39 replies to this topic

[Guess-Works.com]

It doesn't need all of the above, as I said works well in the standard MG engine. Even with the super heavy vert flywheel, I just can't see the point in fitting a cam and then not using the last 700rpms of that cams powerband.........If anything you need to rev past this so your gear change keeps you in a more favourable area of said powerband. A 286 should have a redline of 7500rpms.

Yes to get the maximum from the engine all of the above would be beneficial, but they are by no means needed for the cam to work.........

There's a big difference between the redline of an engine ( or in this case cam ) and what is the optimal point at which to change gear...

As we're all aware an engine will have a peak torque and a peak power, both of which will be in different places and neither will be at the 'red line'

If you're looking for an optimal gear change then the change should be at a point where when in the higher gear the power is dropping off to the point that the rpm drop to the lower gear brings the rpm into the range where the power is increasing towards peak power. It's like going over a hill, there is no point going so far over peak power that you're actually using less power than if you change gear.

Likewise, if you have a torque centric engine, like a diesel, there's absolutely no point flogging the arse off it, much better to use the low down grunt and the gears.

[solihullian]

right guys, i have another engine in the garage that i haven't used for a while (about 18 months), its a 1330 with a stage 3 head (morspeed) and its fitted with a morspeed PH3 camshaft, i found the dyno chart for this engine on my laptop from when it was last tuned, at the time the car that it was fitted to was fitted with a HIF44 carb and it was running on 13" wheels with a standard A+ gearbox.
would it be better for me to use this engine with the s/c box as the max torque was 84.3ft/lbs but it was a pretty lever spread of torque.

the attached picture is the dyno printout for that engine.

this engine was tuned (in a fashion) at smart performance and it was still not running right after the tune as the operator had "no SU needles" so i had to use one of my spares which was a BBC needle but the engine had a big flat spot low down, i'm sure that the engine has more power available than this.

Attached Files

•  1330 dyno chart.jpg   89.49K   14 downloads

Edited by solihullian, 08 March 2013 - 08:28 PM.

[jamiestevenbell]

i have in my garage a set of what i was told are close ratio gt gears im willing to sell is there any way i can verify these then thesee may be of more use to you. and my last engine had a 286 cam in and with the right head and everything set up it had loads of torque and power, and that was on a 3.4 diff and thats what i would go for, it was good around the lanes for fun and wasnt too bad on the motorway, and it would spin my yokohama a539 tyres up n the dry in second gear easy!!

[MRA]

The laygear will have 1040 stamped on it

[Guess-Works.com]

Or an "R" and the laygear could have no stamping at all, or an "M" or if you're lucky DAM3168

only real way is 18 teeth on the 1st motion shaft, and hope the laygear you have with it is the right one, 'cause tooth count wise they are the same as a standard gear, but different diameters.

[solihullian]

if i get a GT gearset it will mean that i've just wasted 2 days cleaning my 5626 gear casing and all of its associated bits as i will need a pre A+ casing and transfer gears!

Edited by solihullian, 09 March 2013 - 11:02 AM.

[MRA]

Unless you get the DAM3168 kit which is a later A+ type kit, also I think from memory but John will confirm some early A+ boxes used the 2 step 4 synchro laygear....

[solihullian]

Unless you get the DAM3168 kit which is a later A+ type kit, also I think from memory but John will confirm some early A+ boxes used the 2 step 4 synchro laygear....

yeah, its the CAM2886 box that used the 2 step laygear, i had 2 of those boxes last year but i sold them........wish i hadn't now..:-(

someone told me that there was no such thing as a close ratio A+ helical gearset!

[MRA]

The last of the 1275GT had A+ gearsets, and Goldseal (Leyland Reconditioned boxes) also had the later A+ gearset fitted, although Goldseal disapeared around 1981/3 so not too many of these about.

You are more likely to see an M or part of an M stamped on them than the full DAM3168 part number

Edited by mra-minis.co.uk, 09 March 2013 - 11:47 AM.

[Guess-Works.com]

Just to clear things up...

There is an A+ close ratio gearset, but it's NOT an A+ gear profile, it is the A Series gear profile running on A+ shafts, the same gear profile as the GT/Cooper S gearset.

During the first years of the A+ the gearset were still A series in profile, but ran on the updated A+ 3 step layshaft and larger mainshaft with the 18mm nose. Later on the quieter single groove ( and double groove for the economy Metro ) gearsets were introduced.

And finally, you can fit an A series gearset into an A+ gearbox case with a little modification which will take 5 minutes with a file and some elbow grease.