Rjc Headgaskets

[notacarlo]

I run a similar set up (sandwiched gaskets) but used the metallic paint instead of the sealant.

I retorqued after the initial heat cycle which was about an hour. Then did it again a couple days later.
I did not loosen the nuts - so essentially I re-checked the torque on the heads. I have had no leakage issues. I run 26 psi at the track and 20 to work.


now....on to my PCV issues.

 

[bison]

Since were on the subject of retorquing heads....

If they don't move why do you want to loosen them and then retorque them again? Wouldn't that unload or unstabilize the fastener and then you'd have to start over your torque check?

The reason you would back off is because the starting friction is alot higher than the friction involved once the fastener is being tightened. If a fastener was torqued to 80 ft lbs it would take a lot more than 80 ft lbs. to break it loose. This way you know you have a consistant clamp load on all the fasteners. I tried a lot of combos back in the mid to late 90's with gaskets, fasteners, and torqueing procedures. The one i stated worked best for me over the years. Back in the 90's almost everyone said the stock gasket was more than adequate. Maybe for them it was but once the car was consistently going over 125mph it was unreliable. I settled on a double steel shim combo for years and watched a lot of other guys replace their head gaskets every week while i continued to pound my engine at 25-28 psi week after week without failures. Now with better head construcion, and better gasket tech if you see failures the engine is usually hurt a lot worse than the head gaskets.

 

[bison]

so on an iron headed car with a/c box intact I wont be able to torque the pass side back head studs?

Ive re-torqued them without any problems.

 

[Turbo Steve]

The reason you would back off is because the starting friction is alot higher than the friction involved once the fastener is being tightened. If a fastener was torqued to 80 ft lbs it would take a lot more than 80 ft lbs. to break it loose. This way you know you have a consistant clamp load on all the fasteners. I tried a lot of combos back in the mid to late 90's with gaskets, fasteners, and torqueing procedures. The one i stated worked best for me over the years. Back in the 90's almost everyone said the stock gasket was more than adequate. Maybe for them it was but once the car was consistently going over 125mph it was unreliable. I settled on a double steel shim combo for years and watched a lot of other guys replace their head gaskets every week while i continued to pound my engine at 25-28 psi week after week without failures. Now with better head construcion, and better gasket tech if you see failures the engine is usually hurt a lot worse than the head gaskets.

this makes alot of sence with starting friction loss. If i'm using RJC headgaskets which would compress very little whats the big deal about retorque after a heat cycle? I could see retorgue after an hr then again next day before initial start up. I had cometics on my Z06 and had to go back over them 3 times before initial start up because of them resting and there was lots of movement.

 

[Turbo Steve]

I run a similar set up (sandwiched gaskets) but used the metallic paint instead of the sealant.

I retorqued after the initial heat cycle which was about an hour. Then did it again a couple days later.
I did not loosen the nuts - so essentially I re-checked the torque on the heads. I have had no leakage issues. I run 26 psi at the track and 20 to work.


now....on to my PCV issues.

was there any movement on the retorque?

 

[2GNS4ME]

was there any movement on the retorque?

thats my question. After heat cycle the people that did retorque did you notice movement?

 

[MSDGN]

Don't loosen the nut/bolt...just set the torque wrench to final torque spec and go over each one...after a few heat cycles I retorqued mine and I think maybe one or two moved very very little...this was with studs...I also had the engine out about a year ago and figured why not...tried retorque and none of them moved...

 

[Jerryl]

Jay,

I am certainly in no position to question your accomplishments but one thing is still unclear to me;

1. Do you loosen the bolt from the final torque setting a bit (1/8 turn), and than re-torque?

or

2. Re-torque where the bolt is at, without loosening first (1/8 turn)?

There are many conflicting views on re-torqing of head bolts and your insight and sharing of experience and knowledge is appreciated.

These are either;
1 - Stupid questions
2 - I am invisible

 

[JayC]

Retorque where its at to compensate for any sealant that might have ooozed out.

