technicalninja

That cut ring gasket is .055 thick.
I believe the compressed stock Mazda MLS is .040-.045 thick.
It MAY be stronger but it will definitely reduce quench which is a BAD thing in my book...
Quench should be IMPROVED, not reduced in any application that will run pump gas.
If you're specifically running heavy fuel it doesn't matter.
E85, methanol, 110+ race gas are not nearly as critical regarding detonation.

Now, If anyone can find a cut ring gasket that is as thin or thinner than the stock MLS that would be the ticket...
The .055 gasket would work fine with the block "decked" .010-.015

andyfloyd

I spoke too soon I think. When I was torqueing the nuts the #4 cylinder passenger corner stud made a cracking sound as I was passing ~80ftlb. I then went and torqued it to 90ftlb but it did require more turns than I thought it should. Didn't think a lot of it, car ran and started fine. Drove it 20 miles it was fine, didn't really boost it that day. Yesterday I went and did some virtual dyno pulls, before I even did a pull I noticed on startup that the car had a slight misfire that went away, little smoke came from the exhaust, I went home and picked up my laptop and when I started the car the same thing happened. Then as I was driving the car and came to a stoplight the car started to sound like a Subaru and white smoke was pouring from the exhaust. Once moving the smoke kinda goes away and drives fine, but at idle it's messed up. Pretty sure I cracked the head in the corner and it's leaking coolant into the cylinder. I pulled all the plugs and they looked ok, the #4 cylinder and #3 looked kinda wet. I pulled the VC and pulled the stud shined a light down there and didn't see anything, but something is definitely wrong. It's odd because on startup the car seems ok, then once it warms up it gets progressively worse. I'm gonna have to pull the head, and luckily I have a spare head I may end up using and pulling all the new springs/retainers I just bought and transferring it over. Pretty disappointed, and I can say I would not recommend 90ftlb now.

sonofthehill

iTrader: (1)

People should listen to EO2K

Twibs415

iTrader: (8)

soo basically you didn’t confirm it cracked the head and are saying it did.

Any real info like it’s consuming coolant or it has intermix of fluids? Or a visual check at the boss area? Sounds like conjecture at this point.

I think people in this thread are well beyond the realm of stock power output and know that “miatas don’t lift the head” is in fact a false and dated.

Threads from 10 years ago when arp was specing wrong washers shouldn’t be mentioned in here.

andyfloyd

Pretty sure I said I didn't pull the head yet, it's consuming coolant, and I did pull the VC and the stud and have a look at the stud boss and didn't see anything. There is no mixing of fluids but it's eating coolant. I'm making an educated guess and yea I wouldn't recommend this much tq, because I never had this particular issue previously at lower 70ftlb. I'll know more when I pull the head but life and a job makes that difficult at the moment.

emilio700

iTrader: (3)

Our reply to the same question you asked in this thread:

"Hi Nick,
On our engine builds we use the recommended value which would be included in the box. On our HB head studs that's 90 ft lbs.
That said, we have seen the same reports you have regarding head cracking. Not something we've experienced. Ultimately that will be between you and your engine builder if you want to use the recommended value or go with something lower.
Ed"

It sounds like you wanted from us, a definitive guarantee that your head would not crack. Of course we can't offer that. There isn't a lot of data for 30+psi, HB studs and 90 lbs torque. Our experience has been positive. Others have reported cracking heads with thinner studs and lower torque values.
We're all in uncharted territory here. Our message is that lacking a definitive scientific answer, it's up to each person to weigh the risks of modifying their BP to quadruple stock power. We can't offer you a cut and dried yes/no answer. Just share our experience and let you decide what's best for your project.