As I hinted at the end of the last video, I'm working on the front suspension and it is slow going. It's a lot of sitting and staring, some measuring, short spurts of fabrication or modification, then more sitting, staring, waiting for parts. To add to the delay I made a stupid mistake with the steering rack, causing me to have to order a new rack from overseas. So I'm editing as fast as I produce footage but it will still be a quite a while before the next Cosmo video.

 

Well the holidays approach, hopefully Santa brings you all the goodies you need.

 

I'm back on track with the steering rack but the next few weeks are weird as we all know, due to spotty business hours. I may need some parts machined sometime next week which I doubt will happen as the machine shops basically take the last half of December off. But I am getting closer to having the front end basically done to the point where I can move on to the next task.

It's traditional for me to release a video on Festivus and this year the tradition will be followed.

 

you must include the festivus aluminum pole in your next video
love your videos.

 

Unacceptable.

 

Sadly the video has already been edited and uploaded, so it's too late for an aluminium pole.

 

Bummer

 

Lol taken the Rotor virginity of that girl :p

 

I know it's been a while and since the front suspension work is still ongoing, I've decided to split it up into two episodes. So for part 39 of my '76 Mazda Cosmo restoration, I begin the work of updating the front suspension and converting the car from recirculating ball steering to rack and pinion. While my original goal was to mount the entire FC RX-7 front subframe, it became obvious very early that was not feasible. Instead I began combining parts of the RX-7 suspension with the Cosmo suspension to create a unique solution. Once the basics were laid out, conversion to rack and pinion steering began utilizing a NA Miata steering rack. And then I hit a silly, obvious snag...

 

Is it possible to get a RHD miata rack, and flip it up side down? I'm having difficulty picturing how the gears would be spinning.

 

Hey ummmm, you may have already caught this as well, or maybe not, but you do realize that the lower ball joint mounting location on the knuckle is not exactly parallel or on the same plane as the the wheel bearing relative to the lower strut mount on the knuckle.

That hole being offset affects the way the car "Jack Steers" due to the Steering Rake Offset that was designed into the knuckle, so swapping them from left to right will, put simply, reverse the geometry. Hope this saves you some headache.

 

Winner winner chicken dinner! That's exactly what I did. An RHD rack spun to LHD.


I gave you a detailed answer to in reply to your comment (I am guessing it was your comment) on the YouTube. Short answer here is that I will heat the knuckle and rotate the outer tie rod mount until the angle is the same as it would be if front mounted.

 

Hey Aaron, I guess we should probably move the convo here since it's probably more fitting. I'm too lazy to go grab a pic of a FC Spindle but let me try and illustrate w/ MS Paint what it is that I'm talking about:



Now this isn't by any means an accurate depiction of the knuckle for FC's, but what I'm trying to show is that the lower ball joint is at an offset from the "Center-Line" of the Strut Mount Location and the Spindle.

Actually, if you get down to it, what IS ACTUALLY offset is the spindle itself. With that you get Steering Jack from what I just fount to be reffered to as Longitudinal Hub Offset.

From my findings however, it seems that moving the spindle forward/aft has no detrimental side-affects BUT it does change the way the car handles.

Suspension upright design - Forum - F1technical.net

 

I have started working with my nr 2 Rx5 now.
Mainly because of your videos !

Thanks for your effort!

/ Magnus

 

Yay! I'm always so excited to see new updates on this build.

Slightly off-topic, but still related to custom builds and fabrication; Have you ever heard of Project Binky, the Mini with the 3S-GTE engine and AWD system from a Toyota Celica, being chronicled on Youtube? I think you may find it interesting (if you haven't seen it already). There's plenty of welding and grinder ****, along with brit humor.

https://www.youtube.com/watch?v=7hCPODjJO7s

 

Hahahahahahahah. That **** right there just made my day. Like one of them bicycles at the fair.

 

Ah, that's what you are referring to. It does seem that the RX-7 ball joint is slightly offset to the rear in stock orientation, and thus offset to the front when reversed. It's something I will have to research further but my quick checking seems to show that I shouldn't see any negative effects.

Keeping all the angles straight is a hell of a mental exercise. What I said about the tie rod angle is totally wrong. Of course if I swap them left to right and rotate them 180 degrees, the tie rod flange is at exactly the same angle to the rack as it would be in the original setup.

I look forward to following your project.

I've know of the project and it's on my long list of things to watch. Just now, finding the time to actually watch these things is an issue.

 

In episode 40 of my '76 Mazda Cosmo restoration, the front suspension is finally finished. This time around I concentrate mainly on steering, completing the Miata rack installation I started in part 1. As I alluded to last episode, there was an easy fix to my rack dilemma; a right hand drive rack which when spun to left hand drive becomes a rear steer rack. With that hurdle out of the way I fabbed up the mounts to adapt it to the Cosmo subframe, figured out the inner tie rods, and then built the steering shaft and related machinery. Steering sorted, the next task was to mount the RX-7 struts in the Cosmo strut towers. The suspension is then completed with the reinstallation of the Cosmo stabilizer bar. This episode runs a little long but I wanted to get everything done, so pour a few drinks and enjoy.

 

First! Suckers...

 

I cant wait till its complete and running. I need to see the final product. Excellent series for sure.

 

Impressive as per usual.

If anyone wants to see an example of bad bump steer, look up and watch the Wheeler Dealers episode that covers a Ford Popular Hot-Rod. The front suspension and steering was poorly engineered, resulting in very dangerous bump-steer. Edd China gives some good illustrations as well along with how he ultimately fixed it (swapped in a front suspension from a Jaguar XJ8 and narrowed the subframe and anti-ollbar to fit).

 

I'll have to look that up. I'm not familiar with that show as it doesn't seem to air on any channel in Canada but I'm sure it's finable.

Interesting you mention "popular ford hot rod". At AutoRama yesterday I was taking a close look at steering geometry and I have to believe that fully 50% of what I saw would bump steer like mad. For that record, I saw a lot of cars with up to 5 steering u-joints, some unsupported.

I forgot to mention in the video that if I need to move the tie rod down to be a little more parallel, an S13 outer rod end does the job. Same thread and taper, but the socket for the inner rod doesn't move up like the FC end. The rod mounts level with the ball, unlike the FC end that mounts level with the taper.

 

"Wheeler Dealers" is a UK car show. The show's two hosts buy, repair and sell (for a profit) classic cars.

http://en.wikipedia.org/wiki/Wheeler_Dealers
They're able to succeed with making a profit as one of the hosts, Edd China, does the bulk of the labor in diagnosis and repair. Mike Brewer, who handles purchasing the cars and sourcing parts nad services, is also careful in what car to purchase.

They've also done an episode using a '95 FD. You might or might not like the changes made to the car's appearance, but otherwise they did right by the car.

 

Hey, I went there today.

 

Nice work , going to forward info to my buddy who is a fabricator and works on old school toyotas I know he will love this .