rotary1307cc

iTrader: (5)

quick question, I just got done installing my new heads and have heat cycled the engine a couple times

I would like to re-torque the headstuds once now

I know to go one at a time in order, but how far do I back the nut off until i torque it back down??

do i release all the tension from the fastener? or instead loosen it like 90* and then torque it again?

this is on 12pt ARP studs and LS9 HG's

Thanks

Zac

Grr

iTrader: (2)

wtf i cant beleive no one is answering this zac. I would just recheck without loosening myself

rotary1307cc

iTrader: (5)

i guess i am not cool enough for a responce

020NN20

iTrader: (13)

I'm subscribed and waiting for an answer to the same question.....If I had an answer, I'd give it, sry man

rotary1307cc

iTrader: (5)

Its the turbo guy! haha

Snyper

iTrader: (27)

I never re-torqued and never had an issue. (even over heated the **** out of the car twice--radiator hose popped off)

Monte4ever

iTrader: (2)

I have not started up my LS yet but on my BBChevy with ARP head studs I never retorqued them and never had any problems with them.

rotary1307cc

iTrader: (5)

well you hear some say it is important and some say it isn't

i know it seems to be a big deal in cummins land when using MLS gaskets and studs, so i dunno

4SFEDSS

iTrader: (19)

I just put mine in and arp says in the instructions that they dont need to be retorqued as long you use thier lube during the install. They say it will produce acurate torque consistently.

AFASTYZFR1

iTrader: (55)

I never re-torqued mine.....80fts lbs

cjg454ss

iTrader: (27)

i retorque to 95lbs, i originally torque to 90, checked after a few passes, they were only at 76-78lbs, torque to 95, seems good to 25psi now. no water pushed during a pass.

willizm

iTrader: (10)

Since we are talking about head studs what about install. Do you measure for stretch or just tighten and losen a few times before finally torqueing?

cjg454ss

iTrader: (27)

with orings you have to retorque, the oring will cut deeper into the gasket and head after some run time and need to be retorqued.

everyone in this thread that posted they dont retorque has oring setups?

without the orings, one torque will work
with orings, you have to retorque.

rotary1307cc

iTrader: (5)

Makes sense with what you say about the rings


although i did do a retorque, and i think it was for the best



what i did was go in order one at a time and back the nut off 90* and then torque it back to spec. Then move to the next stud in the torque sequence

loosening 90* took just about all tension off

Most took a little more than 90* to get up to spec again, but a couple where up in the 130-180* area

I dont think it pays to just go in and check the torque with out loosening them some because overcoming the static friction to start moving the nut ***** with you

Mike454SS

iTrader: (4)

You can't get below the studs, so you really can't measure the true stretch of the fastener. When you do this on rod bolts, you have access to both ends of the fastener while it's in the rod...allowing you to measure the total stretch of the entire fastener. If you're just measuring where the end of the stud is relative to the block, you're not getting an accurate measurement of how much the stud stretched...how much of that delta in measurement is the head/gasket/block seating together? How much of it is the gasket compressing (MLS really isn't compressing, but air gaps between layers of the gasket are being removed)? How much of it is the block distorting slightly under the clamping load and thus allowing the fastener to move up a bit (yes it does distort, a lot more than some think)?

In theory you're right...but thats the entire purpose of using the correct lubrication when you install a fastener, so that friction (between the nut and the head, and to some extend between the threads in the nut and those on the stud) is not only significantly lower, it's significantly more predictable so that you arrive at the correct pre-load on the fastener. Thats why ARP recommends using their lube, especially in more critical applications like rod bolts, main studs and head studs. The pre-load of the fastener is what actually matters, not the torque required to get it there. Thats also why so many torque specs on critical fasteners are a very low torque spec, followed by a degrees of rotation spec. The low torque number is easy to achieve without friction (due to surface prep or lubrication) being a significant factor...it's high enough torque to make sure the 2 parts are actually seated together and that the fastener is ready for pre-load...the rotation spec is then based on math taking into account things like the pitch and diameter of the thread, and the material the fastener is made from among other things.

Since you loosened them all just about 90 degrees from where they were previously torqued, and some of them turned 130 while others turned 180 to arrive at the same torque value, I'd be very nervous about whats going on at this point, as it sounds like you may have done more harm than good. It sounds to me like some of the fasteners yielded, or possibly the surface between the head and the nut on the head studs that took lower torque galled (increasing friction and resulting in torque going through the roof without achieving the correct pre-load. If that were my engine, at this point, I'd yank all the studs out, and throw them all away, inspect the heads, then put in all new fasteners.

rotary1307cc

iTrader: (5)

I agree with what you say, but explain this as I should have explained a bit more
and this is why i still feel good about it

heads are new, I originally torqued these to 80 ftlbs with ARP's lube (I over do it with the stuff too, so there was no lacking lube)

heat cycled the engine 3 times

The "normal" studs acted in this way..... when backed off 90* they just about had no tension but there was just a hair still there..... then took just over 90* to come back to 82 ftlbs


The couple of "un-normal" studs that took the extra distance acted this way....... when backed off 90* there was no tension, they actually lost all tension around that 45* mark..... (which i noticed and thought was weird)

then they took the that 130-180* to come back up to 82 ftlbs


why this is, I do not know, but they all came up very even and progressive


not a biggie either way, i can do gaskets in my setup in no time

camarols1

iTrader: (17)

Very good post by Mike.
I agree completely about the fact that some of the OP's fasteners could have issues.
For MLS apps, I have had good luck letting the fasteners "settle" overnight and then make another pass to double check the installation before moving forward.
You really shouldn't see much change, if you do, something is wrong.
My concerns about backing them off before a retorque is that that you may introduce another variable in to the process. I'm not an engineer, but I would have to think that a simpler installation process would yield (pardon the pun) more consistent results.
The torque angle fasteners used by the OEM's are a good example of eliminating any variables to ensure equal "stretch" of the fastenters.
The best fastener in the world is useless if not properly loaded or 'stretched" at installation.
For an o-ring setup, a retorque is mandatory after the engine is brought to operating temps.

Phil99vette

iTrader: (11)

We run copper and o-rings and dont retorque