Lotus Elan

My Gearbox Rebuild

PostPost by: Kpas » Tue Aug 06, 2019 12:25 pm

A few months ago I was out driving my S2 Elan when I was greeted with a god awful crunching noise and a lack of drive in the first 3 gears.

I managed to limp the car back to the garage in 4th gear (was a short distance away).

It turned out of be a pretty terminal gearbox failure with the input shaft having lost all its teeth.
https://www.dropbox.com/s/8oxfc6unzmefl ... 3.jpg?dl=0
https://www.dropbox.com/s/f4lri16n98dow ... 7.jpg?dl=0

Like any good repair this is where my gearbox rebuild progressed to
https://www.dropbox.com/s/koak0swnx2pii ... 9.jpg?dl=0
https://www.dropbox.com/s/1q2be4e6wmxgz ... 0.jpg?dl=0

Nothing like a bit of scope creep! The thought process was while I've got the engine and gearbox out I should paint the engine bay..... and while I'm painting the engine bay I should paint the rest of the car.

I was lucky enough to have access to Richard Mann who helped with the fiberglass repairs. He also provided the space to rent for storage of the car and it's disassembled bits, as well as a location to paint it.

I use the car frequently, and at the outset wanted to just do a quick and easy respray over a 3 week period whilst my better half and our little one were away...... I ended up a fair bit more involved than that with the bodywork taking about 3 months with a whole bunch of life distractions getting in the way.

As we progressed with the fiberglass repairs, and the body prep the cars shape got better and better. Richard worked through some dodgy repairs on the bonnet (a hole which had been bogged up) which was the worst fitting panel.
https://www.dropbox.com/s/73ewuvexgr3f1 ... 2.jpg?dl=0

The high fill and blocking back process took a few iterations before I landed on the final shape with enough primer still on the car.
https://www.dropbox.com/s/xfmsjo92g1mcx ... 1.jpg?dl=0
https://www.dropbox.com/s/1ge2aqhyfk2p7 ... 6.jpg?dl=0
https://www.dropbox.com/s/2qimv1adm18l0 ... 8.jpg?dl=0

And last weekend I managed to finally get some paint onto the car.
https://www.dropbox.com/s/oriv36ysl032l ... 9.jpg?dl=0
https://www.dropbox.com/s/oriv36ysl032l ... 9.jpg?dl=0
https://www.dropbox.com/s/v32qcjisb7ef1 ... 7.jpg?dl=0
https://www.dropbox.com/s/v32qcjisb7ef1 ... 7.jpg?dl=0
https://www.dropbox.com/s/fmr3kka3d48kw ... 3.jpg?dl=0

Now to build that gearbox.....
Kpas
First Gear
First Gear
 
Posts: 16
Joined: 19 Jul 2016
Location: Melbourne, Australia

PostPost by: types26/36 » Tue Aug 06, 2019 2:55 pm

Wow! ......never seen that! .........that’s some serious gearbox issues.
Is that a close ratio box (2.5) first gear, semi C/R (2.9) first gear or the wide spaced (3.5) first gear?
Have you worked out what caused the g/box problem? .... :?:
Nice spray job :mrgreen:
Brian
64 S2 Roadster
72 Sprint FHC
User avatar
types26/36
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 3634
Joined: 11 Sep 2003
Location: U.K.

PostPost by: The Veg » Tue Aug 06, 2019 5:21 pm

¡WOW!
1969/70 Elan Plus 2 (not S) 50/2036
"It just wouldn't be a complete day if I didn't forget something!" -Me
User avatar
The Veg
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 1294
Joined: 16 Nov 2015
Location: Atlanta 'burbs (southeast USA)

PostPost by: SENC » Tue Aug 06, 2019 5:44 pm

Thanks for making me feel better about my scope creep!!!

That is quite the gearbox damage - any warning? Any root cause?
Henry
69 S4
SENC
Third Gear
Third Gear
 
Posts: 434
Joined: 30 Dec 2015
Location: NC

PostPost by: Kpas » Tue Aug 06, 2019 8:37 pm

The gearset fitted to the car turned out to be a standard cortina ratio, so one upside is that I didn't destroy a rare gearset.

There was no warning signs unfortunately. Rohan came past to cast an eye over thr remains, his determination was fatigue failure of the teeth on the input shaft.
Kpas
First Gear
First Gear
 
Posts: 16
Joined: 19 Jul 2016
Location: Melbourne, Australia

PostPost by: mark030358 » Tue Aug 06, 2019 10:20 pm

Love the colour!
Nice work
User avatar
mark030358
Fourth Gear
Fourth Gear
 
Posts: 856
Joined: 29 May 2004
Location: Willaston, Wirral

PostPost by: geni » Wed Aug 07, 2019 9:38 am

hua!
Very beautiful painting, it has charm! his reference?
could I know the positioning = relays fixing measure in the left front wheel arch!
The rims with these 3x pins to maintain the central hubcap chrome are type car?
geni
Second Gear
Second Gear
 
Posts: 75
Joined: 30 Dec 2014
Location: FRANCE

PostPost by: 2cams70 » Wed Aug 07, 2019 9:56 am

Kpas wrote:The gearset fitted to the car turned out to be a standard cortina ratio, so one upside is that I didn't destroy a rare gearset.

