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after every hour of run time
 

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:p:p:lol:

j/k
 

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I torque them once... at build time. That's it.

Turbo, nitrous... so take my statement for what it's worth. I haven't had any head gasket issues.
 

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It should be done after a good heat cycle. Any competent engine builder would tell you that. You bolt the engine together cold, after you run it, everything heats up and expands
 

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The head bolts are stretched before it heats up. They expand and cool like everything else.

You do not need to retorque them.
 

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yes you do, check them, they will not be have the same torque on them....guaranteed. Like I said, any competent builder would recommend it, now you may not have any problems not doing it.....just no reason not to
 

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All racing engines should be re-torqued regardless of the type of gasket being used. The purpose of re-torquing the cylinder heads is to restore the proper stretch to the head bolts after the first heat cycle. Physics dictates that the engine assembly will expand as the engine temperature increases, this expansion will increase the compressive load on the head gaskets causing a seating effect sometimes referred to as creep relaxation in composite head gaskets. The seating of the gaskets and threads results in a comensurate relaxation of the head bolts when the engine cools. Re-torquing the head bolts/studs restores the proper stretch to the fasteners which will insure proper cold sealing of the gaskets as well as proper combustion sealing under full load. One re-torque is all that is necessary, subsequent re-torqing can cause plastic deformation (stretch) of the head fasteners and damage to the head gaskets.
The process for re-torquing is as follows:
Start the engine & run with no load until operating temperature is reached.
Shut down the engine & let cool completely (overnight).
Retracing the original torque pattern, one fastener at a time, loosen slightly to overcome the friction set of the bolt or nut, then re-torque to specified torque setting.

:)
 

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Oh so now a competant engine builder recommends it? But doesn't say you have to. :rolleyes: No you don't have to retorque them. But hey, if it puts your mind at ease, do it.

If your surfaces are true and you torque it in stages and sequence to the proper torque for your application they will hold.
 

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All racing engines should be re-torqued regardless of the type of gasket being used. The purpose of re-torquing the cylinder heads is to restore the proper stretch to the head bolts after the first heat cycle. Physics dictates that the engine assembly will expand as the engine temperature increases, this expansion will increase the compressive load on the head gaskets causing a seating effect sometimes referred to as creep relaxation in composite head gaskets. The seating of the gaskets and threads results in a comensurate relaxation of the head bolts when the engine cools. Re-torquing the head bolts/studs restores the proper stretch to the fasteners which will insure proper cold sealing of the gaskets as well as proper combustion sealing under full load. One re-torque is all that is necessary, subsequent re-torqing can cause plastic deformation (stretch) of the head fasteners and damage to the head gaskets.
The process for re-torquing is as follows:
Start the engine & run with no load until operating temperature is reached.
Shut down the engine & let cool completely (overnight).
Retracing the original torque pattern, one fastener at a time, loosen slightly to overcome the friction set of the bolt or nut, then re-torque to specified torque setting.

:)
Nice quote. That's old school. Head studs and bolts are better than they used to be. Tom, it all depends what you are building and to what extreme. There are all kinds of different torque specs and sequences for different applications. That above statement couldn't get more generic.
 

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Nice quote. That's old school. Head studs and bolts are better than they used to be.
I assume you didn't really read it, the basic idea does not really involve the the stretch of the bolts. It really has more to do with the gaskets and while the quote mentions composites, mls will do the same to an extent, though it's not really creep, it's more of a compression set.

actually here's a quote from ARP on their site...
The studs should be installed finger tight. Then, when applying torque to the nut, the stud will stretch only on the vertical axis. An undercut shorter stud will have a rate similar to a longer, standard shank stud. This provides a more even clamping force on the head. Because the head gasket will compress upon initial torquing, make sure studs (or bolts) are re-torqued after the engine has been run.

When my 800 Fundy kept blowing head gaskets, you wanna guess what the first thing Ray asked me if I had done :)

 

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There are 8,000,000 pages on the net that say you don't have to retorque. There are 8,000,000 pages that say you can. Who is right? Do a search. You'll be amazed. But everyone on the net is right.

How come you didn't retorque your AMR840 when you did the head gaskets in the camp ground? :hmm:

Alot of factors determine torque ratings. Style of bolt/stud. Length. Diameter. What type of material. What material it is clamping (head gasket choice). What type of material the head and block are made out of. What type of lube you use on your head bolt. Do you back off the bolt a 1/4 turn before retorquing? That's a whole new argument there itself.

Do what you want.
 

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What does it hurt to retorque the heads.

Cheap insurance IMO.

If Monkey said you didnt have to retorque them Camo would have said you needed to. You to just are keeping this going for your own entertainment.:p
 

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You to just are keeping this going for your own entertainment.:p
sorta :lol:

There are 8,000,000 pages on the net that say you don't have to retorque. There are 8,000,000 pages that say you can.
I checked...it's 8,000,001 that say you should :p

I didn't do it out there because......I was probably to busy washing yours instead :wub::lol:
 

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:lol:

But why pull the rocker covers and go through the PITA if it's not needed? Done properly with prefect mating surfaces, steel head gaskets, bur free bolts that run in easily by hand, proper lube on the threads and head of the bolt, along with 3 or 4 stages of torquing in the proper sequence... I'm sticking to my story. You don't need to.

Man I'm gonna catch hell if I start pouring the coal to mine next July and pop a gasket. :lol:
 

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Discussion Starter · #17 ·
Well when I checked mine before it blew the gasket the bolts were fine not one of them had backed out. I put the covers back on went to a race bam it blew a gasket. I have ran the piss out of it here with NO issues since I got it home this last time...
 

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fwiw,

I just tore down my motor to replace headgaskets/freshed up the top-end. Just for grins, I checked the torque on all head bolts. They were the same torque as when I last installed the heads 1.5 years ago...I never retorqued these head bolts.

With that said, I might do the re-torquing proceedure if I had easy access to the heads (like on a V-force)....but its a MAJOR PITA to do this on a Prairie/Twin Peaks (too much plastics in the way, etc.)! So that is why I have never bothered to re-torque the head bolts on mine.

Happy trails...:)
 

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Discussion Starter · #19 ·
Thanks Mike... It has the good head studs in it. I think I'm gonig to let it ride if I have issue's I will cross that bridge when it comes:)
 
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