Series MM oil pump

for those with Series MM sidevalve cars produced between September 1948 and February 1953

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manlyvaleaussie
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Series MM oil pump

Postby manlyvaleaussie » Thu Oct 04, 2018 6:57 pm

Rob, I have a late 1952 918cc and the oil pump is quite different to the earlier type, I wish I could attach a photo but haven't been able to figure that one out, perhaps you could guide me through the process. My pump has just a straight intake tube of approx. 7/16" O.D. and the body of the pump is quite different from the earlier type. I am looking for a filter, also the spring and ball for the pressure valve. In looking at the engine breakdown for the early and late 918 cc's, the type of oil pump I have does not show a filter, when it was removed from the engine someone had wrapped some wire gauze around the intake tube and tied it with wire, I find it hard to believe but maybe it doesn't take a filter, my engine does have an external oil filter. Any and all advise is very much appreciated. Paul Follett. (manlyvaleaussie)

philthehill
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Re: Series MM oil pump

Postby philthehill » Thu Oct 04, 2018 7:30 pm

What you are describing is the oil pump which does not have a filter within the pump body but with the engine having an external oil filter.
See Page A26 of the BMC wksp manual for a sectioned drawing of the engine with oil pump described.
The oil pressure relief valve in the sectioned engine drawing is about halfway up the oil pump drive shaft tube and to the left of the tube.


sirrom918
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Re: Series MM oil pump

Postby sirrom918 » Fri Oct 05, 2018 12:33 am

In both the early and late SV pumps the pressure release valve spring, pad and ball were identical.
Spring - part no. X15093 - illustration no. 118
Pad - part no. X15601 - illustration no. 117
Ball - part no. CA1280 - illustration no. 119

As already mentioned by Phil, the later pump unlike the early one has no need of a gauze filter within the body of the pump as the engine has a much better external oil filter unit.

The same Spring and Ball was fitted to all 1935 to 1948 Morris 8's - Series I / II, Series E and all side-valve Series MM Minors.

Here in the UK the Morris Register can supply its members with new springs and balls. I believe there are at least four branches of the Morris Register in Australia each with their own spares service (Victoria, NSW, QLD and South Australia) - hopefully they may be able to help you locally with the parts. Having said that, the individual balls themselves should be available from any good bearing suppliers such as Simply Bearings here in the UK.

https://simplybearings.co.uk/shop/Loose ... index.html

The late oil pump is shown below - note it has no gauze filter.
img057.jpg
img057.jpg (24.31 KiB) Viewed 115 times

RobThomas
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Re: Series MM oil pump

Postby RobThomas » Fri Oct 05, 2018 3:19 pm

Spring is 1 inch long, if working. Any shorter and it will blow off at too low a pressure. Should be able to test it with a compressor and a probe.
Cardiff, UK

manlyvaleaussie
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Re: Series MM oil pump

Postby manlyvaleaussie » Fri Oct 05, 2018 5:30 pm

Many thanks for the info. I'll be fine from here forward. Just to clarify, I am originally from Australia, hence the "manlyvaleaussie" but I now live in Yuma, Arizona, U.S.A. Thanks again for the invaluable info. Regards, Paul.

sirrom918
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Re: Series MM oil pump

Postby sirrom918 » Fri Oct 05, 2018 9:00 pm

Paul,

I suggest you try a company that's not that far from you called 'From The Frame Up' in Phoenix, Arizona - they're suppliers of new spare parts for MG T Type sports cars. MG were part of the Morris Motors empire and the early T Type engines were based on Morris 10 engines. Certainly the Morris 10 uses the same pressure release ball CA1280 and POSSIBLY the same length spring as the MM Minor.

Just to mention, my new Morris Register X15093 spring is actually 1.1/8" in length and the CA1280 ball 3/8" diameter. Suggest you drop Doug Pelton at 'From The Frame Up' an email to see if either of his T Type balls and springs match the ones in the MM Minor pump.

The 'From The Frame Up' catalogue shows:
MG TA - relief valve ball part no. EE244 @ $3.99 and relief valve spring part no. EE246 @ $13.35

MG TB / TC / TD / TF - relief valve ball part no. EE554 @ $1.93 and relief valve spring part no. EE546 @ $7.65

https://www.fromtheframeup.com

RobThomas
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Re: Series MM oil pump

Postby RobThomas » Sun Oct 07, 2018 2:53 pm

Cardiff, UK


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