There was no warning signs unfortunately. Rohan came past to cast an eye over thr remains, his determination was fatigue failure of the teeth on the input shaft.


Very unusual for teeth to strip like that with an engine in standard tune. Did you check to see whether something might have come adrift inside the box and jammed in between the gears? The primary gear on the countershaft sits lowest in the gearbox and hence is the most likely gear to pick up any debris that may be lying at the bottom. Once something hard gets stuck between the gears it doesn't take long before it's bye bye gearbox. Not saying it's what has happened in this case but nevertheless it is a possibility,
1970 Ford Escort Twin Cam
1972 Ford Escort GT1600 Twin Cam
1980 Ford Escort 2.0 Ghia
Peugeot 505 GTI Wagons (5spdx1) (Autox1)
2015 Honda City 5spd.
2cams70
Fourth Gear
Fourth Gear
 
Posts: 717
Joined: 10 Jun 2015
Location: Australia

PostPost by: rgh0 » Wed Aug 07, 2019 10:01 am

2cams70 wrote:
Kpas wrote:The gearset fitted to the car turned out to be a standard cortina ratio, so one upside is that I didn't destroy a rare gearset.

There was no warning signs unfortunately. Rohan came past to cast an eye over thr remains, his determination was fatigue failure of the teeth on the input shaft.


Very unusual for teeth to strip like that with an engine in standard tune. Did you check to see whether something might have come adrift inside the box and jammed in between the gears? The primary gear on the countershaft sits lowest in the gearbox and hence is the most likely gear to pick up any debris that may be lying at the bottom. Once something hard gets stuck between the gears it doesn't take long before it's bye bye gearbox. Not saying it's what has happened in this case but nevertheless it is a possibility,


The failure was very clearly a fatigue failure of the teeth with most of the failed teeth showing fatigue cracking before failure. The Cortina gears may have done a few hundred thousand miles before being put into the Elan so its not surprising after 50 years. Most Elan boxes will have done a lot less miles.

cheers
Rohan
User avatar
rgh0
Coveted Fifth Gear
Coveted Fifth Gear
 
Posts: 7161
Joined: 22 Sep 2003
Location: Melbourne, Australia

PostPost by: Quart Meg Miles » Thu Aug 08, 2019 10:11 pm

rgh0 wrote:
The failure was very clearly a fatigue failure of the teeth with most of the failed teeth showing fatigue cracking before failure. The Cortina gears may have done a few hundred thousand miles before being put into the Elan so its not surprising after 50 years. Most Elan boxes will have done a lot less miles.

cheers
Rohan

Oh dear, my speedo just passed 80,000 for the third time...
Meg

26/4088 1965 S1½ Old and scruffy but in perfect working order; the car too.

Put your money where your mouse is, click on "Support LotusElan.net" below.
User avatar
Quart Meg Miles
Fourth Gear
Fourth Gear
 
Posts: 894
Joined: 03 Oct 2012
Location: West Sussex, UK (South coast)

PostPost by: Kpas » Sat Aug 10, 2019 3:04 am

Some progress happening. It's nice to be putting bits back onto the car again!

Though it was a bit of a two steps forward one step back.

I pulled all the masking off which has made it loom like a car again, two steps forward.

I'd pulled out the steering column bushes as part of the strip down. In the process of installing the new ones I've damaged the column.... one step back. Silly silly boy.

20190810_114736.jpg and

20190810_114725.jpg and
Kpas
First Gear
First Gear
 
Posts: 16
Joined: 19 Jul 2016
Location: Melbourne, Australia

PostPost by: Kpas » Fri Sep 27, 2019 12:04 pm

Ok so I've been a bit lazy with the updates, but that's not due to a lack of progress.

The car is 98% back together now and is a real joy with the correct gearset in it. I'm quite surprised at how much of a difference it has made, but I guess you don't know what you don't know.

I'll have to wait until the car has seen a bit of sun over the Aussie summer as the paint is still quite soft. The badges and other fittings will also have to wait as I won't polish the csr until after summer.

But all in all, I'm very happy with the results.
Attachments
20190918_231810.jpg and
20190918_231821.jpg and
Kpas
First Gear
First Gear
 
Posts: 16
Joined: 19 Jul 2016
Location: Melbourne, Australia

PostPost by: davidj » Fri Sep 27, 2019 1:34 pm

This is the layshaft from a triumph gearbox fitted in a kit car I built 30 odd years ago. Similar failure....
Attachments
img_20190927_143012.jpg and
davidj
Third Gear
Third Gear
 
Posts: 304
Joined: 09 Apr 2008

PostPost by: davidj » Fri Sep 27, 2019 1:35 pm

Fantastic restoration by the way.
davidj
Third Gear
Third Gear
 
Posts: 304
Joined: 09 Apr 2008

PostPost by: SENC » Sat Sep 28, 2019 3:40 am

beautiful!
Henry
69 S4
SENC
Third Gear
Third Gear
 
Posts: 434
Joined: 30 Dec 2015
Location: NC
Next

Total Online:

Users browsing this forum: No registered users and 5 guests