A hello and a water pump question.

[Mart]

Hello.
Mart here from Solihull in the middle of England.
I recognise a lot of names here from other forums, and have added to a few posts recently, but here is a question.

On the older type block mounted water pumps, there is an oil feed from the timing chest that feeds the water pump bushes. I just pulled a pump apart and I cannot see any drilling through the bush from the oilway.

When a new kit is installed, should the bush be drilled through?

Or is the bush porous and just having oil present at the back side of it enough?

If there should be a through drilling what diameter should it be?

Possibly related is a problem I have with an old 21 stud engine I have been running in my roadster.. The pump leaks bad.. but not water.. OIL!.

I'm wondering if this has been through drilled and shouldn't have been.

Any advice welcome.

Mart.

 

[G.M.]

There is no hole in the bushings they are porous. The bushings need to be reamed about .001 to .0015 larger then the shaft with a dead sharp reamer so the pores aren't smeared closed. The shaft runs in a thin film of oil not touching the bushings. Fitted right and kept oiled the bushings will be more reliable and last longer then most bearings. Plus if water gets in the bushing it won't fail and lock up like a bearing. A shaft that drags won't free up it will gaul the shaft. Blow out the holes in the block while the pumps are off to assure the oil passages are open. The 21 stud is it a 37 with block mounted pumps or a 36 with head mounted pumps? If it is block mounted pumps the clearance in the bushing and shaft is to much or the oil is to thin or both. If it is the head mounted pumps the grease is being forced in and is going into the cooling system and out the front shaft. These pumps are NOT to be greased like king pins. The LOW melt temperature grease only needs one or two strokes of the grease gun once a year, the grease melts and saturates the porous bushing like the oil in the 37 to 48 type. Only LOW melt grease is used, high temperature 500 degree grease will not melt to lube the bushing and cause problems if it gets in the cooling system. G.M.

 

[Mart]

Hey, thanks for that. The 21stud is a UK Pilot motor, with pumps in the block. It is similar to a USA 37 motor. The pumps are identical to the USA units. I'll pull the pump apart and have a look inside.

Here's a tip I can pass on - if you have pumps with plain shafts and bushes (not ball bearing types) You should be able to grasp the pulley and pull it outwards a little - maybe up to 1/8". This is because the seal has a spring and you can see if the seal spring is in good shape by pulling as described. It should return smartly when released. Similarly a pump should have a small amount of drag when spun. If it spins freely then the seal is not pressing against the face of the pump like it should be - this goes for ball bearing types too.

Thanks again for the help.

Mart.

 

[G.M.]

Mart the ball bearing pump shaft don't move forward the shaft has a U grove that is the inner race for the ball bearing so it won't move. The bushing pumps should be pulled forward and let spring return to the rear once in a while to loosen dirt in the spring when sitting. That isn't a seal on the front behind the pulley, it is a phonolic washer and is a thrust washer so the pulley doesn't drag against the front of the pump when the inner seal spring pulls the shaft and pulley back at idle. G.M.