Lotus Cortina MK1 Propshafts

Anything related to Lotus Cortinas. (Open to the public.)

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Superestate
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Lotus Cortina MK1 Propshafts

Post by Superestate »

Hi, Does anybody have length dimensions for Lotus Cortina MK1 two-piece propshafts? I'm trying to find out whether or not they were made in different lengths for A frame and leaf sprung cars.

The A frame Lotus Cortina MK1s have a slightly longer wheelbase than conventional leaf sprung 'Ford' Cortina MK1s (by about 0.4" (10 mm) according to the Ford Dearborn development report), but; were the later leaf sprung Lotus Cortina MK1s designed to have the same wheelbase as the A frame cars (e.g. by using a more rearward location for the axle locating pins)? If so, they would probably have used the same propshaft lengths. Or, did they use the same wheelbase as the conventional 'Ford' Cortina MK1s? If so, they might have been made with reduced length on the second section (unless the sliding joint was deemed sufficient allow for the difference).

I've attached a pdf showing dimensions I've taken from a two piece propshaft, but I don't know if it was originally from an A frame of leaf spuing car (or indeed, if those cars have the same, or different, wheelbases). For reference, I want to fit this propshaft to a leaf sprung estate car, but it seems a bit too long, and wondered if it was from an A frame car, or, if I need a pair of genuine Lotus Cortina leaf springs which might locate the axle further rearward.

Many thanks for any new measurements!
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Brian c
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Re: Lotus Cortina MK1 Propshafts

Post by Brian c »

The later mk1's use the same axle anti-tramp bars as the GT with the same axle/chassis location, so I would expect the later cars have the same wheel base as standard.
scrab
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Re: Lotus Cortina MK1 Propshafts

Post by scrab »

A Frame prop shafts are slightly longer. Both front and rear sections are the same diameter. On the photo you have shown the rear section looks larger diameter which would probably be from a series 1 MK2
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Pete G
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Re: Lotus Cortina MK1 Propshafts

Post by Pete G »

If you look at pictures of the sides of an A frame car and a leaf sprung car the position of the rear wheel of the A frame car is further back in the wheel arch than the leaf srung one.
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Re: Lotus Cortina MK1 Propshafts

Post by Michael Winstock »

In the very first publication from the LCR (early 1981 and pre-dating Quarter Bumper), there was an extremely good article entitled "Split-Prop Overhaul".

Included in this article was the following information:

Part No. 28D/050: Feb.63 - July 64: One piece prop with "A" bracket. Wheelbase 249.9 cms.

Part No. 28D/094: July 64 - May 65: Split prop with "A" bracket. Wheelbase 249.9cms.

Part No. A28D/094: May 65 onwards: Split prop with leaf spring. Wheelbase 248.29cms.

Standard cortina wheelbase 248.92cms.

Perhaps this will help with the queries.
Superestate
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Re: Lotus Cortina MK1 Propshafts

Post by Superestate »

Hi All,

Thanks for the replies, much appreciated.

Is it possible to purchase a copy of the split propshaft article from the club archives?

From the information provided above, it seems as though the leaf spring split prop might be shorter (seems a bit too much for the sliding joint to account for, on top of plunge from axle movement in bump or droop. Does anyone have a MK1 split propshaft they could measure to help confirm (A frame of leaf sprung)?

For reference, my front and rear sections have an OD of approx. 51 mm (2 ") and 70 mm (2 3/4 ")respectively. Does that help identify it as A frame or leaf spring type? Or from a MK2? I've been told that the MK2 series one is the same as the leaf sprung MK1, and that the MK2 series 2 is different again to account for the longer single rail gearbox (and different centre bearing mounting arrangement). Bit is that correct?

Also, does anyone have a length measurement for: The front spring eye to axle saddle locating pin, taken from an original main leaf on a MK1 Lotus Cortina?

Many thanks.
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Steve 155C
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Re: Lotus Cortina MK1 Propshafts

Post by Steve 155C »

Hi Superestate, you can joint the LCR here:

https://lotuscortina.net/membership/join/
Superestate
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Re: Lotus Cortina MK1 Propshafts

Post by Superestate »

Hi Steve, I joined prior to posting.
Superestate
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Re: Lotus Cortina MK1 Propshafts

Post by Superestate »

Hi All, I'm still searching for propshaft length measurements, in particular, the length of the rear section of a two-piece prop (coil or leaf sprung). Is anyone able to get under their car with a tape measure? Many thanks.
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Re: Lotus Cortina MK1 Propshafts

Post by Keith Halstead »

Any use?
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Superestate
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Re: Lotus Cortina MK1 Propshafts

Post by Superestate »

Hi Keith, Yes, that's' really helpful, many thanks. I also get 26 3/4 " and 31 " from the the diff end yoke flange to the end of the main tube, and to the centre yoke flange, respectively (with the splined joint fully compressed). Is this from an A frame / coil sprung car?
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Keith Halstead
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Re: Lotus Cortina MK1 Propshafts

Post by Keith Halstead »

Superestate wrote: Sun 1st Jan 2023 7:42 pm Hi Keith, Yes, that's' really helpful, many thanks. I also get 26 3/4 " and 31 " from the the diff end yoke flange to the end of the main tube, and to the centre yoke flange, respectively (with the splined joint fully compressed). Is this from an A frame / coil sprung car?
I can't remember now as it wa ages ago.
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