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UN1 Holloway reinforced shaft/gears kit available again - group buy - Page 2 - Gearchange/Gearbox/Clutch - The Lotus Forums Jump to content


UN1 Holloway reinforced shaft/gears kit available again - group buy


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Michael I really don't think you'll trash the SE transmission with the stock box and 910 engine...I've personally heard of no cases whatsoever, neither firsthand nor otherwise. The V8 box failures, those I've seen much more frequently. 

I drive my SE like I stole it, not the least bit worried about breaking fifth gear - plus it doesn't have the kind of "oomph" in 5th the V8 does. The latter just accelerates whatever gear you're in. In the SE I usually change down to 4th, depending on speed of course. 

You can invest that 10 k elsewhere in good conscience in other words! 

Vanya Stanisavljevic '91 Esprit SE | '97 XK8

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as for 'figure of merit' ..in engineering you have to match material specification, acting forces and momentum  ..and in terms of a automobile the relation between 'engine momentum' curve (think

I can count on one hand how many people have had gearbox problems, it's not a common problem in the slightest.

I saw that I was thinking of those gaskets etc. Jacques.

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Vanya,

Except it is not a stock 910 and that is what gets me a bit worried. Gonna try and get her on a rolling road in the next month or two and see what I really have in hand as there are parts installed that may or may not be what they were billed to be on paper or wallet so what results may not be reality. Having noted that 5th is the deal breaker, I have made a sticker for the dash as a reminder of this fact for now. Having seen what CHANGES has done (way over what I expect has been done to mine), he has had only one failure that I have read about so not too worried but still a bit freaky due to replacement cost rising fast.

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On 1/20/2016 at 17:41, MikieP said:

Bummed. 1992 SE is looking for improved xmission - what happened to the 6 speed that was around years ago? Was it also improved for torque as well or just 6 gears?

TXL300 6S – Trans Axle 6 Speed Sequential   http://www.eliteracingtransmissions.com/products/txl300-6s/

?

 

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I think you mean the 6-speed from GTO. A few years ago plenty of info could be found, and I believe PUK in Germany also sold them. But I can't seem to find much apart form forum topics anymore... I looked at the 6-speed when I just got my Esprit (and was still dreaming), but found the ratio's would not be suitable for a daily driver.

I have made many mistakes in my life. Buying a multiple Lotus is not one of them.

 

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Hi Mikie,

The one you are thinking of was a six speed H shift dog box. To memory It was a complete straight cut close ratio gear kit fitted into the 027 casing the extension on the back for reverse gear.. All six gears were in the main box area so no overhung gears.  To get all six gears in the main box area meant the gears were smaller, as a result this box is not as strong as the alternative..   This six speed kit was made by Quaife and supplied through GTO Engineering. Starting price was around the £10K mark but that was a few years back, They are no longer available as not financially viable to produce. Some parts are still available to service existing box's  .. The H pattern also had reverse in different position otherwise the format was the same..   The dog gear change is mainly for motor-sport use , so not ideal for the road but still usable with DDC ..  

On 30/01/2016 at 18:28, MikieP said:

Having seen what CHANGES has done (way over what I expect has been done to mine), he has had only one failure that I have read about so not too worried but still a bit freaky due to replacement cost rising fast.

  Yes only one failure , but that was because the uprated kit was fitted as a replacement not standard..   It is also worth noting that unless on/off abuse in fifth, the standard clutch in most cases will give way before the torque limit of the box is reached on an SE. S4 . S4s ..  Depending on your dyno results this may be your first consideration..  

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Filip and Dave,

Bingo. That is the one. Had no idea it was actually weaker. Was also hoping 6th would be of benefit for highway use but again, ignorance is quit blissful . I did buy from JAE, and was told I had the S4s heavier clutch kit installed towards the power increase issue. No idea if I really do. Too many thieving / deceitful hands on the car over the 2.5 year build up to be certain of anything done to her at this point being done, or done correctly, parts stolen / swapped out (alum tanks and tranny for starters) for used, etc.  Great Advert for selling down the road, No? Guess I will stay away from 5th and run on down the road. lol.