 

[bison]

this makes alot of sence with starting friction loss. If i'm using RJC headgaskets which would compress very little whats the big deal about retorque after a heat cycle? I could see retorgue after an hr then again next day before initial start up. I had cometics on my Z06 and had to go back over them 3 times before initial start up because of them resting and there was lots of movement.

I may not have needed to retorque after running it but i did anyway. It sure didnt hurt anything since its been run hard for six months and would lay down 10.50's easily with the current tune in good air.

 

[JayC]

I may not have needed to retorque after running it but i did anyway. It sure didnt hurt anything since its been run hard for six months and would lay down 10.50's easily with the current tune in good air.

If you retorque without loosening, thats probably true but if you loosen then tighten them back, you're disturbing the sealant.

 

[Turbo Steve]

I go to 75#s with bolts and 85#s with studs. I dont believe in torqueing the crap out of stuff like some people do.

Jay, how many steps before final torque?

 

[Rodney87GN]

The reason you would back off is because the starting friction is alot higher than the friction involved once the fastener is being tightened. If a fastener was torqued to 80 ft lbs it would take a lot more than 80 ft lbs. to break it loose. This way you know you have a consistant clamp load on all the fasteners.

Ok I see what you are saying. I am using ARP studs and when I did the initial installation I did the recommended 5 torque cycles. The first 4 I used an old head gasket and the final torque cycle I used the good head gasket. Then the next day I checked them again at 85 ft/lbs and none of them moved.

So I guess my next question is....would the 5 torque cycles eliminate the need to back off the nuts to do a re-torque? After all, the stud has already been loaded and stretched several times and in theory should have achieved consistant clamp load. Sorry if I sound like a pain in the ass but this has been bugging me for awhile.:biggrin:

 

[Mac in SD]

Re: heat cycles. I read an article in Hot Rod about Nelson Racing Engines (TT SBC) build-up for their "Project F-Bomb." Nelson uses a similar sealer with shim gaskets, and uses heat guns blowing into the water passages to heat the heads / block, then retorques after cool-down. All this on the engine stand. That's it, and he warrantees his high-HP TT SBCs (I think.)

Seems like a pretty good idea to me, anyway.

 

[notacarlo]

thats my question. After heat cycle the people that did retorque did you notice movement?

They never budge. I think the main reason for doing this is preventative maintenance. I would say if you went in for a retorque and you twist a couple of pounds back in, there's an issue. So if you didn't go in to retorque - there may even be bigger problems later.

 

[ronbuick]

Just did my friend Henry's car with them, re-torqed after about 3-4 hr's after install and a few of them did re tightened, the next moring just for S%&t and
giggles did it again and none moved, we will leave it at that and not re-torque as Jay says.

Ron

 

[turbows6]

Re: heat cycles. I read an article in Hot Rod about Nelson Racing Engines (TT SBC) build-up for their "Project F-Bomb." Nelson uses a similar sealer with shim gaskets, and uses heat guns blowing into the water passages to heat the heads / block, then retorques after cool-down. All this on the engine stand. That's it, and he warrantees his high-HP TT SBCs (I think.)

Seems like a pretty good idea to me, anyway.

I saw that heat gun trick too and thought it was a great idea. I might do that on the next engine I build. Maybe it would be a good idea to just pull a valve cover and set the torque specification and check one of the bolts that's easy to get to. If it clicks before the bolt moves then I wouldn't worry about it.

 

[Turbo Steve]

Just did my friend Henry's car with them, re-torqed after about 3-4 hr's after install and a few of them did re tightened, the next moring just for S%&t and
giggles did it again and none moved, we will leave it at that and not re-torque as Jay says.

Ron

yeah i'm going to wait 3-4 hrs and retorque also.....not to mention that 85ft lbs is more then 20ft lbs over stock specs and studs are superior to tty bolts.

 

[Turbo Steve]

talked to RJC today when I ordered my head gasket kit and he said dont loosen anything just go over them and make shure you use 90wt gear lube on the threads and not arp moly.torque to 85ft lbs. with a retorque after a few heat cycles at moderate boost.

 

[MSDGN]

Did he give a reason why you shouldn't use ARP moly?...that's what I used on my studs and have had no problems...