transmission spare
Discussion
Hi All,
Got a question for you good folks, hope someone knows the answer. Regarding the UN1 transmission found in the lotus esprit, is this the same UN1 found in the eagle medallion/(renault 21)??? Just curious as I'd like to have a spare transmission for a planned future purchase (hopefully soon). Also any idea on price?? Stay Safe everyone! -medic
If I recall, and I am not claiming to be an expert, the gear ratios on the Esprit versions are different. Not that you couldn't use it, just the gearing will not be the same. I'd say go for it. Do you have a line on these? Some magic junkyard in France where you can get them for U$150?
Dr.Hess
Dr.Hess
lol, no, nothing like that, but I've seen a few eagle medallions still on the road, the rest i'm sure are rusting in some junkyards somewhere. I wonder if picking up a couple of these might not be a good idea. I think i'll call around to a few salvage yards for some of amc/eagles' finest technology.
Best REnault replacement is from the Renault 21 Turbo Phase2 (late model) (UN1-016)
This has a stronger casing than the standard 21 or 25 gearboxes.
Gear ratio's are slightly different but in this case the higher final ratio is beneficial during cruising.
Did have a site with all the gearboxes, their model numbers and ratios, but seems to be down or gone ?
I have been using the R21t gearbox for two years now with no problems. It cost me about £200 when origional 2nd gear broken on origional.
Del
S4s 95
This has a stronger casing than the standard 21 or 25 gearboxes.
Gear ratio's are slightly different but in this case the higher final ratio is beneficial during cruising.
Did have a site with all the gearboxes, their model numbers and ratios, but seems to be down or gone ?
I have been using the R21t gearbox for two years now with no problems. It cost me about £200 when origional 2nd gear broken on origional.
Del
S4s 95
Im just rebuilding and strenghtening a UN1 box as we speak.
I believe the 'medellian' model has a 4.11 or even lower [4.3] final drive. You'd probably wind up with a top speed of 100mph only!
The R21Turbo box has a few minor mods to it. It has 2 extra ribs in the diff part, and an extra small peice added as bearing support on the secondary shaft rear bearing. But in saying that, this bearing on the secondary shaft is smaller than that of the R30, type 369 box, same internal diameter but larger outside. Hence on the 21T box the bearing support in the case is larger, but smaller on the 369 box. I dont believe the smaller bearing size has made any difference in strenght, but the larger bearing pad around it would be beneficial if you put the 2 side by side as I have at the moment.
If you want a stronger box, get a 1-peice input shaft made. Also if you want a 4-spider diff, the unit from a Renault 30 type 369 box will fit. If you want to put this diff onto the UN1 -13 (21 turbo has a 2-spider unit) you will have to have sleeves machined on the crownwheel to take the side gears. Some clever Frenchman made the size bigger, from 30 to 32mm.
It can be done, you have to have a good machinist though. Ive just been through all this carry-on, and its not too painful!
I believe the 'medellian' model has a 4.11 or even lower [4.3] final drive. You'd probably wind up with a top speed of 100mph only!
The R21Turbo box has a few minor mods to it. It has 2 extra ribs in the diff part, and an extra small peice added as bearing support on the secondary shaft rear bearing. But in saying that, this bearing on the secondary shaft is smaller than that of the R30, type 369 box, same internal diameter but larger outside. Hence on the 21T box the bearing support in the case is larger, but smaller on the 369 box. I dont believe the smaller bearing size has made any difference in strenght, but the larger bearing pad around it would be beneficial if you put the 2 side by side as I have at the moment.
If you want a stronger box, get a 1-peice input shaft made. Also if you want a 4-spider diff, the unit from a Renault 30 type 369 box will fit. If you want to put this diff onto the UN1 -13 (21 turbo has a 2-spider unit) you will have to have sleeves machined on the crownwheel to take the side gears. Some clever Frenchman made the size bigger, from 30 to 32mm.
It can be done, you have to have a good machinist though. Ive just been through all this carry-on, and its not too painful!
To strengthen anything in the box means they would have had to remanufacture parts which I believe they dont have the facilites to do, eg: to make a strenghtend c/p means new crownwheel and secondary shaft - a major undertaking. You may well find what they did was to ask Renault to provide the boxes with different ratios (which they did) and retain the larger bearing of the 369 in the newer case, and revise gearset teeth size retaining ratio - which was done with 4th gear on the later boxes.
Im sure the Lotus version box still has the dreaded 2-peice input shaft (anyone care to confirm this). Any uprating of the diff area I have seen is a 2mm increase in the size of the output shafts, which was a part of the 21T boxes UN1-13
Im sure the Lotus version box still has the dreaded 2-peice input shaft (anyone care to confirm this). Any uprating of the diff area I have seen is a 2mm increase in the size of the output shafts, which was a part of the 21T boxes UN1-13
Maybe you should take a look at this....
www.lotusespritworld.co.uk/ETechnical/Gearbox_Testing.html
Paul.
www.lotusespritworld.co.uk/ETechnical/Gearbox_Testing.html
Paul.
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