22 replies to this topic

[ACDodd]

Make it bigger. I helped build an 1150cc 850 engine a couple of years ago, made 71.5bhp and 72lbft of torque, all below 6krpm. Factory smooth idle and keep up with 1275cc engines cars without having to race the gears, as it had the cubes to make torque. Torque is what makes for relaxed driving.

Ac

[Retroman]

Sounds like the way to go....how do you get 1150 ?

[ACDodd]

Sonic check the block and if it will go fit a set of +0.060" 1098 pistons and a 1098 crank. The crank needs modifying narrowung in length and widening on the mains which I can do. The rod will also need clearancing as they will hit the side of the block.
In all honesty it's far cheaper to simply install a bigger 998 or 1098 or 1275 based engine.

Ac

Edited by ACDodd, 06 November 2018 - 07:44 AM.

[Retroman]

I thought you must have been using the 1098 crank

 

Like you said its an expensive route

 

Whats your opinion re 848 EN16T crank and revs / life ?

[ACDodd]

Retroman, I have no opinion, as I would never use a small engine for a road car. Torque is required to make brisk progress. 850 based engine are fighting a loosing battle. Fast road cams are around. 65 to 70ftlb/litre, why have an 850 when a 1275 or bigger will generate much more torque!

Ac

Edited by ACDodd, 06 November 2018 - 10:50 PM.

[Cooperman]

Indeed, I had an 850 into which I put an MG1100 engine and my wife used it as her daily car. But that was back in the late 1960's. It still had single leading shoe brakes and stopping was a bit of an adventure when driving it hard. In the end I put 998 Cooper brakes on it and it was much safer.

 

These days the original 850 is an iconic car in itself and evokes the spirit of the Mini as it started out. 

 

So it becomes a choice between performance with a loss of originality, or keeping it original and a real 'classic' with some 'period modifications' to make it just a bit easier in modern traffic whilst keeping the period retro driving experience (and the retail value as these 850's are becoming rarer).

 

The choice is all yours.

[Spider]

Make it bigger. I helped build an 1150cc 850 engine a couple of years ago, made 71.5bhp and 72lbft of torque, all below 6krpm.

Ac

 

That is some reasonably respectable results and agree with the 'more cubic inches' for sure, but it's not really in the '850 cc class' anymore, even taking in to account standard off the shelf oversizes for 850 pistons.

 

I had similar results many years back from a 1115 engine (1098 + 0.020"), would easily and happily keep pace with 1275s, was very easy to drive ( "put it in top and leave it there") but it was different engine to 'drive' when compared to a 1275, while the power figures were similar, the torque curve was quite different. While I was happy with the results, that was the last small bore engine I really bothered with. The same or better results could be be achieved from 1275's for far less money and work.

[Spider]

Hi all,
I have recently brought a 1980 Austin mini 850, i love it but its a bit "slow"
Does anyone have any simple and cheap tuning ideas?????

Thanks

 

Just a word of caution here.

 

As many others have suggested in this thread, yes, you can definitely get more power from the 850 and still have it reasonably drivable, however, it's also very easy for such an engine to cost crazy money, the kind of money that would make the purchase and overhaul of a 1275 engine, with change, much cheaper and end up with better overall results.