Head bolts too short for High Compression Head

[MikeK]

Les Andrews mechanics handbook and other sources has installed length dimensions for the studs. Screw them until they protrude the correct length. That should fix the problem.

John, that will not fix the problem. You missed something here. The new Snyder 6.0 head is too thick, not like an original head. With standard studs set the correct height you do not have enough stud left to completely fill the nut.

 

[George Miller]

Well their method fixes one end and compromises the other. Why not just correct the head?

The amount of thread length that screws into the block was designed for the stock head. A significant reduction in that amount forces the remaining threads to carry all the load. Next, add the torque increase for the high comp head along with old blocks with used threads and you have a condition where some blocks may take it and some may not.

If any of them pull out or fail, their method and the head will get the blame every time along with possible distributor shaft complaints regardless. Moreover, the ones who don't like the idea of unscrewing the studs (or don't know) will have problems and complain just as they have done in this thread.








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I think Larry is right on. I would rather take a chance with less thread in the nut. But I would counter bore the holes or buy longer studs, which you can find on line. I would also counter bore the dist hole. The threads in the block on a lot of engines are not that good to start with. A lot of them have been re-tapped with the wrong class tap.

 

[Model A Apprentice]

Attached shows a 3.75" ignition head stud on the left and the 3.5" standard head stud on the right. The side view also shows the higher "collar".

 

[Model A Apprentice]

The far right picture is a profile of the speed head.

 

[1931 flamingo]

This is a perfect example of what everbody complains about. Someone (knowledgible about A's) has gone to the time, trouble AND expense of providing us with a "new" part, WITH known "defects". I can remember all the previous posts of anticipation that the "new" head was coming. Now the disappointment starts to set in. If you're going to go to the expense of tooling up to manufacture, why not do it right or complete (if the "stock" length studs were known to be too short, why not tool up and make NEW grade 8 studs avail as a pkg to install the "new" head???) ? On the Brumfield heads, were the stock length studs long enough to install head correctly and torque? Sorry for the rant.
Paul in CT

 

[Larry Brumfield]

On the Brumfield heads, were the stock length studs long enough to install head correctly and torque? Sorry for the rant.
Paul in CT

The answer is yes.

Except for one head made for Marshall Daut. I made him one a little thicker years ago so he would be able to have a "lifetime of resurfacing" or so I thought and never run out of thickness if he desired to do so. He had to locate longer studs. The dist. boss height was correct. Of course the compression would come up with it but I thought I was making a selling point to reward Marshall for being such a great customer. He liked it.

(This does not mean that you can automatically mill off Snyder's head or any other head for that matter to get the desired results discussed in this thread. The bottom thickness may be too thin for excessive milling and you may also foul up the dist. boss height; a measurement that must be correct; if you get carried away with milling. A special mold was used for Marshall's head.)

Marshall was indeed a great customer and a knowledgeable automotive man and Model A restorer. He posted frequently on the old Fordbarn but he grew tired of the left-wing p.c. police who were controlling it and stopped posting.








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[George Miller]

In life I have learned, that usually it is not good to be the first one in line for a new part. or the first car of a new model year. When I worked in a Ford dealership the new 1957 Fords came out. With them came lots of problems, bad camshafts, mud came up between the hood and front fenders, rear main problems plus more. They got all the problems fixed, but not for awhile.

 

[GOW]

so it would seem as the new snyder 6:1 is NOT the way to go. any ideas on who's/where to get a good hi-po head?

 

[Craig Lewis]

In life I have learned, that usually it is not good to be the first one in line for a new part. or the first car of a new model year. When I worked in a Ford dealership the new 1957 Fords came out. With them came lots of problems, bad camshafts, mud came up between the hood and front fenders, rear main problems plus more. They got all the problems fixed, but not for awhile.

.....good point George.
The early bird gets the worm, but the 2nd mouse gets the cheese

 

[hardtimes]

Attached shows a 3.75" ignition head stud on the left and the 3.5" standard head stud on the right. The side view also shows the higher "collar".

THANKS for the pics, as 'they' say...worth a thousand words!
Hmm, if handed lemon...make lemon juice.
So, considering the problem, would it cost more to buy new grade 8 proper length studs....or....to have 1/4" milled from stud bosses, including dist boss??
One question...someone apparently thought (mabe not) that the additional thickness on the stud bosses would strengthen this head for high compression/higher torque load?? Then if milled 1/4"..would that milling then weaken this head in some areas/fashion?
BTW...considering the outrageous cost/labor/investment involved in/with a completed A/B engine...it is ludicris, in my opinion, to back out studs from a 80 YEAR OLD block to compensate for this nut problem!

