head bolts

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dhosh
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head bolts

Post by dhosh » Sun Oct 04, 2020 12:25 pm

I'm reassembling my engine and about ready to put the head on. Current head bolts have a 3 1/4" shank. The shallowest head bolt hole in the head is 15/16" deep.

If I put a head bolt in the old head, with no washer, I'm left with 9/16" to go into the head .. and that's with no gasket in place. With my almost NOS WH head, I am left with only 17/32". Is that sufficient? A cursory look for new head bolts show them at the same 3 1/4" length. Should I be looking for longer bolts?

Thanks!

Dennis
'24 RPU
Petoskey, Mi


John Codman
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Re: head bolts

Post by John Codman » Sun Oct 04, 2020 12:51 pm

Obviously the stripping strength is proportional to the number of threads engaged. The more threads engaged the better. I have a friend who is a mechanical engineer who told me that his rule of thumb is 1 1/2 diameters of thread engagement if possible. Doing some checking, I found tables that say one diameter is adequate, but I don't know the alloy of the T engine block, but I would assume that it is not as strong as the modern cast Iron blocks. I would therefore, go with as much thread engagement as I could get. JNHO.

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Richard G
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Re: head bolts

Post by Richard G » Sun Oct 04, 2020 1:16 pm

DEHOSH, DO YOUR SELF A FAVOR BUY NEW BOLTS FROM LANGS, THERE THE RIGHT LENTH , NOT STRETCHED 3 OR 4 TIMES, YOU DONT WANT THEM BOTTOMING CRACKING THE BLOCK, BE SMART BE SAFE..DONT FORGIT TO BLOW OUT THE HOLES,


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Re: head bolts

Post by HPetrino » Sun Oct 04, 2020 1:29 pm

Good advice above. I'd be sure to clean the holes thoroughly. I used an ice pick (or similar instrument) to loosen any crud in the bottom, then held my shop vac over the hole while blowing compressed air into it. A couple of times and the hole should be pretty well cleaned out. (It was amazing how much crud there was!)


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dhosh
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Re: head bolts

Post by dhosh » Sun Oct 04, 2020 1:53 pm

Yes, I understand all this, and certainly agree with all of it. whataburger I was planning on buying new bolts. However, I'm saying is that even if I bought new bolts, unless I went to Fastenal or something, the new bolts are still going to be too short. The new bolts I have seen that I can order from Lang's or Snyder's, are the same size as what I have. So if I have insufficient thread now, I'll have insufficient thread with new bolts. I did, however only do a cursory search. There are obviously many other places to buy these. But at Snyder's and Lang's, at least, it looked like all the bolts were three and a quarter inches long. Currently, my problem isn't bolts that are too long that will bottom out... They appear to be too short. and a standard bolts are three and a quarter inches long, it seems like they would be too short from the factory! It looks like I could go up to three and a half inch bolts and still be nowhere near bottoming out.
'24 RPU
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Re: head bolts

Post by HPetrino » Sun Oct 04, 2020 2:45 pm

Dennis,

I did a little looking around on this. As near as I can tell the 3 1/4" bolts are "stock" for a high head T. I suppose you could get away with a longer bolt, but I really don't think it's necessary. I would imagine the vast majority of T engines our there are using this length and doing just fine.

My $0.02 worth.

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Re: head bolts

Post by George Mills » Sun Oct 04, 2020 3:01 pm

If you promise me we won’t get into torque up 🥴🤷‍♂️

The original design was for a 3/8 fine bolt. (This was also when the water outlet used head bolts) Take a 3/8 bolt and us the old 1.5 x engage for iron and you get ....wait for it.....ready.....you sure.....anxious....9/16”.

When Ford used a cannon to swat a mosquito on the early ‘09 and the birthing problems were all solved in one big singular effort the 3/8” fine went to 7/6” coarse and the depth of engagement never changed, and “worked” for 15 million subsequent production.

I suspect they had a head leak probably at the front on the first 500 that defied being fixed after lots of tries, lots of expert opinion, debated over how 2 longer bolts in the set would not result in equal load distribution (it does work out equal but they didn’t know it then) and the fact I presume that a bunch of those 3/8” stripped in the troubleshooting. I further speculate that in the midst of a super internal fuss someone said, “what are the field guys doing to get by?” And someone said...they go to 7/16 coarse taps in the stripped holes and it seems to button up leaks. ( I’m open to any other plausible solution) and further, the Dodges probably had the next 500 or 2000 engine blocks poured already they decided good enough, let’s revisit later and no one then ever added more meat to the block to make the practice match the theory.

This is why you “should” have 9 threads by any engineering book and are lucky to find 6, maybe pushing 7 threads.

