Jaguar Etype V12 Water Pump Replacement

[Ian Hutton]

Hello, I wonder if anyone has experience with SNG Baratts complete water pump replacement for series 3 V12?

The water pump is supplied with both fan belt pulley and water impeller already installed which is great. However, there is a gasket pre-installed between the two castings that make up the pump. I’m not talking about the large gasket that fits onto the engine block and the pump. The gasket I’m referring to sits between the two metal casings that go together to form the pump before it’s bolted to the engine block.

My question is this. Does the pre-installed gasket require any gasket sealant to be applied prior to installing the water pump on the engine? There is a very small gap between the castings where the gasket is located but not that easy to apply sealant. As the gasket is pre-installed and the surfaces are new and perfectly flat I’m wondering if this is a type of gasket that doesn’t require sealant and you simply tighten the bolts up. Any views would be most appreciated. Thanks. Ian Hutton

[angelw]

Ian Wrote:

As the gasket is pre-installed and the surfaces are new and perfectly flat I’m wondering if this is a type of gasket that doesn’t require sealant and you simply tighten the bolts up. Any views would be most appreciated.

Hello Ian,
The surfaces are far from being perfectly flat. The face of the Water Pump Body where it interfaces with the Sandwich Plate (the area of your concern) is the only face that's machined; neither side of the Sandwich Plate is machined. Original equipment water pumps also had no post casting machining of either face of the Sandwich Plate, but these were Die Cast and were sufficiently flat and parallel to seal. Sand casting, which is what your new water pump is, is a totally different kettle of fish.

The following picture shows the transfer of Marking Blue from a Surface Plate I made (surface ground plate with a hole bored in it to clear the impeller) to check the flatness of the surface that interfaces with the engine. Although very small deviations from flatness would indicate the same, I was able to get up to 0.4mm feeler gauges between the surface plate and Sandwich Plate in the areas where no Marking Blue was transferred.



I reported the matter to the supplier and received the reply that it is OK.

Having an informed opinion as to the result, just for giggles, I mounted the water pump dry on an engine I had out of a car, filled the water galleries with water and applied a pressure of circa 7psi to the system; it leaked like a sieve from both sides of the Sandwich Plate. The same test was applied using increasing amounts of Permatex Sealant with the leak being stopped when the amount of sealant was way past what I would trust in the medium to long term.

I stripped the Water Pump and machined both sides of the Sandwich Plate. The same test applied with clean, dry gaskets resulted in no leaks.

Regards,

Bill

[Ian Hutton]

Thanks very much Bill for your prompt reply. As a matter of interest, was it easy to remove the water impeller from the pump and then press it back on again after you had completed your machining? Kind regards, Ian

[angelw]

Ian Wrote:

As a matter of interest, was it easy to remove the water impeller from the pump and then press it back on again after you had completed your machining?

Hello Ian,
I operate an E Type Restoration business in Victoria, Australia, part of which is a well equipped CNC machine shop and I have, or have made, every tool you can imagine for dismantling and reassembling component parts of the E Type. Accordingly, its not that hard for me.

You will note the two holes in the impeller, shown in the picture attached to my previous email; these are threaded hole for the purpose of removing the impeller. Don't use a typical pulley puller, the type that grips the OD of the part. The chances of breaking the impeller using such a puller are high.

You need a plate drilled with two holes clearance on 5/16", the centre distance the same as the tapped holes in the impeller. Another hole is drilled and tapped at the centre point between the two holes drilled in the plate; mine is drilled and tapped 1/2" UNF. In operation, the plate is secured to the face of the impeller via the two drilled holes. A bolt applied to the centre threaded hole will pull the impeller from the shaft.

I take the precaution of warming the impeller to give the part every chance of moving without damage. Cast Iron is more likely to break when stone motherless cold than when warm.

When pressing the impeller onto the shaft, ensure that the opposite end of the shaft is supported and that you're not transmitting load to the body of the bearing assembly and hence the bearings.

Regards,

Bill

[Ian Hutton]

Hello Bill,

Thank you for such a comprehensive reply and I only wish I was a little nearer to you in Victoria! It must be great to have all the tools and equipment for the V12 engine. With your accumulated knowledge you should perhaps write a book for enthusiastic amateurs like me!

I’ll take on board everything that you have said and thanks again for all your help.

Best wishes,

Ian

Ian Hutton
1973 Etype S3 V12 Roadster.

[abowie]

I reported the matter to the supplier and received the reply that it is OK.

Having an informed opinion as to the result, just for giggles, I mounted the water pump dry on an engine I had out of a car, filled the water galleries with water and applied a pressure of circa 7psi to the system; it leaked like a sieve from both sides of the Sandwich Plate. The same test was applied using increasing amounts of Permatex Sealant with the leak being stopped when the amount of sealant was way past what I would trust in the medium to long term.

I stripped the Water Pump and machined both sides of the Sandwich Plate. The same test applied with clean, dry gaskets resulted in no leaks.

Regards,

Bill

That's just laughable.

Sorry, I'm not supposed to criticise our parts suppliers but really?