Head Lifting at 1.8 bar of boost ~ 450hp
Hey Guys, which studs are and headgasket are you using at that power level ?
we do door 2 door racing with the cars and time attack. engines are complete built bp engines. Jan |
|
Yea I had the same issue but at 1.6bar but closer to 400whp not quite 450. I am going with the HB studs that are linked above, they allow more tq they are arp2000 instead of the standard head stud material.
|
Originally Posted by andyfloyd
(Post 1582341)
Yea I had the same issue but at 1.6bar but closer to 400whp not quite 450. I am going with the HB studs that are linked above, they allow more tq they are arp2000 instead of the standard head stud material.
|
Originally Posted by nick470
(Post 1589270)
Is head boss cracking a concern with the higher specified torque of the HB studs? I'm going to be installing mine soon and I'm nervous about taking them to 90ft-lb.... Supermiata was unfortunately not very helpful when I asked. Wondering if my understanding of fasteners is just lacking here, maybe forces are way different given the different stud material and dimensions? I'd like to avoid destroying a $2000 head before I even have the chance to fire the car up
|
Use lots of the goo that comes with the studs.
|
Compressive forces do not break things.
Tensile stress and metal fatigue do. |
I'd encourage all of you to do some serious reading about the torque specs included with various aftermarket head studs sold for the Miata.
It shouldn't take much searching to find some real world experiences |
One thing that WILL crack a block, it torquing studs down into the block.
You never torque a bare bolt right down into a blind hole, it acts like a screw jack and cast iron does not like being stretched. Studs go in finger tight, or just nipped up, until the bottom of the thread in the block is reached. Plonk on your head, and then torque down the nuts to the specified figure. Top of the block is in compression, stud in tension, head in compression. If anything does go pop, its going to be the stud. |
Yeah, I read that thread when I installed mine now that I look at it again. I went big washers, 3 steps, lots of the ARP lube, and 65ftlb.
|
I've read quite a bit, and used that information the last time I installed ARP head studs. My question was specifically about the HB studs as what SuperMiata recommends is substantially different than what the popular consensus seems to be on head stud torque. I'm sure there are some gaps in my understanding of fasteners, and was wondering if there is something else going on with the HB studs that might lend itself to a 90ft-lb torque spec being safe in our application. Different thread design, ARP2000 vs 8740, etc.
|
FWIW, just took a cheap caliper to each stud/bolt variant I have sitting around. Middle ARP studs were purchased about 3 years ago, HB studs purchased earlier this year. HB are ARP2000, the Miata studs are 8740
https://scontent.fapa1-1.fna.fbcdn.n...78&oe=600A6848 |
Originally Posted by nick470
(Post 1589313)
FWIW, just took a cheap caliper to each stud/bolt variant I have sitting around. Middle ARP studs were purchased about 3 years ago, HB studs purchased earlier this year. HB are ARP2000, the Miata studs are 8740
https://scontent.fapa1-1.fna.fbcdn.n...78&oe=600A6848 |
So I lifted the chrysler studs last year.. moving onto bigger things for this next year
|
It might be worth checking your head for hardness.
If its ever run dry and been seriously overheated, the aluminium may have been annealed and become soft. That can make holding down head gaskets problematic, no matter how strong your studs. |
Might be worth a shot trying this https://www.summitracing.com/parts/s...da/model/miata . Supposedly it can deal with very minor head lift and maintain seal.
|
Originally Posted by Newaza
(Post 1589398)
Might be worth a shot trying this https://www.summitracing.com/parts/s...da/model/miata . Supposedly it can deal with very minor head lift and maintain seal.
|
Cometic HG (copper sprayed Permatex), sees about 25 psi quite often, ARP torqued to spec. No issues and not afraid to beat on it. I am afraid of turning the boost up any more with the 6MT though.
|
Originally Posted by Turbomack
(Post 1589402)
Cometic HG (copper sprayed Permatex), sees about 25 psi quite often, ARP torqued to spec. No issues and not afraid to beat on it. I am afraid of turning the boost up any more with the 6MT though.
https://cimg1.ibsrv.net/gimg/www.mia...8b63fb7d35.jpg Block side of hg was fine https://cimg3.ibsrv.net/gimg/www.mia...6a52d062a8.jpg Head side of hg showed a different story. |
Originally Posted by andyfloyd
(Post 1589400)
Wow, that's interesting. I went with a oem MLS this time instead of the cometic MLS last time. Will see how it goes, I don't expect I'll have any issues at 25psi (hopefully)
|
All times are GMT -4. The time now is 06:14 AM. |
© 2024 MH Sub I, LLC dba Internet Brands