10 replies to this topic

[JonnyAlpha]

A couple of questions on Drop Gears.

 

I need some 1:1 ratio Drop Gears and bought a second hand set of A+ (Primary and Input Gear), these need re-busing and I have bought the bushes from MSC (Been reading all the threads about Silicone Bronze / Clearances etc). Just about to get the Primary Gear Re-Bushed and spotted a SH set of Jack Knight Drop Gears 1:1 Ratio, with the roller bearing Idler?

 

Contemplating getting them simply for the safety of the Idler Gear? 

 

Couple of questions:

 

(1). Would this be a wise purchase?

 

(2). If the Primary Gear needs re-busing, would the 1275 A+ bushes fit? Or do JKD 1275 Primary Gears need different bushes? 

 

 

Background on the Engine Spec:

This is for a 1310, AC RS Cam, Modified Head (Guide Bosses, Ports etc), Weber DCOE44 or HIF44, Electronic Ignition, 9.75 CR, 1.3 Rockers.

3.1 X Pin Diff. Potential output will be 85 BHP / 85 lb/ft Torque.

I will be adding a Supercharger an upping the HP / Torque to around 120 / 130?

 

 

 

 

 

 

These are the bushes I have DAM8889 / 22G109

 

 

[nicklouse]

First question you should be asking. With those drop gears fit my gearbox and transfercase. 2nd is can I get bearings for the idler gear?  If yes to both then the rest is simple. 

[RooBoonix]

https://www.med-engi...set-roller-type

 

I'm not one to recommend whether they are suitable for your build or not, but MED make these sets ready to go. Just incase you weren't aware

[JonnyAlpha]

https://www.med-engi...set-roller-type

 

I'm not one to recommend whether they are suitable for your build or not, but MED make these sets ready to go. Just incase you weren't aware

 

Yes at nearly £400

[JonnyAlpha]

First question you should be asking. With those drop gears fit my gearbox and transfercase. 2nd is can I get bearings for the idler gear?  If yes to both then the rest is simple. 

 

Looks like he sold them anyway.

 

I have been asking around for advice on whether I need Straight Cut Drop Gears and it would seem that, in the Forced Induction community, there are plenty of people running Helicals in excess of 130 lb/ft, with no issues.

 

Mine will be getting new bearings and setting the correct end floats.

[Cooperman]

For a road car straight cut drop gears are far from ideal.

The noise can be a bit 'wearing', to put it mildly. Really they are for competition where a crash helmet is worn.

I once fitted them to my Cooper 'S' historic rally car and it was horrible to drive on the road. In the end I took them out and re-fitted helicals.

If you are happy to use ear plugs when on any sort of journey they may be fine for you, but I found the constand whining simply horrible. They whined even more than Prince Harry  .

[MiniCarJack]

For a road car straight cut drop gears are far from ideal.

The noise can be a bit 'wearing', to put it mildly. Really they are for competition where a crash helmet is worn.

I once fitted them to my Cooper 'S' historic rally car and it was horrible to drive on the road. In the end I took them out and re-fitted helicals.

If you are happy to use ear plugs when on any sort of journey they may be fine for you, but I found the constand whining simply horrible. They whined even more than Prince Harry  .

 

I've heard similar feedback on straight cut drops from others, and was quite worried about how I'd fare with them in my car. But to be honest I'd say they're "not too bad" personally, the only time I've started to grow weary of the noise was on longer drives to events at Goodwood, Brooklands etc last year after a long day out and just wanting to get home. For short journeys the straight cut whine adds to the thrill factor in a way, but for longer trips this year, I've now purchased a high-end pair of in-ear wireless earphones (Sony WF-1000XM4 to be precise), these do an incredible job at reducing the whine but also have an ambient mode which allows other noise in through the speakers, so you can still hear traffic and other normal road noises whilst also listening to music (so no need to wire in a sound system which would look out of place in a Mk1!).

[JonnyAlpha]

Thanks everyone. I did get a very comprehensive response by email on not using Jack Knight (especially second hand), whilst they may have been fine, replacing the bearings is very costly and with my expected build Helicals would be fine.

[burchy35]

Hi, I have had straight cut drop gears in various incarnations of my minis. And yes they can grind on you after a while but the last set I bought for a mini I mainly use on track was from swiftune and to be honest they are nowhere near as harsh as previous sets i have had from other suppliers. I know there not cheap from swiftune but well worth the quality in my book 👍

[burchy35]

Come to think about it I am probably going deaf after all the years of running them.😁

[Gaz66]

Anything straight cut is music to my ears.
When combined with a heavy breathing 45 its damn good!