300+ rebuild

[mechohaulic]

2 hours ago, Freightrain said:

That is kinda why I am puzzled.

Both my 237 and this 300 have a shut off valve in the rear water manifold where a hose connects.  But both have different fittings at the pump end.

I was looking at engine and trying to determine water flow directions.  Water should come from bottom of block and up per say and out at thermostat at front of engine.  So the water at rear manifold is "hot" and returning to radiator.  Thus it is going TO the heater core.  Then the line at the pump is the heater "return" and needs to be on the suction side of pump.

rear shutoff valves are installed since the b's didn't have best air conditioners back in the day. without the shut offs. coolant would still circulate in cab. is it possible reason for two different fittings in front were due to one had brass pipe return other rubber hose ??

[Freightrain]

237 was from late 60s firetruck supposedly.  It had shutoff.  This 300 came from late 70s R model and has shutoff.  Factory?  Or something someone put on?

The water pump housing on 237 came from my 673.  The housing on this motor was the original and has stand pipe instead of nipple down by the oil cooler. 

I actually installed a shut off valve from a 70s Ford truck and have a choke cable running up to dash so I can adjust heat while driving.

[Geoff Weeks]

I think you have that backwards, it draws through the oil cooler to the center of the pump, centrifugal pumps always pump from center to outside. 

The block is on the pressure side of the system.  

edit: hum the post I was replying to seams to have been deleted?

Edited 1 hour ago by Geoff Weeks
missing post

[Geoff Weeks]

2 hours ago, Freightrain said:

But, thinking more about it, the suction side is at about 9 o'clock(draws from front of block).  The fitting is at 12, so it that still suction? As the output is at about 4 o'clock as it goes into the oil cooler and then out to lower radiator hose.

This was the one.

[mechohaulic]

isn't the pipe coming off the housing a 3/4 dia ?? while heater hose pipe nipple a 5/8 ? I found a picture of a tip turbine Mack on line(can't figure this posting yet) it has a 3/4 +- hose going to water pump housing ; fans blocks clear picture. one version of tip turbine engines had water coolant used to lower air temp another went to air then to front mounted intercooler in front of radiator. point is : my guess is pipe on WP housing was for a tip turbine engine. this would also put pipe on right side of pump.

[mechohaulic]

28 minutes ago, Geoff Weeks said:

I think you have that backwards, it draws through the oil cooler to the center of the pump, centrifugal pumps always pump from center to outside. 

The block is on the pressure side of the system.  

edit: hum the post I was replying to seams to have been deleted?

a simpler version; if you check the engine picture from wayne86 and his '55 B, the water pump has a 1/4copper line off the housing pic 1 then pic2  shows the other end of line going to the thermo housing. this 1/4 line was known as the cavitation line; top housing would hold air. modern technology this line no longer needed. water pump draws from lower radiator through engine back to thermo housing and top radiator. heater copper pipe on lower radiator(suction side) pulls coolant from heater core while other copper goes to heater .