950 to 998 rebuild

[shivey]

Hi thanks for help with my 10cc post,while waiting for my APT studs i've striped my 950.in my shed i've found a pin drive marked up cooper s lobes are 1/2 inch wide,could this be ok in my above rebuild i have a load of accumalated spares from my garage days ,also i have brand new boxed 40+ flat top pistons ,the 950 block at the moment has been bored to +40 making it 978 with 998 +40 cooper pistons should bring it up to 1030 is this achievable i have the parts and an ex colleague worker who does my boring..any thoughts...Glyn

[philthehill]

1/2" wide cam lobes are to be preferred rather than the 3/8" wide lobes of earlier cams. I only use cams with 1/2" lobes.
Go for 998cc plus 0.060" will give a cc of 1050 at 2.6" dia bore.
If you fit the Cooper cam - pin drive with a Cooper oil pump to a small bore engine you may have to shorten the oil pump drive of fit a spacer between oil pump and block. The oil pump body may need modifying to fit under the oil pump cover.

Original Cooper S oil pump pictured below, One fastening has been converted to use a countersunk screw and the other two fastenings have had the pump body reduced in depth around the holes to allow the pump cover to clear the pump. The pump cover was also slightly domed to clear the pump body. The centre boss was also reduced in height to clear the pump cover The original length pump drive has been refitted as the pump was last used on my 1400cc engine. At the time the Cooper S oil pump was the best.

Oil pump spacer.jpg (308.81 KiB) Viewed 566 times

100_2020.JPG (261.01 KiB) Viewed 564 times

100_2021.JPG (235.42 KiB) Viewed 564 times

[shivey]

I've got new +40 in my shed complete with rings circlips ,could'nt quite follow oil pump problem,is the 950 casting different for the oil pump ? my oil pump is like that.will it not fit? i hav'nt got the spider drive

[philthehill]

Ignore the spider drive it just came with the spacer plate.
All you can do is try and fit and see what needs to be modified. The things listed above are what I had to do to get a 1275cc Cooper S oil pump to fit a small block but that was possibly over 40 years ago.

Have a read of the Calver link:-

https://www.calverst.com/technical-info ... oil-pumps/

[shivey]

The cam is an early s one 63/64 i helped a mate 20 plus years ago to fit i think it was a Kent,i've has it in a bag with oil in it that long ,i've also got some sprite 1100 ones.i've had a look the 950 pump is different from the others i've got i'll take it off my stand tomorrow and have a play..thanks..fitting new guides in head tomorrow

[philthehill]

Have a read of this as well:-

http://www.somerfordmini.co.uk/eshop/in ... age&id=119

especially the section on pump interchangeability.

The oil pump spacer in the photo above is Pt No: 12G1127.

[liammonty]

I took my 948 to 998 + 0.040” (i.e. 1030cc) - the rationale being that there is then the option to recite it one more time if needed. It’s a great engine - puts out around 55bhp according to the dyno at Southam Mini and Metro Centre. Let me know if you’d like any details of what I did to it if you’re going down the same route

[shivey]

My first plan after totally stripping and cleaning is to get it bored my friend live 30 miles away so i think i won't be allowed to drop it off with him for boring,i'll find out.thanks for replies I probably will want some advise.