Re-Torque Head bolts [Archive] - Team Camaro Tech

: Re-Torque Head bolts


DenRS
Mar 13th, 08, 07:06 AM
I used a Felpro 1094 .015 rubber coated embossed steel shim head gasket on my 350 when I installed my trickflow 195cc aluminum heads. I used the arp bolts sent in the kit with arp thread sealer and moly lube on the heads of the bolts. I broke my cam in a few weeks ago and haven't fired my engine since. Trickflow says if I followed their instructions which I did, it's not necessary to retorque the bolts with the 1094, but it wouldn't hurt to check a few to see if they loosened up. The speedshop I bought the gasket from says I should. Waiting from a response from arp. Should I re-torque the head bolts? If so what is the correct procedure to do this?

tgifford5
Mar 13th, 08, 08:24 AM
I would go back and check. I don't know what the correct order is off the top of my head. But if you have a factory owners manual it will give you the torque specs and proper order. There may even be a post with the torque order in it. Do a search.

BlackoutSteve
Mar 13th, 08, 11:58 AM
If you retorque your head bolts...
Crack each one back anti-clockwise about 1/8 turn and then bring back to spec torque again. Do this to each bolt, one at a time in the correct bolt sequence/order.
It is necessary to undo each bolt slightly as the bolt's static friction in the threads (the break away torque) will almost always exceed the dynamic friction at the correct torque value.
If you don't back the bolt off slightly, the torque reading of a loose bolt will actually appear to have as much, or more torque than originally applied/specified. :thumbsup:

osin68
Mar 14th, 08, 06:44 AM
I have never had to retorque head bolts. If you use a good bolt and your surfaces are straight and clean it all will be good.:beers:

wildman926
Mar 14th, 08, 09:02 AM
I had to go back and retorque. One day after about 500 miles, I had white smoke coming out of one side, and I saw coolant/oil going down the block. Retorqued head bolts, all is fine. It may not stay that way since I did not retorque it sooner, but I am close to 4000 miles now without any issue. My heads and deck were milled. I should not have had an issue according to some I spoke with.

Bottom line, retorque, up to 3 times if necessary.

camaroman7d
Mar 14th, 08, 10:50 AM
You shouldn't have an issue, you used a good gasket and good bolts. I doubt you will have any problems. It wouldn't hurt to retorque them but, I think you will be wasting your time. If it will give you peace of mind then do it, nothings worse than worrying about something that you have doubts about.

Fred Ficarra
Mar 14th, 08, 11:06 AM
I re-torqued once. In 1964 on my '54 Hudson. Then I stuck to Chevy's.;)

BlackoutSteve
Mar 14th, 08, 11:58 AM
It's not about high quality bolts or gaskets as to whether you need to retorque.

After several heat cycles, head gaskets "relax" (their compressive resistance reduces) and therefore the preload of the head bolts is reduced. Like slack in a rope.

It's just like with hose clamps. With a small amount of heat and time, a new hose conforms to the clamp, and the clamping force is effectively reduced resulting in a leak. Retorquing restores the clamping force and stops the leak.

rojo
Mar 14th, 08, 12:07 PM
Question. What happens to the thread sealant on the bolts when you retorque? Is there a chance that a coolant leak could develop?

camaroman7d
Mar 14th, 08, 03:10 PM
Why would Fel-pro and Trickflow tell him that they do not need to be re-torqued? What do they have to gain or lose? It is about the quality and type of gasket and the material it's made of as well as the quality of the bolts/fasteners. When all else fails follow the manufactures directions. Most of the more modern gaskets do not "require" a re-torque. My Cometic head gaskets on my blown SBC were not re-torqued nor were any the of the Fel-pro head gaskets on any of the several engines I built for my Camaro. I never had an issue with any of them. In the end we all have to do what works for us, a re-torque won't hurt anything but, I personally don't think it is needed and I wouldn't worry about it.

BlackoutSteve
Mar 14th, 08, 08:58 PM
Thread sealant like GM sealing compound is a non-hardening type so it reseals without a problem. It's designed for head-bolt applications where retorquing is a standard proceedure.
If you're worried about leaks created by retorquing, use a stud kit.

Some head gaskets are also preflattened and/or are designed not to "relax". If the manufacturer of the gasket says a retorque is required, I'd follow that advice.

