Head bolts too short - followup

kenparker

kenparker

Well-known member
This is a followup of the short bolts and the Snyders 6.1 head that was posted all weekend.

I went ot my local Independent auto parts dealer and started asking questions. He handed me his Dorman Nuts and Bolts catalog and said "make yourself happy". Did some research and found a Dorman head stud that perfectly fits the problem. In fack two studs. One is 3 5/8" long with 5/8" of coarse threads on one end and 1 1/4" fine threads on the other end. He had a box of these on the shelf.. The other Dorman stud is also 3 5/8" long but has 11/16" Coarse thread on one end and 11/16" fine thread on the other end. - Perfect. but had to order them and will be a few days before they come in. There IS a Santa Claus.

BTW the parts number in the Dorman Catalog were 675-016 and 675-032 for the perfect fit one.
 
Ken,

I looked on the Dorman web site and they do not list the 675-016 or the 675-032. Perhaps they are special order or no longer available. They do have a 675-013 which is 3 5/8" long with 5/8" of coarse threads on one end and 1 3/4" fine threads on the other end. The web site is at http://www.dormanproducts.com/ .

Bob
 
Seems odd Snyders did not supply this information.

How can you make and sell a product without telling people the necessary information to install and use it?
 
I have always got my head bolts for any antique engine I have been working on from dorman they have many sizes.
 
kenparker said:
This is a followup of the short bolts and the Snyders 6.1 head that was posted all weekend.

I went ot my local Independent auto parts dealer and started asking questions. He handed me his Dorman Nuts and Bolts catalog and said "make yourself happy". Did some research and found a Dorman head stud that perfectly fits the problem. In fack two studs. One is 3 5/8" long with 5/8" of coarse threads on one end and 1 1/4" fine threads on the other end. He had a box of these on the shelf.. The other Dorman stud is also 3 5/8" long but has 11/16" Coarse thread on one end and 11/16" fine thread on the other end. - Perfect. but had to order them and will be a few days before they come in. There IS a Santa Claus.

BTW the parts number in the Dorman Catalog were 675-016 and 675-032 for the perfect fit one.
Click to expand...



Perfect?

The first stud you selected is an 1/8 too short on the coarse end thread depth in the block hole as compared to the original Ford stud.

The second stud you selected is 1/16 too short as compared to the original.

Moreover, more than likely neither one has the FULL diameter 7/16" base for the first inch above the block like Ford's original (This is the part that's not threaded that sits directly above the block for the first inch after the stud is screwed in. Some people refer to it as a shoulder.). This full 7/16 base (shoulder) is necessary for good head and gasket alignment and also to help limit, in conjunction with proper head and block surface finish, any lateral movement of the gasket when the engine is running. Very necessary for a high comp head to help prevent premature gasket failure and blowouts and also a plus for the stock head as Ford intended.

The original stud was extruded above the first 1-1/4 inches to the correct diameter (smaller than 7/16") for rolling the fine thread on the nut end of the stud which of course restores the full 7/16 in the threaded area only.

Most if not all of the available auto supply studs are extruded to the smaller rolling diameter for the ENTIRE LENGTH and then the threads are rolled on both ends leaving the center, including the shoulder base, as an unthreaded smaller area. Not good for a Model A. The use of such a stud will increase the clearance between the gasket hole and the stud to right at .070 of an inch.

Also, if this type stud is lightly seated once installed, the stud may rotate a little with the nut; a tiny bit but enough; when torqued and jam the stud hard down in the block hole thus damaging the upper block threads because the unthreaded shoulder is less than 7/16. Screwing the stud in tight beforehand to prevent movement would have the same effect.

BUT, what you have is certainly good enough for "Gubment Work."



.
 
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Here is a picture

Here is a picture and specs from the Dorman web site. I could not find the studs that Ken mentioned. This stud is similar except the fine thread section is much longer.

Bob
 

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Re: Here is a picture

Bob Johnson said:
Here is a picture and specs from the Dorman web site. I could not find the studs that Ken mentioned. This stud is similar except the fine thread section is much longer.

Bob
Click to expand...


A picture is worth a thousand words.

This stud is a poor selection as well and confirms that Dorman studs are made in the same manner as all the rest of the auto supply and hardware store studs.

Notice the shoulder is clearly smaller than the threaded area. The rolling diameter (unthreaded shoulder area on this stud and ALL THE REST) increases the overall clearance between the gasket stud holes and the studs to right at .070 of an inch! .... lotta room to slide.

