cylinder head bolts 812

Although some have used stainless, I strongly advise against it

Hi Al,
The head bolts lengths listed in the service bulletin for 1935 are A 1 5/16", B 1 21/32", C 2 1/32",
In the 1937 spares list they are given as A 1 9/16", B 1 13/16", C 2 5/32".
Did Cord modify the head thicknesses and do the second lengths reflect this?
What do you reckon the lengths should be with later replacement heads?
How much deeper should the threaded block holes be than the bolt lengths when the bolts are fitted with the 5/32" washer?
Regards, Barrie.

Hi Barrie,

The head bolts for repro heads should be 1/4" longer then the originals. If they are too long, you run the risk of damaging the block. In the past, I had stainless steel head bolt sets made that had the proper head height. The only thing they lacked were the raised letter that appeared on the original head bolts. You can get them made with raised letters but it is almost cost prohibitive.

Unfortunately, I do not have any repro head bolts sets left and only have one set of standard head bolts left.

CORDially,

Al Hatch

Hi Barrie:

I would have to defer to one of the geniuses here such as George Arakelian, Henry Portz or Al Hatch to name only three, for that answer. I haven't worked with the replacement heads yet but do know for certain that there is a difference. Good Luck!

Mark

Thanks Mike,
Origional head bolts were 1 9/16",2 5/32" and 1 13/16" long, what would be the lengths for replacement heads?
Thanks, Barrie.

Hello Barrie:

Your question has a few answers. First, if function is what you're looking for, then any grade 8 bolt will work better than any 1937 feeble, 70 year old grade of metallurgy. You can generally find them in a ARP catalog or quite frankly at your local hardware store. The bigger question is which bolt will work as well as appear correct. Three fixes;
1. Take a silver grade 8 bolt and mill the top off of it to give it a smooth headed appearance. Then either re-plate them or simply paint them with any number of commercially available silver zinc/cad paints.
2. Take a silver grade 8 bolt and weld an additional 1/8" of material to the head. Regrind and reshape it to a smooth hex then plate or paint it. The original bolts had a thicker or higher hex head from the factory.
3. Post a wish on the 812 parts forum and find someone who still has a set of reproduction head bolts that were made a few years ago with the correct dimensions that sold for about $400 a set. These bolts are like little pieces of jewelry and would cost some multiple to reproduce one-off. You will find all of the folk's on this Forum incredibly helpful when it come to locating a needle in a haystack.

It will all depend how nuts you wish to get. Most engines that I have seen use silver grade 8 bolts or utilize method number 1. Also keep in mind that the original head takes a shorter bolt than the reproduction head. A Pebble Beach or Meadow Brook car will almost always have either the second, third or NOS alternative.

Good luck and have fun.

Mark

I am replacing the head gaskets and wish to replace the head bolts.
What are the modern grades of material that compare to the origional specs of AN7-14,AN7-22,AN7-16, and for the washers AN960-716.