Retorquing has nothing at all to do with bolt or stud type or quality. :)

zdld17
Mar 15th, 08, 05:35 AM
Yes this question does raise a question as Felpo calls their blue gasket, the Permatorque gasket, needs retorquing. Yes, good head studs is another reason that retorquing lessens the chance for leakage.

77wolf10.85
Mar 15th, 08, 06:06 AM
quote:The speedshop I bought the gasket from says I should. Waiting from a response from arp. Should I re-torque the head bolts?


ARP recommends retorque after run due to gasket. See their 2007 catalog pg 36

hhott71
Mar 15th, 08, 06:30 AM
the cost benefit ratio is a good measurement of what to do.

It costs you nothing to check them.
The benefits of knowing all is good is priceless.
The benefits of finding a problem now will save you 10-fold later.

phel69
Mar 15th, 08, 06:21 PM
If you used teflon type sealer then I would not retorque the bolts. The teflon sets up and you would create the possibility of a leak by retourquing them. If you aren't having a problem then why try to create one. If you have no leaks then leave it alone.There's no performance gain to be had by retourquing the head bolts.
If you used a non hardening type sealer on the bolts , no big deal, go ahead. Teflon type sealers should be left alone.

rojo
Mar 15th, 08, 06:37 PM
I guess that's what I was questioning as I recently used the Permatex Teflon Sealer. Instructions read "...adjustments can be made up to 24 hours without damage to seal". Most engine builds from first torque to break in would far exceed 24 hrs. In my case more than 24 days.

prostock
Mar 16th, 08, 03:14 PM
the thin gskts have been the racers choice forever, they call em steel shims, or beaded steel , they are thin and provide great heat transfer, the old school race engine had two stacked up with a double coat of K and W copper spray, and they always need retorque after u get it to temp. we used to leave the rad cap off till we did the retorque. beaded steel always needs retorque, composition gaskets or steel in a paper sandwich don't need retorque and thats why they call em permatorque.

BlackoutSteve
Mar 16th, 08, 04:17 PM
If you used teflon type sealer then I would not retorque the bolts. The teflon sets up and you would create the possibility of a leak by retourquing them. If you aren't having a problem then why try to create one. If you have no leaks then leave it alone.There's no performance gain to be had by retourquing the head bolts.
If you used a non hardening type sealer on the bolts , no big deal, go ahead. Teflon type sealers should be left alone.


Sounds like a good reason not to use teflon paste.

If a gasket asks for a retorque, it's usually because the gasket requires a retorque.

camaroman7d
Mar 16th, 08, 09:15 PM
I used a Felpro 1094 .015 rubber coated embossed steel shim head gasket on my 350 when I installed my trickflow 195cc aluminum heads. I used the arp bolts sent in the kit with arp thread sealer and moly lube on the heads of the bolts. I broke my cam in a few weeks ago and haven't fired my engine since. Trickflow says if I followed their instructions which I did, it's not necessary to retorque the bolts with the 1094, but it wouldn't hurt to check a few to see if they loosened up. The speedshop I bought the gasket from says I should. Waiting from a response from arp. Should I re-torque the head bolts? If so what is the correct procedure to do this?


Let me correct myself. I ASSuMEd you were talking about Permatorque (silicon embossed) gaskets when you said "rubber embossed" after researching I see that the gasket you have is a steel shim with a coating. In that case I probably would re-torque. I would do what Fel-Pro suggests, after all it is their gasket.

hollywood406
Mar 17th, 08, 07:56 PM
I run Fel-Pro perma-torque gaskets and they're not supposed to require re-torque but since I started running aluminum heads they're ALWAYS loose after I go thru several hot/cold cycles. I don't need to loosen them either, I can put a torque wrench on them and pull on some of them at least a quarter turn. I also use the ARP head studs. I would re-torque. The ARP assy lube should still be flexible enough.

Straight-line-69
Mar 17th, 08, 09:00 PM
According to Fel-Pro, retorquing their "Permatorque" gaskets is counter productive. I'd follow the advice of the engineers who designed the gasket.

DenRS
Mar 18th, 08, 03:43 PM
Thanks for the responses. I think I'm going to retorque before I fire it up again. The reason I asked is I couldn't find anything from felpro stating I needed to retorque. The instructions that came with the head gaskets didn't mention it. The speed shop said yes, trickflow no. Someone posted that in the felpro catalog it requires a retorque so I'll follow their instructions. I used arp thread sealant on the threads, so hopefully no leaks after the retorque. Not looking forward to removing my headers again.