Water Pump hole in block

[pharriso]

Can someone tell me the diameter of the hole in the front of the engine block that the water pump fits into please?

TIA

[jono]

The water pump aperture is 60mm

[pharriso]

The water pump aperture is 60mm

Thanks Jono, that's 2.362"

[jono]

It is (I measured with a metric vernier).

[alan.barker]

Hi Phil,
Why do you want to know dia of hole to nearest thou/.001"
Not bad for a sand casting lol.
Alan

[pharriso]

Hi Phil,
Why do you want to know dia of hole to nearest thou/.001"
Not bad for a sand casting lol.
Alan

Ah well this all goes back to a topic from 10 years ago https://lotuselan.net/forums/viewtopic.php?f=39&t=22662&start=0& since you asked....

An engineer friend designed his own cassette system based around the Burton water cartridge was concerned that the impeller of the pump was shrouded by the cast iron hole of the block & wanted to move the impeller more into the waterway in the block. Here is a photo of a standard Burton cassette out the back of a modified Lotus Twin Cam timing case:

He modified a Burton pump by extending the nose & also reduced the OD so the end of the cassette would go into the block casting:

Now I know the size of the hole in the block (2.362") I can see that the modified pump nose with an OD of 2.350" will fit into the hole, whereas the original pump nose OD (2.5" OD) would not.

I can now sit back & appreciate the cleverness of my friend's design (& wonder where I could find a longer pump bearing/ shaft assembly...)

Hi Phil,
Why do you want to know dia of hole to nearest thou/.001"
Not bad for a sand casting lol.
Alan

The block may be cast, but the hole is machined. Aren't cylinder bores & all the bearing surfaces in the block machined within tenths of thous?

[alan.barker]

Hi Phil,
Yes and no, i don't think that hole is machined as "Chunky" would have to pay for that. Castings i think would be in general + and - .015" at least.
Cylinders and Pistons are one tenth of that and graded for size.
Alan