Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Ford 1600 5spd Conversion? Rev reducton.

Not quite the same, but probably the best mod I have had done is changing the diff ratio from 3.97:1 to 4.1:1 makes the car so much more drivable. 30 mph in 4th & 40 in 5th perfectly doable. 70 mph on the tacho = 3000 rpm. About 300 rpm more than standard. Would recommend. Just 1 comment, for some reason the diff does “ring” a bit. Seems the replacement gears are not that well manufactured. For those interested the “ring” starts to show above 50mph & varies a little depending rpm. The “ring” unfortunately occurs only when cruising. Accelerate it stops deceleration it stops. Having said that it is not bad, can’t be heard roof down. (2011 4/4, 1600 sigma)

I'd certainly agree that the 4.1:1 final drive ratio is ideally suited to the 4/4. As for the ringing, have you tried a slightly thicker diff oil, would that help maybe? I can heartily recommend the Quaife ATB diff, but it's admittedly not a cheap fix for a ringing diff

I think you will notice the 1st gear ratio change if you fit the standard T9 box. My MT75 box also has a similar short 1st gear and it is useless unless you're taking a fully laden Ford Sierra towing a caravan up the side of a mountain.

It's why I have been looking at the Mazda box which has a good spread of ratios for Sports car use and still with a good overdrive in 5th.

I now know that the Mazda is not an easy fit in your car so if you are going to fit the T9, I would really suggest you look at the alternative ratio set which whilst being quite expensive will be a much better driving experience.

I'm also not sure about the numbers changing the axle ratio will make if the original is 3.97:1

At 3000rpm the difference will only be about 100 rpm, not 300 rpm. It's only about 3%

The final drive on mine is 3.73 and that would give about a 300 rpm difference at 4.1.

Haven't noticed it at all but then again I only use first gear for moving off.

An alternative would be to get a gear cluster from a V6 Type 9 and modify (shorten the input shaft) which would give you the benefit if an improved 1st gear. The downside of that is that you will end up using parts from two different boxes which is poor engineering practice

Arwyn

Yeah, I'm similar.

I'll have a chat with Simon - we're going to go for a recon box, so may be the ability to change.

Bob, Think you are right. Standard was probably 3.7:1 I remember the rpm difference at 70 but not the standard ratio.

The 4.1:1 rear axle was pretty standard on the Kent engined 1600s. It's what I have in both of my 4/4's. I believe the option was a 4.5:1. We spend hours driving in the 70-80mph range and 5th has transformed the car.

It does appear that everyone who has actually done the conversion seems to be very happy with it. I spoke about it with Mike Pullen last year and he was also an advocate.

Take a look at the Retroford website.

They offer recon T9's in both standard and close ratios. CR about £350 more expensive. Maybe have a chat with them.

RetroFord T9 gearboxes

I know it's down to personal choice but I know which way I would go.

I'm sure Simon will be able to get both sets of ratios.

Checkout BGH Geartech as well. Specialist in the Ford gearboxes and UK based.