The 'E' Type Forum

The original pump had alwAys Ben the best
Anyone have a new or modern water pump for a 4.2 Etype?
Gtjoey13-4

Why do want a hi-er output water pump?
You can achieve that just by altering the ratio of the pulley sizes.

The only time you might conceivably want a higher output is when you are at idle. At any other time, the thermostat throws away the excess cooling capacity and simply recirculates a portion of the water around the block anyway.

kind regards
Marek

Just a thought as I had it out again

MarekH wrote: ↑

Sat Jul 30, 2022 5:25 am

Why do want a hi-er output water pump?
You can achieve that just by altering the ratio of the pulley sizes.

The only time you might conceivably want a higher output is when you are at idle. At any other time, the thermostat throws away the excess cooling capacity and simply recirculates a portion of the water around the block anyway.

kind regards
Marek

Marek,
Jaguar thought it was necessary as they increased the size of the impeller in '71 presumably to increase volume.
Spinning it faster with a smaller pulley invites cavitation no? There have been quite a few XK engines that have suffered serious involute corrosion....perhaps this is why

Damage by cavitation is an exponential function, so persistently running revs above a certain threshold value would indeed be bad news. I seem to remember David (Heuer) posted something on this a while ago.

By contrast, most reported cooling problems occur when waterflow and airflow are at a minimum, e.g. at idle speed, crawling (uphill) in stop-go traffic or when stationary. This is an unavoidable daily hazard.

Davies Craig make electric water pumps which are temperature controlled. A drop in replacement that looks stock would appeal to lots of people I'm sure.

Norman Lutz originally developed his restrictors on XK engines in the outback to stop overheating before transferring the idea to the v12s which we are more familiar with.

kind regards
Marek