SBC Cyl Head bolt tightening ft lb sequence?

[BRUTAL64]

Being cheeep and lazy I allways use RTV on the bolt threads, not an issue then....:

i also used bathroom grade clear silicone last time and many times and it works fine.

I did use the permatex #2 once and noticed the stuff never completely hardens. I would think this is the best stuff and we all should be using that.

I suspect that #2 Permatex was what the GM guys had in mind when they wrote the specs the first time. That info is lost in the history at GM. Now there are so many sealers, thread lockers, and just plain goo out there it's tough to decide. I use Locktite Thread sealant with teflon. Seems to work fine. Stays pliable, and is a PITA to clean up.

I also read something years ago -- I torque SB head bolts to 70 for all but the row of short bolts under the manifold- those go to 65. Reason is that the short bolts don't stretch as much... But that's with stock iron heads too. Aluminum I'd go with the mfr's specs. And most of the alumunim heads have a deck that's 1/2 to 3/4 thick.

70 lbs long bolts
65 lbs short bolts. This is correct for MOST chevy head bolts. I have been using that spec for 30+ years. ARP changes the torque spec depending on the shit you put on the threads.

It has to to do with bolt stretch not the material of the head. The bolt must stretch to hold torque and stay tight.:bump:

you are gonna warp them cheap chineese heads with that much torque.

:chinese:Yea,right> Well, it's been a year and 2 months since it first fired.:lol:


Maybe if you stare at them long enough they'll warp.:tomato:

 

[enkeivette]

I suspect that #2 Permatex was what the GM guys had in mind when they wrote the specs the first time. That info is lost in the history at GM. Now there are so many sealers, thread lockers, and just plain goo out there it's tough to decide. I use Locktite Thread sealant with teflon. Seems to work fine. Stays pliable, and is a PITA to clean up.

I also read something years ago -- I torque SB head bolts to 70 for all but the row of short bolts under the manifold- those go to 65. Reason is that the short bolts don't stretch as much... But that's with stock iron heads too. Aluminum I'd go with the mfr's specs. And most of the alumunim heads have a deck that's 1/2 to 3/4 thick.

70 lbs long bolts
65 lbs short bolts. This is correct for MOST chevy head bolts. I have been using that spec for 30+ years. ARP changes the torque spec depending on the shit you put on the threads.

It has to to do with bolt stretch not the material of the head. The bolt must stretch to hold torque and stay tight.:bump:

you are gonna warp them cheap chineese heads with that much torque.

These are AFR heads!!! The best street heads you can buy IMHO. Made in San Diego CALIFORNIA USA!

You still haven't answered my question Turtle. Have you ever built a high performance engine with aluminum heads?

I've run the L-98 heads for a long time. What is the definition of high performance.?

Hopefully you can make yours last more than a few months at a time. You should listen up.

So you've only run factory castings is what you're telling me? Hmmm, wonder why you're throwing factory specs at me.

So should I "listen up" to you? Or everyone else in the forum and the techs at AFR and ARP? What do you advise oh great Turtle?

 

[Stroker-427]

For my esperience (Edelbrock, Trick-Flow, Dart) all the manufacturers call for 65 lbs of torque.

My personal sequence is 35, 50, 65 and several.... several..... several re-torquening!
My block (Motown) have blind holes, so I have used only usec ARP molysulfide in the threads.
It is important to well coat the threads..... but in more important to coat the under surface of the bolt's head and of the washer. thios is the lace where you will have a lot of friction.

The last time (with Dart PRO1 227cc CNC heads and multilayer gaskets) I had to retorque the bolts 10 times (yes.... ten times!!!) before to stabilize the clamping force!!!

Pay attention to this thing if you use the very good multilayer gaskets!!!!

 

[Twin_Turbo]

AFR is by no means the best money can buy. There's a difference between heads machined for the hot rodder enthusiast and those made for the pros to rework to their own specs. Now, you show me a top end race car with afr heads and I'll show you a hundred with brodix or dart heads. No BS! Not saying AFR aren't great heads but they are soo overhyped, it's incredible! Advertising does work.

I agree with Pier Paolo like I said above, the washer is VERY important. On ARP bolts the washers only go on ONE way. The bolt heads have a radius profile into the shank. The washers are chamfered on one side of the ID hole. That's the side that goes up.

 

[enkeivette]

AFR is by no means the best money can buy. There's a difference between ehads machined for the hot rodder enthusianst and those made for the pros to rework to their own specs. Now, you show me a top end race car with afr heads and I'll show you a hundred with brodix or dart heads. No BS! Not saying AFR aren't great heads but they are soo overhyped, it's incredible! Advertising does work.

i agree with Pier Paolo like I said above, the washer is VERY important. On ARP bolts the washers only go on ONE way. The bolt heads have a radius profile into the shank. The washers are chamfered on one side of the ID hole. That's the side that goes up.

TT, this is why I was very careful to specify that AFR makes the best STREET heads that you can buy. I realize that the pros are not likely to run AFR heads.

When I researched the heads in 2005, AFR had the best flowing street heads (<200) that you could buy. Canfield was a close second best, and the Edelbrock Vic Jrs and the Trickflow 195 were close behind also. I almost went for a set of Canfields, but I was able to get the AFRs for the same price.

The washers are all placed correctly and I used penetrating oil on the washers, they tightened smoothly.

 

[Twin_Turbo]

I must have missed the street part :thumbs: Use moly lube on the washers.

 

[enkeivette]

I must have missed the street part :thumbs: Use moly lube on the washers.

