maxpro

I'm running a 1.8 sleeved to a 2.0 L, Garrett GT3071R and seemed to be making good power. Took it out on a cold day (30 degrees) and was running 18 PSI of boost. I had a backfire in the engine and it blew the head gasket. Now here is my question. The ARP head studs are recommended to be torqued to 65 ft lbs., is this too low for the level of boost that I'm running?
Thank you in advance for your help.

Zsanz

The lubed ARP head studs are recommended at 65 ft-lbs so no it is not too low.
How do you know its the head gasket?

Head Gasket Brand:
Mileage:
18 psi on 12:1cr?...

Lexzar

iTrader: (2)

We would need more info, either, head/block wasn't flat enough, detonation, both?

psyber_0ptix

iTrader: (4)

What do you think will happen when you torque them even tighter?

matrussell122

iTrader: (1)

Id guess that something will break and the guy will see zero gain from over torque.

maxpro

I did a compression test on all cylinders and have a leak between #2 and #3. It also blew out a freeze plug and the back of the engine block. I will have it apart in the next day or so to confirm. Thank you for your help.

maxpro

I was just wondering if the boost was too much and raising the head from the block. Thanks for your help.

matrussell122

iTrader: (1)

Your good. You aren't running a crazy amount of boost just use the torque spec given. Now if you didnt have arp studs id say every day of the week that they are stretching. Just replace gasket and freeze plug and torque to spec and you will be golden. Maybe even re deck the head and block depending on how they look.

patsmx5

iTrader: (16)

I have lifted a head with stock head bolts, lubed with engine oil, torqued at 45 ftlbs, with 23 PSI boost. (bad torque wrench). I have run ARPs at 65 ftlbs, with the arp lube, to 40 PSI and not lifted a head. I now run ARPs at 72 ft*lbs with bigger washers at 35 PSI and no problems. I'd check your torque wrench and see if the head/block is warped.

maxpro

Thanks, this is very helpful. Just curious what size washers did you go with? Thank for your help.

18psi

iTrader: (76)

People have cracked heads before several times from going over 65lb. I would not recommend. Esp since many of us have gone to 350-450 on standard arp's without issue

maxpro

I have seen several quotes of over torquing the heads and damaging the heads but I didn't seen anything related to higher boost. This is why I'm here to save me from myself..... Ask the questions and get the wealth of experience from the forum. Thanks.

18psi

iTrader: (76)

That's a good approach.
Higher boost shouldn't matter until you get into the really high numbers (think 30+ on healthy snail that can maintain that pressure for a broad range). Over tightening fasteners will yield or strip them 9 times out of 10.

patsmx5

iTrader: (16)

I posted part numbers in my build thread, I don't recall off the top of my head, sorry. They fit a supra I think.

mx5-kiwi

One of our earlier builds on a 1600, we over torqued the ARP's. The engine would just hit a wall at 6k on the dyno and was pumping a lot of oil/breathing heavy. Fortunately our tuner had seen it before and called it quits.

Sure enough, newly machined block was ovaled. A re-bore and reassemble head to 65 on the studs(maybe 60?) and every thing was good again.