11 replies to this topic

[BUCKERSMINI]

Hi I hope someone could help me. Can a 1071 crankshaft be used to build a 1430 engine? Or does it have to be a 1275 offset grind crank or the cooper s (EN40B) crank shaft. Already got 1380 block and 970 cooper s rods.

Many thanks

[cian]

I always thought it was a 1275 / en40b but I may be corrected

[Spider]

You'll be struggling to get a 1430 from a 1071 Crank.

 

As cian has suggested, you'll need to use a non-S, 1275 Crank and have it off-set ground and then use it with Cooper S Con Rods or one of the after market types kicking about.

 

<Edit: the 970 Rods will be miles too long, the ones to use will be 1071 / 1275 types. >

Edited by Moke Spider, 01 November 2016 - 09:14 PM.

[cian]

Are the gains worth the cost of the machining and extra parts rods etc over a 1380

[OzOAP]

With a 1071 crank it would have to have around a 82mm bore....

[Spider]

In all fairness I think you are really the only one who can weigh up if it's 'worth it' and there's probably more to consider than just money in that.

 

If it were me, for a road car, it's not the type of build I would do. Done right, yes, there would be gains over say a 1330, but I really done feel that for the extra effort and cost the gains would be utilised often enough to make it all worthwhile.

 

I'm sure many others here have a different view / take on this, and this is just my own personal opinion.

 

You can get some very happy performance in say a 1293 or a 1310 for little more cost than that of a straight forward reconditioning job. And if you still have it when that wears out, it can be done again, where as by the time you go to a 1400 + in size, it's generally a throw away.

[mab01uk]

1430cc were briefly all the rage in the late 1970's when David Vizard featured them in magazine articles and his books......but as said above for the small gains on a road car when set against reliability and robustness it is rarely worth it today. One small cooling problem and your expensive overbored block with thin cylinder walls is toast. If you really want a large capacity engine it would be cheaper and more long lived to fit a more modern non-A-series engine conversion. eg. Vauxhall, Rover or Honda......

Edited by mab01uk, 02 November 2016 - 12:46 PM.

[Ivor Badger]

With a 1071 crank it would have to have around a 82mm bore....

The trouble would be the power loss from the pistons colliding as they passed, this would offset the power gains from the increased capacity.

[dyshipfakta]

With a 1071 crank it would have to have around a 82mm bore....

The trouble would be the power loss from the pistons colliding as they passed, this would offset the power gains from the increased capacity.

This would only happen once or twice though wouldn't it. So not an issue after that

[mini13]

to go to 1430 you need a 1275 non S crank, preferably non A+ so it dosent have the fillet radii,

 

you will also need to sort out the pistons which will now be sticking out of the block at TDC, you can get ( or used to get) low deck height pistons for this purpose, although you may find you need to take a bit more of if you are using 970 rods as they are longer.

[ACDodd]

I like 1430's for road work, can't beat the sheer low andmid range twist that the extra 1/8" stroke length gives. However, not a cheap conversion.

Ac

Edited by ACDodd, 03 November 2016 - 01:19 PM.

[OzOAP]

Im aiming to build one for my new toy, (bit heavier than a mini). I have crank/rods so some of the way there.