tobymack
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 posted on 3/4/07 at 07:58 PM |
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how to mod a 2.8 box to fit a crossflow?
Hi,
I've got a 2.8 capri box that I want to fit on a crossflow. Given that the input shaft is too long, I gather I have two options
1) shorten the existing one with an angle grinder
2) replace it with a shorter one.
For option 1, anyone got any advice as to how best to do it. It looks like I not only need to chop the end off, but I also need to shorten the
splined area. Is this right? It sounds more like a lathe job than an angle grider job but that would mean removing the shaft.
for option 2, can I just swap it for the input shaft off a normal box? I have a standard box I can rob of bits but how do I get the shaft out? I have
removed the nose and the shaft will come out a short way but then something in the box stops it- I suspect it is the gears on the lower shaft. Advice
needed!
ta,
Toby
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RichieW
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| posted on 3/4/07 at 08:14 PM |
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Cant you fit a spacer plate between the bellhousing and gearbox body? Might be easier, I think some places sell the spacer to do the job.
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mookaloid
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| posted on 3/4/07 at 08:16 PM |
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Best option is to fit the spacer from caterham - it doesn't cost too much.
Fitting a shorter shaft is very expensive. Because the ratio is slightly different.
Cutting the shaft doesn't always work anddd it's a shame to spoil a good long shaft box.
Failing that I'll buy it off you and get you a regular box instead
Cheers
Mark
[Edited on 3/4/07 by mookaloid]
"That thing you're thinking - it wont be that."
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tobymack
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| posted on 3/4/07 at 09:15 PM |
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Thanks for that offer Mark. But having gone to the trouble of getting a 2.8 box I'd rather stick with it 
A spacer is an option but it would move the box back so I'd need to shorten my prop (which I have only just rebuilt with a new nose) and mod my
chassis to clear the end of the gearlever extension.
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mookaloid
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| posted on 3/4/07 at 09:36 PM |
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Well good luck. You will have fun trying to mod the existing shaft properly as it is too hard to lathe off.
The replacement short shaft is a custom made jobbie cos they didn't make that ratio with the short shaft as standard.
Could you move the engine forward? the spacer is about 30mm if I recall.
Let me know if you change your mind.
Cheers
Mark
"That thing you're thinking - it wont be that."
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stevebubs
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| posted on 3/4/07 at 09:46 PM |
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quote:
Originally posted by tobymack
Thanks for that offer Mark. But having gone to the trouble of getting a 2.8 box I'd rather stick with it
A spacer is an option but it would move the box back so I'd need to shorten my prop (which I have only just rebuilt with a new nose) and mod my
chassis to clear the end of the gearlever extension.
Can you not move the engine forward a little?
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Chippy
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| posted on 3/4/07 at 10:07 PM |
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Not absolutely certain, but reasonably so. The short shaft fitted to the "standard" box is the same as the 2.8 box in all aspects, other
than it has the shorter section in the bell housing, so should be a straight swap. For a definative answer give Brian at BGH Geartech a ring, 01580
714114, I found him very helpful, plus he know's the type 9 backwards. You definately wont be able to lathe the existing shaft, its case
hardened. HTH Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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sarahjane
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 posted on 4/4/07 at 07:25 AM |
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type 9 shaft.
if you need to cut the shaft use a small angle grinder with a thin cutting disk,did this on my 2.8 type 9 box to fit it to a rover 1.4 k,shaft is hard
so go steady and dont force it,Ray from Riddlesden.
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tobymack
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| posted on 4/4/07 at 10:58 AM |
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Thanks for all the comments.
Yes, I was thinking of putting it in a lathe but, as said, it is hardened so I can't do that 
I don't think the engine will go much further forward, it is very close to the bottom of the bonnet and I'd have to redo the engine mounts
as there is not more than 10mm adjustment in them.
Swapping the shafts is looking complicated. It looks like I need to strip the box to get it out and I am not sure I fancy doing that....
I'll do some careful measuring, if I am lucky then I can just chop the end off, if not I'll see what BGH say.
BR,
Toby
I'll talk
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ned
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| posted on 4/4/07 at 11:42 AM |
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if you cut the end off the shaft how will you support the end of the shaft, what about the thinner end piece where the spigot bearing goes?
Ned.
beware, I've got yellow skin
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tobymack
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| posted on 4/4/07 at 12:11 PM |
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on the 2.8 box the spigot end is longer than on the normal box. So you can chop the end off and still have some left to go into the spigot bearing.
BUT the extra length of the shaft is partially in the spigot end and partially in the splined bit. So I suspect I need to reduce the diameter on the
splined bit as well as just chopping the end off.
It needs much more careful measurement to see if this is possible or not.
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