2 bolt oil pump

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kevin s
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2 bolt oil pump

Post by kevin s »

We bought a 2 bolt star drive oil pump from mini spares which was described as fitting all engines this is to go with a kent star drive cam we have and is going in a 1969 1098 engine , it fits in the aperture in the block fine and the semi circle in the bottom lines up with the hole in the block but only one of the fixing bolts lines up with a hole in the block, am I missing something or is it simply a case of needing to drill and tap another hole?
philthehill
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Re: 2 bolt oil pump

Post by philthehill »

http://www.minispares.com/product/Class ... o%20search

The 1098cc 'A' Series is fitted with a pin drive, three bolt oil pump. Therefore the two bolt pump will not fit without drilling and taping an additional hole. When drilling and taping the hole make sure that the drill and tap are kept square to the block.

You have an additional choice of three bolt oil pump http://www.minispares.com/product/Class ... o%20search by using the adapter in the link below:-

https://www.ebay.co.uk/itm/252314870396 ... SwyjBW4I9A

Make sure that the oil pump body will inside the oil pump cover which fits into the rear engine plate. I have just been looking at a oil pump that has had the alloy body of the pump ground away to enable it to fit inside the pump cover.

kevin s
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Re: 2 bolt oil pump

Post by kevin s »

Drilled the hole today used the pump as a guide to keep it square. Just need to wait for the tap now, but this got me thinking and I' m going to have another problem, the cam and oil pump are for a 1275 so the pump needs a spacer as well, it appears these used to be widely available but not now, looks easy enough to make one out of a piece of alloy plate though. Measuring up a 5mm spacer seems to give about a mm of end float on the cam and the pump bolt heads still fit under the cover, has anyone ever seen one does 5mm seem about right or even better have one they could measure?

Cheers kev.
philthehill
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Re: 2 bolt oil pump

Post by philthehill »

The spacers are available.
Here is the link:-

https://www.ebay.co.uk/itm/184794395926 ... SwyThgWOFP

The spacer I have is 6.4mm thick.
It should be noted that the oil pump laterally does not contact the oil pump other than the radial contact of the lugs/splines - so there will be end float (sic) between camshaft and oil pump.

kevin s
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Re: 2 bolt oil pump

Post by kevin s »

I looked at all the mini and minor specialists completely forgot ebay!
I've put a bid in, find out if I get it in an hour.

6mm will just fit, the top of the bolt head was 18 mm from the rear face of the block, the can in the backplate 24mm deep.
Assembled as it is the front face of the cam bearing protrudes 7.5 mm from the front of the block, I made the front plate 4.5mm thick so it needs a minimum of around 4mm to give a bit of end float which I would think is a must to make sure you only put a radial load on the pump as things warm up and expand.
philthehill
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Re: 2 bolt oil pump

Post by philthehill »

The end float of the cam shaft is 0.007" and is controlled by the triangular plate at the front of the block.
To adjust the end float - the cam gear boss is reduced in height (see 1.JPG below) to reduce the end float or increased in height to increase the end float (see 2.JPG below).
Camshaft end float 1.JPG
Camshaft end float 1.JPG (1.4 MiB) Viewed 547 times
Camshaft end float 2.JPG
Camshaft end float 2.JPG (1.7 MiB) Viewed 547 times

kevin s
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Re: 2 bolt oil pump

Post by kevin s »

That's on it's way, it's going to be close so I may have to locally deform the cover by a mm or so over each bolt or fit countersunk bolts.

I am also as a side project working on making an MX5 gearbox fit, the adaptor plate is based off of a 1275 one so takes the larger 93mm pump cover which I don't yet have, any one know if these are the same depth as the 1098 one? (24mm inside).
philthehill
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Re: 2 bolt oil pump

Post by philthehill »

The 1275cc oil pump cover has an internal depth of 25mm plus the the central recess of approx 3mm.
Way back when I fitted a 1275cc Cooper S oil pump to a small block engine I had to deform the small block oil pump cover and reduce the body of the oil pump itself.

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