Posted by Clint Dixon [172.68.58.86] on Saturday, May 05, 2018 at 20:22:51 :
In Reply to: Re: Cylinder Head posted by Matt Wilson [108.162.221.227] on Saturday, May 05, 2018 at 19:32:34 :
Thanks for the suggestions Matt.
After I did what Spence suggests, and "let the grey matter rest awhile", I think I have it figured out.
There was a long period when Dodge did not produce a new parts list - late 1948 through mid 1951. The 1951 issue clearly states that it supersedes the 1948 issue. The older one lists the early parts, and the later one lists the newer parts. I also have a 1953 "Parts Supersedence List" which shows all the old numbers up through the years that were replaced with newer numbers and what that newer number happened to be. It agrees with the 1951 list and shows that the changes took place, there is just no year, serial number, or engine number listed anywhere indicating at what point the changes actually occurred.
Then I remembered that I have an old replacement engine that I removed years ago from a Power Wagon used as a blasting truck in a quarry. It is an industrial engine of some size, the numbers make no sense on it (it is not a T137), and it is tucked away and I have not paid any attention to it in probably 30 years.
The engine still has the head mounted and it is a "humped" head with the internal bypass. Fortunately, I removed the waterpump years ago. I started probing around on it and found the the hole in the top of the block does not connect to any of the water jackets inside the block. It angles sharply to the waterpump. Then it started coming back to me. I replaced the old waterpump on the '51 years ago with a rebuilt one. The rebuild was an exact replacement, with the top port for the external bypass, etc. However, it had a back cover plate that had an extra hole in it. This hole aligned with the front hole in the block when the pump was bolted in place. I noticed this at the time and replaced the plate with the one off of the pump I had removed as it did not have the additional hole. I must have scratched around at the front of the head and saw the sliver of hole poking out from under the head and head gasket. Thus the deja vu that hit me earlier.
Problem solved. If coolant does not have a hole in the pump cover plate to exit, it cannot get into that bypass hole in the block and it does not have to be covered with the correct head and gasket. I guess I solved the problem years ago, forgot about it, and today was trying to solve a problem that no longer existed.
It appears that Dodge may have switched to a new block with the bypass port drilled in place before they actually switched heads, waterpumps, and thermostat housings. My truck is a very early B3PW, so it was probably made right when changes were just starting to take place.
I have not examined my head real closely yet, but so far, I have not seen any cracks. So far so good. But none of the head bolts that entered into the water jackets had any kind of sealant on them. There still may be a place where a slight amount of coolant is getting into a cylinder until it heats up and closes. And maybe that is not completely closing anymore as evidenced by the rise in operating temperature.
Thanks,
Junior
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