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Using Cortina uprights with Haynes Roadster-spec wishbones?
kevyo89 - 14/1/19 at 11:40 AM

Is there any modification needing done to the Chris Gibbs Haynes Roadster book-spec wishbones if using the Cortina uprights to ensure correct caster, self-centring etc?

Charlie C - 14/1/19 at 12:26 PM

A quick Google search directed to the two threads below


http://www.locostbuilders.co.uk/viewthread.php?tid=141750
http://forums.haynes.co.uk/showthread.php?t=2487&highlight=cortina+uprights

kevyo89 - 14/1/19 at 12:48 PM

quote:
Originally posted by Charlie C
A quick Google search directed to the two threads below


http://www.locostbuilders.co.uk/viewthread.php?tid=141750
http://forums.haynes.co.uk/showthread.php?t=2487&highlight=cortina+uprights


Thanks for your response mate. Neither of those give definitive instructions regarding arm lengths or angles to ensure proper caster etc. Please correct me if I am wrong or of I am overlooking something.

Charlie C - 14/1/19 at 02:13 PM

Your right there is no definite answer, I would like to convert over to cortina uprights and have better castor angle than the sierra set up.
I did consider swap to an MX5 upright as there are plans for the wishbones and changing the front wheel due to the PCD is different.

kevyo89 - 14/1/19 at 02:25 PM

quote:
Originally posted by Charlie C
Your right there is no definite answer, I would like to convert over to cortina uprights and have better castor angle than the sierra set up.
I did consider swap to an MX5 upright as there are plans for the wishbones and changing the front wheel due to the PCD is different.


Haha yeah - that's why my head is fried. I am fitting the haynes wishbones to my Ron Champion locost - wider track etc but I have a perfectly good set of reconditioned cortina hubs which I would rather use to be honest.

I might just make a set of the standard geometry to suit the Sierra uprights and offer them up, then reposition the mounting brackets for the upper wishbone - hopefully that will work and if not, I will see what I can do from there

big_wasa - 14/1/19 at 05:35 PM

No that won’t work, the Sierra tops are shorter. So the mounting points will be in free air.

Your making hard work of this.

Make a jig as per book but make Bottom and top 2” longer to match the +4” rear axle.

The top wishbone transit drag link bush wants offsetting between 22 and 25mm instead of the 11mm in the book.

Make the bottom plates around 5mm and make them curved with no sharp edges. Use a good seamless tube or go up a size for ERW like 2mm.

It works....tried and tested....it will pass Iva.....




Dave’s vid






[Edited on 14/1/19 by big_wasa]

kevyo89 - 15/1/19 at 03:21 PM

quote:
Originally posted by big_wasa
No that won’t work, the Sierra tops are shorter. So the mounting points will be in free air.

Your making hard work of this.

Make a jig as per book but make Bottom and top 2” longer to match the +4” rear axle.

The top wishbone transit drag link bush wants offsetting between 22 and 25mm instead of the 11mm in the book.

Make the bottom plates around 5mm and make them curved with no sharp edges. Use a good seamless tube or go up a size for ERW like 2mm.

It works....tried and tested....it will pass Iva.....




Dave’s vid






[Edited on 14/1/19 by big_wasa]


Hi mate, I want to use the specs of the Haynes Roadster (Bush tubes, threaded tubes etc) but adapt to reflect the correct geometry suited to cortina uprights.

I have drawn the following upper wishbones accordingly and to scale. Would you mind having a look at these for me? You can see that the centre line is offset by 22mm as advised.

big_wasa - 16/1/19 at 12:11 PM

I don't have the book to hand to check dimensions but I would try and get the tubes as central on the bush sleeves as you can.

It doesn't make any odds what bushes you use as long as the width adds up.