Jason's Coyote Powered RCR40 Downunder

Fran Hall RCR

Moderator
GT40s Sponsor
New borns are the easiest time ....

As parents we cant wait for the kids to start walking and talking.....and then we spend the rest of the time trying to get a word in edgeways and running after them....Its the best job in the world.
 
Last edited:
Hi Jason,
Congratulations on the baby girl,
So you and your wife are happy now....
Your car is looking great, the engineering work that you have put into it, fantastic...
I don't think I would of been up to it.
I will have to have a look next time I am in Melbourne.

Neil
 
RCR40 Sway Bar Kit For My Car

I received some more back ordered parts for the front and rear sway bar kits today for my RCR40 (thanks RCR Australia for passing them on to me). However I have a few questions (the pictures may make things clearer).

Firstly there still appears to be some parts missing :sad:



a. Pair of drop link bars.
b. Bolts and nuts for the steel arms to tighten them onto the roll bars.
c. Bolts and nuts to connect the heim joints to the 4 arms
d. A pair of bushing blocks for the speedway solid roll bar.

I think that is it, possibly someone could confirm this as I have no parts list.

Regarding the parts I received I also have a few questions:

1) Can someone tell me which roll bar is for the front and which is for the rear. I’m assuming the solid wider bar (black with steel arms) is for the rear but I’m just making sure.



2) Why is one set of arms steel and the other alloy? Is it a strength requirement thing?

3) Is it possible to find out the rating for each of the roll bars supplied?

4) Are the drop links supplied for the front or rear roll bar?

5) I cannot see how the straight arms can be fitted to the RCR 40. Even the instructions for the front sway bar fitment in the RCR online build guide show a different kit to what I have and with bent arms to reach the lower suspension arm. There are no instructions for the rear kit to assist in the fitment. Can I get some information from any current owners please? My car has a Ricardo gearbox and +2 rear arms. I cannot see how these parts will fit and I would love a little help. Even a few pictures would be appreciated at the least.

6) The bushing blocks for the hollow bar are not a very tight fit on the bar (bar OD 28.5mm, bushing ID 28.9mm). Will the roll bar rattle in the bush?



7) The alloy arms have mis-aligned splines. When fitted to the roll bar the two arms will not line up properly (I have not positioned them on the wrong spline). It looks like the broached splines in the arms are not the same. The image below shows them fitted on one spline so its not the bar. Can anyone suggest what can be done here?



Thanks in advance.
 
Last edited:

Ron Earp

Admin
I don't know about the other stuff but I've experienced point (7) before with other (non-RCR) roll bars. Point (7) doesn't matter because you will have (should have) adjustable links with heim joins on them that can be lengthened or shortened at the twist of the center coupler. This will be used to compensate for the slight difference in arm position.
 
Thanks for the help guys.
I have tried turning them over, it does not help (thanks for the suggestion though). Also, for the front kit with the alloy arms the short length of the links that are used (see below from "Keith's RCR GT40 Mk I Build") means there would not be enough adjustment to allow for the manufacturing error in the arms and still provide enough even preload adjustment.



This coupled with the difficulty in bending the alloy arms with the holes already in them (bending the alloy will be very difficult anyway) has led me to believe it's probably better to get another solution. RCR has graciously agreed to take them back if I do not want them.
 
Last edited:

Rob

Lifetime Supporter
Hi Jason,
I'll back up the rear pan link must be on top side of the mounting tab. I had no issue assembling mine that way. It is very close though... I placed the heim in place, then put the bolt through.
 

Attachments

Thanks Rob, tried again today, definitely wont fit. Must be a manufacturing tolerance issue and yours are on the good side for this. I will just need to change the RCR bracket out for something else. Thanks for checking though.
 
Robs Heim joints are a different breed to yours Jason, probably a dimensional difference between makes that is preventing fitment.

Should never have got past QC @ RCR . Faili F would never have let that out the door!!:)
 
Re: Jason’s Australian Supercharged RCR40 Build - Temporary Coil Over Replacement

Ah, yest they are Jac Mac. I did not notice that. Oh well not to worry.


Temporary Coil Over Replacement

To assist in the setup of the suspension I made some small adjustable links to replace the coil over shocks today. This means I can setup the suspension in the air exactly as I want it and when I drop it on the ground it will hold the final position independent of the load as I build the car. I really did not want to have to compress the suspension with sand bags or ties etc (yes I am that lazy). I was very careful and made spacers to simulate the the lower rear heim widths on the coil overs so that the geometry does not change when the coil overs are put back on.



Also ripped the engine and trans out today to do some chassis measurements, every time I pull it out I freak out at the size of it!

 
You could always turn a bit off the head off the bolt its fouling on, dont know if that would compromise your ADR's etc, I better be careful or Fran might have to double my trouble shooting allowance for the Greater Pacific Basin!!:)

& before he says it --2 x 0 = 0, yeah I know!!!!
 
Jason
Do the steel arms happen to have the same spline as the aluminium ones ?
If so i would use the steel ones on the front bar. This arms you could bend like shown in Keiths thread. There is no way you could bend the alu ones without compromising there stability.

The mounting blocks for the speedway bar is a plain 2 piece alu block (they will be mounted without bushings)

TOM
 
Hi Eglitom, unfortunately the splines are different sizes. I was told to bend the alloy arms but I don't think it will work. They may crack or be structurally compromised. I'm going to look at alternative local setups next week and hope I can get myself out of trouble. RCR has been good and said I can return them if its not going to work so all is OK :thumbsup:
 
Suspension Setup - Datum Bars

I have begun to attempt to setup my suspension as close as I can to enable the fitting of the body and flares.