 

[Mitch]

I really don't have a dog in the hunt on this, but I would get longer studs, making sure there are enough threads for the nuts to tighten down. Regarding the distributor hole, I would measure it first to see if it is really a problem before changing anything there.

 

[GOW]

the concern is with studs and NOT using bolts. i would thik ARP would have the corect size/length studs

 

[Jim Parker Toronto]

I just came in from the shop where I measured the distributer hole in the new 6.0 head and compared it to the original head. In doing the math, I found the new head to be 0.031" higher at the edge of the lip. I don't consider this to be a major problem in the overall picture. Thanks to all you who think the sky is falling, but I feel I am safe for the moment. I don't know where anyone came up with the 0.250"........

 

[Larry Brumfield]

Thanks to all you who think the sky is falling, but I feel I am safe for the moment. I don't know where anyone came up with the 0.250"........

Nobody said the dist. hole was off .250" and the ones who implied it used question marks ????

However, if the head is made to the specs of an original head it's logical to assume that the distributor boss is off as much as the stud bosses because they are machined to the same height relative to the bottom of the head.

Mind telling us your exact measurement?








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[kenparker]

Finally, some answers. After a full day of removing the head and the offensive (short) studs, measuring the length of studs and lengths of threads on each end, measuring the thickness of the head and comparing all this to old original heads and a bucket full of old studs, here is what I found.

1. The "chrome moly - grade 8" studs measured only 3 7/16" long. Not the 3 1/2" as they should be. 2. The 6.1 head measured .020 thicker than stock Model A heads. (grantd the old heads could have been milled more than once). 3. The coarse threads at the bottom (the threads that insert into the block) were longer than any of the old studs in the bucket by as much as ane full thread, thus letting the stud screw into the block deeper.

Put these three factors together and you have studs that are 1/8" too short.

My solution will be to order 12 of the ignition studs (3 3/4") Monday morning.

The two studs holding the gooseneck were just fine - no change needed.

Final note: I am not a purist and dont care waht it looks like. I just want it to perform right. Two of the nuts has so little thread holding that they had begun to strip.

 

[Jim Parker Toronto]

Just for you Larry, the old head that I took off measures 2.235" and the new Snyders measures 2.266". A difference of increased height of the new head by 0.031" Jim


Final note: I am not a purist and I do care what it looks like. I also want it to perform right as well. If it looks like****, smells like ****, don't eat it!

 

[Larry Brumfield]

Just for you Larry, the old head that I took off measures 2.235" and the new Snyders measures 2.266". A difference of increased height of the new head by 0.031" Jim

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 in the head (above the pistons) measured .100 of an inch.

According to Model A Apprentice's measurements Snyder's head would be off at most about .096 of an inch regardless of the studs and with an effect to the dist. shaft's engagement by the same amount. With yours about .050 of an inch. (One or the other of you can't read a mic. The preponderance for being accurate leans toward Model A Apprentice in my opinion. Or, the machine work is not consistent and varies widely, nearly .050, from head to head.)

Add in Ken's measurements of Snyder's incorrectly made studs:

.0625 shorter in length

.0715 farther in the block (1 divided by 14 Threads Per Inch)

.0625 + .0715 + .096 = .230"

This makes a total of approx. .230 or right close to 1/4 of an inch!


The main thing that's for certain is the nuts don't fill up with original length 3.5 studs and that is not good. Moreover, backing the studs off puts more load on the old block threads and that is not good either.






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[Art Bjornestad]

Can the 6.0 head be installed with the grade 5 bolts? I thought I read that they are longer then the grade 8 bolts.

 

[Jim Parker Toronto]

Larry, I used a digital caliper, that I check often, so reading between the lines, (on the caliper, no pun intended) is not a problem. Maybe the paint is 0.020 thick, I don't know why your number is different. I am only comparing the heads that I have, with the tools that I have used for years and trust. At the moment, I am happy with the product I bought, and until it fails, have no complaints. When I wanted it, it was available. I had the money, and did not have to wait, or beg to get it. Snyders has been very accommodating to me and I am sure that if there are any problems in the future, they will be available to correct them in a timely manner.

 

[Larry Brumfield]

I don't know why your number is different.

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.