renrut
|
| posted on 5/7/12 at 10:18 AM |
|
|
Gearbox spigot bearings
I'm in the process of trying to mate up a Rover 1.4 K series to a midget 1500 gearbox (single rail triumph box).
But my question is more general - the recieved wisdom is that you must have a spigot bearing in the end of the crank for the gearbox input shaft.
However I've seen several factory original gearbox + engine combinations that don't have spigot bearings at all. In fact the end of the
gearbox did't have anything to locate them in the end of the crank. This was the case with the original gearbox fitted to the 1.4K. So is the
spigot bearing really necessary in all cases?
I'm asking as it would save me having to either A remove the crank from the 1.4K to get it bored out or B concoct some heath-robinson system for
mating the 2 up.
Why are all the fun things in life expensive!
|
|
|
|
|
itsawindupuk
|
| posted on 5/7/12 at 11:49 AM |
|
|
If the engine originally had a front wheel drive gearbox then it wouldn't use a spigot bearing. Because it's a rear wheel drive box you
must use one as the input shaft bearing will wear rapidly without one .
|
|
|
renrut
|
| posted on 5/7/12 at 11:57 AM |
|
|
That confirms what my digging on the interweb has turned up. Seems odd that rwd boxes only have one bearing and fwd ones have 2.
Never mind, means I'll definitely need to get my crank bored out to accept a bearing. 
Why are all the fun things in life expensive!
|
|
|
Agriv8
|
| posted on 5/7/12 at 01:29 PM |
|
|
I have a Rover V8 crank and BMW Getrag Gearbox so Imp to Metric.
I looked at lots of options but my Mechanic mate told me to get down to local bearings supplier with a spare cank and gearbox. took some measurments
ummed and arred flicked thorough some books / parts catalog finally went off and came back with some dusty old boxses 2 synther Bronz bushes were
extracted checked ( pushed togeteher to create one ) and job sorted cost about £4 IIRC.
So option 3 is either go the above route
Or option 4 or get a chap with a lathe to run you one up may be easier and cheaper ( synther pronze is easy to machine i belive )
ATB Agriv8
Taller than your average Guy !
Management is like a tree of monkeys. - Those at the top look down and see a tree full of smiling faces. BUT Those at the bottom look up and see a
tree full of a*seholes .............
|
|
|
renrut
|
| posted on 5/7/12 at 02:14 PM |
|
|
Problem is the hole in the crank as it stands is 13mm and the input shaft for the gearbox is 12.7mm (1/2" . Not gonna find a bearing 0.25mm
thick. So one will have to be changed.
Turning the input shaft down might be easier but it will end up weaker. how much weaker can I get away with?
Opening up the crank end will necessitate taking it out of the block but I suppose is the technically correct solution.
Getting an actual bearing should be quite easy as its not big and my dad has a model making lathe I can use so big enough for a small bronze bearing.
Why are all the fun things in life expensive!
|
|
|
owelly
|
| posted on 5/7/12 at 04:22 PM |
|
|
For the cost of a bearing, I wouldn't bother making one.
http://simplybearings.co.uk/shop/index.php?cPath=3_4523
http://www.ppcmag.co.uk
|
|
|
owelly
|
| posted on 5/7/12 at 04:28 PM |
|
|
http://simplybearings.co.uk/shop/index.php?cPath=3_4523
http://www.ppcmag.co.uk
|
|
|
renrut
|
| posted on 9/7/12 at 08:54 AM |
|
|
Yup I saw them when I started looking at buying material.
Just need to get the crank bored out now. I've seen some pretty nifty setups for doing it. The 16V midget forum has some pretty unusual ways of
doing it but all seem to involve using a very large and accurate drill/boring tool/ lathe at some point none of which I have.
It occurred to me that I need to make an adaptor plate up to hold the gearbox anyway, maybe I could have them make a second plate up to help me bore
the crank out accurately. Anyone have any thoughts on that especially those experienced in machining and the practical side of things being
'good enough for pit work'.
Why are all the fun things in life expensive!
|
|
|
owelly
|
| posted on 9/7/12 at 09:05 AM |
|
|
Mag mount rota-broach or drill. Mount on the flywheel and centre. Bore out hole to desired size and depth. Eat cake.
http://www.ppcmag.co.uk
|
|
|
renrut
|
| posted on 9/7/12 at 01:40 PM |
|
|
They're coming out rather pricey to hire ~£80 plus any fancy bits needed just for a day.
I'm keeping my eye out on ebay at the minute as they seem to pop up once in a while for sub £50 used.
Why are all the fun things in life expensive!
|
|
|
