1971 Heerey GTM Race Car Project

[roger mcnab]

hi what is the best way of fixing the mini hubs from turning i e keeping them pointed straight ahead when used on the rear like on unipower gt or cox cars as when i get to that point it will be helpful to know in advance the best solution
cheers roger mcnab

[AndyB72]

hi what is the best way of fixing the mini hubs from turning i e keeping them pointed straight ahead when used on the rear like on unipower gt or cox cars as when i get to that point it will be helpful to know in advance the best solution
cheers roger mcnab

I've fitted the Rossa Bitz kit on mine, quite over engineered but worth it in my mind. Here are some photos of his display setup I tuck when we paid him a visit...









The kits for rear discs with his handbrake kit...

[AndyB72]

Thanks All,
What with 2 kids and a job it is slow progress, but I am getting there, never built up a race engine completely on my own so engine advice from ACD has been invaluable! Once painted the progress should be a bit faster, though I am having a lot of fun doing the building up and fixing all the issues that arise.

Just noticed the Dunlop wheels in your photos, you've got to go for them. How are you for clearance at the front? Mine is very tight, it either catches the front edge of the bonnet or rubs against the tub footwell.

[GTM71]

hi what is the best way of fixing the mini hubs from turning i e keeping them pointed straight ahead when used on the rear like on unipower gt or cox cars as when i get to that point it will be helpful to know in advance the best solution
cheers roger mcnab

Roger
Look earlier in the thread and you will see my solution, not sure what Unipowers had though, something better I'm sure!
S

[GTM71]

Thanks All,
What with 2 kids and a job it is slow progress, but I am getting there, never built up a race engine completely on my own so engine advice from ACD has been invaluable! Once painted the progress should be a bit faster, though I am having a lot of fun doing the building up and fixing all the issues that arise.

Just noticed the Dunlop wheels in your photos, you've got to go for them. How are you for clearance at the front? Mine is very tight, it either catches the front edge of the bonnet or rubs against the tub footwell.

Hi Andy
My plan is to use the D1's as the main race wheels, they clear ok but I have trimmed the leading edge of the wheel arches to miss the Yokohama A032's, also I am going to machine up some restrictors for the rack so it wont rub the tub.
I also have Minilites which are going to have Yokohama A008's on for wet weather, these foul the rear wishbone as the offset is 10mm more so I will need spacers on the back for those.
Trouble is that I can't have them outside the bodywork so wheel choice is limited.

S

[rpb203]

Hopefully attached rear suspension shot of Gerry Hulford's Unipower GT race car - this one has Rose joints on the set up to allow adjustment. Standard cars didn't have the Rose joints.

[GTM71]

Hopefully attached rear suspension shot of Gerry Hulford's Unipower GT race car - this one has Rose joints on the set up to allow adjustment. Standard cars didn't have the Rose joints.

That system is very similar to the original Cox GTM set up, the issue was that the steering arm bends under load and you get rear steer.

[roger mcnab]

thanks for the info it looks like a good solid arm is the answer i might get my engineer to look at the problem and see what he thinks as this car will have a rover v8 in the tail it will need all the help it can get keep up the good work
making progress with body shape but a long way to go
cheers roger

[Lakeland997]

I'm not sure that the issue is bending of the steering arm (after all they are designed for the job of steering).

I understand the problem lies in the fact that the tie bar operates from a different pivot point to the upper suspension arm and is a different length so as the suspension rises and falls the outer end follows a different radius and so ‘steers' the rear suspension.

The Rossabitz kit eliminates this by having a tie rod that uses the same pivot point as and nominal length as the upper suspension arm.

Andy

[turbocox]

I seem to remember that this “bending” was found to be the case by Allan Staniforth, from his findings on the terrapin single seaters.

They (the terrapins) used to use the steering arms like the Unipower gt does.