Enhancing an 850?

[haynes]

Posting in general rather than technical because i'm more intested in the 'moral' implications of enhancing an 850?

I'm really just curious as ive no immediate plans for an engine rebuild. But if/when I do i have thought perhaps i could get the head gas flowed and converted to unleaded. Possibly lighten the flywheel. Definitely no external changes.

Car is a '65 morris 850, 65,000 miles young in Maroon with beige interior. I love the way it drives and really really dont want to spoil that and never want it to fell in anyway modified.

So 850 owners what have you done, have you kept it standard or given it a little tweek?

[sclemow]

I love the way it drives and really really dont want to spoil that and never want it to fell in anyway modified

Why modify it if you don't want it to feel in anyway different from standard??

[mk1]

If you don't want it to drive like a modified car then stick with a mildly ported head with a CR of about 9:1 & gas flowed inlet & exhaust manifold, along with a K&N type free flow air filter & probably something like a MK1 sprite rear silencer box. All these mods are totally invisible. You will probably still need a dyno session to get the carb needle & ignition spot on but the original "Rich" option needle will probably be very close.

These mods are worth doing on ANY mini, smoother running & better fuel efficiency being the two major advantages.

Don't do anything to the flywheel!!!!! This will only make tickover more lumpy & the engine harsher.

[minitravellerman]

Back in the '60s my dad tuned his '63 Mini Minor to the Special Tuning book that the garage he worked for had (Wesley Turkington BMC dealership in Lurgan Co Armagh). He did tell me the full spec on a few occasions and I always mean to write it down as I would love to build a replica of it some time (he went a bit mad on the exterior look - well mad for Minis at the time!).

If I remember correctly the spec was as such;
- std bore 848 block
- 998 Cooper cam
- 12G295 head with double valve springs
- twin 1.25" SUs with 1.5" ram pipes and blue springs
- MG 1100 exhaust manifold

When I get home from work this evening I'll ask him again and put up the exact spec. He said it was a real screamer and through the gears was every bit as quick as a 1275 S (until about 60!), plus before the speed limit was introduced on the motorways here, he remembers the speedo reading empty on the fuel guage!

[abri]

Have a look at this thread and the links to previous threads mentioned in it.

viewtopic.php?f=3&t=7417&p=52906&hilit=12G202#p52906

[mk1]

As Abri suggests, this topic has ben discussed many times before. But not in the case of leaving all thing externally standard.

[In the shed]

I have 2 subframes. One has a 998 and rubbish brakes and the other is a full race job.

I'd be tempted to get a set of 3.5 S wheels and S brakes and spaced drums and a big bore engine and put everything else in storage until you/other want it back normal. That way you can have it low mileage and TOTALLY standard when required.

[gs.davies]

Interesting subject. On my rebuild I'm going to go down the period mods only route. If it couldn't be done in 61 when the car was new, it can't be done now. That rules out a 998 engine I think.

I'm looking at a 202 head, twin carbs, cooper 997 cam and exhaust. I also don't want to lose the authenticity of the car in any way either. Putting a 1275 in is cheating!

[mk1]

Good way to go GS, I have always modded my cars using that rule of thumb.

[AJB398B]

I modied my 850 by putting in a 1463cc motor with a close ratio box and a 45 Weber, much more entertaining.

[surf-blue-850]

I'm thinking of doing similar. I have a ST 850 crank, I rebored a 850 block to take 998 pistons and decked it to take account of the shorter pistons. Having the block line-bored to take cam bearings.

Question is what cam do I use? The aim is to end up with a revvy engine, but still need some driveability for traffic.