16 replies to this topic

[Leekr89]

I've just got my engine/box back from my local mini specialist, having my gearbox rebuilt again due to a problem with second gear (apparently due to rubbish rover spec baulk rings) they fixed this free of charge though so I'm happy with that.

whilst it was in I asked them to fit a set of drop gears I supplied them with,(minispares evolution 24t) they said they would shim them up and fit them for me, all the bearings were replaced approx 1500 miles ago

I've just got the engine running and on tickover the whine I get of the drop gears is really loud, it sounds like a supercharger noise. it dissappears completely when I disengage the clutch though, it's not somthing I noticed on other people's engines who run straight cuts, now I know they make a lot of noise, but I've never heard it when then the engines just running and not being driven.

Do you think this is an issue? or is it somthing that will dissappear once the car has done a few miles? Any help will be much appreciated ☺

[Dusky]

It's quite normal on some gears, depending on make.

[mini-geek]

You should get an awful clatter at idle, however if they've fitted new baulk rings the box can be tight while they bed in so could be while it's bedding in.. (edit because the box is tight it will be taking a certain amount of effort to rotate it so the gears are under a small amount of load, like when driving)

Give it a drive and see what's it's like.. you'll hate the SC drops soon anyway.. lol

Edited by mini-geek, 10 February 2017 - 06:39 PM.

[Leekr89]

Ahh yes that could be the case that the gearbox is still tight, I will finish building it up and get some miles put on it, will see how I get on, cheers

[Chris.Williams]

Give it a drive and see what's it's like.. you'll hate the SC drops soon anyway.. lol

Haha

[Cooperman]

Unless necessary for out-and-out competition, the SC drop gears really are unpleasant.

Next time my engine comes out of the 'S' they are going to be replaced with helical ones. I just hate them!

[Northernpower]

Unless necessary for out-and-out competition, the SC drop gears really are unpleasant.
Next time my engine comes out of the 'S' they are going to be replaced with helical ones. I just hate them!

Couldn't agree more, my engine doesn't need to come out having just built it last year but it coming out in April. New helical gears here we come.

[pogie]

I've just got my engine/box back from my local mini specialist, having my gearbox rebuilt again due to a problem with second gear (apparently due to rubbish rover spec baulk rings) they fixed this free of charge though so I'm happy with that.

whilst it was in I asked them to fit a set of drop gears I supplied them with,(minispares evolution 24t) they said they would shim them up and fit them for me, all the bearings were replaced approx 1500 miles ago

I've just got the engine running and on tickover the whine I get of the drop gears is really loud, it sounds like a supercharger noise. it dissappears completely when I disengage the clutch though, it's not somthing I noticed on other people's engines who run straight cuts, now I know they make a lot of noise, but I've never heard it when then the engines just running and not being driven.

Do you think this is an issue? or is it somthing that will dissappear once the car has done a few miles? Any help will be much appreciated ☺

When you say "engine running and on tickover" is the car in neutral, because the drop gears don't spin when in neutral and you usually get a chattering noise from S/Cs in neutral?  Usually this chattering noise will go away when the clutch is depressed and the gears should only whine when the car is moving.  From your description the opposite seems to be happening which may mean you have a clutch issue.

[Northernpower]

I've just got my engine/box back from my local mini specialist, having my gearbox rebuilt again due to a problem with second gear (apparently due to rubbish rover spec baulk rings) they fixed this free of charge though so I'm happy with that.

whilst it was in I asked them to fit a set of drop gears I supplied them with,(minispares evolution 24t) they said they would shim them up and fit them for me, all the bearings were replaced approx 1500 miles ago

I've just got the engine running and on tickover the whine I get of the drop gears is really loud, it sounds like a supercharger noise. it dissappears completely when I disengage the clutch though, it's not somthing I noticed on other people's engines who run straight cuts, now I know they make a lot of noise, but I've never heard it when then the engines just running and not being driven.