Now some of you may think that a gasket can't move ... but you're wrong.

When the engine is running, the head is teetering or rocking on the gasket from one combustion to the next. Now you can't look down and see it moving, BUT IT IS. It's a vibration type movement. If a head gasket has a lot of room to slide they often won't hold up for the long haul and it's even worse if the surface finish of the head and block is not correct allowing the gasket to move easier.

Unlike the Model A, modern engines have precision dowel pins to help hold things in place and provide good alignment.




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My apologies. The wrong numbers were brought to my attention ( by phone ) a few minutes ago.The number for one of the studs is MTM 675-013. I am reading the number from the ticket from the parts supplier. Cost is 1.69 each plus tax. This stud is the one pictured by Bob Johnson above.

The other stud 675-032 as Larry says above has coarse threads 1/16 inch longer. I have ordereed a set of them but wil be a week before they socme in.

Thanks, Larry for the lesson on quality studs.
 
kenparker said:
Thanks, Larry for the lesson on quality studs.
Click to expand...


You're welcome, Ken, and most important is the lesson of using improper hardware for a Model A (The stud you selected is equally as poor in the shoulder area as the one not chosen. Both are a bad choice for a Model A, especially one wearing a high comp head) and bush league methods which can lead to gasket failure and blowouts.



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Here we go again with a 'work around' for an obviously bad repro part. I would think fixing the head, like cutting the stud pads to the proper height with a piloted spot facer would be a better solution than cobbling together a mix of studs. If I followed correctly, the water outlet height is OK, the other 12 spots need work. From the picture posted by Model A Apprentice in the precious string LINK to Picture there appears to be plenty of meat for the required correction (about 0.100) to reduce the height to what I measure on an original head, 2.212. That would be two full threads on the 7/16-20 nuts. Look at the stock stud on the right in Model A Apprentice's picture, it is two threads too short. If I had one of the heads, I'd spotface down to 2.200", about 2 1/4 threads. You need a 7/8 diameter spotface if the cut touches the cast surface beyond the raised pads.
 
MikeK said:
Here we go again with a 'work around' for an obviously bad repro part. I would think fixing the head, like cutting the stud pads to the proper height with a piloted spot facer would be a better solution than cobbling together a mix of studs. If I followed correctly, the water outlet height is OK, the other 12 spots need work. From the picture posted by Model A Apprentice in the precious string LINK to Picture there appears to be plenty of meat for the required correction (about 0.100) to reduce the height to what I measure on an original head, 2.212. That would be two full threads on the 7/16-20 nuts. Look at the stock stud on the right in Model A Apprentice's picture, it is two threads too short. If I had one of the heads, I'd spotface down to 2.200", about 2 1/4 threads. You need a 7/8 diameter spotface if the cut touches the cast surface beyond the raised pads.
Click to expand...


Yup, that would fix it.

I'm pretty sure the reason that it was not done to start with has more to do with the avoidance of possible scraps or heads with a poor appearance than it does with a mistake in the machine work. It would take a lengthy post for me to explain it and many would not know what I was talking about.
 
To be honest I put on a Synyder 5.5 late last year with replacement grade 8 studs that are a bit short, similar to the photos in the previous string about the 6.0 head.

In this case I think it's just poor quality studs as the nuts that came with them stripped out. I ended up using some original A-nuts that torqued down OK. To be fair to Synders, I didn't buy the studs from them and I love the 5.5 head.

Getting longer studs is on the to-do-list.
 
I bought a 5.5 head from Snyder's a couple of months ago. I opted for the 5.5 over the brand new 6.1 because I didn't want to be a lab rat. Alas, the 5.5 was thicker than the original like the storied 6.1. My guess is that Snyder's has a new supplier for the castings and that they machine the chambers for either 5.5 or 6.1 as the case may be. I thank Fordbarn for all the discussion on the problem and I have ordered the longer studs from Snyder's ($25.00 or so including shipping) and will make the repair myself in my abundant spare time.
I am not particularly po'ed at Snyder's. They are not a Ford or GM with a gaggle of QC engineers and I can see how a combination of errors could have led to this situation.
All my problems should be solved as easily.
Just MHO.
 
it's synder's head it's their fault only. they had to have been aware of the problem but still sold the head. you would think the least they would do would be to advise the customer who's about to purchase the "bad" head.
 
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