MTFCA Forum

Hi all,
I'm re installing the coil box on top of the engine for my 26/27. Should I use anti seize on the head bolts or not?
Thanks.
John

Does help prevent a stuck bolt, just a small smear on the ends of the lowest threads.

I was always told no. I was told it can throw off an accurate torque and you could over torque them.

Some say yes and some no, I know which will screw out without grief years down the track. As a engine builder I've always used it and no issues for more that 50 years.

Before anyone can accurately answer this question, we need to know if the torque specification is "wet" or "dry". To date, I have seen torque specs. quoted but never with the complete spec.

Did Ford, torque with lubricant on the threads (wet) OR without lubricant on the threads (dry)? Knowing this will prevent over/under torqueing of the fasteners.

I suggest using anti-seize on all fasteners that will be exposed to weather and/or torqued to a specification.

NOT FORD TORQUE SPECS: 7/16"-14 tpi, "grade 5", NOT PLATED = 50 ft-lbs, "grade 8", NOT PLATED = 70 ft-lbs Plated bolt torque specs are different. This information is from current industry standards and NOT FROM/FOR FORD specifically or originally.

No, not a head bolt. Almost anywhere else is fine.

Now I know that the T engine is no racing engine but this applies to modern diesels and standard practice in high end preformance engines.
Quote.

The torque method is sometimes inaccurate because of the uncertainty in the coefficient of friction at the interface between bolt and thread, this inaccuracy can be minimized by using the lubricant supplied by ARP. The same considerations apply in the design of studs.

Cannot stress enough the importance of using a bottom tap to clean out the thread wells. Vacuum/blow out. I use anti-seize very light coat, never have any problems. Ré-torque head as your normal maintenance.

Hank

I would use it, sparingly. Most all Model T blocks are now well-used, and the head bolt threads in the block are very likely off-specification due to wear, heat cycling, stress cycling, having bolts run in dirty, over-torqued, run loose, unevenly torqued, etc, which likely would affect torque readings to some degree. Some judgement is required.

As far as I know, Ford did not publish torque specs for the T. Most on this forum seem to think that about 50 ft.lbs is good. As a practical matter the actual torque depends on the coefficient of friction between the threads on the bolt and those in the block (as was previously stated in an earlier post). Since we cannot guarantee that that friction will be the same in all cases, we level the playing field by carefully cleaning the threads and placing a lubricant on them. I bolted the head onto my first engine in 1960; I have always used anti-seize on headbolt threads and have never had a problem.

The most accurate method of tightening a bolt is by the angle method, a high is the way modern car head bolts are tightened. This procedure can be used with model ts, but becomes complicated because the bolts must be retightened. If anyone is interested, I can describe it but would have to do a little digging.

With aluminum heads I very much recommend this method because the coefficient of friction is different.
Art Mirtes

OK, so people are divided. One thing that many have stated is that I clean out the threads on the block. I don't have that size tap. What size are the head bolts? I do have some new head bolts but don't have a way of measuring the thread pitch. Can someone supply that info and I'll buy a thread tap for it. Thanks for all the suggestions.
John

7/16” X 14 TPI.

Hank

In aircraft maintenance they always emphasize that bolt torque is achieved with a clean, dry, thread.

..but many torque tables specify clean, lightly-lubricated threads...

I have never used it. It might be good, however it could also cause the bolt to work loose. I don't know.
These things I do know, however: The threads must be good on both the bolt and the block. And there must be no crack nor thread extending into the water jacket. The main reason a bolt will seize up is rust. If the thread extends into the water jacket you will get rust which will freeze the threads. I have not tried this, but it might be possible to use some permatex sealer on the lower threads to seal out the water, but if you need to re-thread the block, try hard not to drill too deep. I have used helicoils on several engines without any problems. Most important to get the threads clean and blow or vacuum out all dirt in block. Also re-torque after the engine has been warmed up either hot for iron head or cool off again for aluminum.
Norm

The most accurate method of tightening a bolt is by the angle method, a high is the way modern car head bolts are tightened. This procedure can be used with model ts, but becomes complicated because the bolts must be retightened. If anyone is interested, I can describe it but would have to do a little digging.

With aluminum heads I very much recommend this method because the coefficient of friction is different.
Art Mirtes

I don't use it on head bolts and have had a devil of a time getting some off and thats on pre-23 where the bolt shank automatically rusted to the cylinder head drilled holes!

I'll also add to the chart tracers....the Ford system and the chart system have nothing in common...

When Ford changed from 3/8-24 to 7/16 - 14 they violated every rule in the book....simply because...they could...and proved their 'hack' in 15 million or so copies.

The thread engagement was LEFT at the 3/8 spec...too much work to modify to go by the rules for a 7/16-14.

So what's the torque? Depends on who you talk to. Some of us go 35-40 and are willing to do a bit of a pull down if something wicks after the first run. That does occur but less than half the time. Others go 50-55 because it also works...with only an occasional thread tear. Then we have the big guys who start at 55, may even go to 60 and beyond but will usually pull at least one thread in the process (Yeay Helicoils! I never understood why just one gets replaced though...they already proved their setting shears threads? Do they secretly Helicoil all?) There is an irony to a proper installed thread-set or Helicoil...just like magic, the head bolt torque now is good with the published tables!

As far as the wet and dry thing? I think we reached consensus a long time ago that normal cutting fluids and oil with bolts picked from a barrel was probably the definition of dry...just wipe them off.

To each his own...my O2....

I like George Mills definition of a dry bolt. Many torque charts that I have seen says dry threads.
The torque caused by the bolt head shoulder contributes a significant amount of the total torque. My past research shows about 40 percent goes to the shoulder torque. Consequently, don't forget to lube the shoulder if you are into thread lubrication.
Art Mirtes

This is an interesting post. And what is recommended/personal experience regarding seldom-seize compounds and torque with Stainless Steel head bolts and Model T block? Aren't SS domed headbolts now being offered for the improved Fords? Thanks, jb

If anybody’s counting I’m with the clean the threads, in dry and 50lb. group. 1 retorque after a duty cycle.

jab35 wrote: ↑

Fri Oct 22, 2021 1:47 pm

This is an interesting post. And what is recommended/personal experience regarding seldom-seize compounds and torque with Stainless Steel head bolts and Model T block? Aren't SS domed headbolts now being offered for the improved Fords? Thanks, jb

Have not seen SS offered. Langs shows nickle plated.
Stainless bolts are a whole nother kettle of fish.

Haven’t used anti seize on head bolts. I clean up the block holes, chase the threads all the way making sure the head bolts aren’t stretched, and apply a little grease, retighten and alls good every time. Issues happen when the bolt holes aren’t cleaned out all the way.

Once again, you guys (and I) are responding to a 2 year old thread dredged-up by a Chatbot.

Apparently the chatbot doesn't know whether to use anti-seize either !

Technicalities make for interesting speculation. A surfeit of knowledge can lead to paralysis ! Comparisons between a model T Ford and the requirements of a refined aircraft engine seem a wee bit strained. How many million times were Ford T cylinder heads removed and replaced successfully by mechanics and owners who had never heard of a torque wrench ?

Hi Scott,
Good catch, thanks.
Craig.

What I've done for past 35+ years
Clean threads bottoming tap blow out
Dip the bolt in anti seeze prefer the one with copper in it
Install and torque cold to 45lbs
( stock head)
Next get it hot retinue 45lbs
Used to do 50lbs but 45 seems just fine
Side notes copper coat copper gasket
Ford I bet never retouqued head bolts