Early or later water pump?

[71 V12]

The water pump on my early V12, engine no 7S4226 has failed, bearing completely shot. My pump is the original single outlet pump.

Is the later pump introduced from 7S7785 with twin outlets more efficient? Whilst my car would not overheat whilst moving the temperature would creep up worryingly in traffic and would take quite a while to drop again even when the fans would kick in.

Also are the repro pumps good, I see Barratt’s do a conversion kit old pump to newer type.

Any experiences appreciated.

Regards,
Kevin

[Jack the lad]

Hi Kevin, my car is also an early type with the single outlet water pump and when my pump was worn I bought a kit to re-build it, it was many years ago but it was an easy job, this was 30 years ago and it has been perfect since with no over heating at all.

[71 V12]

Good morning Jack,

Thank you for the reply. Just to be clear did you rebuild your original single outlet pump or did you fit the twin outlet conversion kit?

Many thanks,

Kevin

[Jack the lad]

I did a rebuild on my original single outlet pump, just fitted new bearing and shaft seal, at this time I had a 30 ton garage press and it was a breeze, I think I could have fitted it with my garage vice as it was very easy.

[71 V12]

Hi Jack,

Thank you for the clarification. I called Rob Breere Racing in Coventry as they know a bit about V12’s and they also confirmed an early pump in good working order should be sufficient for the job as long as the rest of the cooling system is in good condition.

The bearing for the early pump is now unobtanium, however a later bearing can be modified to fit by EP Services in Wolverhampton who recondition water pumps for many of the Jaguar parts specialists, so hopefully this will resolve the pump.

I am also having the radiator re cored whilst it’s out as I believe it is the original radiator and could be partially blocked.

Regards,

Kevin

[AussieEtype]

My engine is earlier that yours and still has the original water pump - never modified, still working fine. Is more than adequate to handle Australia hot summers as long as the rest of the cooling system is up to scratch.

[71 V12]

Thanks for thats good to know. I am having the original pump rebuilt.

My chassis is 1S1036, so 36th RHD roadster off the line in the first week of series production at Browns Lane. Is yours earlier than mine?

Regards

Kevin

[AussieEtype]

Yes - number 11.

[71 V12]

Yes - number 11.

[lowact]

These brgs are only unobtainium because Jaguar heritage part suppliers don’t stock them, you can still buy them from bearing suppliers; because “water pump bearings” are a bog standard thing that are used universally by everybody for everything. Available in an almost infinite range of sizes. So just take yr old bearing into a brg supply shop, they will look at, measure it and give you from a catalogue one that is exactly the same for a fraction of the cost that you would pay a Jaguar heritage parts supplier. E.g.:

Note that a Jaguar (or Mercedes or GM …) P/N is meaningless to a bearing supplier.

In my case I made it even more difficult; because I was trimming my water pump(to line up my modified pulley arrangement), for it to fit flush and neat I needed a bearing that was not a standard retail size ...


To source this I had to find a manufacturer who was prepared to sell me just two (one spare). I eventually stumbled across Jason (forget his last name) from Outer Mongolia. He was very obliging, even sent me a screen shot of their AutoCAD drawing showing the dimensions and tolerances. The two bearings that duly arrived via DHL were the best quality of this type of brg I’ve ever seen. I.e.: I still had to trim a couple of millimeters off the end of the output shaft; the metal was so hard we couldn’t cut it, had to get it ground off. Overall including freight) it cost me about a 1/3 of the local asking price for closest available size.
Btw seals are the same, just take yr old one down to the local seal shop, it’ll be the same as the bearing shop …