Over torque Head bolts?

[hubert3317]

Is it a good idea to retorque the head studs to over the factory specs? and can you pull the out of the head one at a time to oil the threads like i saw on a u tube video

[JOHNFAK]

Yes you can and people do to hold more pressure. Just obviously there is a breaking and stretch point ... So have to be careful how far u go.

[Wild and Free]

Ok the title says bolts and in the thread you ask about studs so which are you wanting to know about because they are both very different animals?

[hubert3317]

sorry about the confusion. my truck still has the stock head bolts in it. Should i retorque them to a tighter spec or just leave it alone? Also can they be removed one at a time to oil them for the retorquing process?

[Wild and Free]

I would leave the stockers alone. Don't mess with it if there is nothing wrong, you won't gain anything at this point. Stock bolts have a stretch to them when torqued to the correct spec where as studs are done by torque because the material doesn't have the stretch factor of the stock bolts.Another way to think of it is the stock bolts keep the head "pulled" down and studs keep the head "Clamped" down.

[bristoy]

i agree with the previous reply,leave them alone.your running your stock injectors& turbo basiclly making stock power.the bolts as they are will hold just fine.those that are retorquing them are doing so to try to hold in more cylinder pressure than stock due to the engine mods they've done.

[pepsi71ocean]

the only reason you should over torque them, and not check their torque is because you are runnign more boost.the stock bolts at stock torque are good to about 28psi, and should be re torqued down if your going up to 40psi. anything above that and you should consider head studs.

[Wild and Free]

the only reason you should over torque them, and not check their torque is because you are runnign more boost. the stock bolts at stock torque are good to about 28psi, and should be re torqued down if your going up to 40psi. anything above that and you should consider head studs.

You would be surprised at how many high performance guys use stock head bolts over studs and run without problems with o-rings to 50+ psi. Stock studs are absolutely safe to 40 psi consistantly. Retorques on stock bolts should only be done after a new head gasket is installed and not to the extent that studs need to be either, after a few heat cycles one retorque round is all they would need to take up the initial gasket compression.

[pepsi71ocean]

You would be surprised at how many high performance guys use stock head bolts over studs and run without problems with o-rings to 50+ psi. Stock studs are absolutely safe to 40 psi consistantly. Retorques on stock bolts should only be done after a new head gasket is installed and not to the extent that studs need to be either, after a few heat cycles one retorque round is all they would need to take up the initial gasket compression.

and yet they are not torqued to handle 33-35psi, i know of plenty of trucks that came through the Cummins shop that had lifted heads. if you run over 30 psi you should re torque the head studs. if this was not the case why do the guys at the Cummins shop re torque them to 135lbs instead of 125 when they reinstall a new gasket on the blown 5.9l's?

[Wild and Free]

and yet they are not torqued to handle 33-35psi, i know of plenty of trucks that came through the Cummins shop that had lifted heads.

if you run over 30 psi you should re torque the head studs. if this was not the case why do the guys at the Cummins shop re torque them to 135lbs instead of 125 when they reinstall a new gasket on the blown 5.9l's?

Once again we are talking about 2 different things, I am referring to head bolts you are referring to studs. Refer back to my first 2 posts in this thread.

My 02 has 140K miles on it and 100k of those have been over 450 hp and the last 60k have been at 560 hp and 42 psi on my silver 62 with 150 hp injectors and my engine is virgin and has the original stock head gasket in it yet and has never been retorqued.

It all goes back to the OP and retorqing on an older higher mileage head gasket. there is no benefit to it at this point in its life as one would have to remove them clean them up then retorque them down 1 at a time as over time they almost freeze in the block.

I am not telling anyone not to do it just saying it is of little benefit on a Head gasket with high miles on it already with stock head bolts.

[Blueox01]

and yet they are not torqued to handle 33-35psi, i know of plenty of trucks that came through the Cummins shop that had lifted heads. if you run over 30 psi you should re torque the head studs. if this was not the case why do the guys at the Cummins shop re torque them to 135lbs instead of 125 when they reinstall a new gasket on the blown 5.9l's?

Where did you get torque specs? Every thing I've ever read was to torque in sequence 59 Ft.lbs,77 ft lbs, recheck at 77 ft lbs then 1/4 turn,nothing at 125 or 135 ft lbs.

[Wild and Free]

Where did you get torque specs? Every thing I've ever read was to torque in sequence 59 Ft.lbs,77 ft lbs, recheck at 77 ft lbs then 1/4 turn,nothing at 125 or 135 ft lbs.

The 125-135 is an estimated torque they give as the 77ft lbs plus 1/4 turn would be close to that, reinforcing my description of the stretch on stock bolts having constant pull down on the gasket versus the clamping force of studs with set torque values and thus the constant retorque procedure needed do to the lack of stretch that studs have.

[Blueox01]

The 125-135 is an estimated torque they give as the 77ft lbs plus 1/4 turn would be close to that, reinforcing my description of the stretch on stock bolts having constant pull down on the gasket versus the clamping force of studs with set torque values and thus the constant retorque procedure needed do to the lack of stretch that studs have.

Ok, I pull close to 30-32psi and used stock bolts with a gasket set from cummins,it came with a stretch gage for the bolts,hav'nt had any problems in 300k.

[JOHNFAK]

Ok, I pull close to 30-32psi and used stock bolts with a gasket set from cummins,it came with a stretch gage for the bolts,hav'nt had any problems in 300k.

Yeah most problems don't seem to come until your over 40 psi from what I've read ... Sometimes stock will hold higher but depends on age of gasket and straightness of deck .... Mighty bolts seem interesting as a cheap alternative ....