Anti-seize on Manifold Bolts

[calvinator2]

I have a 77 FJ40 -- cleaned and prepped manifolds -- ready to install. I've researched for days whether or not to use anti-seize (never-seize) on the bolts. There seems to be a big difference of opinion as to the effect this would have on the torque values, actually reducing the torque required by a large percentage. I was planning to use a RemFlex gasket since it is recommended by many, but apparently RemFlex only requires 20-25 ft-lbs of torque and warns against over-torquing. My question is: if I put never-seize on my bolts, what torque would I need to apply on my RemFlex? I usually find the answers I need somewhere on Mud and I tried to find another thread dealing with this but so far I've come up with very little - if there is one, please direct me. Otherwise, any and all opinions/suggestions would be greatly welcomed! Many thanks.

 

[charliemeyer007]

I have a man-a-fre header since about 84 on my 72. I made my own stepped washers to apply equal torque to the two different thickness on the manifold. I installed longer "studs" to account for the quarter inch+ thick step washer and running 2 of the manny header gaskets that were also installed wet. I bought stainless steel nuts and used high heat anti seize compound - C5A copper colored aviation stuff. I also cut a notch in the air cleaner mounting bracket so I could get a socket on that nut. Before all that I planed both manifolds on a big piece of glass with sandpaper.

That header and gaskets have been on 3 times in at least 2 different engines and have never leaked. I torque them as soon as I can, then fire it up to get hot 20 minutes or so, let cool and re-torque them.

 

[Grayscale]

Anti-sieze is a lubricant as well; it will not change the torque spec, rather it keeps the torque spec from being wrong due to excess thread friction. I'd shoot for 25 ft-lbs.

 

[calvinator2]

I have a man-a-fre header since about 84 on my 72. I made my own stepped washers to apply equal torque to the two different thickness on the manifold. I installed longer "studs" to account for the quarter inch+ thick step washer and running 2 of the manny header gaskets that were also installed wet. I bought stainless steel nuts and used high heat anti seize compound - C5A copper colored aviation stuff. I also cut a notch in the air cleaner mounting bracket so I could get a socket on that nut. Before all that I planed both manifolds on a big piece of glass with sandpaper.

That header and gaskets have been on 3 times in at least 2 different engines and have never leaked. I torque them as soon as I can, then fire it up to get hot 20 minutes or so, let cool and re-torque them.

Glad that worked for you - I hope I can be as successful! My concern is the effect of using anti-seize on the bolts, (copper, nickel, whatever), will have on the torque the RemFlex gasket requires. If I anti-seize reduces the torque required by 15%, (as I've been reading), the RemFlex required torque, (20-25 ft-lbs), will be reduced to about 17-20 ft-lbs. Really?

 

[calvinator2]

Anti-sieze is a lubricant as well; it will not change the torque spec, rather it keeps the torque spec from being wrong due to excess thread friction. I'd shoot for 25 ft-lbs.

Thanks - if the physics guys are to be believed, the concern is that if I apply the 25 ft-lbs with anti-seize on the bolts, I will be applying at least 15% more torque than required, which would mean that my torque wrench would read 25 ft-lbs but would actually be applying about 30 ft-lbs. Keeping in mind RemFlex's caution about not applying too much torque....what do you think?

 

[calvinator2]

Here's one source that suggests a 25% reduction in torque! At this rate, I'll be installing the manifolds finger-tight!

 

[charliemeyer007]

I do my torque sequence in 1/3 - you could do yours in 1/4 and stop at the third. If your unit leaks add the 4 to get to 100%.

 

[Pighead]

I do not use bolts there, I use official Toyota studs, nuts and washers. Anti-Seize on both ends of the studs. Sometimes those studs break and have to be removed. I replace all the studs and nuts every 3 or 4 times that I R&R the manifold/header. I tried the Remflex gasket once, it didn't work for me at suggested torques nor at higher torques. Now I use the Fel-pro gaskets, I've used two at a time in some cases. After some machine shop time I'm down to just one. I routinely snug up those nuts, I might even exceed the FSM recommended torque by just a little bit sometimes.

 

[Grayscale]

I have VersaChem anti-sieze in my box. It didn't mentioned torque adjustments, but, that doesn't mean that you shouldn't be aware of them.

So, for a 2F manifold set, 33 ft-lbs is mentioned in the book. My opinion is that this torque spec is for new and/or oiled hardware. Why, because metal and meal-oxide friction is a wild card, not a datum reference. The only thing that goes on dry is wheel studs and lug nuts - those go on clean, not dirty or oiled. However, Remflex and the A.S.T. product sheet say different - I'd stick to the respective manufacturers' answer. Assemble, run around for a while, then recheck your torque values.

 

[calvinator2]

Thank you all for weighing in on my question - I realize I may be overthinking this, but I've put a little extra work into the manifold this time around and I didn't want to make any wrong moves or miss something at this point. The truck was suffering serious manifold vacuum leaks and really needed attention so I pulled the manifold and carburetor off and cleaned them up. (rebuilt the carb, too) Did a little sanding of the manifold on a piece of glass (well within limits), however, the cylinders on the ends of the exhaust manifold that the horns (with rings/springs) go into were really corroded - to the point that the rings were not seating at all. A machinist friend of mine fabricated stainless sleeves and honed out the cylinders to receive them - now the rings seat nicely. I threw in a couple of pictures to show you - off topic, but might be an option of some interest to others with the same problem. Anyhow, your insight is valuable to me and I'm grateful you've taken the time to share it. I won't be able to install the manifolds until the snow stops falling so if you have any other observations/advice that come to mind, I'm listening! Thanks again.

 

[Slow Poke]

It looks like you’re doing a very thorough job. I’m following you down this same path with my 77. How did the torque specs pan out for you?