Too late! And the Pyroil penetrating oil smells sooo good, like a banana milkshake. I'll keep it in mind for next time.

 

[BRUTAL64]

I must have missed the street part :thumbs: Use moly lube on the washers.

Too late! And the Pyroil penetrating oil smells sooo good, like a banana milkshake. I'll keep it in mind for next time.

Now, my farvoite is Dr. Pepper with chocolate Ice Cream. Haven't been able to find any grease or oil to smell like that.:suspicious:

 

[enkeivette]

I must have missed the street part :thumbs: Use moly lube on the washers.

Too late! And the Pyroil penetrating oil smells sooo good, like a banana milkshake. I'll keep it in mind for next time.

Now, my farvoite is Dr. Pepper with chocolate Ice Cream. Haven't been able to find any grease or oil to smell like that.:suspicious:

Do I smell a patent?

 

[BRUTAL64]

I must have missed the street part :thumbs: Use moly lube on the washers.

Too late! And the Pyroil penetrating oil smells sooo good, like a banana milkshake. I'll keep it in mind for next time.

Now, my farvoite is Dr. Pepper with chocolate Ice Cream. Haven't been able to find any grease or oil to smell like that.:suspicious:

Do I smell a patent?

Yea, but we have to break down the chemicals in Dr. Pepper. That could be a problem.:amused:

 

[MYBAD79]

I think I have to disagree with TT here, the better the lube, the less torque you need to achieve the same clamping force (less friction at the threads and under the head).

I torqued mine to 75F-lbs instead of 65 so IF they really loosen a little I'm still good. :smash::bounce::bounce:

I did doublecheck Edelbrock's tech info on their website - they say to torque to 65ft-lbs. Bird got me worried a lil with the comment about some manufacturers requiring 100ft-lbs....


And yes, Enkei, if you did not sealant the first time that is likely why it leaked.

 

[turtlevette]

I think I have to disagree with TT here, the better the lube, the less torque you need to achieve the same clamping force (less friction at the threads and under the head).
.

YES, i didn't want to say anything and stir up yet more trouble.

The bolt will turn easier and achieve more clamping force with less torque when a slicker substance is used such as molly.

 

[enkeivette]

I think I have to disagree with TT here, the better the lube, the less torque you need to achieve the same clamping force (less friction at the threads and under the head).
.

YES, i didn't want to say anything and stir up yet more trouble.

The bolt will turn easier and achieve more clamping force with less torque when a slicker substance is used such as molly.

But i don't know shit because i didn't take a second on my house to buy 2 vipers and build a gaudy looking vette.

I don't know what you expect from me Turtle, you've never built a high hp engine, everyone on the forum disagrees with you, and all of the techs over the phone disagree with you too. But you expect me to take your advice. Would anyone? And do you honestly believe that 5 ft lbs will make or BREAK my heads?

 

[SmokinBBC]

I think I have to disagree with TT here, the better the lube, the less torque you need to achieve the same clamping force (less friction at the threads and under the head).
.

YES, i didn't want to say anything and stir up yet more trouble.

The bolt will turn easier and achieve more clamping force with less torque when a slicker substance is used such as molly.

But i don't know shit because i didn't take a second on my house to buy 2 vipers and build a gaudy looking vette.

I don't know what you expect from me Turtle, you've never built a high hp engine, everyone on the forum disagrees with you, and all of the techs over the phone disagree with you too. But you expect me to take your advice. Would anyone? And do you honestly believe that 5 ft lbs will make or BREAK my heads?

Don't think he'll be answering for a while.

 

[MYBAD79]

Well.... I'll give Turtle this: with stock style low CR low HP engines you really don't have to worry about balancing, torquing stuff to exactly the recommended torq... just like GM.... as long as the piston doesn't fit sideways into the hole the clearance is just fine :lol::lol:

Now, if you want to take pride in your work and want to build an engine as good as you possibly can ... and use aftermarket parts like forged rotating assembly with longer stroke you will have to pay a little more attention to detail.... especially if you want that engine to run smooth and last a long time...

 

[big2bird]

65 lbs.ft is the most common torque figure for most sbc & bbc heads.
The only engine I can remember that had 100 & 110 lbs.ft torque specs was the ford FE ehad, but it's a head with only 4 bolts surrounding each cylinder! The holes are also BLIND. That's where the difference comes from. There is NO way you torque your SBC to 110.

I can't find that dam sheet now. It may very well have been a Ford head. I know I read 100-110lbs, but it could have been Ford. Sorry for any confusion.:banghead:

 

[MYBAD79]

I can't find that dam sheet now. It may very well have been a Ford head. I know I read 100-110lbs, but it could have been Ford. Sorry for any confusion.:banghead:

Confusion ? You scared the crap out of me and made me look up the tech info ...:crutches:

 

[kwplot34]

Wow lots of advice given out here :banghead: I'm sure you have the info from the manufacture as to what they say you should tq the heads too,and from some reputible builders and that is what i would go with. I am no pro at this,but i do have a set of Brodix IK200 heads and Brodix says the tq should be 70ft/lbs and if i need to to re-tq the heads i will do it as the manufacture says :thumbs:

I do not believe that you can go wrong by following the manufactures directions.

just my $.02 worth

 

[big2bird]

I can't find that dam sheet now. It may very well have been a Ford head. I know I read 100-110lbs, but it could have been Ford. Sorry for any confusion.:banghead:

Confusion ? You scared the crap out of me and made me look up the tech info ...:crutches:

Well clock me on the head. I had a DB moment. :clobbered:

 

[MYBAD79]

:lol::rain: