New small block water pump backing plate?

[Patrick H.]

Does anyone know of a replacement water pump backing plate for a small block?

Working on a car that had its original pump rebuilt by a well know water pump rebuilder. I can tell that the holes for the bolts were overtorqued at some point in the pump's life, as the area around each is bent down. The newly rebuilt pump is now dripping from the plate-to-pump interface despite the copious amounts of sealant the rebuilder placed there. I doubt any attempt was made to straighten the plate.

I would like to consider a new backing plate, as straightening this one might be a bit difficult. If someone knows of new ones that would be great. Otherwise I will probably attempt top straighten this one or one from a spare water pump we have to see if there is a "best" usable one here.

Thanks for any tips you may have.

Patrick

[Edward J.]

Re: New small block water pump backing plate?

Pat, I would just try to straighten the old plate unless you have a good one from donor pump. Its likely the easy route. My advice is once you straighten, coat the new gasket, both sides with the brown non hardening permatex sealer.

[Joe L.]

Re: New small block water pump backing plate?

Does anyone know of a replacement water pump backing plate for a small block?

Working on a car that had its original pump rebuilt by a well know water pump rebuilder. I can tell that the holes for the bolts were overtorqued at some point in the pump's life, as the area around each is bent down. The newly rebuilt pump is now dripping from the plate-to-pump interface despite the copious amounts of sealant the rebuilder placed there. I doubt any attempt was made to straighten the plate.

I would like to consider a new backing plate, as straightening this one might be a bit difficult. If someone knows of new ones that would be great. Otherwise I will probably attempt top straighten this one or one from a spare water pump we have to see if there is a "best" usable one here.

Thanks for any tips you may have.

Patrick

Patrick------


If you could find an NOS GM #3782610 you'd be all set. However, I don't think you'll find one as this part was discontinued from SERVICE in October, 1971. Obviously, they continued to be produced after that time but they were no longer available in SERVICE. (And, no, I don't have an NOS example).

I don't know of a source for a new plate but I think a good used one should be pretty easy to find. Rebuilders re-use these things all the time without problems. You might try Bill Mock. He might have access to new plates from rebuilder suppliers.

In any event, you want the plate with the rolled edges AND the type that has impressed ridges between bolt holes. That was the latest design and the only type that I found would seal reliably. Beware: there are some plates out there that have an extra deep rotor relief cavity. These will bottom on the timing cover before the legs contact the block and require extra thick or multiple leg gaskets. I do not recommend this. Also, in the same vain, you don't want to use thick plate gaskets as these can cause the same problem.

[Joe L.]

Re: New small block water pump backing plate?

Does anyone know of a replacement water pump backing plate for a small block?

Working on a car that had its original pump rebuilt by a well know water pump rebuilder. I can tell that the holes for the bolts were overtorqued at some point in the pump's life, as the area around each is bent down. The newly rebuilt pump is now dripping from the plate-to-pump interface despite the copious amounts of sealant the rebuilder placed there. I doubt any attempt was made to straighten the plate.

I would like to consider a new backing plate, as straightening this one might be a bit difficult. If someone knows of new ones that would be great. Otherwise I will probably attempt top straighten this one or one from a spare water pump we have to see if there is a "best" usable one here.

Thanks for any tips you may have.

Patrick

Patrick------


This is the style you want to use:

DSCN0799.jpg