RCR’s New In-house Steering Rack

[Randy Folsom]

Hoping someone has had a chance to figure out how RCR’s new in-house steering rack is installed in an LHD RCR40.

My assumption is that the center of the holes in the tub should align with the center axis of the steering rack.

If that is the case then the rack needs to stand-off about 3” from the inside of the front of the tub. There is just enough room from the inside of the tub top to provide clearance for the large jam nuts on the top of the rack and pinion box.

The mount that came with the rack only aligns with what has to be the bottom of the box. Also the rack can’t be mounted from the top because of the jam nuts.

 

[Jim B.]

this is one tip from Fran:
Biggest tip is to mount the gearbox first then shim very accurately the secondary mounts so as not to put load on the rack
Its a very high precision rack and bending or twisting will create a bind

the first time I read it I was wondering why I had to mount the graziano first

 

[Randy Folsom]

Thx much for sharing guidance. If I understand correctly, you are saying that Fran said to install the power train before the steering rack. Maybe because of chassis flex?

 

[Lee Patterson]

I think he means the gearbox of the rack?

 

[Jeff B.]

Thx much for sharing guidance. If I understand correctly, you are saying that Fran said to install the power train before the steering rack. Maybe because of chassis flex?

Mine is mounted, I’ll snap some pics tomorrow for you. Otherwise it’s probably visible in some of the videos in my build thread.

 

[Neil]

Mine is mounted, I’ll snap some pics tomorrow for you. Otherwise it’s probably visible in some of the videos in my build thread.

If the chassis flexes THAT much,....shudder.

 

[Randy Folsom]

I think he means the gearbox of the rack?

Lee,

I am a little slow. I am sure you are right and the reference to the trans was a joke.

Cheers, Randy

 

[Alex]

Looks like a nice steering rack ... hopefully the mounting is backwards compatible with the old Maval units for simplcicty .... I recently had to replace the steering boots on mine and the call with Maval started friendly until I gave them the part number, then they were basically like 'no parts/service available for those types of rack' and basically hung up on me

 

[Jim B.]

Thx much for sharing guidance. If I understand correctly, you are saying that Fran said to install the power train before the steering rack. Maybe because of chassis flex?

sorry for the confusion, I added the smiley face because I felt silly for my drivetrain thoughts. yes it would be the gearbox of the rack

 

[Randy Folsom]

I got the new RCR rack installed. I asked a friend for measurements since his car was delivered with the new rack. I found that if I had used the same measurements my rack would have been off center by 5/8”, too far forward by 5/16” and too low by 3/16”.

I measured stick-out on both sides when fully extended on each side to determine where to position the rack from left to right. I used this method because the travel extends further past the housing tube on one side as compared to the other.

I made slot shaped holes so I can move the rack back and forth a bit if needed. Measuring from the outside of the tub from the DS and front, the forward/DS bolt hole center is 6-3/8” from the side and 3-13/16” from the front.

I used a stack of 8 washers on the gearbox and 5 on the PS tube support. They are a fraction more than 1/16” thick. The height difference between the gearbox top and support is 1/4” so the stack height difference is a bit less, however the position within the pre-cut exit holes is just about perfect on both sides. There is no binding so I assume the slight difference is caused by distortion in the top of the tub.

I ordered replacement Heim rod ends to complete the assembly. I found that the provided rod ends are 12 degree misalignment which is about 10 degrees less than needed when the suspension is fully bottomed. The ones I bought are high misalignment (55 degrees). I hate to think what would have happened if I had hit a pot hole :-(

https://www.speedwaymotors.com/Pro-1-Chromoly-Heim-Joint-Rod-Ends-5-8-18-LH-Male-1-2-Inch-Hole,29763.html

The provided boots are interesting. Normally one would expect that the boot to be zip tied to the housing tube on the rack. However, the boot ID is clearly too big for that. It turns out the zip tie groove in the provided boots actually fits snugly into the exit hole in the tub. Unfortunately, the rod end of the boot is only 5/16” ID so I will have to cut them. It will have to be just a slip fit.

