Did lotus ever build a different Water Pump?

[Exbury]

Well, the story gets stranger. The genuine M100 pump arrived today, looks identical to the aftermarket one from the states except plastic impellor blades instead of metal ones.

However, it still doesn't fit. It goes into the space, but the metal or plastic impellor blades hit the sides. Additionally, just to make it really strange the bolts don't line up. In fact the original pump bolt holes are about 4mm different.

To make matters worse exactly the same code is stamped on the alloy casing with the M100 and the original pump.

Looking at the at first glance (Lotus or aftermarket compared to the original unit) they look identical (bar the impellor), its only when you use a micrometer that you can start to see the differences between the edges (the new one has a slightly wider body and thinner housing edges) and the bolt holes are slightly different.

I thought Lotus only had one engine for the M100 ??? As the original matches the aftermarket one for size etc. I am assuming that it is the original pump that is the problem. The garage are puzzled. I am puzzled. Any ideas? Help please!

At this point I am sending the original back to Christopher Neil's and hopefully they can recondition the old one.......but Why I ask, how could a genuine one not fit a genuine Lotus engine!

[Exbury]

lotus pumps01.jpg (244.41 KiB) Viewed 8847 times

Look identical enough; aftermarket top left, genuine lotus top right and original as from car bottom right. now looking underneath, the same code is stamped on the inside, the outside has the same casting mark. there is a inked mark on the old pump of J15 and on the new pump of H21,

lotus pumps01.jpg (244.41 KiB) Viewed 8847 times

However assumingthe lotus one is correct, how could I have different bolt hole spacings!

Jason

[Specky]

I've got something in my grey matter that says there is Two types.. and I seem to recal Steve Williams knows about it...

I think he had to mod mine, but I've got something in mind saying it's a casing issue...

I just can't remember...

TTFN

[Specky]

This was mine if it helps

http://wikilec.9600.org/index.php/Image:Pump_2.jpg

TTFN

[Exbury]

It looks similar, i am guessing it is not a Lotus original? The inner stamping is different though and the vanes look to be a different metal, possibly cast?

I am guessing not many people had the 'unusual' water pump....or just haven't found out about it yet! Need to get it in the post to Lotus tomorrow!

I guess it might have been able to make the new one fit if you elongated the mounting holes and cut down the vanes of the pump. Does this mean that the actual engine block was slightly different if the new ones cannot fit? Wonder if they had a different block on the N/A which was carried over into a few SE's until they ran out??

[Specky]

This was the replacement for my SE....

I'm not sure about the N/A thou...

http://wikilec.9600.org/index.php/Water_Pump

TTFN

[bobbrown]

You have got me puzzeled as well, I may have a very small leak from the water pump and was intending to do it in a month or so.

Now you have me wondering which one I have fitted as I have a N/A, I would have thought the engines them selves would have been the same apart from the turbo running lower compression pistons.
I can not see any them making two different engines and I have look at other Isuzu cars that had the engine fitted and can not see a differance in water pumps
Does the parts list show two pumps or one I'll have to dig mine out but I think on other parts when they were changed it shows both part number like up to a certain vin number and from a vin number

Bob

[RayD]

With the two castings being different... but having the same casting number, I wonder what the chances are of the newest one being made wrong, by a different manufacturer from scratch.

Being a different casting you’d expect it to have a different number.

Ray

[bobbrown]

in the pictures there is a differance that can be seen, if you take the top picture the middle right bolt face has the outside edge squared off , the one that was on the car has not, not sure if this has been machined off or is cast that way

Also there appears to be a cast in number seen in the lower pictures but I can make out what looks like S1B but can not make out what is under the gasket on the one removed from the car

Bob

[Nige]

I would have thought the engines them selves would have been the same apart from the turbo running lower compression pistons. Bob

There are quite a lot of differences between the Turbo and N/A engine. Whilst they have their origins in the same unit and major castings are similar there are significant differences in detail. The one I recall specifically is that the turbo engine sprays on the underside of the pistons to cool them, this is not feature ofthe N/A. This attaention to detail and engineering is probably why the Turbo engine seems able to cope with the sort of boost level that have ben put through it by owners such as Costas.

[RayD]

There’s a number of differences, they can’t have come from the same mould.

[Specky]

Jason can I confirm you have an N/A...

I'm confused...

One thread with four N/A drivers, 2 SE, 1 S2 all trying to work out the problem...

TTFN

[Exbury]

My car is an SE 1991. All I can say is that I don't know at this stage. I believe the car had a front end rebuild in its past (post accident - but this would have been a long while ago and therefore probably repaired at Lotus or a dealer), the shiny red paint and previous hear-say seems to suggest accident (or well garaged). Whether it damaged the engine and the engine was replaced I cannot say. If the engine was replaced (or the block) potentially they just swapped the block for one in the Lotus spares.

Could I have an N/A engine in an SE car. I guess its possible. Are the N/A and Turbo engines different? i never thought so, but the information from Nige seems to suggest yes. Now my worry is that with the Everest Chip, will the engine cope!

Could the N/A require less cooling, but when they did the turbo engine it required great cooling pumping, therefore the pump was upgraded. This is all i can think of. i have been talking with Paul at ChristopherNeil but this has got him stumped. After getting the various pumps we have gone down the reconditioning route, however this is a big delay.

I guess I need to find the engine number and see if Lotus can confirm if the block is an N/A or not. it might also tell me if I need to update the V5 and whether to take it easy when the Everest is in!

[Specky]

N/A and SE engines are different

First easy check... Is the rocker cover breather straight or 90 degrees

Second The Number on the engine(somewhere near the mating face of the gearbox) should match the sticker on the clam... I haven't found mine yet and I've got most of the car stripped....

The N/A has no oil jet under the pistons and the compression is alot higher

TTFN

[ailwyn]

Why would they have different water pumps though?

[Exbury]

Thats another thing why the front may have had a rebuild, there is no sticker in the engine bay. It may be that the engine block was damaged and the block was replaced with a N/A block that was around. Assuming the basic blocks are simialr and that technically the parts are interchangeable. I will pop by the garage on teh way back and see if I can get the engine number with plasticine as its under the metal pipe (will photo) and difficult to see without moving that pipe. Also will look at the breather hose!

Thanks for your help everyone, hope this may help anyone out in the future! A WikiLEC once we have figured this out maybe!

[Exbury]

Think I managed to get the engine number with blue-tac, however it is different to that on the V5.



Engine Number looks like: NP7 06WT 041 (the first 3 digits I had to get with Blue-tac), the silver stamped number is on the gearbox casing.

Does this look correct?

[Specky]

That looks like just thhe casing No... Not an engine No

I'll have a look at mine...

TTFN

[Specky]

The engine No is about there..

Mine is below the metal pipes..(Just)

The location is....

The front of the engine...

Find the split in the cooling hose where it goes to the electric pump...

follow a direct line 45 degrees down from the Y-junction aiming at the engine...

On the engine side of the gearbox there is a machined flat face... It's on there...

I think it's easier for me to locate as I have no turbo on the car I'm looking at...

My No does match the V5

I hope that helps

TTFN

[Exbury]

More bad news the water pump cannot be reconditioned and is now at Lotus to see what Lotus can make of it! Will keep you updated!