The Stovebolt Site Forums The Shop Area Engine Shop 235 Water pump adapter plate thickness

I am in the middle of doing the short water pump conversion to my 1957 235 engine. Can anyone who has done this tell me how thick the adapter plate is? The plate I bought is about 1/8 thick which is roughly the same thickness of the plate you remover from the pump. I am starting to think a thicker plate say 1/4" would be better and I was honestly expecting that because I thought I read the pump would sit a little closer to the radiator than normal. What bothers me about the thin plate is the two holes you drill in the engine has an 1/8 gap to the engine. If you tighten the bolts too much it will possibly bend the plate and water pump and cause a huge leak. The other thing that bothers me is they want you to bolt the plate to the pump in a way that two bolts are inside the engine. This bothers me because it may be tricky to seal, also impossible to retighten the bolts without removing the pump. I always like to retighten the bolts after a few hundred miles. If the plate was 1/4 thick those holes could be threaded. Just a few thoughts I had about this conversion process. I think the 1/8 plate will work I just need to be conscience of the gap to the engine and also I am considering tack welding the bolts to the inside of the adapter plate so that I can retighten them. I was also curious maybe I just got cheaper version of what the adapter plate should be.

I've installed two of Dave's adapter plate (both on 261s, 1959 &1960). No leaks/problems with either installation.

The thickness of the plate is correct, except as Dave notes in his blog site:
"*Note: When installed in a 1939-40 Chev, the fan will be ¼” forward from stock but will fit fine."

http://chev235guy.blogspot.com/search/label/Water%20Pump%20Relocation%20Adapter

If the gap really concerns you, just epoxy thin flat washers to the front of the block. If you're as OCD as some of the guys here, you could have a machinist set the washers up on a magnetic surface grinder platen and grind them to a perfect flush fit with the rest of the pump mounting surface before attaching them to the block. That would cost approximately three times what you spent on the plate, though! A little blue LocTite will stop any seep leaks from the bolt threads, or you could install studs, not bolts in the drilled/tapped holes in the block and use threadlocker on them for a permanent installation. Tighten the nuts on the studs every couple of weeks if you want to after that.
Jerry

I haven't had any problems with mine as well . I believe the plate thicknesses are the same .

Tim

Its good to hear there are no issues with this setup. It makes me feel a better. I didn't have any serious doubts just a couple concerns. I thought of the washer trick but the block in that area is not flat or parallel to the adapter plate so that would not be a perfect fix. I think it will be fine just have to remember not to wrench it down too tight. Since I am replacing a 1/8 pump plate with a 1/8 adapter plate I dont quite get how it moves things 1/4 forward but no big deal, probably something I am not seeing or considering.

Grind or file the front of the block flat. Use a straightedge across the pump mounting area, and a feeler gauge or a depth micrometer to get a measurement, and keep filing until it's exact. Then fabricate the spacers so the gap is eliminated. Stuff like this was "auto mechanics 101", that every journeyman mechanic was expected to know a few years back. These days, if something isn't a perfect fit right out of the box, nobody is interested in doing anything that involves thinking, or working!
Jerry

I grew up helping dad as a mechanic, and later got into doing fab work, and for the last 10 years I have been a machinist. Today I work with fabricators and mechanics every week and many of their ideas make the machinist inside me cringe. Everyday we assemble and rebuild equipment thats wore out or was not made quite to spec but we always make it work. The straight edge and feeler gauge just doesn't work for me. If I cant sweep an indicator across the face I cannot say its exactly flat or parallel. The best way to do this would be to set it up in a milling machine and cut a counterbore square to the surface just deep enough to clean up and flatten the block. And If I really want to complicate things I could make a new plate thick enough to machine some raised bosses on the backside and it would almost look like this water pump belongs on this engine. But if I wanted to go to that extent I would probably just build a new pump from scratch that fit the engine holes but just had a raised impeller shaft. I am just in a weird position with this project. I need it done good enough that it works and is reliable but I need it done somewhat cheap and fast so I can use it to build my dream house in the spring. I refuse to buy a new plastic truck for that use. Once its done I have every intention of completely restoring it back to like new original perfect condition. While building it this first time I am making notes of everything that needs to be further addressed when I do a frame off restoration in a year or two. Its not that I dont want to think or work I just need the most sensible way to get this truck running for the spring. Maybe I will look into renting a magnetic drill and using it to counterbore the block with about a 3/4 endmill. I could also use it to drill and tap the new holes square. It probably wouldn't be perfect but just good enough to satisfy my OCD machinist mentality.

