Before I go further, I’ll
outline the experience which has led to the comments below.auto oil seals Citroen.We have competed intensively in our K series engined
Midget, which had 185bhp in normally aspirated form, and has done a
decade of serious competing on the orignal rear axle fitted with a
limited slip diff and uprated halfshafts.
The type of event which gives the hardest test for the rear axle is use in autotests or autosolos, or motorkhanas and autocrosses as we call them in NZ. When racing, the most stress is placed on the axle as the car leaves the start line thanks to the torque multiplier effect of the gearbox being greatest in first gear. auto oil seals. Generally, this happens only once in a race, thereafter the car is in higher gears and the torque experienced by the rear axle is reduced accordingly, and the impact loading of a clutch dump is not present either. In autotests in particular the car is in first gear for usually the whole time, and during the course of a single test will have a great many torque reversals, and several clutch dumps .. one with each handbrake turn!
Hence a day’s autotesting will punish the rear axle more than a whole season’s worth of racing.auto oil seals Citroen.
In addition, in our case, we have used sticky tyres to transmit the extra power of the K, so this has placed even more load on the axle. So in 10 years competing we have given the rear axle a great deal of punishment.
Differential:
We use a 3.9 standard Midget crown wheel and pinion. It is a replacement 3.9, not an original. This may be significant as the cone angle of the pinion was greater than the original. On the other hand it might not affect it at all! Instinctively I think the sideways thrust between crown wheel and pinion may well be affected by the different angle, but I’ve been too lazy to work it out. All I know is the current CWP has been up to the job.auto oil seals Citroen.
The reason we fitted the new CW&P is relevant. It’s because the old one broke first time out. However, the reason it broke was not any inherent weakness – it copped a piece of spider pinion which caused one of the pinion teeth to crack.
The real culprit was wheel spin. Without a Limited Slip Diff to lock up both wheels the inside wheel spun much faster than the other, the diff lubrication couldn’t cope and the spiders seized to their shaft. Then one shattered as they were trying to go in opposite directions and something had to give.auto oil seals Citroen.
At the time, we already had a limited slip diff ready to fit but were waiting for the halfshafts to be made for it. We did rather hope it would survive one event! So we fitted the LSD along with the new CW&P and we’ve had no problems ever since, despite giving the rear axle a real hammering over the period of a decade at the time of writing (said he hastily looking for some wood to touch).
Where this is all leading is that the standard Midget diff will survive the pounding of intense competition if you fit an LSD. It’s a nice change to have a modification which enhances reliability as well as performance!auto oil seals Citroen.
The type of event which gives the hardest test for the rear axle is use in autotests or autosolos, or motorkhanas and autocrosses as we call them in NZ. When racing, the most stress is placed on the axle as the car leaves the start line thanks to the torque multiplier effect of the gearbox being greatest in first gear. auto oil seals. Generally, this happens only once in a race, thereafter the car is in higher gears and the torque experienced by the rear axle is reduced accordingly, and the impact loading of a clutch dump is not present either. In autotests in particular the car is in first gear for usually the whole time, and during the course of a single test will have a great many torque reversals, and several clutch dumps .. one with each handbrake turn!
Hence a day’s autotesting will punish the rear axle more than a whole season’s worth of racing.auto oil seals Citroen.
In addition, in our case, we have used sticky tyres to transmit the extra power of the K, so this has placed even more load on the axle. So in 10 years competing we have given the rear axle a great deal of punishment.
Differential:
We use a 3.9 standard Midget crown wheel and pinion. It is a replacement 3.9, not an original. This may be significant as the cone angle of the pinion was greater than the original. On the other hand it might not affect it at all! Instinctively I think the sideways thrust between crown wheel and pinion may well be affected by the different angle, but I’ve been too lazy to work it out. All I know is the current CWP has been up to the job.auto oil seals Citroen.
The reason we fitted the new CW&P is relevant. It’s because the old one broke first time out. However, the reason it broke was not any inherent weakness – it copped a piece of spider pinion which caused one of the pinion teeth to crack.
The real culprit was wheel spin. Without a Limited Slip Diff to lock up both wheels the inside wheel spun much faster than the other, the diff lubrication couldn’t cope and the spiders seized to their shaft. Then one shattered as they were trying to go in opposite directions and something had to give.auto oil seals Citroen.
At the time, we already had a limited slip diff ready to fit but were waiting for the halfshafts to be made for it. We did rather hope it would survive one event! So we fitted the LSD along with the new CW&P and we’ve had no problems ever since, despite giving the rear axle a real hammering over the period of a decade at the time of writing (said he hastily looking for some wood to touch).
Where this is all leading is that the standard Midget diff will survive the pounding of intense competition if you fit an LSD. It’s a nice change to have a modification which enhances reliability as well as performance!auto oil seals Citroen.
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