 

[Jim B.]

can you share your mounting measurements and your friends to use for starters? can you post a picture of the mounted rack? Thanks

 

[Randy Folsom]

can you share your mounting measurements and your friends to use for starters? can you post a picture of the mounted rack? Thanks

I need to clean up a bit. I will post tomorrow.

 

[Dominic]

Gents: I also received my "new" RCR steering rack but did not get any form of standards for the install. I have "zero" holes pre-drilled in my SLC respective to steering (it's a clean slate). I read Fran's comments about critial "shimming", "Twisting" and "alignment". I understand the importance of centering but the rack height (relative to the foot box) is not clear.? Is the goal to have a perfectly straight linkage system when the car is at a theoretically ideal ride height.? How much is too much of a variance if the estimated ride height would be off ? Should you error on the pinion being too high or too low? Does anyone have a publication for best practices.? It's not clear in the Herb Adams - Chassis Engineering book.

In addition, I understand that the steering linkage can get too close to the pedals if the rack is too low. Obviously this would be bad too.

Thank you Randy for your comments about the heim rod end angles. These are the issues that we need to work out.

 

[Joel K]

Guys,

I’m an admin over on the Superlite Owners and Builders FB page. Fran posted these install pics last week of the new rack on a GT40 and SLC…

 

[Rob Hurley]

Nice rack! Someonme was bound to say that. Cheers!

 

[Randy Folsom]

It will be a few days before I can post rack final assembly pictures. I was accidentally sent the parts bag for an SLC instead of the RCR40 (I confirmed the rack I received is the correct one).

I also sent Fran my installation positioning notes for confirmation that the rack on the RCR40 should indeed be centered in the hole in the tub.

To center the rack I positioned the rack such that when fully extended left, and then right, the extended distance of the tube ends from the tub is equal on either side. I found that using the gearbox tube ends as a guide resulted in the rack being 3/8” off center.

The center of front/left bolt ended up 6-3/8” from the side DS of the foot box.

To position the rack horizontally in the exit hole the front/left bolt is 3-7/8” from the front. I actually slotted the holes fore/aft so I can tweak the position if needed. I added steel doublers to make sure it stays put if I decide to go off-roading (or just drive in Houston).

To center the rack in the hole vertically I started off with a stack of eight 3/8” washers on the gearbox (0.55” total thickness) and five washers on the PS mount (0.28”) which works out to 0.27” difference. The measured difference between the gearbox top and PS mount top is 0.25” but the top of the foot box is not exactly level from side to side.

I checked the rack’s smoothness as I tightened the bolts. I ended up adding a shim washer to the bolts on the left hand side of gearbox to tip it up slightly on the right hand side.

The ball joints on the ends of the rack have about 1/16” shoulders and rack ends are not chamfered so the ball joints need spacer washers to seat securely. When tightening, Fran said to make sure to secure the rack’s end tubes so that when tightening the ball joint no torque is applied to the gearbox.

 

[Brian Kissel]

Randy. You say "When tightening, Fran said to make sure to secure the rack’s end tubes so that when tightening the ball joint no torque is applied to the gearbox". Are you talking about the tie rod ends on the steering rack ??

Regards Brian

 

[Randy Folsom]

Randy. You say "When tightening, Fran said to make sure to secure the rack’s end tubes so that when tightening the ball joint no torque is applied to the gearbox". Are you talking about the tie rod ends on the steering rack ??

Regards Brian

Brian,
I am not sure what these things are called, but this is what I am referring to. Don’t just put a wrench on that big nut and tighten. The tube it is going into must be prevented from twisting.
Cheers

 

[Brian Kissel]

Randy, can you please share a picture of the wheel end? Is it a heim joint, tie rod or a rod end ??

Thank Regards Brian

 

[Randy Folsom]

Randy, can you please share a picture of the wheel end? Is it a heim joint, tie rod or a rod end ??

Thank Regards Brian

Brian, I am not sure I am using the correct names. Heim, rose, rod end. Too confusing.

This is what’s connected to the steering arm. It’s got 12 degrees of misalignment with a 1/2” hole and 5/8” male treads. The safety washers and other hardware is what I had available in my parts bin. I ordered some with 55 degrees of misalignment. Those won’t need safety washers and will allow full suspension travel without risk of binding.