I am so glad I did not have to go through those "steps" installing that plate on my two trucks.

Dave,

How many time have you installed that plate?
How many times did it not lay flat (not make a seal).

Thanks,

I installed one, and I’m a picky machinist too. Don’t remember anything difficult or tricky about it, about all I can remember is doing it in the garage with hand tools.

I have not had a problem with leaks (and I have lost count of how many I have installed), and sold many many more with few problems.
Early on I did not direct installers to only tighten the two bolts that go into the new drilled holes to 25 ft. lbs. and there were a couple that got bent. Since then there has been no complaints.

To answer an earlier question, it is not the plate that is affecting fan position on the earlier installations, it is the 1941-54 pump design that affects that. My plate needs to be the same thickness as the plate it is replacing to keep the belt in alignment.

A big thanks to all that have bought and used my plate.

Dave

I installed one on my 235 a few months ago. The installation instructions were straight-forward and the end result was just as I hoped for-no leaks. IMHO it's a quality product at a reasonable price.

I finished up my water pump conversion today and I had some concerns but it turned out good and I am happy with it. One issue that I currently have that I have not seen discussed anywhere is that my fan does not fit. I have the 57 235 engine from a 3100 truck in my 54 3100 truck. I was hoping the fan that came off the engine would fit the water pump but it does not. The hole in the fan is too small to fit over the stem on the water pump. I can drill the fan quick and easy, I just wasn't sure if there was any other difference between a 57 and 54 fan. I am pretty sure there is no shroud on the 54 so diameter should not affect anything. What does everyone usually do for a fan with this conversion? Thanks

Find a fan for a 216/early 235. The hub of the water pump is a different diameter. If you choose to enlarge the hole in the present fan, be sure it stays centered. Even a little runout will cause some annoying and possibly dangerous vibrations. A shaky fan can develop fatigue cracks and lose blades.
Jerry

Jonald,

As previously mentioned, I recently installed the water pump adapter plate on my 1955 235. I ran into the same problem with the fan. I purchased this fan from Classic Parts. I didn't want a fan failure to ruin a new radiator. It's difficult to determine what condition a used fan is in, so I would replace it to be on the safe side.

Good luck,

Thanks for posting that link, that is cheaper than used fans I have seen on Ebay. I will get one on order soon. Also thanks for posting the pic of your engine, very nicely done. Can I ask what is the story with your heater hoses? I have seen that setup several times in pictures but cannot figure out where they go. Are they running two heater cores in the cab of the truck? The heater I have is I believe is a generic aftermarket, that has one in and one out. Is the tube towards the center of the fire wall possibly a shutoff valve?

Thanks again

"Can I ask what is the story with your heater hoses? I have seen that setup several times in pictures but cannot figure out where they go. Are they running two heater cores in the cab of the truck?"

That would be the "plumbing/control" for the 47-55 GM truck RPO "deluxe" heater.

The names and design of that "deluxe" truck heater system changed a little between 47-55, but the "plumbing" was/is the same. It was called the Air Flow Heater or the Fresh Air Heater.

Thanks Jonald,

I have a Harrison air flow heater that is connected to a Ranco heater valve. There is one heater core. The The 1951 Chevy Installation Manual does a nice job of illustrating all of the necessary connections.

Post some pictures of what you have. There's a wealth of knowledge and experience here on the SB, and someone will have the answers you're looking for.

Jonald, you might want to do a bit of checking before ordering that fan to check on the diameter. Your '57 would have come from the factory with a 20" four blade fan with a 5/8" hub. Earlier 235's and 216's came with smaller diameter fans and 1" hubs. The fan shown on that link has a 15 3/4" diameter and is listed for a '47-'53. I'm not sure what diameter fan the 54/55.1's used, but you might want to check.

If you do open up the hub of your existing fan, I suggest doing it with a step drill. That should keep you centered. Harbor Freight sells a large one that would do the trick if you don't have one or don't have access to borrow one.

https://www.harborfreight.com/2-pie...-high-speed-steel-step-drills-96275.html

Matt

That heater hose setup occcurs on my '54 GMC 630.

Ed