Replaced water pump - found this groove on outside of cyl bore

[spt87a]

Hi, I replaced my water pump yesterday. I noticed the outside of the cylinder bore facing the pump has a wear/machine groove at where the bottom of the impeller would be.

Anyone seen this before - is it normal? Was that machined like that at the factory originally?

Both the old pump and new after install spun freely with no sign of rubbing.

[svono50]

It has been too many years since I had a water pump off (knocking on wood), so I can't recall if I ever noticed that myself. The mark looks purposely machined vs damage from the pump impeller (i.e.- too 'perfect'), so I would go with it being from the factory. Only thing that puts a slight amount of doubt in my mind is that it is still so clean with no scale/buildup/rust on it. I have to look at my block in my garage now to see if still has its pump on it...

[MIKESVO]

I just looked at the engine I'm rebuilding and the same machine mark is present.

[svono50]

Checked out my spare 87 Merkur block tonight and it is on mine too. You can see some other circular marks on the cylinder wall as well, which line up concentrically to the water pump hole. That tells me that is from the tool that finish machined out that hole. Interesting that Ford allowed the contact of the cylinder wall like that.

[spt87a]

Ah, ok, thanks for the confirmation with two others having the same mark. I was thinking it was for impeller clearance but it doesn't seem the impeller would stick in that far. Overshooting while machining out pump hold makes sense even if it seems like that shouldn't have been happening.

On a related topic - anyone know of a source for a water pump rebuild kit? Looked around online and didn't see anything. I put a new pump on it but was thinking I would like to rebuild the original and keep it as a spare (and since it was the original I just want to hang on to it anyway).

[svono50]

I have honestly never looked for or seen a rebuild kit for our pumps...doesn't mean they don't exist, but in today's world of replace vs repair not sure if one exists.

I am not sure it was an 'overshoot', more likely a tooling design related issue. I wouldn't suspect an overshoot condition like that would last multiple years, but you never know. Some tooling engineer was asked to create a tool for making/cleaning up that hole in the block, but either didn't pay attention or wasn't aware of the clearance depth or was given incorrect information as to the depth available and the tool ended up doing what it did. Working in mfg for the past 25 years, the amount of opportunities for this kind of thing are virtually unlimited. Wonder if anyone left at the Lima plant is still around and could speak to that interesting little 'feature'?