Do you think this is an issue? or is it somthing that will dissappear once the car has done a few miles? Any help will be much appreciated ☺

When you say "engine running and on tickover" is the car in neutral, because the drop gears don't spin when in neutral and you usually get a chattering noise from S/Cs in neutral?  Usually this chattering noise will go away when the clutch is depressed and the gears should only whine when the car is moving.  From your description the opposite seems to be happening which may mean you have a clutch issue.

The drop gears are in constant mesh and run in neutral. They stop when you press the clutch in.

[Spider]

I've just got my engine/box back from my local mini specialist, having my gearbox rebuilt again due to a problem with second gear (apparently due to rubbish rover spec baulk rings) they fixed this free of charge though so I'm happy with that.

 

Sorry for going OT here, but the Rover Baulk Rings are usually really good, though I have had the odd one that's been out of round. Other brands are usually harder and so only wear the Synchro Cone on the gear itself. I'd rather replace the Baulk Ring than the Gear!

 

Also, 99999 times out of 100000, I've found that the binding fault is nothing to do with the baulk rings, but the way the later gearbox cases have been machined,,,,,, It can sometimes be bodged by fitting thinned down baulk rings,,,,,,

 

Going back OT, the whine is pretty normal for SC Drop Gears. It ceases when you put your foot on the clutch as these gears stop spinning when you do that.

[pogie]

 

 

I've just got my engine/box back from my local mini specialist, having my gearbox rebuilt again due to a problem with second gear (apparently due to rubbish rover spec baulk rings) they fixed this free of charge though so I'm happy with that.

whilst it was in I asked them to fit a set of drop gears I supplied them with,(minispares evolution 24t) they said they would shim them up and fit them for me, all the bearings were replaced approx 1500 miles ago

I've just got the engine running and on tickover the whine I get of the drop gears is really loud, it sounds like a supercharger noise. it dissappears completely when I disengage the clutch though, it's not somthing I noticed on other people's engines who run straight cuts, now I know they make a lot of noise, but I've never heard it when then the engines just running and not being driven.

Do you think this is an issue? or is it somthing that will dissappear once the car has done a few miles? Any help will be much appreciated ☺

When you say "engine running and on tickover" is the car in neutral, because the drop gears don't spin when in neutral and you usually get a chattering noise from S/Cs in neutral?  Usually this chattering noise will go away when the clutch is depressed and the gears should only whine when the car is moving.  From your description the opposite seems to be happening which may mean you have a clutch issue.

The drop gears are in constant mesh and run in neutral. They stop when you press the clutch in.

 

Whoops apologies, I got my facts arse about face.  So they don't normally whine in neutral because they are not under load?

[tiger99]

Straight cut gears are not the answer to any particular problem except idler bearing and thrust washer loading. I have only recently found that a helical gear per se does not have any more loss than a straight cut gear. If both are of the correct tooth profile, the frictional loss is the same, as the points of contact roll rather than slide against each other.

That can't be said for those abominable gears with a step up or down ratio and badly compromised tooth geometry.

The answer to drop gear problems is to address the idler gear bearing problem, not do away with the helical gears. Unfortunately that has so far proved to be too difficult for the aftermarket suppliers to comprehend.

[Cooperman]

The original reason for the SC drop ears was that they were available in slightly different ratios. This means that for different circuits the overall gear ratio can be altered easily without taking the engine out and changing the diff. and the car could be geared so that peak revs could be reached at max. speed down the longest straight.

For racing or hill-climbing, where a helmet is worn, this is not an issue, but on the road it is horrible. 

[mini-geek]

It's very easy to fall into the SC trap.. I do agree the sound is great but for 5mins I now just have a SC gear set, I'm surprised how loud they are probably the most you'd cope with, I'm still considering fitting a helical gear set..

[mini-geek]

And before people think I'm a kill joy it's not I'm just trying to help people avoid doing something that they'll regret