Head bolts too short for High Compression Head

[PC/SR]

FWIW, Larry and I sure do not agree on politics (thankfully we cant argue that here anymore) but we sure do agree that using short studs on an HC head is not a good idea. I would be really surprised if any of the FAST or SOS guys, who know this stuff, used short studs. Some years ago Brattons sold a long set of Grade 8's and I do not known why they dont anymore when more guys are going to HC heads that need them. I hope that the suppliers will see this thread and respond to the need and demand and it is a service to all that this issue is being debated.

 

[Model A Apprentice]

Just for you Jim, here is the measurement of an original Ford head that has never been milled:

2.216"

The dist. boss and the stud bosses are the same. There would be a tolerance of a few thousandths or so from one head to the next but not much. Each counterbore measured .100 of an inch.


.

Just to clarify, I never thought to measure the distributor opening. Doubt that my calipers would fit. Nor did I ask the machine shop to measure the distributor opening. So I can't add to the conversation. If required, a new distributor shaft of the correct length is simple to make. While the shop makes the first, I would just have them make up a spare shaft for the future.

The head stud kit was purchased from Bratton, not Snyder, so I would not know about the Snyder hardware. The various parts distributors may order their stock from different providers, so the measurements may vary. Attached are the caliper readings of the 3.5" grade 8 studs that were not used in the assembly.

Walter Bratton told me they order the head studs in bulk to be made up in kits. As of now, from Bratton's, the correct length grade 8 bolt is not available. The Bratton head stud kit does have a 3.75", grade 8, stud which was long enough for our purpose. But it is only available in the kit. I suppose you could order 11 kits to get 11 extra 3.75", grade 8 studs but.... Bratton did have the 3.75", grade 5 stud, available individully and sent me 11 of these at no charge.

It was determined not to compromise the integrity of the rebuild by leaving threads short in either the block or the nut. So the grade 5, 3.75" ignition studs were used in place of the 3.5", grade 8. The engine rebuilder assured me that grade 5 studs are regularly used in the much higher compression performance engines. (I am not competent to comment they accuracy of his comment regarding grade 5. Can someone verify the accuracy of that?) Using grade 5 versus short studs did appear to be the lessor of two evils.

At least with the Bratton ignition stud, care must be taken when using the longer ignition stud. The normal head studs have a shoulder on the course end which acts as a depth guide. The Bratton ignition stud does not have a shoulder on the course end. Over "snugging" the stud could place the stud too deep into the engine, creating other issues.

Right, wrong, or indifferent, that is what we did. The engine is back and I should get it installed tomorrow or Tuesday. Be great to get the truck back on the road as the roadster is a bit cold this time of year.

Appreciate all of the feedback.

 

[Larry Brumfield]

It was determined not to compromise the integrity of the rebuild by leaving threads short in either the block or the nut. So the grade 5, 3.75" ignition studs were used in place of the 3.5", grade 8. The engine rebuilder assured me that grade 5 studs are regularly used in the much higher compression performance engines. (I am not competent to comment they accuracy of his comment regarding grade 5. Can someone verify the accuracy of that?) Using grade 5 versus short studs did appear to be the lessor of two evils.

A grade 5 stud in the Model A's diameter, 7/16, is not designed for the higher torque values necessary with a high comp head on a Model A and can stretch too much which makes them undepenable.

The difference between what your engine rebuilder is talking about and the Model A is grade 5 will work fine on engines with larger diameter studs and more of them OR just more of them.

An early Ford V8 is a good example. They use the same diameter stud as the Model A but look how many they use on one head to do the job; 21 to 24 of them. The Model A has 14.

And last but not least, Ford's original studs, designed for only the stock heads, were stronger than a grade 5.



.

 

[Model A Apprentice]

A grade 5 stud in the Model A's diameter, 7/16, is not designed for the higher torque values necessary with a high comp head on a Model A and can stretch too much which makes them undepenable.

And last but not least, Ford's original studs, designed for only the stock heads, were stronger than a grade 5.

Thanks Larry. Exactly the type of information I was looking for.

I am hoping that this will provide a short term fix until the proper hardware is available. Perhaps later the head should come off and have the boss milled down to accept the grade 8 hardware. Then when my teenage daughter is out driving her truck I will have piece of mind.

 

[Larry Brumfield]

Thanks Larry. Exactly the type of information I was looking for.

I am hoping that this will provide a short term fix until the proper hardware is available. Perhaps later the head should come off and have the boss milled down to accept the grade 8 hardware. Then when my teenage daughter is out driving her truck I will have piece of mind.

One last comment, Apprentice:

If you or anyone else needs a longer distributor shaft or decides that they want a longer dist. shaft, then obtaining a longer shaft is the only option (other than milling the bottom of the head) to provide better tang engagement on the shaft.

