Technical 5 Speed Kit Installation Instructions
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Technical 5 Speed Kit Installation Instructions
the hobbler
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Ian;
Try to get hold of Andrew Harvey down in Canterbury---he had a 5-speed conversion carried out on his gear-box and from what I can remember his kit came with instructions. 1 thing that i have been advised by MBG--do NOT use the 5th gear as an 'accelerating' gear---use it as a 'cruising' gear only.
Try to get hold of Andrew Harvey down in Canterbury---he had a 5-speed conversion carried out on his gear-box and from what I can remember his kit came with instructions. 1 thing that i have been advised by MBG--do NOT use the 5th gear as an 'accelerating' gear---use it as a 'cruising' gear only.
OP
OP
Thanks Tom, I'll chase him up. Interesting about the 'cruising' only in 5th!!
Is this because of some weakness in the mod or something else????
Ian.
the hobbler
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I honestly don't know the answer to your question Ian, but when BOTH Tony and Anton (Boutier--chief mechanic at MBG) advise the same, I think that it might be wise to listen, and obey!
Ian, even through I realise that your engine will be in a different league from most of them, I'm not sure you will even need to put this warning to the test; once you hit 5th gear you'll be going plenty fast enough.
I'll probably get shot down for this as a non-modder, but my understanding is that the 5th cluster is outside the main box in an enlarged rear cover at the end of the gearshafts. This means that it has bearings only on the inboard side and the shafts, gears and bearings will be put under a lot of sideways thrust; especially since the gears are quite far outboard. I guess the lubrication might also be a bit marginal. That would give plenty of potential for failure if put under excessive load.
[ame]https://youtu.be/_i-WtfHkL8E[/ame]
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OP
OP
Ian, even through I realise that your engine will be in a different league from most of them, I'm not sure you will even need to put this warning to the test; once you hit 5th gear you'll be going plenty fast enough.
I'll probably get shot down for this as a non-modder, but my understanding is that the 5th cluster is outside the main box in an enlarged rear cover at the end of the gearshafts. This means that it has bearings only on the inboard side and the shafts, gears and bearings will be put under a lot of sideways thrust; especially since the gears are quite far outboard. I guess the lubrication might also be a bit marginal. That would give plenty of potential for failure if put under excessive load.
Hi Peter, No you will not be shot down by me at any time, given your milage in Murf is probably the same as everyone else on here and your wise words help so many
Although I do think that changing the roof colour and fitting spotlights is not 'non-modding' I will bear your sage advice in mind about the 5 speed mod though, it does seem to me that maybe a slight change in the diff ratio would elicit the same result without the potential for failure - I'll have a look at what is available and crunch some numbers, it may work out cheaper too
Ian.
Good...I'd hoped you wouldn't have a gun.
I thought you'd have had the 9:39 in any case? Are there any more extreme ratios? Tell me more.
OP
OP
Good...I'd hoped you wouldn't have a gun.
I thought you'd have had the 9:39 in any case? Are there any more extreme ratios? Tell me more.
Hi Peter, yes I do have a gun and I do have a 9:39 diff too, but the web is a wonderful place to while away your time and look up daft things like diff ratio's
Anyway the range of replacement diffs can be put into two distinct groups - higher ratio and lower ratio. The lower types seem to be available for close ratio applications of which I will pass !!If we take my tyre size - 165/60R12 and add a 5th ratio to the box of 0.742:1
the figures for mph in 4th and 5th at 4k and 5k rpm with a change of diff are as follows -
standard diff - (8/39) @5k rpm gives in 4th 69mph in 5th 81mph
@4k rpm gives in 4th 55mph in 5th 65mph
BIS diff - (9/39) @5k rpm gives in 4th 78mph in 5th 91mph
@4k rpm gives in 4th 62mph in 5th 73mph
Hi Ratio - (9/38) @5k rpm gives in 4th 80mph in 5th 94mph
@4krpm gives in 4th 64mph in 5th 75mph
Hi Ratio - (10/39) @5krpm gives in 4th 86mph in 5th 102mph
@4krpm gives in 4th 69mph in 5th 81mph
So, it will be noted that the same speed can be gained from a four speed box utilising a 10/39 diff at 4k rpm as at 5k rpm with a standard diff and 5th gear.
As the engine is running much slower reliability should be greater.
What must be understood is the ability of the engine to 'pull' a higher ratio at lower speeds, the engine must be able to give more torque or remain inside the workable torque band sufficient to remain drivable. The gearbox reliability should remain as normal providing the extra torque from a tuned engine does not overcome the components. The approx cost of a pinion and crown wheel is the same as a 5 speed mod - where did I put the cheque book
Ian.
Hi from New Zealand I'm trying to find a step by step instructions on how to fit my 5ft gear conversion on my fiat 500 did you have a copy regards LoganGreetings All, Do any of the good and great on here have the step-by-step Installation Instructions for a 5 speed gearbox Kit ????? If you know the location of the same let me know please.
Ian.
I just finished rebuilding my transmission. Although i haven't put a 5 speed in yet.. Still contemplating if i want a 5 speed, or upgrade the ring and pinion for more speed and keep it a 4 speed. The down side of changing the final ratio is the speedometer will read wrong, and will require some "customizing"
With that said, i did some searching to see what basically the 5 speed kit entailed.
But yes, a written up conversion instruction is hard to come by. I was contemplating making a photo instruction book and post it up here if i were to do the 5 speed kit.
With that said, there was a decent video i came across that shows how the 5 speed works/installs. Its actually a pretty straight forward kit when you understand how the trans works.
might be of help if you have time to watch.
With that said, i did some searching to see what basically the 5 speed kit entailed.
But yes, a written up conversion instruction is hard to come by. I was contemplating making a photo instruction book and post it up here if i were to do the 5 speed kit.
With that said, there was a decent video i came across that shows how the 5 speed works/installs. Its actually a pretty straight forward kit when you understand how the trans works.
might be of help if you have time to watch.
