Torque spec ram horn manifold

[TJ1978]

Was reading around and I wanted make sure this is correct.
20-25 ft lbs for ram horn exhaust bolts?
Tighten from inner two to outer.

Reason I bring this up is I had to pull the bolts to add anti seize because I forgot when I put the ram horns on...


Is it 20-25ft lbs dry in the Chevy manual? No antiseize?

What is the torque ft lbs with anti seize?

 

[Fastereddie]

Was reading around and I wanted make sure this is correct.
20-25 ft lbs for ram horn exhaust bolts?
Tighten from inner two to outer.

Reason I bring this up is I had to pull the bolts to add anti seize because I forgot when I put the ram horns on...


Is it 20-25ft lbs dry in the Chevy manual? No antiseize?

What is the torque ft lbs with anti seize?

I can’t tell you the correct torque, but the torque wrench setting will be less with a lubed bolt. Most torque listings are dry unless it says otherwise.

 

[TJ1978]

Right, I've read 10,20 upto 40% reduction in torque spec when anti seize is used. So it's confusing as hell.

Chevy says 25 ft lbs for exhaust bolts with ram horns, which I assume is a dry torque spec..

I did 20ft lbs WITH anti seize. So should I leave it or run it down to 15%

 

[Fastereddie]

Right, I've read 10,20 upto 40% reduction in torque spec when anti seize is used. So it's confusing as hell.

Chevy says 25 ft lbs for exhaust bolts with ram horns, which I assume is a dry torque spec..

I did 20ft lbs WITH anti seize. So should I leave it or run it down to 15%

If you already did it, I’d leave it where it is.

 

[rampage]

Right, I've read 10,20 upto 40% reduction in torque spec when anti seize is used. So it's confusing as hell.

Chevy says 25 ft lbs for exhaust bolts with ram horns, which I assume is a dry torque spec..

I did 20ft lbs WITH anti seize. So should I leave it or run it down to 15%

Someone has a chart of bolt size/strength for dry vs lubed fasteners. Forget who it was, maybe ARP or Loctite.

 

[Wes Harden]

Even with anti seize, 25 Seems low. 3/8 course bolt, is 35 ft pnds.
So no worries about over torque.
After you go for a nice drive and warm those up re torque to 20-25 ft pnds. Remember the torque wrench is most accurate in the middle of it's range.

 

[TJ1978]

Even with anti seize, 25 Seems low. 3/8 course bolt, is 35 ft pnds.
So no worries about over torque.
After you go for a nice drive and warm those up re torque to 20-25 ft pnds. Remember the torque wrench is most accurate in the middle of it's range.

Everywhere I've looked states 20-25ft lbs.
I did 20 (since I added some antiseize) I'll drive it and re-torque upto 25

 

[Wes Harden]

To be honest I can't remember the last time I put a torque wrench on an exhaust manifold. Mostly you want all the bolts to be tightened evenly.


Edit on a gen 1 Chevy. I do it to modern cars and trucks all the time. But they are using smaller diameter studs and aluminum heads.

 

[TJ1978]

I started on the inner ones are alternated outward. Though driver side is kind of pain with brake lines, and oil dipstick tube. So those two are not torqued. Put a boot on that plug wire.

Got a nifty cup holder to go on the bench,
Held in place by velcro.
Also, Jumper cables, harbor freight tool set and a fire extinguisher, thankfully they just fit under the seat.

 

[TJ1978]

For reference: torque specs for Chevy

Small Block Chevrolet V8 Engine Specs | Torque Specs - Cylinder Numbering - Firing Order - Distributor Rotation - SB Chevy 267 305 327 350 400 Cid

 

[mrk5]

25ft-lbs is the typical spec. I would say you are fine at 20ft-lbs. If it leaks, tighten it to 25ft-lbs. It also helps to check them again after a couple of heat cycles.