Alan B
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| posted on 17/10/02 at 04:10 PM |
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Gearchange discussion
Guys, I thought this would be a hot topic so I'm just setting up the thread.
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interestedparty
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| posted on 17/10/02 at 05:02 PM |
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On my Mondeo donor engine/gearbox the gearchange comes out the back of the gearbox and is operated by a single rod which goes to the separate gear
lever. The reverse detent is built into the gearlever unit so what I have in mind is to mount the gearlever in the chassis (possibly on the right) and
find a way of transmitting the motion of the gearlever output shaft to the input shaft on the gearbox. Pity they will be facing in opposite
directions! Cable would seem to be the way, Alan sugggests looking at an MR2 but so far I haven't had the opportunity to do so. Anyway, obviously I
need two cables, one to transmit fore-and-aft movement and the other to transmoit rotary motion. Haven't worked out how to do it yet, but later
Mondeos have cable change so I might be able to use that.
If I were the only person ever going to drive the car then I would have used an auto box but for some reason other people don't seem to like them.
Shame, don't know what they're missing I reckon
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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Alan B
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| posted on 17/10/02 at 05:07 PM |
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John, I'll try and find some photos of the MR2 parts.
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theconrodkid
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| posted on 17/10/02 at 05:08 PM |
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i am using an escort remote,it will go under the box then a link to the selector rod,may work back to front,if so ill play round with the pivot.
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interestedparty
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| posted on 17/10/02 at 07:13 PM |
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I did think of using a rod to connect the remote to the gearbox, the two would need to be in line, then put a crank in the rod so it could pass under
the gearbox. Then it could carry both the fore-and--aft and rotary motions. I won't know it there's room to do that until I've got the whole thing
laid out, need to get rid of the donor first.
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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MrFluffy
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| posted on 18/10/02 at 10:50 AM |
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Alan, isnt the MR2 reknown for its terrible clunky gearchange?
How much is this the linkage and how much is it the box?
Id be interested in using the system, but I dont want to end up with a gearchange that should be a on a vw camper...
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Alan B
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| posted on 18/10/02 at 12:49 PM |
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Hmmm....I've never heard that!
My donor had 160K miles on it and the gearchange was silky smooth
I can imagine it brand new being a bit stiff for a 100 miles so, but nothing else.
I just checked MR2.com on the FAQ's and they do mention notchiness in cold weather but suggest a change to different
gearbox oil.
[Edited on 10/18/02 by Alan B]
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merkurman
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| posted on 19/10/02 at 06:51 PM |
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wow a notchy action would be nice in my fairlane....I don't like not being able to feel whats going on...and that is with a hurst shifter. not used
to these FWD things...never had one.
nick
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Spyderman
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 posted on 21/10/02 at 12:32 PM |
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Hi guys!
You could try looking at how it is done on the "Formula V" cars.
Also VW based kits that use the VW tranny reversed.
Usually a solid rod is used with a rocker at the end to reverse the for aft motion and a cross rod from lower to upper shaft to translate rotation.
Sounds complicated, but is very simple in use.
Terry
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thetankwad
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| posted on 18/12/02 at 01:06 PM |
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spanner in the works
If you mount a fwd engine and box in the rear of the car, facing the same way, surely the gear change positions for 1st, etc would be in the same
direction, only with the rod pulling when it would be pushing and vice versa. Am i right in thinking this could be done with next to no mods, just
rotating the linkage rod to go forwards rather than rearwards?...Or is is time for my pills again.
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Alan B
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| posted on 18/12/02 at 01:34 PM |
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Yes, basically it is simple. The hardest things to do are keeping it light and smooth.
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Spyderman
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| posted on 18/12/02 at 01:55 PM |
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If you are simply moving an engine and box back without altering it's orientation then the direction of the selector and gear lever will still be the
same.
The only difference is that the selector rod (if it uses one as opposed to cables) is then at the rear of the selector instead of infront of it; ie;
rod goes from gear lever to engine behind driver, not from gear lever to engine in front of driver.
It sounds more complicated than it really is!
For example; if when you select first gear from neutral the selector rod moves forward, then having the rod behind the lever will still move it
forward.
Hope this helps.
Terry
Spyderman
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interestedparty
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| posted on 18/12/02 at 03:39 PM |
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Problems with a rod change-
The place where the rod enters the gearbox will nearly always be higher than the sump/gearbox or whatever that the linkage will have to pass under in
order to get to the front of the car.
Assuming one uses the original shifter in order to use the reverse detent which may be built into it, it may not be easy to get the rod to come out of
the back of the shifter when obviously in the donor car it will be coming out the front
My advice, finds a donor that has a cable change, and use longer cables
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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Spyderman
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| posted on 18/12/02 at 04:06 PM |
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Agreed, the rod linkage is not always ideal.
If it is too complicated to get around then make up a cable system.
I would assume that as all of you have built your own chassis and in this area are making a mid engined car, then fabricating a cable linkage should
be well within your capabilities.
I'm sure Alan B or Steve Graber have pictures of the MR2 setup, which is simplicity in itself, which would enable you to replicate.
Really, all you need do is transfer motions from one area to another, and just studying the MR2 linkage at the lever would give you all the info you
need to duplicate at gearbox.
I was amazed at how simple the MR2 system is, but is very positive in use.
Terry
Spyderman
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fastenuff
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| posted on 18/12/02 at 07:13 PM |
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I have a pic of a set up fwd engine in a single seater (a terrapin) if interested i'll put it in the photo section. Prob some of you have that book
aswell
Ingmar
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Rorty
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| posted on 19/12/02 at 06:12 AM |
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I've built five road-going MECs, and quite a few for off-road too, all with cable change. In the past I've driven a few mid engined
grassers/hillclimbers with rod change, and there's no comparison. Rods flex, period.
Whichever trans/cable shifter you end up with, you'll almost certainly have to have new cables made to suit. In which case, it's fairly simple to
combine the cable ends of the two units onto two new cables.
I've one or two pics of a cable/mid engine set up if anyone's interested.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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