One of the reasons I hesitate to discuss torque...lol. You already have 3 bad threads before any of that modern theory kicks in 😊😉


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Re: head bolts

Post by Dan Hatch » Sun Oct 04, 2020 3:02 pm

Blowing out the holes by itself is a waste of time.
Take a drill bit smaller than bolt and run it in each hole than blow out. After that use BOTTOM tap and clean each hole, blow out again.
The stuff in bottom of the hole is hard as , well you know. Blowing by itself will not remove it. Dan

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Re: head bolts

Post by CudaMan » Sun Oct 04, 2020 3:39 pm

And please wear eye protection when you blow out the holes, because the crud will come shooting out right into your eyes and face! :)

If I wanted to run the longest bolts I could get away with for maximum thread engagement in the block while keeping them from being too long for good clamping of the head, here is what I would do:

1) With the head off, I would clean out all of the bolt holes using a small drill or pick and a bottoming tap.

2) Blow out the crud while wearing eye protection. I would use a small nozzle on the air hose and have a vacuum cleaner sucking next to the hole to try and catch most of the crud.

3) I would get a long stud the same thread size as the head bolts. Set the head on the block without a gasket.

4) Run the stud through each head hole down into the block until it bottoms. Mark the top of the stud. Remove the stud and measure the length from the bottom to your mark. Draw a picture of the head bolt pattern on a piece of paper and mark the stud length for each hole.

5) The minimum stud length found in step 4) is the longest bolt length you can use and still have all the bolts be the same length. Find good grade 5 (or grade 8 if you wish) bolts as close to (but not over) the minimum length.

6) When you bolt the head down with the gasket in place, the thickness of the gasket will ensure that none of the bolts bottom out in their holes.
Mark Strange
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1924 Cut-off Touring (now a pickup)


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Re: head bolts

Post by ModelTWoods » Sun Oct 04, 2020 9:39 pm

Dennis, correct me if I'm wrong, but what I think you are asking in this post is referring to using stock high head bolts with the Waukesha Ricardo head that I sold you. Why don't you lay both your stock high head and the Waukesha Ricardo head on a flat surface and measure the head from the head gasket side, to the top of head bolt surface (where the head of the bolt head contacts the head). Then you will know for sure that each head measures the same height. If they are at, or very near the same, then stock head bolts should work. I have never heard of anyone having to use "custom" length head bolts with any 'flathead' style head, regardless of manufacturer. Like others, I would recommend new head bolts to be safe.


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dhosh
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Re: head bolts

Post by dhosh » Sun Oct 04, 2020 10:12 pm

Hi, Terry...

Yes... That's what I did. Hence the measurements. Really, there's not that much difference ... 9/16 vs 17/32 ... What, 1/32? I was more alarmed, initially, as I had read where many were worried bout the bolts bottoming out in the block, before the bolts were tight. I have almost an inch of thread available in the block, and even on the old head, only 9/16 of it being used. ... And 'even less' with the WR head (albeit only 1/32 less!). I thought I had read about folks using longer bolts, but I couldn't immediately find any.

For the life of me, I can't see bolts stretching a 1/2" to the point where they would ever bottom out.

I'm going to get a 1” bolt of the same thread size and count, and make a square end thread chaser to clean out the threads, clean out the holes, and use what I have. They are all right on 3 1/4" in length. Then again, they aren't that much... I will probably just order a set of new ones and be good.

I am more concerned about the head gasket. I'll probably just re'use my old copper sammich one, until the new ones get back in stock. Guess they've been out for 3+ months!


The WR head is a smidge taller, bit likely because it hasn't been decked before. Like you said...it looks hardly used if at all.
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Re: head bolts

Post by RajoRacer » Sun Oct 04, 2020 10:22 pm

I've installed 2 W.R. heads on 2 of my T's - all using stock length bolts - bolt it up & enjoy !


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Re: head bolts

Post by ModelTWoods » Mon Oct 05, 2020 12:43 am

dhosh wrote:
Sun Oct 04, 2020 10:12 pm
Hi, Terry...

Yes... That's what I did. Hence the measurements. Really, there's not that much difference ... 9/16 vs 17/32 ... What, 1/32? I was more alarmed, initially, as I had read where many were worried bout the bolts bottoming out in the block, before the bolts were tight. I have almost an inch of thread available in the block, and even on the old head, only 9/16 of it being used. ... And 'even less' with the WR head (albeit only 1/32 less!). I thought I had read about folks using longer bolts, but I couldn't immediately find any.

For the life of me, I can't see bolts stretching a 1/2" to the point where they would ever bottom out.

I'm going to get a 1” bolt of the same thread size and count, and make a square end thread chaser to clean out the threads, clean out the holes, and use what I have. They are all right on 3 1/4" in length. Then again, they aren't that much... I will probably just order a set of new ones and be good.

