LooseBoltsRob

I have put a good 7k miles on my silver 62 and love it. When I installed it, I adjusted the actuator rod to squeak out 50 psi in high gears. With the Smarty beta and TS MP-8, I'm seeing 51 to maybe even 52 psi when I roll into the throttle in 5th or 6th gear. Making a WOT pass from a lower gear will NOT see more than 45-46 psi in 5th and 6th gear, so it's only when I'm rolling into the throttle. I have ARP head studs sitting on the work bench, but I'm pretty happy with everything the way it is now so I am thinking I may not install the studs. Am I pushing too much boost and risking blowing the head gasket? I hate to lower it since it will not see much over 45 psi in lower gears and when rowing through the gears at WOT.

Thanks!!

tritont

wow ! I'm surprised you haven't blown it yet. They're are suppose to be good to around 45 to 50psi.

You can torque down the stock bolts very carefully to 100ft. lbs or even 120 if you're good. Do some searching for the correct way to do it and you really won't need to install the studs.

Even with studs you can lift the head running a lo0t of boost.

OldSmokey

Ive been told around 45 psi without studs.

PS how do you like the Spec clutch. I havent heard much about them in a long time?

CDoskocil9

TritonT Got any more info on tourqing the stock studs????

kantdrive55

Our 05 ran over two years seeing in up to 70psi with stock head bolts. We normally ran it to 55psi without any issues.

tritont

edited.....

OldSmokey

Do you have to pull the studs and grease them? before you start torqueing them down.

tritont

I don't know for sure. I'm pretty sure though they're already lubed from the factory because I've seen may trucks with the goo coming out around the threads so, you should just be able to torque them down

OldSmokey

I think this might be a little to scary for me! Anyone know what stock studs are torqued to?

LooseBoltsRob

Woah....well, I guess I should do the safe thing and tone it down some.

The SPEC is great with a stock turbo, but I'm slipping it now with 5th and 6th gear roll ons. It held fine for a while w/ the Crazy Larry and regular Smarty tunes, but with the beta program and 50-52 psi, it's slipping. I was going to go with a SPEC Super Twin, but decided to play it safe and go with a SBC DD 3250 12 CB. Peter said it should be good for 650+ HP and 1400 ft/lbs.

Watch...I'll lower the boost to 46-47 and the dang clutch will probably hold! GRRR!! Well, I need something to be stupid with, like 3rd gear burn outs and hard 4WD launches in 2nd.

Thanks for all the replies guys! Has anyone on here personally blown a head gasket at 50-55 PSI with stock studs?

tritont

the manual says to do it in four steps

1. tighten to 52 ft.lbs.

2. back off 360 degrees

3. tighten to 77 ft.lbs.

4. rotate 90 degree.

then you'll want to get the engine up to running temp, shut it down and retorque. You should be good for there.

enafzige

Stock head bolts are to be torqued to 77 ft-lbs and then an additional 90°.


This is from the '06 manual:

a. Torque bolts to 70 N·m (52 ft. lbs.).
b. Back off 360 degrees in sequence.
c. Torque bolts to 105 N·m (77 ft. lbs.).
d. Re-check all bolts to 105 N·m (77 ft. lbs.).
e. Tighten all bolts an additional 1⁄4 turn (90°).


When using stock bolts/gasket, you're taking chances on anything over 45 lbs boost. One reason is because there is a tolerance on the "flatness" of both the deck and the head from the factory; thus, this variation will allow some to hold more boost than others before comprimising the head gasket.

Second, heat is also a major factor when it comes to blowing head gaskets. On my '06 I ran for a couple months hitting 1450° EGT and 60 lbs boost before I had gauges...and I count my blessings that things didn't blow. Maybe the tolerances on mine are a little closer than most, but I would not be comfortable running at those levels with the stock bolts.

I've bottom tapped and studded the head now, and have been running 60 psi daily for 6 months with no problems yet. It's just one of them things, you never know till it blows...

--Eric

LooseBoltsRob

Thanks for the info Eric! As far as high EGTs go when risking a gasket, that isn't an issue thankfully! I never see over 1200 degrees, so maybe the higher pressure with cool combustion temps will let her live. well, if the bug keeps biting like usual, I'll wind up throwing the studs on and doing injectors while I'm there....I can never leave stuff alone as much as I want to.

As far as adding torque to the stock bolts....be careful! I may be wrong, but usually ANY bolt that requires an additional amount of turn beyond a set torque figure is a torque-to-yield bolt....these are NOT supposed to be reused or retorqued. Again, they may not be T2Y bolts (all T2Y bolts use that type of tighenting sequence), but if they are, you don't want to add torque or reuse.

KMKDiesel

If you even wondering just throw your studs in and you wont have to worry about snapping a stock one trying to tighten them more, or go for it you snap on then you got a whole set of new ones.

cquestad

I ran 100k at 55-58 psi daily on the stock bolts...

Its drive pressure that kills um...not boost. With the right turbo(2) the OEM set up lives fine for a long time.