Late 26 and 27 T's were reported to use domed nickel plated bolts to hold the manifold ears against the manifolds. Not sure of the size; either 5/16's or 3/8's. (Same size and tread of the former manifold studs). Same fine thread. What should the torque value be for the bolts? Is it different from the torque value for the earlier stud and nut arrangement?
They are 3/8" bolts and there was no torque specs.
Tight and then a little more after going thru heat cycles.
In general, there are torque "ranges" for bolts and nuts, depending on diameter, steel grade and thread pitch, and also whether you're twisting a bolt, or stretching a stud by drawing up on a nut. Torquing the manifold nuts is a bit subjective because it depends to a degree on the type of gaskets used, and the optimal amount of "crush". That's why it's a good idea to check them after several heating / cooling cycles.
There's probably an SAE table somewhere for torque specs, but I can't seem to find one.
I just put the copper crush gaskets on my 24 and their instructions call for 18 lbs torque.
Just don't over do it. Fine thread is wrong for cast iron anyway and it would be really easy to pull the threads.
Thanks to all. I have Vic Zannis' engine rebuild book and the torque value chart in it says 35 ft/lbs for a 3/8 - 24 bolts. I guess that's a little too much.
For steel or a nut that might be ok but not for cast iron.
I torqued mine at 35lbs.
Geo., Are you using the studs and nuts as in earlier production, or the domed nickel plated bolts?
Bolts Terry ,Bolts. Stainless from Lang's.
Mark G, I was always taught that fine threads are much stronger than coarse threads because they have more contact area. Is cast iron different? Just curious. Dave
I torqued mine to 35 ft/lbs. No leaks yet four years running. Using aluminum heads on my engines.
One thing to make sure you do is coat the threads with high temp anti-seize compound. You just never know when or if they need to come out.
35 ft/lbs, is perfectly alright for a newer modern engine, but in my opinion is wrong for a Model T. As stated, there are no specified torque values which drives me nuts as a person who really likes to use a torque wrench.
That said, These are 90+ year old engines that have been used and abused and put away wet. And some sat wet outside for years before being rescued. If you have perfect or near perfect threads in the block, 25 ft/lbs is sufficient using the original rings and glands (which is what I only use) to seal the manifolds.
The other issue with going tighter is bending the manifold clamps. Some of them seem to bend easier than others I have found.
By the way, most people don't know, but you can easily pull a typical 9/16" wrench to 40-45 ft/lbs in typical tightening--sometimes higher if your aggressive enough.
I've never heard of bending a manifold clamp. Why bother torqueing anyway? Can you visualize the guys assembling those engines using torque wrenches?
It would be interesting to know when torque wrenches came into general use. They certainly never were mentioned in the Ford "bible" 90 years ago. There's a certain amount of tact a feller needs to learn when pulling wrenches - break a few things over-tightening, have other things come undone for not being tight enough, after a while the mechanic learns skill.
Larry, you have never seen a manifold clamp that wasn't bent? I don't mean beyond the point of it wont work, but definitely bent out of shape. I can tell alot easier on the later ones, in my opinion. Maybe I am just to picky?
Rich, I agree, that you get a feel for it after a while--if you do it long enough. Some here have not. To me, would you rather a feller comes on here and says I pulled it snug or tight like you guys said and stripped it out, now what? And he may not have the skill set to run in a thread insert, or whatever the repair requires.
Or would you rather say, generally if you can torque to this value, you shouldn't pull the threads IF they are good. And if you do pull the threads and strip it at a certain torque, they weren't in good shape.
I would always error to the side of caution in these cases. People have said on here you can torque headbolts to 40-50 ft/lbs. I can tell you the threads in my block are not that good, and I have multiple bolts that will barely take 30-35 ft/lbs of torque. again, my experience says don't go tighter as I can feel what is happening. Defiantly not ideal in my eyes, but it keeps the coolant in and doesn't over heat or get into the cylinders.
To new guys that don't have experience, torque some fasteners and then put a regular wrench on them and pull. Feel where that resistance is and learn where to tight or not tight enough may be.
The posted torque values of bolts in several publications and online is pretty darn tight, and NOT acceptable for what some of these threaded holes and threaded hardware look like in 90+ year old parts--in my opinion. Sometimes those posted values are just too tight for the parts being fastened in general. The whole idea is you are actually stretching the bolt to a certain point that will hold, but not strip, and not back off because it isn't stretched enough.
Again, experience is key in knowing what good threads look like as well as the fit up of fasteners to mating parts. That part I do agree with you on (not trying to pick on you or single you out here).
We all can agree to agree or disagree all day long, but knowledge is power and people can choose to use it, use some of it, or none at all---after reading or listening to it.
According to patent search on the typical bar type torque wrench with arrow pointer, 1942 is the date. Probably accepted by mechanics after WWII
Patent US2283707 - Torque wrench - Google Patents
Patented May 17, 1942 Paul A. Sturtevant, Elmhurst, IL. 'Application March 28, 1938, Serial No. 198,375. 2Claims. This invention relates to a torque wrench ...
The Ford needs only the use of Ford tools provided with the car, and the Ford service tools. The wrench tools are the proper length for the hand power to tighten fully at the fasteners, and to use cotter pins on those fasteners that need them, or wire for those with holes.
If you use the spark plug wrench for example and pull normal pull, (not like Arnold) and remind yourself, its a 'pipe thread' , its tapered, and pull with hand pull toward the rear of the handle, that spark plug will be snugged just fine.
If you must use a torque wrench on your T's old stressed fasteners on tired cast iron and steel parts, then only use this Ford Model T Verified Torque Wench
I don't use a torque wrench. I just use a 10" box wrench and tighten until with a light pull it feels like the nut is not turning. Then after I run the engine and get it hot, I do the same again. I do it again after getting hot and when it feels the same as the last time I stop. I use the glands and copper rings. It might be a bit different with the flat 3 hole gaskets which I do not use.
I either use the German torque, Gutenteit, or else the old proverbial "Tighten it 'till it strips and back off a quarter turn."