I am more concerned about the head gasket. I'll probably just re'use my old copper sammich one, until the new ones get back in stock. Guess they've been out for 3+ months!


The WR head is a smidge taller, bit likely because it hasn't been decked before. Like you said...it looks hardly used if at all.
Dennis, I don't know if you have an industrial supply store near you like Fastenal or Graingers, but thy can probably sell you a "bottoming tap". I think that I bought mine from McMaster-Carr in Atlanta. They aren't that expressive and are the right way to chase threads and clean out bolt holes in blocks. Once you hit bottom with the tap, all you have to do is blow out the loose crud with air pressure or vacuum the crud out.


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Re: head bolts

Post by Humblej » Mon Oct 05, 2020 7:32 am

Dennis,
My bad experience has been stripping out the threads in the block with new vendor supplied head bolts. I agree, they do not seem to be long enough, if they are made to the original Ford bolt specs then it is not the fault of the vendors, but nevertheless, the bolts I used stripped out 3 holes tightened to 55-60 FPT. And the short bolt length only gets worse when you attach a horn or a coil box to the head using the same short head bolts.

I agree with others, bottom tap the threads, blow out holes, place head on block without a gasket and measure the depth of the holes and choose the length of the longest bolt that will fit in the shallowest hole and use that length for all your bolts.

After almost 100 years of head bolt twisting my head had some nasty looking bolt faces so I had the head spot faced for each bolt, and now I use modern hardened steel head bolt washers under the bolt head except where the coil box mounts, that gives all the bolts the same thread engagement. Did the whole depth measuring with gasket and washers off and picked up new grade 8 bolts of the proper length from Fastenall. Tractor Supply in Petoskey has grade 8 bolts, some lengths are 1/4" increments, others are 1/2 " length increments. Fastenall usually has more length increments to choose from, and there is a Fastenall here in Charlevoix. If you come to Charlevoix you can borrow my bottom tap.

Jeff

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Re: head bolts

Post by RajoRacer » Mon Oct 05, 2020 11:12 am

I believe you are over-tightening your bolts - I stop at 45 lbs. - run several heating & cooling cycles, re-torqueing at 45 - never have lost a head gasket or stripped the block threads.


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dhosh
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Re: head bolts

Post by dhosh » Mon Oct 05, 2020 9:09 pm

Hi, Jeff..

I might take you up on the bottom tap! I had a few when I was doing pen turning, but gave them away with a small wood lathe I sold. Weren't this size, anyway. ☺️

Are original bolts grade 5-ish? I wouldn't think they would be stretching if grade 8.... But maybe tougher than the block.

Dennis
'24 RPU
Petoskey, Mi

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Re: head bolts

Post by George Mills » Tue Oct 06, 2020 9:08 am

Dennis,

The original bolts until about 1920 (for general purposes, let's round the time frame low head?) were simply Bessemer Steel and if you look at the Ford Ferrous Chart that would be anywhere from 1008-1013 Steel. I am not near my post heat Ford processes data, but realistically, such a grade is difficult to harden so probably would be used as is, or rather even if flame heated and quenched wouldn't do a lot. You may be surprised, but that actually works out to be a Gr. 2/3 bolt.

Later, Ford changed to a cold headed steel, a steel that contained Chrome, but it was not technically a Chrome Steel as the Manganese was but 0.2 max and the carbon was 0.95 so leaves one to wonder...why did Ford even go there? My thought is that it probably eliminated cracking in the heading process but where it would fall on the Grade chart? I can't guess as the Carbon being that high with the Manganese being so low would almost lead to very shallow almost false hardening...

No need to overthink this subject or you'll conclude that Ford intended a torque rating of somewhere around 35-38 ft lbs, and the iron block wouldd handle a bit more if there needed to be a cinch after a heat cycle.

Folks comment that they are able to get up to 60-65ft lbs and not pull out threads in the block...others will tell you that at 55 they pull out 10-20% of the threads. It is all over the place.

I have always recommended that if you plan on really torquing the head down hard because of going to a high performance head or aluminum head...then the mindset should also consider thread-serts or helicoils as part of the engine build up process. Others say...no big deal, strip a bolt or two there is a way to add an insert or two without spoiling everything else already done. I wince simply because how many of the other bolts are simply on the razor edge and its not known yet?


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dhosh
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Re: head bolts

Post by dhosh » Tue Oct 06, 2020 6:40 pm

Jeff..
I'm good on the tap!! I found mine! 7/16 #14 thread. NAPA has longer grade 5 bolts, so will play it safe, and go with those! I should be good!

George.... Thanks for the background! Interesting!
'24 RPU
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