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View Poll Results: Re-Torque small block heads or not?
YES: Always retorque regardless of gasket tech info 10 29.41%
No: Never Rettorque a head gasket 10 29.41%
MAYBE: Depends on gasket manufacturers' instructions 14 41.18%
Multiple Choice Poll. Voters: 34. You may not vote on this poll

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Old 06-29-2010, 07:20 AM
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Re-Torque Poll

Should we Re-torque small block heads? Yes or NO

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Old 06-29-2010, 07:45 AM
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I really don't like the idea of breaking the bolt sealant. Use decent bolts and don't re-torque torque to yield bolts.
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Old 06-29-2010, 07:51 AM
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Still having tech problems

Hey AirBoat

Are TTY bolts available for early V8s? If so I think that would save a lot of bacon.

Still having tech problems getting the correct link to send people to the poll, Can someone fix it?

I'm not very good on a keyboard, Thanks Duntov
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Old 06-29-2010, 08:28 AM
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Don't know, but we've run 410 sprint cars for years, using everything from 1004 Felpros, to now using Cometic gaskets. Compression 15:1 and up, and up to 8500 rpms. Have always torqued to 65 ft-lbs with ARP lube- one time and that's it. No retorque.
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Old 06-29-2010, 09:21 AM
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They say with todays gasket materials, that it isn't necessary.......
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Old 06-29-2010, 10:05 AM
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Something my old man taught me, and it seems this theory works, is to torque the head bolts to 67-70 lbs instead of 65 lbs. I gave this a try and it seems to work well.
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Old 06-30-2010, 04:27 PM
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But you believe them?

Quote:
Originally Posted by poncho62
They say with todays gasket materials, that it isn't necessary.......

A----------Some of the time
B -------------All of the time
C---Depends on who "They" are
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Old 06-30-2010, 05:04 PM
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The first 20 or so engines that I built I retorqued only to find they were all in spec.

However... I have never built one with head gaskets that said to re-torque. I've always used Cometic, Fel-Pro and ROL - all of which were a one-torque type gasket.
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Old 06-30-2010, 05:08 PM
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Quote:
Originally Posted by Duntov
A----------Some of the time
B -------------All of the time
C---Depends on who "They" are
Thanks for the PM- it also was a reminder about the poll. You know my position already, but I will add it to the poll just the same.

AFA the questions- they're fine, IMHO.

Last edited by cobalt327; 06-30-2010 at 05:13 PM.
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Old 06-30-2010, 06:14 PM
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I'm learning a lot from this poll

Quote:
Originally Posted by curtis73
The first 20 or so engines that I built I retorqued only to find they were all in spec.

However... I have never built one with head gaskets that said to re-torque. I've always used Cometic, Fel-Pro and ROL - all of which were a one-torque type gasket.

I've never heard anyone say that before.. So it brings up the question; "What kind of sealant did you use on the head bolts?"

One comment though. A lot of people mark the bolt and the head, then break the bolt loose and retorque. People who do that almost always say the bolts traveled 3 hours on more on the clock position past the mark. Maybe they're breaking a combination of thread sealer and engine paint. I don't know.. Glad you participated in the poll.
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Old 06-30-2010, 06:19 PM
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Do you torque them to the full amount or do you stage it?
I torqued mine in 3 stages 30 - 45 - 65 and let them rest between stages.
I have had no problems at all.
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Old 06-30-2010, 06:30 PM
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Quote:
Originally Posted by Jake_Dragon
Do you torque them to the full amount or do you stage it?
I torqued mine in 3 stages 30 - 45 - 65 and let them rest between stages.
I have had no problems at all.

We stage in a similar way as you do. Do you ever go back and check a couple hundred miles down the line?

I should have ask in the poll what thread dope people are using also. Thanks for the comment..........Duntov
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Old 06-30-2010, 06:51 PM
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Quote:
Originally Posted by Duntov
We stage in a similar way as you do. Do you ever go back and check a couple hundred miles down the line?

I should have ask in the poll what thread dope people are using also. Thanks for the comment..........Duntov
Sounds silly, but I use teflon tape on my head bolts. An old engine builder told me this was the best method.
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Old 06-30-2010, 07:08 PM
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that seems like that is the real question, if you retorque what do you seal the headbolts that go into the coolant passages with that isn't going to leak when you retorque.

The problem with this question is that when you tighten a bolt and let it sit it "sticks" so you need a break away torque to overcome that before it will turn. If you just walk up to the engine with your clicker torque wrench set to the proper torque even if the gaskets did compress some, the break away torque will be high enough that you won't overcome the sticking and the wrench will click without tightening the bolts. The only way that you're going to tighten the bolts to the same torque setting is if you back them off first, then retorque.
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Old 06-30-2010, 07:27 PM
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Quote:
Originally Posted by Duntov
Should we Re-torque small block heads? Yes or NO
I re-torque, because, I suppose repetition builds a false sense of security if for no other reason.

For bolts, I use non hardening sealant either Permatex #3 or Hylomar, or non-hardening plumbers Teflon pipe joint compound such as Otay 31230. Since this stuff doesn't harden, it allows the fastener to be re-adjusted without loosing a coolant or oil tight seal.

Studs are set with a hardening sealer such as epoxy or some cyano-acrylic (superglue) compound so the stud will not move to break it's seal when the nuts are adjusted.

Re-torquing is a bigger issue with engines where iron blocks and aluminum heads are used with composition or multi-layered steel gaskets. This is for several reasons:

1) Aluminum expands and contracts more than cast iron, so the fastener has not only to deal with operating loads of the combustion cycle but also with the greater material expansion of aluminum. So the fasteners see actual loads that may equal or exceed their stretch (torque) loads.

2) Aluminum is soft and deforms plastically to escape loads. Which is to say that the area under the fastener will try to escape the force applied to it. You can see this on disassembly where there will be a depression under the fastening device head be it bolt head or a nut. A hardened washer helps but doesn't eliminate the condition. Related to this is the abrasion action of the soft aluminum rubbing the underside of the fastener's "head". Both actions place a loose dimension between the parts allowing the fastener to lose its grip. Tension To Yield fasteners work better in this situation as they are in a what one could call a spring (plastic) state and they will adjust to these movements to a degree that pretty much eliminates re-torquing. But these are one time use items, once pushed to their yield limit, unloading and reloading them is an invitation to failure.

3) In a reaction to #2 above, aluminum deforms along the gasket surface and will "bend" with gasket deformation (crush) and block deformation that warps the deck surface. Things like zero decking, large over-bores, extreme compression, detonation events, solid engine to chassis mounting, and most certainly overheating and in engines with paired exhaust valves super heating the center of the head all result in movements of the aluminum part to chase these events which will loosen the head bolts as the head deforms.

I'd say how often I see this depends a lot on the use of the engine. Easy street use doesn't seem to require re-torquing, I still do it for checking purposes but mostly everything is fine. Race motors are more problematic, the harder and hotter they are run the more I find that chasing proper torque is needed. This is especially true where aluminum heads have been welded on and not re-tempered to a T4 or T6 condition. The heat of welding removes the tempered hardness which resists these deforming forces. When that is removed the actions of deformation and abrasion in the weld's heat affected zone substantially increase.

Bogie

Last edited by oldbogie; 07-01-2010 at 05:31 PM. Reason: Replace incorrect use of Torque to Yield with Tension to Yield
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