Lotus Elan

Throttle pedal travel

PostPost by: quaybook » Tue Jun 09, 2020 9:00 pm

Hi

My type 26 Elan has the original 40 DCOE 18 Webers. I've always found the throttle pedal travel very long and find that in normal driving I frequently fail to open the throttle fully when accelerating. I've measured the pedal movement and it takes 5 inches of travel to reach full throttle; this compares with 3.5 inches on my 1974 Alfa saloon, and 3 inches on my Westfield Seven. Presumably this long pedal travel was adopted to help avoid drive line surge with Rotaflex couplings. As I have CV jointed driveshafts I've been toying with the idea of making up a shorter carb throttle lever, thinking that this might give the car a more responsive feel. As it is, it feels less responsive to the throttle than my crossflow engined Westfield which has similar power, although the Westie is lighter of course.

I think this is probably a silly idea, but would appreciate your thoughts.

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PostPost by: mbell » Tue Jun 09, 2020 9:41 pm

I did this a few months ago and I prefer it. I took around 7mm out of the throttle lever on the carb by cutting it and welding it back together.

I also made sure to fit the throttle pedal stop that was missing (I have a +2 not sure if elan have them.)

I think Lotus might have done a similair mod back in the factory as I believe the cars came with shorter throttle lever:
viewtopic.php?t=33943&f=40&start=0#p230264
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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PostPost by: andywatts » Thu Jun 11, 2020 8:55 am

mbell wrote:I did this a few months ago and I prefer it. I took around 7mm out of the throttle lever on the carb by cutting it and welding it back together.

I also made sure to fit the throttle pedal stop that was missing (I have a +2 not sure if elan have them.)


Very interesting post. Mbell - can you give any info on the throttle pedal stop for +2, as I'm sure I don't have one. Can't find it in the Parts Manual or the suppliers.

Thanks
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PostPost by: oldelanman » Thu Jun 11, 2020 10:42 am

andywatts wrote:
mbell wrote:I did this a few months ago and I prefer it. I took around 7mm out of the throttle lever on the carb by cutting it and welding it back together.

I also made sure to fit the throttle pedal stop that was missing (I have a +2 not sure if elan have them.)


Very interesting post. Mbell - can you give any info on the throttle pedal stop for +2, as I'm sure I don't have one. Can't find it in the Parts Manual or the suppliers.

Thanks

The throttle pedal stop is normally just a bolt on the underside of the pedal it's the same on the two seater Elan and Plus 2

Pedal box assembly.jpg and
Elan pedal assembly

Pedal boxes 2.jpg
Plus 2 pedal assembly
Pedal boxes 2.jpg (108.28 KiB) Viewed 421 times
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PostPost by: 661 » Thu Jun 11, 2020 12:54 pm

I'm sorry I can't measure the distance again for you as the car is at the painters, but I did measure this a coupe of months ago as I was dry building the type 26.
If I recall ( and the synapses ain't firing like they used to) it was a 69mm full throw from open to closed.
Have a look at your carb end throttle linkage. Perhaps the arm on it is a bit long??
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PostPost by: ElanDNA » Thu Jun 11, 2020 4:27 pm

quaybook wrote:Hi

My type 26 Elan has the original 40 DCOE 18 Webers. I've always found the throttle pedal travel very long and find that in normal driving I frequently fail to open the throttle fully when accelerating. I've measured the pedal movement and it takes 5 inches of travel to reach full throttle; this compares with 3.5 inches on my 1974 Alfa saloon, and 3 inches on my Westfield Seven. Presumably this long pedal travel was adopted to help avoid drive line surge with Rotaflex couplings. As I have CV jointed driveshafts I've been toying with the idea of making up a shorter carb throttle lever, thinking that this might give the car a more responsive feel. As it is, it feels less responsive to the throttle than my crossflow engined Westfield which has similar power, although the Westie is lighter of course.

I think this is probably a silly idea, but would appreciate your thoughts.

Vernon


Hi Vernon
Me too found ever the throttle pedal travel very long.
A very long time I have need to create a solution for my self.
What one can see on the picture is a transmission ratio from 1: 1.25. See the different in outside diameters.
The force is transmitted in the same ratio. Thats better for the springs in the carbs.
It should only a inspiration to be for any solution.
It's very good to handel. I will never to do without it. It's very comfortable now.
And all holes in the head and camcover (stromberg) have preexisted. :wink:
DSC01027.JPG and

Cheers Urs
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PostPost by: quaybook » Thu Jun 11, 2020 5:40 pm

Thanks everybody.

I'd like to fit a shorter carb throttle lever but can't find anything available other than what appears to be the standard one (part no 4504800700). Maybe I'll follow Mbell and try shortening one. I don't have welding equipment so I'll have to make sure I do a proper job that can't fail under load or, worse still, jam!

Urs, your solution is so inventive, I think it is great, but beyond my powers to replicate. I also want to keep the underbonnet look of my S2 as near original as possible.

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PostPost by: RichardHawkins » Thu Jun 11, 2020 6:27 pm

Urs,

Beautiful work. I have not seen a cam cover like that with Lotus on a yellow background, I rather like it.

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PostPost by: MarkDa » Thu Jun 11, 2020 10:17 pm

I wouldn't be surprised if the Press cars had a "faster" throttle.
We can all recall the 'tune up' that consisted of just fitting a softer spring!
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PostPost by: reb53 » Sat Jun 13, 2020 6:40 am

MarkDa wrote:I wouldn't be surprised if the Press cars had a "faster" throttle.


I believe the press cars had "faster" engines.......
And bonnet openers that were "broken" so testers couldn't go poking about in the engine bay.
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PostPost by: MarkDa » Sat Jun 13, 2020 11:55 am

Graham Arnold used to say that all engines hard a series of variables and all they used to do was ensure that all the tolerances were in the 'right' direction - not cheating as sooner or later an engine with performance would have come off the production line!!
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PostPost by: 661 » Sat Jun 13, 2020 12:38 pm

Presumably you've compared yours to the Burton ones?
https://www.burtonpower.com/parts-by-ca ... -kits.html
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PostPost by: quaybook » Sat Jun 13, 2020 5:51 pm

Thanks Graeme. They Burton ones look the same length as mine I am afraid. I've ordered one and will check out properly when it arrives, but expect that I'll have to try to shorten it. The question now is how to shorten in a safe and reliable way.
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PostPost by: 661 » Sat Jun 13, 2020 5:55 pm

TiG !
But with the standard throttle lever on I can't see why you would have an extended travel
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PostPost by: mbell » Sat Jun 13, 2020 6:15 pm

As far as I know only one length is available. Cut and weld is I think the only real option.

I have also found the spring hole on new lever toi small for the (replacement) return spring and needs drilling out. Drilling this out push the metal into the cable connection and that needs cleaning up.

They are also plated, so technically need replating.
'73 +2 130/5 RHD, now on the road and very slowly rolling though a "restoration"
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