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-   -   Head bolts (http://www.toyota-supra.info/forums/mkiii-supra/8467-head-bolts.html)

G-string 05-17-2007 04:09 PM

Head bolts
 
Blowen head gasket, replacing it , what would be some good head bolts to put in and that torque should they be at to hopefully prevent this fromt happe ing again .

dcrusupra 05-17-2007 04:13 PM

ARP head STUDS

Supra_87_mk3 05-17-2007 04:32 PM

thats the only way to go. ARP studs are good up to 100ftp thats what i'll be running on mine or close to it.

dcrusupra 05-17-2007 06:36 PM

Supra_87_mk3 - the edit button is your friend, lol

supramacist 05-17-2007 06:39 PM

ARP studs. I took mine up to 85 flbs. In 5 settings instead of 3.

G-string 05-18-2007 03:15 AM

have you found any problems with putting so much torque on the block, the fac specs say liek 55 pounds or 65 pounds some thing like that. since you put the new studs in have you had any head gasket problems

supramacist 05-18-2007 04:14 AM

g-string....., What up?

Do the studs. Some of these guys actually know what they are talking about and they aren't here to hold your hand.

I went with the studs. I torqued them in five stages. I threw a few 5lb passes in there mixed with 10 lb passes.

I went to 85ftlbs. You are not going to hurt the steel, that is your block.
Make sure you atleast lap your block. Machining the head is a must.

IMO, studs are superior to arp bolts. But that is only an opinion.

Get the tsrm for your car. There is an online tsrm that may be of use to you.
I have the book so I don't know the link but someone does.

G-string 05-21-2007 05:52 AM

here is a tsrm website.
h:tp://www.cygnusx1.net/Supra/Library/TSRM/MK3/default.aspx

cre 05-21-2007 05:57 AM

Arp studs and headbolts are the two most popular choices. The problem with the MKIII's head gasket wasn't due to anything wrong with the OEM head bolts or the OEM head gasket... it was the low torque rating. The OEM head gasket can take quite a beating when properly torqued.

I'm running ARP head bolts at 75ft lbs (the OEM head bolts will work fine at this level too, but I'd recommend new ones over reusing the 20 year old ones in your car now).

IHateHacks 05-21-2007 02:56 PM

Yes, ARP studs are superior to ARP bolts but the difference between any ARP hardware and stock hardware is far greater than any difference between ARP studs and ARP bolts.

The block is iron, not steel, and is about the strongest material you can thread a bolt or stud into. But it does have its limits. In my opinion anyone that goes higher than 80 ft/lbs is crazy and just asking for trouble (in the form of stripped block threads). Titanmotorsports says use 75ft/lbs for high boost applications. I believe Toyota reissued a torque spec of 72ft/lbs for stock head bolts, and thats with using 30wt motor oil for lubricant on the threads like the TSRM says. That is the biggest factor when torqueing head bolts, what kind of lubricant you use. ARP comes with moly lube that is the slickest lubricant you can buy, far superior to motor oil. It says right on the package that 85% of torque applied to any dry, unplated fastener is lost due to friction between the male and female threads. With motor oil the loss is lower and with ARP moly lube its far lower than with motor oil. Just to put it in perspective, for a 12mm stud (7M's are 10mm thread size studs) ARP recommends 86ft/lbs with ARP moly, and with the same stud with 30wt oil you would need to torque that stud to 109ft/lbs to get the same clamping force. Thats a big difference. ARP doesn't list a torque value for 10mm thread sized 190,000psi tensile strength bolts (the bolts I used) so I just went with 70ft/lbs. For 10mm studs, ARP recommends 60ft/lbs with moly and 70ft/lbs for 30 wt oil.


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