35 replies to this topic

[mattyglover16]

Matty,

 

If you're currently at 1275, and the bores are worn, then I would only take it out to 1293. Good blocks are getting rarer, and you won't gain as much from the extra few ccs as you can from other improvements.

 

If the bores are good then use the money saved by not reboring and would suggest following:

- MD266 cam

- set of Keith Calver's 1.4 ratio rockers

- head flowed (36mm inlet, 29 or 30mm exhaust)

- CR about 9.5 with 95 octane, or 9.75 with 99 octane

- Maniflow freeflow with twin box RC40

- stick with HIF44, on a well ported inlet manifold

 

 

 

 

 

Hmm I like the idea of saving money, but If the engine bores are worn, to me it makes sense just to go for the 1330 rather than the 1293 because you can only bore it out once so why not go for the higher cc ? I know it might not make much difference in power. Just not sure whats best, but thanks for the idea and reply I appreciate it :)

[Dusky]

Matty,
 
If you're currently at 1275, and the bores are worn, then I would only take it out to 1293. Good blocks are getting rarer, and you won't gain as much from the extra few ccs as you can from other improvements.
 
If the bores are good then use the money saved by not reboring and would suggest following:
- MD266 cam
- set of Keith Calver's 1.4 ratio rockers
- head flowed (36mm inlet, 29 or 30mm exhaust)
- CR about 9.5 with 95 octane, or 9.75 with 99 octane
- Maniflow freeflow with twin box RC40
- stick with HIF44, on a well ported inlet manifold

 
 
 
 
 
Hmm I like the idea of saving money, but If the engine bores are worn, to me it makes sense just to go for the 1330 rather than the 1293 because you can only bore it out once so why not go for the higher cc ? I know it might not make much difference in power. Just not sure whats best, but thanks for the idea and reply I appreciate it :)

You can rebore it more than once.

[KernowCooper]

No real gain from going from 1293 to 1330 you just loose rebore options

[carbon]

Matty,

 

Also when considering the engine spec you need to take gearbox into account. With a relatively mild cam like the 266 and normal spaced helical gear ratios then you will easily be able to pull a 2.95 diff.

 

I'm using a 3.1 with the slightly closer 'S' pre-A+ helical gears, which effectively makes first second and third the same as running a 2.95 on the standard helical pre-A+ ratios. This works very well on 10 inch wheels.

[mattyglover16]

Yeah I'm currently running 13" wheels, just think it would be a lot to change all the brakes for accommodate smaller wheels. I'm just trying to get pros and cons of everything really, I was going to have a gearbox rebuild anyway when the engine is out. Do you have to put different ratio gears and that in for a 1330 then ? Thanks

[Spider]

 

Matty,

 

If you're currently at 1275, and the bores are worn, then I would only take it out to 1293. Good blocks are getting rarer, and you won't gain as much from the extra few ccs as you can from other improvements.

 

If the bores are good then use the money saved by not reboring and would suggest following:

- MD266 cam

- set of Keith Calver's 1.4 ratio rockers

- head flowed (36mm inlet, 29 or 30mm exhaust)

- CR about 9.5 with 95 octane, or 9.75 with 99 octane

- Maniflow freeflow with twin box RC40

- stick with HIF44, on a well ported inlet manifold

 

 

 

 

 

Hmm I like the idea of saving money, but If the engine bores are worn, to me it makes sense just to go for the 1330 rather than the 1293 because you can only bore it out once so why not go for the higher cc ? I know it might not make much difference in power. Just not sure whats best, but thanks for the idea and reply I appreciate it :)

 

 

Some of the best true numbers I've seen have been from engines in the 1293 range.

 

As some of the other guys have said, with these small changes / advancements in CC's, more and better gains can be had from a quality build rather than small increase in CCs. Have a read here;-

 

http://www.theminifo...gine-machining/

[Cooperman]

Yeah I'm currently running 13" wheels, just think it would be a lot to change all the brakes for accommodate smaller wheels. I'm just trying to get pros and cons of everything really, I was going to have a gearbox rebuild anyway when the engine is out. Do you have to put different ratio gears and that in for a 1330 then ? Thanks

A 1330 cc engine is no different from a 1275. It has just been re-bored to remove wear and tear. There will be no actual power gain really, or none that you would notice. Maybe a couple of bhp going from 1275 to 1330, but not noticeable. The real key to slightly more power is a better cylinder head, accurate engine build and better inlet & exhaust.

So there is no need to alter the gearing from what you have.