I wanted to understand any misalignments in the chassis before I started setting up the whole car so I decided to setup two very straight steel angle bars on either side of the car. I want them exactly parallel, level and distanced evenly from hard points measured on the chassis. Determining the points to base the bar positions from became tricky.

ALIGNING THE BARS TO CREATE A VEHICLE CENTERLINE

To align the bars along the sides of the car I was able to measure from the top of each fuel tank side pod at the front and the rear. Measuring out 16mm at the rear and 20mm at the front gave me two parallel bars spaced at 1680mm. The two tanks have a taper to the front of 4mm per side. Not the end of the world, just worth noting.




The position of the rear of the steel angle was also checked to the upper heim joint bolt marked "D" below. I chose this point as it was a critical and accessible main mount position that should be correct on both sides of the chassis. This suspension point lined up very well left (550mm) to right (549mm). Dimensions were also taken from the inside of the tanks, as above a good result here. This reinforces the position of the steel angles with the centerline of the chassis. The centerline lines up with the RH inside edge of the alloy tunnel tube, pretty good really.



Checking that the angles were perpendicular to the rear cross member resulted in a good pass result also. The front face of the chassis (face between A & B) is also perpendicular (within a few mm) to the steel angles. Basically the front face and rear "horseshoe" are parallel which is great.

However the front alloy chassis box at "A" (where your feet go) is "parallelogramed" by 5 mm to the RHS of the vehicle (looking from behind it). This did have a slight affect on the suspension settings. I was wondering why the two metal angles were originally skewed to the RHS of the car, it was caused by taking measurements from the front top edge of the chassis at "A". The image below shows pictorially (exaggerated) what I mean. The bottom chassis plate was aligned perfectly.


ALIGNING THE BARS IN THE VERTICAL PLANE

In order to set the bars up vertically a level bar was placed on top of the tanks through the passenger compartment and in the engine bay (with the engine removed). This did show that all surfaces were level with one point worth noting. The top of the LHS tank drops by 5mm at its extreme edge.



This occurs only on the LHS along its full length. 5mm spacers are placed under the LHS steel angle and I now also have a vertically level plane. This top plane based on the top of the tanks was compared to the bottom chassis plate. At the rear the LHS of the chassis plate sits 2mm lower than the right, a pretty good result. Measurements at the front show it to be level.



With the bars held firmly some checks were made on some chassis features with the following results:
1) Both tanks are 1565mm in length
2) Base of the RH A-pillar (where the door hinge attaches) is 7mm further forward than the LH one.
3) RH top radius arm mount (near the firewall) is 3mm further forward than the left.
4) Rear edge of the top of the tanks is the datum for me to set axle distances etc.

Overall the chassis has a few dimensional "characteristics".

With two parallel bars aligned to key chassis features I can begin to setup the suspension.
 
Last edited:
Jason, I hope you have the front of the tub clamped to your lift platform, with all that rearward weight bias of engine / trans it wont take much to exceed the point of balance and end up with the whole deal on the floor.
 
Suspension Setup

I have chosen to setup the front ride height as 108mm (4.25") and the rear 127mm (5"). Too low anyone?

Front and rear castor was set to 6 degrees, camber rear 1 degree and is at 0 for the moment (will be set to 1.9 later). Front and rear toe in is about 1.5mm. I will set all these accurately during a professional alignment later as it will all be coming apart for painting etc. anyway.

After a lot of work the suspension was set. A lot of fiddling, I hope I do not have to start from zero again as now that I'm very close small changes are easy to make.

One thing that concerned me slightly was the wheelbase, I believe the original had 2403mm (94.6"). In order for the front wheels to clear the chassis when turning and with the rear radius links almost as short as they go I could only get as short as 2408mm (94.8"). I' sure this will not cause body fitting issues.

Some issues that hopefully are not problems:

1) Front lower arms look quite "angled up", I believe they should only be 3-4 degrees, maybe something is set incorrectly? The lower angle may be for cars with lower profile wheels, not sure.



2) I had to move the upper ball joint locking nut between the arm and the joint to dial out excessive positive camber. I think I have seen others do this as well.



3) Rear radius links for the +2 kit are quite long, I really have no adjustment to make them any shorter without shaving them a little shorter.

All in all a good day adjusting all the suspension and watching the Australian Indycar race!

Next step is to drop the car on the ground and double check clearances. Then source some anti-roll bars and assemble those.



Engine & trans back in ready for the next job.

 
Last edited:
Pretty sure you have that top w/bone outer lock nut wrong Jason, that will be a threaded sleeve in the alloy w/bone which requires jam nut on outer side in order to tighten properly. Think you may have to adjust rod ends at lower w/bone inner points to acheive settings you require. My thoughts are its too low at front, but others with lots of RCR knowledge should be able to help.
 

Randy V

Admin
Lifetime Supporter
Suspension Setup

I have chosen to setup the front ride height as 108mm (4.25") and the rear 127mm (5"). Too low anyone?

Front and rear castor was set to 6 degrees, camber rear 1 degree and is at 0 for the moment (will be set to 1.9 later). Front and rear toe in is about 1.5mm. I will set all these accurately during a professional alignment later as it will all be coming apart for painting etc. anyway.

2) I had to move the upper ball joint locking nut between the arm and the joint to dial out excessive positive camber. I think I have seen others do this as well.



3) Rear radius links for the +2 kit are quite long, I really have no adjustment to make them any shorter without shaving them a little shorter.
http://www.gt-forty.com/GT-Forty/Suspension.html

I had similar findings with settings quite close to yours...

I preferred to set my ride heights to have the lower control arms level to the ground.

Your wheelbase is literally identical to mine after I aligned the front and rear suspension.
My body lines up pretty well I think.









I like the work you're doing.. Very thorough!
 
Top