Because if you mill off the top of the dist. boss to reduce the thickness or height of the head in that area, the lock pin screw on the side will no longer fit in the groove on the side of the distributor when the distributor is in its operating position.

Also, the guide pin boss (little dot with a hole in it next to the distributor boss) would have to be milled down as well and possibly have to drill the hole for the pin a little deeper which could get real close or too close to the water jacket if one is not exactly sure in that area.

In other words, leave the distributor boss alone.

 

[PC/SR]

I drove my HC head with grade 5 for awhile but went to 8 for the reasons Larry stated for peace of mind. For me, the stock Dist shaft worked, but I got the longer shaft because mine "clinked" from the excessive end play, or maybe the drive was overcoming the hold down spring.

 

[Jim Parker Toronto]

Didn't mean to rile you up too much, Jim.

Your number won't be much different if you have an original Ford head that has never been milled. You ought to know not to measure thick paint.

So since you know how to read your caliper, your new head varies from Model A Apprentices new head by .046 of inch, with his being off by .096" and when added to the recommended studs nearly 1/4 of an inch.

You didn't rile me too much Larry, I enjoy a good discussion. You made a lot of good points, and for that, I am sure we are all greatful. You have the ability to look further down the road, and that is a good thing.

Like all new products, its not wise to get the first issue of anything, but times being what they are, no one knows when a good product that is not available, will ever come back on the market again.

Thanks again Larry, see you on The Barn, and Merry Christmas to you and your family, Jim

 

[30 A coupe]

Hi guys, I contacted ARP and this is what they said (I frogot to ask if they have studs for water neck).
Hope this helps!!!!!

Hello Eduard,

We do have some studs that should work for you. They are 3.750" long
with 1.000" of 7/16-20 fine thread and .750" 7/16-14 coarse thread. The
part number is AP3.750-1SB (1 piece not including nut or washer). We do
not sell direct overseas. Here is a link to the list of European
Distributors on our website. This part can be ordered by any
distributor.

 

[kenparker]

I am having to backtrack again on my solutions to the problem - using Dorman studs. After comtemplating and measuring (twice) then worrying for two days I am discarding the Dorman studs that dont fit right.

My Snyder 6.1 head is going to the machine shop today to have the "bosses" or "collars" machined down to where standard 3.5 inch grade 8 Model A studs from the major suppliers (Snyders, Brattons, Berts, Mikes) will fit and torque down to the correct values with out worry. I dont want something to go democrat in the middle of the desert and cant find an odball part to fix it and get home. It aint wort da risk.

The "bosses" have more than enough protrusion above the flat surface of the head to mill off and make it fit right. Model A Apprentice has the same measurements as measured on my head/s.

Will post resulth when finished. Ken

 

[1931 flamingo]

kenparker: I f you don't mind could you post what this machining sets you back. Thanks in advance,
Paul in CT

 

[30 A coupe]

The ARP partnumber for the waterneck studs is AP5.750-1SB, sold by the piece. So you can get all the studs from ARP (I don't know the price)

http://www.arp-bolts.com/

 

[Larry Brumfield]

I am having to backtrack again on my solutions to the problem - using Dorman studs. After comtemplating and measuring (twice) then worrying for two days I am discarding the Dorman studs that dont fit right.

My Snyder 6.1 head is going to the machine shop today to have the "bosses" or "collars" machined down to where standard 3.5 inch grade 8 Model A studs from the major suppliers (Snyders, Brattons, Berts, Mikes) will fit and torque down to the correct values with out worry. I dont want something to go democrat in the middle of the desert and cant find an odball part to fix it and get home. It aint wort da risk.

The "bosses" have more than enough protrusion above the flat surface of the head to mill off and make it fit right. Model A Apprentice has the same measurements as measured on my head/s.

Will post resulth when finished. Ken

Better pay a close eye to "more than enough." Sometimes there are small irregularities in the thickness of the surface exterior's texture (best way I can describe it) of a casting in various areas, and in this case as well some areas around some of the bosses may not be the same. If you make any cuts on the bosses that happen to come out close to flush (or even fairly near the flat area of the top exterior) the tool will kiss these outer areas wider than the stud boss and make the head look bad. Some may even cut in a slight recess. So make sure of the tool size and the machinist's method before he starts.

Moreover, the machinist may not have the exact right tool but he will have something that he knows will work and he won't think anything about what I'm talking about; he just knows that you said, "I want this amount milled off these stud bosses."

He may even decide to cut the bosses horizontally, from side to side across so to speak, and ANY tool size may possibly kiss or cut into the other areas of the casting when the bosses are cut down close.

Also, what's right for milling as an "exact amount" as far as your head is concerned may not apply equally to the other heads. In addition, if these heads are made exactly like Ford's original, the top exterior flat area is only an 1/8 inch thick before you hit water!






.