However, the 13" wheels are not ideal for a Mini and 12" are much better as the deeper tyre sidewalls give better suspension compliance and the narrower tyre gives better wet skid resistance and wet road holding. But that's up to you. If a car has 13" wheels it can take 12" without changing brakes. For 10" wheels smaller discs and callipers are needed, but the overall feel is best with 10".

[mattyglover16]

 

Yeah I'm currently running 13" wheels, just think it would be a lot to change all the brakes for accommodate smaller wheels. I'm just trying to get pros and cons of everything really, I was going to have a gearbox rebuild anyway when the engine is out. Do you have to put different ratio gears and that in for a 1330 then ? Thanks

A 1330 cc engine is no different from a 1275. It has just been re-bored to remove wear and tear. There will be no actual power gain really, or none that you would notice. Maybe a couple of bhp going from 1275 to 1330, but not noticeable. The real key to slightly more power is a better cylinder head, accurate engine build and better inlet & exhaust.

So there is no need to alter the gearing from what you have.

However, the 13" wheels are not ideal for a Mini and 12" are much better as the deeper tyre sidewalls give better suspension compliance and the narrower tyre gives better wet skid resistance and wet road holding. But that's up to you. If a car has 13" wheels it can take 12" without changing brakes. For 10" wheels smaller discs and callipers are needed, but the overall feel is best with 10".

 

 

 

 

 

Hmm might just go for 1293 then, it seems the better idea as I could spend more money and time on quality. Will I still need all the parts you listed earlier for the 1330 or do I need different ones ? thanks

[Cooperman]

The only difference between parts is that for a 1293 you'll need pistons part no. 21253-20 and for a 1330 the pistons are 21253-60. Prices are the same as they are identical apart from being just 40 thousandths of an inch bigger, which is not a lot. It's just a standard service re-bore to +020, +040 or +060 oversize. Not a big thing at all. Engine re-builders usually go to the next size up as that makes the most sense.

The only real reason for going straight to 1330 is for competition where a small gain of, say, 2 bhp could mean 1/2 a second off a lap time on the track. That's the only place you'd notice any difference.

[mattyglover16]

The only difference between parts is that for a 1293 you'll need pistons part no. 21253-20 and for a 1330 the pistons are 21253-60. Prices are the same as they are identical apart from being just 40 thousandths of an inch bigger, which is not a lot. It's just a standard service re-bore to +020, +040 or +060 oversize. Not a big thing at all. Engine re-builders usually go to the next size up as that makes the most sense.

The only real reason for going straight to 1330 is for competition where a small gain of, say, 2 bhp could mean 1/2 a second off a lap time on the track. That's the only place you'd notice any difference.

 

 

 

Thanks really appreciate your help! so the kent 266 cam should be fine and the aldron yellow dizzy aswell as the clutch. What weight do you suggest the flywheel to be ?

[Cooperman]

Is it a Verto or pre-Verto clutch. Sorry if you don't know the difference. If you don't know then take a look at the clutch operating arm. The pre-Verto is a long arm and the clutch slave cylinder is bolted on directly to the alloy transfer case cover in the horizontal plane, whilst the Verto has a black steel plate bracket with a short operating arm and the cylinder is at an angle to the horizontal.

The Verto flywheel is heavier than the pre-Verto, but each type can do with a bit of lightening, although not too much for a road car. Lightening the flywheel doesn't give more power, it just allows more of the torque produced to accelerate the car as it does not have to overcome quite so much flywheel inertia during acceleration. Make a flywheel too light and it will be lumpier at low revs and will be easier to stall when pulling away from rest.

Just have a good machine shop machine a bit from either type. If they are any good they will know from where to machine it. Aim to reduce the weight by about 1/3rd from the original (just weigh it yourself).

Ideally then have the crankshaft, flywheel, clutch, front pulley and rods balanced, although if you don't intend revving it hard, like much over 6000 rpm, then it's not vital.

The 266 cam is really excellent in a road car and provided smooth power right up to just over 6000 rpm with peak power coming at around 5700 rpm. It is very similar to the MG Metro cam.

[mattyglover16]

Okay thanks, So are the clutches different for certain cars or is it just a personal choice of which one I would like to put in ?

[Mini Manannán]

The verto is the 'refined' version with a slightly lighter pedal, whereas the pre-verto is the original design and there is more choice of flywheel.  If you have a verto clutch now you'll need extra bits to swap over to pre-verto and vice-versa. 

[mattyglover16]

Thanks the clutch has never been changed some guessing it will be a pre verto

[Mini Manannán]

i can't see you saying what age of car you have Matty?  Cooperman ^^^ has given you all the indicators as to which clutch you have.