850 tuning

[mmm850]

Hi, I am new to this forum and I live in malta and own a 1961 morris mini 850, has anybody here tried fitting a cooper 997 cam (2a948) and a 12g202 or 12g295 head on a an 850 bored out +30 ?

[Joss_D]

I had an 850 in my car before I changed to a 998.

I did get it running better than the standard engine, but to be honest none the mods made a huge difference. It was a fun engine nevertheless.

Changing the cylinder head provided the most improvement. I started with a 'stage 3' 850 head from Mini Sport (which was rubbish), then changed to a modified 12G295 head, which was fantastic.

The only other modifications I made were to the exhaust and carbs. It had an RC40, and twin HS2s. The twins were probably a little big for the engine, in hindsight, but it was definitely better than the single.

As for camshafts, I don't think there's much you can do with an 850 without fair amount of work, due to the 850 block not having cam bearings.

[mk1]

The 997 Cooper cam is absolutely BRILLIANT!

Although as Joss says it would be better if you have a block with cam bearings, I would have no worries about running a 997 Cooper cam in without. A 206 or 295 head that has been skimmed to give a Compression Ratio of around 9.5 : 1 would be ideal. RC40 or other freeflow exhaust would be good, and either twin H1 1 1/8" carbs of HS2 1 1/4" carbs would be great.

Should make an appreciable improvement on your 850, but will never turn a small fun engine into a fire breathing monster.

Heres a pic of mine;

[mmm850]

Very nice it looks very close to mine, is it clipper blue ? I was thinking of using the 997 cam without the bearings as I do not want to strip the engine and change the cam with the engine in place by cutting a piece of the grill behind the radiator

[mk1]

As long as you don't thrash the living daylights out of it the cam should run fine.

I think we will draw a veil over the cam change in place though

Not known anyone do that for about 25 years

[mmm850]

I was thinking of making one of the vertical stats of the grill removable with two self tapping screws, it will only be vizable from underneat the wheel arch.
At the moment my car is bored +30, fitted with a 12g202 head, hs4 carb on std cast manifold, copy of RC40 made by a firm here in malta, lucas sports coil, accuspark electronic ignition, ngk spark plugs BPES, front brakes upgraded to twin leading shoe, 4.5 cooper reverse rims.

I have ready to fit a reground 997 cam and new cam followers, and a 12g295 head that needs new inlet valve seats.

The reason that I do not wish to remove the engine is that it has only covered about 1000 miles since it overhauled and rebored.

By the way I am having throuble uploading a picture.

[mk1]

Sorry for my comments above,

I'm sure there are good reasons to do your cam change in situ. Its just that I usually find that its easier to take the lump out before surgery. I guess its just down to personal preference.

[mmm850]

I think I am going to leave it as it is for now, as it is very good for an 850, and save the cam and head for later on to build a 998 or 1098.

[mmm850]

It was like this

[mk1]

What an excellent restoration, you have certainly put some hours in haven't you!

I think its a good thing that you have decided to hold off on the engine mods. Building a complete new engine is far more sensible than chopping the existing one about in situ. It would be a real shame to cut into such a lovely little car.

[mmm850]

I have known the car since i was a young boy (I am 51 now), as it use to belong to my father in the 60's, he sold it in 1971 and after he passed away in 1981 i decided that i want to buy it back, the problem was that the new oner was very proud with it and never wanted to sell, and after 30 years i managed to buy it back as he was getting old and decided to sell it to me, but it was in a very bad condition so i started the restoration at once, it took me about two and a half years to complete. the body work and spray was done by prfesionals, and i rebuild the engine and put the whole car back together again. sorry if i made some spelling mistakes as i am maltese.

[Red Mist]

Lovely car, is the license plate number genuine?

[mmm850]

No the licence plates here in malta have been changed two times since 1961 and we are not allowed the keep and use the old plates, but the new plate is personalized MMM850 stands for Morris Mini Minor 850, the original plate was 31258 white numbers on a black plate.

[YMJ]

What a super story......and car.