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On 1/20/2016 at 10:26, MrDangerUS said:

The original UN1 design, although durable and lightweight, was not crafted for the high torque of a Lotus Esprit. The OEM gearbox possesses three weaknesses, all of which are managed by the Holloway Performance upgrade.
The primary shaft is two pieces connected by a weak spline configuration subject to breakage

I would like to question this statement. I have never heard of anyone breaking the input shaft or primary shaft at their junction. Furthermore, by eliminating this flex point, you remove all tolerance for misalignment between the primary shaft and the crankshaft, which could be detrimental if more than a few thousandths.

Carry on.

Visit Sanj's Lotus Esprit Turbo SE pages

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Numtpy question here......

this is just a v8 problem isn't it ????? And there has been lots of shaft snapping and 5th gear breaks ???

Only here once

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I can count on one hand how many people have had gearbox problems, it's not a common problem in the slightest.

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88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

For forum issues, please contact the Moderators. I will aim to respond to emails/PM's Mon-Fri 9-6 GMT. 

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Is it running ? Is it running ??? Where you been??? It's even got a bloody mot now ............

check out the video !!

not drivable now as it needs some urgent love - but I now have a fantastic starting point.

Only here once

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On 2/21/2016 at 18:18, sanj said:

I would like to question this statement. I have never heard of anyone breaking the input shaft or primary shaft at their junction. Furthermore, by eliminating this flex point, you remove all tolerance for misalignment between the primary shaft and the crankshaft, which could be detrimental if more than a few thousandths.

Carry on.

I am confused by the statement. There are hundreds of engine/transmission swaps done and almost all manual transmissions used have a one piece straight shaft. Most of engine/transmission adapter plates machined have a lot worst misalignment between the primary shaft and the crankshaft than Lotus will ever have and they do work fine. 

 

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On 2/21/2016 at 18:42, Barrykearley said:

Isn't it also advisable not to drag race the v8s on 1st to 2nd as well ??

Lotus had to reduce the power output of V-8 Esprit in order to preserve the transmission.  Even 4 cyl S4 and S4S has boost limited on 1st and 2nd due to the inherent weakness of the Renault gears and too high of the gear ratio difference for capabilities of the 1-2 synchros. 

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I agree, the 1-st/2-nd is too steep for the 4-banger.

Perhaps for V8 it does not matter as much, but in either case, the tranny eats up the synchro rings like Tostitos. LOL

When it comes to the shaft-it always brakes at the same spot.

In the UN1 , there are three weaknesses:
1) the overhung 5th gear (the 5 speed UN1 is the earlier 4 speed Renault 369 with an extra gear hung on the end!)
2) the small diameter splined link between the clutch/input shaft, and the first motion shaft
3) Flexing of the first motion shaft between the two ball bearings due to the thrust pushing them apart.

 

Well, add these shafts on pictures below and you'll need two hands to count them. LOL.

broken-shaft-ends.jpg

broken-shafts.jpg

broken-shaft-taper-bearing.jpg

Edited by MrDangerUS
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1 hour ago, Zig said:

Even 4 cyl S4 and S4S has boost limited on 1st and 2nd due to the inherent weakness of the Renault gears and too high of the gear ratio difference for capabilities of the 1-2 synchros. 

Not true.

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Visit Sanj's Lotus Esprit Turbo SE pages

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A Lotus mechanic that I know (and he is very knowledgable) said that it was not wise to floor it in 1st. Once you were in second though, you could go for your life.

All we know is that when they stop making this, we will be properly, properly sad.Jeremy Clarkson on the Esprit.

Opinions are like armpits. Everyone has them, some just stink more than others.

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  • Gold FFM

Drove my four pot like it was a stolen hire car....... I never heard of a shaft issue on these - I was sure it was just v8 only........

is this un1 shaft kit the same as the v8 ? If so how much and when are they available 

Only here once

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1 hour ago, sanj said:

Not true.

This. Boost was only limited in 1st and 2nd in the V8,  and even the not in the Sport 350 and I don't recall a single Sport 350 owner having gearbox issues. 

The 5th gear issue can only be caused by heavy on/off throttle application support in 5th at motorway speeds. 

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88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

For forum issues, please contact the Moderators. I will aim to respond to emails/PM's Mon-Fri 9-6 GMT. 

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