I've already posted this in the transmission section but its something kinda exclusive to middis so just in case you chaps don't visit that
section often - any suggestions........
Sometines the apparantly simplest things are the most difficult. I have a UN1 transaxle I plan to turn upside down, with the diff reversed and mate it
to my rover engine.
Reason is to get the engine/transmission as low as possible and still keep reasonable drive shaft angles.
Problem is the flywheel is now the lowest part and I need a smaller diameter flywheel something around 240 to 280mm.
First thoughts were simple! I still had the flexiplate from the original engine, turn it down and bolt/weld on a smaller ring gear with the same tooth
form and remount the existing starter motor somehow. Multiplate 7.5" clutches are available at not too bad a cost
First problem the toothform is wierd - are there different standards for these things I wonder - perhaps I should get a ring gear and a matching
starter?
Next difficulty is finding something suitable - another forum suggested Renault/peugeot diesel starters but I'm blessed if I can find details of
diameters etc. Another suggestion was porsche 944 as they are cheap (so he reckoned!!!!!) and the starter turns the other way so I can mount it on the
gearbox side of the bellhousing.
Any suggestions?
Cheers
David
Use the renault flywheel ring gear, the bolt spacing is pretty close actually if you could find a way of redrilling them oval that was secure..
Anyway, older masters use a un5 transaxle, and a smaller diameter flywheel than the later one (which also confusingly is a un5), that way you'd
have the right pitch gear for the flywheel ring gear and a small high torque starter.
If you want the flywheel diameters post here, and Ill measure up the two ive got lying round..
the porshe 944 unit is the same as a Audi 5000 tranny. which around here can be had for even less than the porsche unit. (funny considering they're the same)
I assume that you are modifying your bell housing to give the right ground clearance?
In verting the transaxle is the commonest way to lower a midmounted longitudinal engine. Most builders who do this have big tyres with big diameters
which which helps with their drive shaft angles. Ultima get away with it for this reason, the angles aren't too bad if you're using a big
tyre.
How are you planning to modify the bell housing to give the extra clearance made possible by using a smaller flywheel?
Cymtrics - I can cut about 25% of the upper part (soon to be lower part) of the bellhousing off. Of course sods law comes into play and 2 of the 4
main mounting bolts are in this bit. I have no confidence in welding aluminium castings without extensive heat treatment which I aint got the skills
and experience for so I will have to rig up some sort of bracket.
I was planning on utilising the adaptor plate and welding an extension at 90 degrees to pick up the bellhousing to gearbox lower mounting bolts. Still
have the problem of mounting the starter though and I really need an offset drive to get the gears to line up - hence the need to find catalogues I
can browse through to find summat.
I am using 13" wheels because there are more wide tyres available for 10-11" wide rims in this diameter - I have in excess of 400/400
lbft/bhp from the engine and really need this width. It may well be that I have to compromise possibly by angling the engine up towards the back by
2-3 degrees this will give me a bit extra clearance at the flywheel, raise the output flange a little but not too much and the average rise in c of g
I just will have to put up with. However I'd like to try for a little better first before I compromise.
Phil can you give me a measurement on those flywheels please?
Cheers
David
ok, sorry about the delay, busy busy as usual.
early master circa '89 flywheel ring gear is 300mm total diameter, with the ring gear inner diameter at 270mm.
Later master circa '92 (bigger clutch, bellhousing etc) 335mm Total, 305mm inner diameter.
Please dont machine to these measurements, as they were taken with a steel rule, but should be fine for sizing components etc.
Hope this helps.
quote:
Originally posted by v8kid
I've already posted this in the transmission section but its something kinda exclusive to middis so just in case you chaps don't visit that section often - any suggestions........
Sometines the apparantly simplest things are the most difficult. I have a UN1 transaxle I plan to turn upside down, with the diff reversed and mate it to my rover engine.
Reason is to get the engine/transmission as low as possible and still keep reasonable drive shaft angles.
Problem is the flywheel is now the lowest part and I need a smaller diameter flywheel something around 240 to 280mm.
First thoughts were simple! I still had the flexiplate from the original engine, turn it down and bolt/weld on a smaller ring gear with the same tooth form and remount the existing starter motor somehow. Multiplate 7.5" clutches are available at not too bad a cost
First problem the toothform is wierd - are there different standards for these things I wonder - perhaps I should get a ring gear and a matching starter?
Next difficulty is finding something suitable - another forum suggested Renault/peugeot diesel starters but I'm blessed if I can find details of diameters etc. Another suggestion was porsche 944 as they are cheap (so he reckoned!!!!!) and the starter turns the other way so I can mount it on the gearbox side of the bellhousing.
Any suggestions?
Cheers
David
Hi, I am new to the forum and came across your thread regarding running a UN1 upside down. This is something I would like to try in a new design for
the same reason as you ie. drop down the whole driveline assy. How did you get on? Was it easy to turn the diff over?
Any advice greatfully received.
Simon,
Diff dead easy to turn over - I got a UN1 box manual from Mr Fluffy if i remember correctly and it was straightforward.
I measured the backlash on the ring gear before and after the conversion and it was exactly the same without any shims at all!!
I've been diverted recently renovating another house to get some income and the engine fitting has taken a back seat over winter.
The sprinting and hillclimbibg season starts soon so I don't expect much progress before late summer.
Keep in touch