Water pumps

Talk about the E-Type Series 3
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lowact
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#1 Water pumps

Post by lowact » Wed Jan 15, 2020 2:28 am

What I’ve learned about water pumps; here are pic’s of the pump impellers discussed in this post; 1st/2nd /3rd = left/centre/right = top/middle bottom.
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The 1st impeller, in “early” pumps (C39768), was quickly superseded. Seems (?) this impeller never had a unique part number and was never sold separately by Jaguar.
The 2nd impeller was in the “later” pumps (C34549) fitted after engine 7S7785. The 2nd impeller had part number C36363 and was sold separately, to enable early e-types to be upgraded. The benefit was higher flowrate. But it also had a simpler (cheaper?) shaft seal, required the impeller to be taller. With this seal the impeller clearance and shaft seal are not independent, this can lead to miss-fit, consequence is wearing of the end of the impeller causing leakage from the shaft vent hole.
Here is illustration of the C.36363 (2nd) impeller from the Jaguar parts manual, along with pictures of what is claimed to be this from SNGB and XKs Unlimited catalogues, evidently XKs Unlimited sell the correct part while SNGB’s is the original (1st) impeller.
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SNGB also offer an early-to-later water pump conversion kit. While this has the appearance of the later type, internally it is the early type (1st impeller). It is ironic that this early design, that Jaguar tried so hard to eliminate, is now the most common “upgrade”.

From HE engines onwards, the 3rd impeller (EAC3212) was back to original height, an independent pump shaft seal could again be used. This 3rd impeller was designed to provide even higher flowrate, necessary for HE engines. HE engines are more efficient; less heat is produced. However, if the “lean-burn” capability of HE engines is exploited, the drier exhaust gases are much less effective at removing heat. Hence the redesigned (HE onwards) cooling system, including the pump impeller thinned out (water passages enlarged), for the most (unrestricted) flowrate. Except it is “NLA”.

If your pump has the 1st impeller and a higher flowrate is desired, the impeller could be changed, there are two options: Option 1 is the 2nd impeller (C36363, not the SNGB version) that has been shortened to the same (1st/3rd impeller) height. Option 2 is the 3rd impeller (EAC3212, if you can get one), this enables the highest possible flowrate. I’ve suggested to SNGB that it is the EAC3212 impeller they should be selling, including in their conversion kits. Response was that their tech team will be “asked to look into this”. So, if you are contemplating an SNGB water pump upgrade, maybe “watch this space” for a bit?

Another thing to be aware of, the different pumps have different length shafts/bearings including the housing. I.e.:
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There can be no hydraulic/performance effect from this, presumably it is just for lining up the different configurations of drive belts. Just means you cannot simply swap whole pumps without considering belt alignment/interference issues.
Regards,
ColinL
'72 OTS manual V12

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angelw
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#2 Re: Water pumps

Post by angelw » Wed Jan 15, 2020 9:25 am

Hello Colin,
The conversion from early to late model water pump for the S3 E is rather expensive; not so much for the pump unit itself, but the difference in price to get the kit containing the plumbing infrastructure required.

The main reason for the conversion to the later model is that the bearing unit for the early model is not available. One alternative to the unavailable, off the shelf early model bearing unit, is to purchase a generic blank with the correct bearing body size and soft, oversize shaft and machine the shaft to size.

The following picture shows the comparative sizes of the early and late model bearing unit.

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I offer a conversion device for the early S3 water pump that allows the fitting of a late model repair kit. The following picture shows the longer, late model bearing unit fitted to an early model water pump housing. The bearing housing feature of the late model pump is approximately 6mm longer than that of the early model. The bearing unit is still very well supported.

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Colin Wrote:
Just means you cannot simply swap whole pumps without considering belt alignment/interference issues.
The following picture shows the same water pump in the previous picture, with the V Belt Sheave attached; the V Belt Sheave has to be the late model unit. When the late model V Belt Sheave is used with the longer, late model Bearing Unit, there is correct alignment with the other V Belt Sheaves in the system. Outwardly, you see no difference to an original early model water pump V Belt Sheave, but the axial position of the centre boss is quite different. Accordingly, the early and later model water pumps are able to be swapped (if you wish to go that way) and the alignment of the V Belt Sheaves retained.

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I manufacture a Stainless Steel sabot that is pressed into the rear end of the bore for the water pump bearing. This locates the seal in the correct axial position for the impeller location. The only part of a standard late model water pump repair kit that can't be used, is the supplied gasket that needs to fit on the face indicated in the following picture. This is a fairly easy gasket to make.

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Once the conversion sabot has been fitted and a late model V Belt Sheave obtained, any future repairs only requires the purchase of a late model water pump repair kit.

Regards,

Bill

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PeterCrespin
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#3 Re: Water pumps

Post by PeterCrespin » Wed Jan 15, 2020 10:00 pm

The best posts on J-L and here lately, cram so much info I have to swallow them in two bites. No wonder I had trouble with that gasket a year ago on my XJ12. The best posts nowadays also tend to be signed 'Bill'. :yellow:
1E75339 UberLynx D-Type; 1R27190 70 FHC; 1E78478; 2001 Vanden Plas

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AussieEtype
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#4 Re: Water pumps

Post by AussieEtype » Thu Jan 16, 2020 12:32 am

Yes I agree - my engine being very early still has the early water pump on it - it deals with Aussie hot summers OK but the gaskets where the housings bolt up to the engine are suspect - first noticed 37 years ago driving through the back streets of Paris and a squirt of green fluid coming out of it but fixed by tightening but still in the back of my mind.

When I put my car back on the road I think I will need to have a look at the water pump and I have bookmarked this thread as a reference for when I do it.

Thanks for posting

Garry
1971 Series 3 E-type OTS

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angelw
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#5 Re: Water pumps

Post by angelw » Thu Jan 16, 2020 10:19 am

Hello All,
Further to my previous Post on the Water Pump conversion, of the following pictures, the first shows the Water Pump bearing and the Stainless Steel Sabot in place:

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the next shows the Water Pump bearing, the Stainless Steel Sabot and the Seal assembled, waiting for the sandwich plate and impeller.

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Regards,

Bill

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Nick V12 e type
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#6 Re: Water pumps

Post by Nick V12 e type » Thu Jan 16, 2020 10:15 pm

Excellent very useful post Bill.
It will help me when I tackle my water pump bearing replacement.

Thank you
Nick
e type series 3 V12 2+2 1972, Tesla Model S 2016

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MLBS3V12
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#7 Re: Water pumps

Post by MLBS3V12 » Sat Jan 18, 2020 6:10 pm

Very interesting post for sure! :police: :yellow:
I would have like to get it 3 months ago when I was looking around mine. :doh:
Le chemin sera long!...

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