locoboy
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| posted on 1/9/03 at 12:47 PM |
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Quick question: offset prop shaft tunnel
hiya all,
i have been having a search for info regarding seating and found a post that stated that to fit a certain type of seat in a Book chassis you needed to
reduce the width of the seat - fine and fully understandable.
The bit i did not understand is why the drivers seat had to be made narrower than the passengers, is the prop shaft tunned supposed to be running off
centre? thus making one compartment narrower than the other?
I also noticed that my Formula 27 had a narrower drivers tub than the passengers but some 4cm at the rear bulkhead? is this normal?
or did the guy who built mine just have a fat arsed woman  cheers and beers
colin
ATB
Locoboy
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David Jenkins
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| posted on 1/9/03 at 01:14 PM |
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The fixed axle diff is offset, so the propshaft flange is an inch or two towards the driver.
As the tunnel is only a little wider than the flange, it has to be widened on the driver side a bit.
Hope this helps,
David
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locoboy
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| posted on 1/9/03 at 01:23 PM |
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Well bugger me, i didnt know that, i just though mine had been put together by a complete clown.
i am knocking about the idea of converting it to IRS, does this mean that i will need to A) mount the independent diff off center to line up with the
tunnel, or B) square up the tunnel so i can mount the diff on the centre line and avoid having to guff about with drivers side rear wishbones being a
different length to passenger side ones?
Colin
ATB
Locoboy
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timf
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| posted on 1/9/03 at 01:40 PM |
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to convert to irs the diff is mounted centrally in the car and the drive shafts are different lengths. The wishbones are normally made same length and
pick up points are equal distance from the centre line
Tim
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locoboy
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| posted on 1/9/03 at 01:51 PM |
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Tim,
How cant the diff be mounted centrally and still use different length drive shafts?
colin
ATB
Locoboy
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timf
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| posted on 1/9/03 at 01:59 PM |
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the prop flange is mounted centrally and the drive shaft mounts on the diff housing are different from the central point of the diff. also if you look
at a irs set of drive shafts you will see they are different lengths as standard
have a look at this in vipers archive for visual aid
http://forum.locostbuilders.co.uk/xmb/photos/cgi-bin/showpic.pl?rear1.jpg
[Edited on 1/9/03 by timf]
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locoboy
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| posted on 1/9/03 at 02:35 PM |
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steep learning curve!
Tim,
Thanks for the piccy, all clear now. Only concern is that i still couldn't use an independant diff mounted in the middle of the tunnel centre
line because the whole diff assy will be closer to the drivers side (purely due to tunnel angle) and the short shaft is on the passengers side, making
it too short and the long one too long, unless i could swap them over?
Hope this made sence, it did to me when i was writing it!.
Colin
ATB
Locoboy
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timf
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| posted on 1/9/03 at 03:10 PM |
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colin
have a look at the pic again the offset side is rear ward of the top mount which should be in the area the current diff. if the prop flange is mounted
in the centre line of the chassis (Not tunnel) then there shouldn't be a problem.
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locoboy
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| posted on 1/9/03 at 03:49 PM |
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Tim,
It looks like the centre casting line on top of the diff is in the centre of the tunnel -correct?
My issue is that the centre line of the tunnel is not the centr line of the car, therefore if i mounted the riff flange in the centre of the car it
would foul the inside of the tunnel, if on the other hand it was mounted in the centre of the tunnel the shafts would be too short on onje side and
too long on the other - Correct?
or am i falling off my steep learning curve!
Colin
ATB
Locoboy
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James
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| posted on 1/9/03 at 03:59 PM |
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quote:
Originally posted by colmaccoll
Tim,
Thanks for the piccy, all clear now. Only concern is that i still couldn't use an independant diff mounted in the middle of the tunnel centre
line because the whole diff assy will be closer to the drivers side (purely due to tunnel angle) and the short shaft is on the passengers side, making
it too short and the long one too long, unless i could swap them over?
Hope this made sence, it did to me when i was writing it!.
Colin
Hi Colin,
Unless yours is very fat (your tunnel that is) you'll have to move the tunnel to the centre and then mount the diff in the centre of that.
The only way round it I can see is if the tunnel is larger than necessary and you can fit a small diameter prop down the centre of the car but not
down the centre
of the tunnel. Can't see it being too likely though.
HTH,
James
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timf
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| posted on 2/9/03 at 07:29 AM |
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quote:
Originally posted by colmaccoll
Tim,
It looks like the centre casting line on top of the diff is in the centre of the tunnel -correct?
My issue is that the centre line of the tunnel is not the centr line of the car, therefore if i mounted the riff flange in the centre of the car it
would foul the inside of the tunnel, if on the other hand it was mounted in the centre of the tunnel the shafts would be too short on onje side and
too long on the other - Correct?
or am i falling off my steep learning curve!
Colin
the rib is the centre of the diff
as james said the tunnel would most probably not be in the correct place but if you are considering converting to irs then you would have to add tubes
so moving a couple of the existing ones shouldn't be a problem
tim
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locoboy
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| posted on 2/9/03 at 07:45 AM |
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Thanks chaps, info much appreciatedlooks like a bit of chassis trickery and a bit of re panneling inside the car is required.
It makes it a bit of a bigger job than just making wishbones and a diff cage now
Thanks again.
Colin
ATB
Locoboy
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