24 replies to this topic

[MK1russ]

What's the stage 3 head consist of?

 

While I agree that a HIF44 would be better (almost academically so), the HS6 will give it that period look you are after, though, if it were me, and for a period look, I'd probably run with twin HS2's given your spec and usage.

 

The stage 3 head consists of stainless steel 35mm in & 29mm ex valves, bronze valve guides, all ports are fully ported all the way through but not 'over ported'

 

If you are going to use it to 6k which it will comfortably do I would go 3.76 not 3.1, I live in a similar area to you and will never fit a 3.1

 

3.44 is a good all-round ratio

 

People are obsessed with the higher ratio diffs which the mini was never designed for...

 

1275 Cooper S options started at 3.44 went to 4.1

 

http://www.retromini...d=19&chapter=20

 

I've got a 998 in it currently with a 3.76 diff and i just find that it hasn't got the legs on the faster roads around here, it just runs out of puff and it's doing 5k revs before you know it and not really getting anywhwere but i suppose that's down to the lack of power.

 

I used to have a Metro a few years ago with a 3.4 diff on 12" wheels and liked the gearing on that. Using Guessworks gear calculator, a 3.2 diff on 10" wheels is the same as the Metro's gearing, that's why i suggested the taller 3.2 diff.

 

I am however looking for more experienced Mini owners advice on this subject, so i'll highly likely go with the 3.44 diff i already have now.

 

 

Another under-rated suggestion which would keep it exactly in period... a single HS4 1 1/2" vizarded

 

More flow and gas speed than a pair of standard 1950's tech HS2's

 

Cheaper insurance, easier and cheaper to set up and looks dead standard.

 

What about a vizarded single HS6 carb? I've already got a HS6 in good condition.

[Retroman]

No real reasons not to go with the HS6, modified or not, modified they gain better throttle response and overall output

 

My thinking was that the HS4 was fitted to the 1275 GT's and all other Minis in the '69 era ( other than Cooper and S)

 

And by reworking it you would not feel the difference between it and the standard HS6

 

You would possibly gain a little over 4.5k revs with a DV modified HS6 over a DV modified HS4 but loose a little below 4.5k, not sure you would feel it either way

 

The reason being that the modified HS4 is capable of supplying enough air for your spec, without being restrictive.

 

[DeadSquare]

When you think of what Paddy Hopkirk, Barrie Williams and a host of other rally drivers did to their Minis on spacial stages, a cross pin diff is a bit of an overkill for 50 MPH on a country road.

[DeadSquare]

 

What's the stage 3 head consist of?

 

While I agree that a HIF44 would be better (almost academically so), the HS6 will give it that period look you are after, though, if it were me, and for a period look, I'd probably run with twin HS2's given your spec and usage.

 

The stage 3 head consists of stainless steel 35mm in & 29mm ex valves, bronze valve guides, all ports are fully ported all the way through but not 'over ported'

 

If you are going to use it to 6k which it will comfortably do I would go 3.76 not 3.1, I live in a similar area to you and will never fit a 3.1

 

3.44 is a good all-round ratio

 

People are obsessed with the higher ratio diffs which the mini was never designed for...

 

1275 Cooper S options started at 3.44 went to 4.1

 

http://www.retromini...d=19&chapter=20

 

I've got a 998 in it currently with a 3.76 diff and i just find that it hasn't got the legs on the faster roads around here, it just runs out of puff and it's doing 5k revs before you know it and not really getting anywhwere but i suppose that's down to the lack of power.

 

I used to have a Metro a few years ago with a 3.4 diff on 12" wheels and liked the gearing on that. Using Guessworks gear calculator, a 3.2 diff on 10" wheels is the same as the Metro's gearing, that's why i suggested the taller 3.2 diff.

 

I am however looking for more experienced Mini owners advice on this subject, so i'll highly likely go with the 3.44 diff i already have now.

 

 

Another under-rated suggestion which would keep it exactly in period... a single HS4 1 1/2" vizarded

 

More flow and gas speed than a pair of standard 1950's tech HS2's

 

Cheaper insurance, easier and cheaper to set up and looks dead standard.

 

What about a vizarded single HS6 carb? I've already got a HS6 in good condition.

 

 

GAS SPEED is important for torque, and if you are not building a screamer, HS4 is better than HS6 below 6K rpm.

 

You mention your 998 "running out of puff", well a 1275 won't unless you are overtaking in third at well over 7K.

 

Minis are noisy tin cans at 6k, so I understand people going for long diffs, but a 3.4 is 96 mph at 6K, ample even on a motorway.

[MK1russ]

When you think of what Paddy Hopkirk, Barrie Williams and a host of other rally drivers did to their Minis on spacial stages, a cross pin diff is a bit of an overkill for 50 MPH on a country road.

 

Yes i agree that a cross pin diff probably is a bit overkill for my spec and driving style, although i suppose it has the advantage of being a 'fit and forget' part. I did think about the Minispares bushed planet gears too but there doesn't seem to be much said about them or anyone recommending them?

 

I think i'll probably go with the 3.44 diff now, as the extra acceleration would be useful on the hilly roads around here.

[Arthy]

If it's any help I ran a 3.1 before my complete engine rebuild. I switched to a 3.44 and haven't noticed much difference in top end cruising ability! 

 

Can easily cruise at 50-55 at around 3000-3200RPM with 12inch wheels, with the power being there if needed! Although this is a rather modified 1330

[MK1russ]

If it's any help I ran a 3.1 before my complete engine rebuild. I switched to a 3.44 and haven't noticed much difference in top end cruising ability! 

 

Can easily cruise at 50-55 at around 3000-3200RPM with 12inch wheels, with the power being there if needed! Although this is a rather modified 1330

 

That's good to know, there's only a 2mph difference between 10" and 12" wheels, so it'll be almost the same. Looks i'll be going with a 3.44 diff and the S/GT ratios then.

[johnR]

I replaced my diff with a cross pin one on my 1275 re-build because the carrier was un-useable and the cost of replacing it was virtually the same as the complete cross pin one. I suppose it comes down to budget - could you use the money better on another component that would deliver more benefits?

[MK1russ]

I've got 2 good diff carriers in good condition, one an A series with unworn trust washer faces (was from a mk1 22A108 850 gearbox) and a good A+ one.

Like you say, I'll see what the budget has to be spent on.

[grizzler73]

John at Guessworks replaces the plain bearing in the difference side plates with a needle roller I believe. A nice modification I think.
Simon