, you would know that
The reason is to account for the greater thermal expansion of aluminum on a steel block. More torque is not better...you are cutting into the yield strength safety margin ARP designs for its hardware. Just because you don't "seem" to have a problem, does not mean that you don't...this kind of statement does not hold water.
I'm pointing this out because the next guy that reads this "recommendation" just might take the "more is better" route just like you did and go to 90 ft/lbs. Then the next guy goes to 95, etc, etc. That's the problem with "forum specs", they are all based on hearsay and can end up doing more harm than good.
FT413 - Regardless of what you "hear", just stick with the ARP spec for the hardware you choose. The ARP engineers know what they are doing
^yeah, they were already on my motor and i just went off what i was told on sf. i'm just trying to help him sleep at night. lol. i was really paranoid after the hg job too. now i don't even worry about it.
i know better know, but at the time nobody had the sheet. so i decided i would go inbetween what people were telling me and cross my fingers. lol.
i know better know, but at the time nobody had the sheet. so i decided i would go inbetween what people were telling me and cross my fingers. lol.
jdub;1199051 said:gts - I wouldn't worry too much about it. Now, if you said 95 ft/lbs (which I've seen guys do)...that would be something to worry about
My heart just about skipped a beat reading this thread! I too mistakingly over torqued my ARP studs. Mine are at 90 w/the moly lube.
Any recommendations jdub...should I back them down?
Kenny - No, I would not.
Studs are not subject to the twisting stress bolts are...the torque spec is higher as a result. If you do a re-torque (which I would do), do not go higher.
Studs are not subject to the twisting stress bolts are...the torque spec is higher as a result. If you do a re-torque (which I would do), do not go higher.
And how does one retorque the HG? Just set the torque wrench to, say, 85 lbs-ft and go, or did i hear i have to back them up a little? TIA.
One at a time, in the TSRM sequence, crack the bolt/stud counter clockwise (barely moves) with a breaker bar...then re-torque to ARP spec or slightly above. If you have already exceeded spec, stop where you previously had it.
You're welcome guys
You're welcome guys
Perhaps...he may have used motor oil for lube too. The torque specs are significantly higher when you use motor oil and you can't mix the specs when you use moly. If a person would just take the time to read the ARP spec sheet.......