9 replies to this topic

[Burgerdale]

Hi everyone, im building a new engine and looking for some thoughts before I put hand in pocket.
Im currently running a 1275 with water cooled/heated 1 3/4 hif44, stage 2 head (not large valve), rimflow exhaust valves, lcb, 2" stainless 2 box exhaust and what I think is a standard cam but ive not checked the cam yet.. The car is just for fun and throwing around a bit in weekends/nice days.
I've got myself a large valve metro head that I will be porting and shaping the combustion chambers on and also a set of twin su's. Ive seen a 296 and a 285 fairly cheap so im open to thoughts on what would be the best match and with what rockers?
I know this is a can of worms and has probably been asked before but each mini is different for different uses.

[Burgerdale]

Forgot to add that im open to re-bores too but as the cost of decent pistons is mega id prefer to avoid is possible.

[jaydee]

Have you ever been on a car with a 296 fitted? Its a trackday cam

I'd say go for something less mental like an SW10, similar to a 296 power wise, but still usable low down 

[KernowCooper]

The crank will need a main bearing strap and balancing to use the revs the 296 works at and rebuilds will be frequent and the gearbox ratios/diff will need matching to the cam. To much for a road car in  my opinion

Edited by KernowCooper, 09 September 2013 - 11:51 PM.

[Burgerdale]

What about the 285? Same issue? The twin carbs I have got are hs2, guessing im better off swapping them out for hs4s?

[jaydee]

There are a lot other things you need to match to the cam, define what use and what power range you want, then decide what cam to use.

Then we can talk about carbs, head and diff ratio.

[Burgerdale]

Ok, its not for track days. Its for weekends and purely for fun. I have another car for work etc.
I was thinking of going down the sw10 route but then I saw the other cams cheap. Say I go for the sw10 what do I need to match up to it? Better to get it right first time.

[jaydee]

The SW10 works even with a 3.44 diff, best will be a short diff like a 3.67 and a close ratio gear set, so you can have a tall first gear then the other 3 closer so you're always keeping it in the power band. Its a cam that, depending on spec, is usable from 2500-3000 rpm and goes full power from about 4500-5000 rpm to 7000-7500 rpm. Narrow power band but enough torque to be used on the road.

Twin HS4 will be better than a single HIF44 on such an high performace engine, and will make it less lumpy due to the shorter inlet tract.

Forget the stage 2 head, you need a big valve head with seats cutted accordingily.

And of course a light flywheel fully balanced together with the crank and pulley, piston and rods weight matched, centre main strap etc, its an engine that can hit 7000 rpm in top gear so needs to be engineered properly. Have a chat with swiftune and they'll help you.

[Burgerdale]

Thanks jaydee. Ill save my pennies to match up an sw10 and get everything balanced. Ive just got a big valve head so that'll work nicely. Any simple mods to the head that will get the most out of it or am I best working to get the right compression?
Ill source a pair of hs4s now.
Dale

[jaydee]

Ask swiftune about CR details.

I also reccomend to talk to them before buying and possibly have a ride on a similar spec mini, so you can get your own idea before spending the money.

Plenty of people around that got an SW05 expecting it to be exiting, and found its a mild cam, others have built engines with a 286 and found its too wild. Thats why i really reccomend try before deciding.