SBC Cyl Head bolt tightening ft lb sequence?

enkeivette

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What is the proper way to torque down an aluminum head on a SBC?

I remember finger tight, then 50 ft lbs, then 60, then 70. Am I missing a step or do you go straight to 50?
 
What is the proper way to torque down an aluminum head on a SBC?

I remember finger tight, then 50 ft lbs, then 60, then 70. Am I missing a step or do you go straight to 50?

I see nothing wrong with going finger,50,70 then recheck. Use thread sealant on the threads, and moly on the washers/bolt heads. Some aluminum heads require 100-110lbs final torque. Just pattern inside out.
 
I was going to skip the thread sealant this time. Is that a big mistake?

I used some last time and the bolts still came loose. I plan to retorque them after one heat cycle and the periodically. And my line of thinking is that thread sealant or thead locker (anything that dries) will inhibit retorquing in the future.
 
What is the proper way to torque down an aluminum head on a SBC?

I remember finger tight, then 50 ft lbs, then 60, then 70. Am I missing a step or do you go straight to 50?

I see nothing wrong with going finger,50,70 then recheck. Use thread sealant on the threads, and moly on the washers/bolt heads. Some aluminum heads require 100-110lbs final torque. Just pattern inside out.

WTF,

sbc aluminum heads only take 55/60 ft lbs torque. You know better than that.

And you MUST have sealant unless you have an aftermarket block with blind tapped holes.
 
What is the proper way to torque down an aluminum head on a SBC?

I remember finger tight, then 50 ft lbs, then 60, then 70. Am I missing a step or do you go straight to 50?

I see nothing wrong with going finger,50,70 then recheck. Use thread sealant on the threads, and moly on the washers/bolt heads. Some aluminum heads require 100-110lbs final torque. Just pattern inside out.

WTF,

sbc aluminum heads only take 55/60 ft lbs torque. You know better than that.

And you MUST have sealant unless you have an aftermarket block with blind tapped holes.


AFR requires 70 ft lbs.
 
What is the proper way to torque down an aluminum head on a SBC?

I remember finger tight, then 50 ft lbs, then 60, then 70. Am I missing a step or do you go straight to 50?

I see nothing wrong with going finger,50,70 then recheck. Use thread sealant on the threads, and moly on the washers/bolt heads. Some aluminum heads require 100-110lbs final torque. Just pattern inside out.

WTF,

sbc aluminum heads only take 55/60 ft lbs torque. You know better than that.

And you MUST have sealant unless you have an aftermarket block with blind tapped holes.


AFR requires 70 ft lbs.

that's strange, i wonder if the head gaskets can take that much pressure. Those fire rings can over-crush.

They think their head design is that much stronger?
 
WTF,

sbc aluminum heads only take 55/60 ft lbs torque. You know better than that.

And you MUST have sealant unless you have an aftermarket block with blind tapped holes.

I checked AFR, Motown, Brodex, and Edelbrock. Some Edelbrocks are 100-110lbs.
 
What is the proper way to torque down an aluminum head on a SBC?

I remember finger tight, then 50 ft lbs, then 60, then 70. Am I missing a step or do you go straight to 50?

I see nothing wrong with going finger,50,70 then recheck. Use thread sealant on the threads, and moly on the washers/bolt heads. Some aluminum heads require 100-110lbs final torque. Just pattern inside out.

WTF,

sbc aluminum heads only take 55/60 ft lbs torque. You know better than that.

And you MUST have sealant unless you have an aftermarket block with blind tapped holes.


AFR requires 70 ft lbs.

that's strange, i wonder if the head gaskets can take that much pressure. Those fire rings can over-crush.

They think their head design is that much stronger?

I would think that if AFR recommends it with their recommended head gasket, they have come to that conclusion.
 
WTF,

sbc aluminum heads only take 55/60 ft lbs torque. You know better than that.

And you MUST have sealant unless you have an aftermarket block with blind tapped holes.

I checked AFR, Motown, Brodex, and Edelbrock. Some Edelbrocks are 100-110lbs.

all well and good but the deck of a stock block may distort under those kind of loads.

let's get some more opinions about this.
 
I was going to skip the thread sealant this time. Is that a big mistake?

I used some last time and the bolts still came loose. I plan to retorque them after one heat cycle and the periodically. And my line of thinking is that thread sealant or thead locker (anything that dries) will inhibit retorquing in the future.

Just retorque them after a couple cycles. Use a thread sealer that is non-hardening. As Jim said, some holes are not blind. Ask Black Rat. LOL
 
Damn you guys, now I'm second guessing myself. Well all the bolts are at 50 ft lbs right now, I think I'll leave them till tomorrow and call AFR to verify the final torque.

Turtle, I don't think an aluminum head no matter how hard you torque it on is going to screw up an iron block. You'd prob strip the thread first. There was some slight brinelling on the heads where the rings seated, but only about 1 or 2/1000 of an inch. It came off easily during resurfacing. Have you built any aluminum headed motors in the past?

Jeff, I've got the thread sealant on there now. After shining a flash light in the bolt holes I now realize why you need to use thread sealant. Those bolt holes go right into the cooling passages. I wonder if this is one of the reasons that my last HGs failed. I used thread locker per AFRs recommendation, maybe the thread locker didn't keep the coolant away from the threads which is what allowed my bolts to loosen. :idea:
 
Being cheeep and lazy I allways use RTV on the bolt threads, not an issue then....I torque them down to 65 ft lbs which is the shop manual recommendations for a '87 alumminum headed SBC outta the vette manual....

I have used that figger for all heads that been on the engine, Edel, iron, and now the stock 113 aluminum.....

I typically start in the middle tap them down with the 3/8 impact doing the pattern, then do the torque wrench to 65 directly......

it works....

:crutches:
 
Definitely use sealant.

The ARP torque figures are always higher because of the arp moly lube and the bolt quality. The slicker your thread lube the easier the bolt will torque down, so youll need a higher torque loading for the same clamping force (thread resistance is reduced). The washers play an important role here also!

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.

Enkei, why are you NOT using studs? Sure, pulling heads is a PITA with studs but since you have a blown motor, studs are so much better for you. Not oly will you not have a sealing issue, you dab sealant on the threads and then thread in the studs fingertight. They will never move again and grab more meat (threads in the block) so distortion is less. it's also stronger and you will be able to clamp down those ehads a little tighter without worries.
 
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.
 
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.
 
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.

yep, that's why i posted 55/60 above. 5 less on aluminum heads.
 
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:
 
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.
 
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.


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 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.


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.
 
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