midget rack

cadreamn67

Platinum Forum Member
Messages
608
grelley,

Thanks so much for posting the pictures.

I still need a some help in understanding the mods and what you had before making things so much better. Candidly, your current setup seems to be very similar to mine (which followed the tigersunited Ackerman Angle tech article, except for the Mobil I grease).

Respectfully, the difference I see is the spherical joint instead of the Alpine tie-rod end. Like mine, the ball joint is attached to the underside of the steering arm. Were yours on the top side before?

Did you switch the steering arms so the one marked "Left" is now mounted on the right side and the one marked "Right" on the left side?

If I understand it correctly, you machined a shim of some sort to fill the tapered hole in the steering arm so that a straight bolt would fit firmly into the tie rod attachment end of arm. If so, how were you able to replicate the taper angle for the "shim" part you made? It is a pretty odd angle as I remember reading once.

Now I am going to go out on a limb. I cannot help but wonder if you would get even better results if you were to put the spherical joint on the top side of the steering arm? Would that make everything more horizontal with the rack in a static, at rest, wheels on the ground mode? If so, that might minimize the change in toe-in caused by a wheel moving up and down. At least equalize the effect whether the wheel is going up or down.

I am nowhere close to being a chassis engineer, so my apologies for even suggesting something I know nothing about! But if it did help things, you would be taking the MG rack conversion another step beyond what any of the rest of us have.

Regardless, I, for one, greatly appreciate your work and your sharing it with the rest of us. Thanks for doing that, and for any additional info you can provide per the above.

Gene
 

grelley

Silver forum user
Messages
70
Midget rack

Re the taper for the bush, I measured the dia at the top and the bottom of the taper and the thickness of the arm and then drew it out. I calculated the taper to be 6.08 degrees included angle. I then machined a taper on a peice of bar and made minor adjustments until the taper was a good fit,then bored it to 7/16". I have since rechecked the tightness and it has remained firm.When I got the car the arms were fitted so that the ball joints connected from underneath. This gave excessive toe out on rebound. I thought I had fixed it by swapping the steering arms over and fitting the tie rodes from the top, but they fouled the wheel.
If the steering arms were mounted with the widest part of the taper down I couldnt get the end of the tie rod high enough to get the required angle. By reversing the tie rods, this lifted the ends of the steering arms to give me sufficient height to get the correct angle, albeit with using rod ends and shimming them down .200"
Hope that makes sense.
Regards
 

cadreamn67

Platinum Forum Member
Messages
608
grelley,

Thanks for the additional detail. I think I get it now.

My cross-member is off my car right now so I went and looked closer at the MG steering arms. I see that the steering arms bend away from the center-line of the two mounting bolts, causing the tip to be either above or below that center-line, depending on how they are mounted.

You must have yours steering arms mounted with the end angled up. That would put the bigger part of the tapered hole for the tie rod on the top side. You filled the hole with the tapered adapter plug and attached the spherical rod end on the bottom side of the steering arm. The .200 inch shim goes between the bottom of the steering arm and the top of the spherical rod end.

I see the spherical rod end has a male threaded shaft. Your adjuster link to the rack end looks different from the one I got in Dale A's kit. Mine has a male threaded shaft to fit into the female end of an Alpine tie rod. Did you also make your own adjuster link with two female ends? Do you have to disconnect the spherical rod end from the steering arm to make toe in adjustments?

Gene
 

grelley

Silver forum user
Messages
70
Hi Gene, yes that pretty much sums it up. I made up a new link. It has a 5/8 F/M RH thread on the inner end, and a 7/16 L/H female thread on the outer end allowing adjustment of the toe in place.
Regds
 

cadreamn67

Platinum Forum Member
Messages
608
grelley,

Thanks again. I think you have come up with a great improvement to the original MG rack conversion. You also have skills, and equipment, way beyond mine!

BTW, it occurred to me If I were to try and replicate your design, maybe I could make a "filler plug" out of the tapered shaft from an old tie rod end. Just cut it off and somehow drill a 7/16 hole in the center. The metal may be hardened, but if it was heated hot enough with a torch, maybe the hardening would "relax" enough to make drilling easier. Just an idea.

Last question if I may: Is there a brand and part number of the rod end you used? I seem to recall that they come in all sorts of load ratings, teflon bearing surfaces or not, etc.

Thanks again for sharing all you have already.

Gene
 

grelley

Silver forum user
Messages
70
Hi Gene, I am sure any half competent machinist could reproduce the tapered plug. Take a steering arm and a tie rod end in to them. As I said, the taper is approximately 6.08 degrees.If you do get some made, make sure they sit below the surface of the steering arm at the narrow end,so they dont bottom out, and proud of the top surface so that they can be tightened sufficiently. I am not sure of the brand of the rod ends I got, they are teflon lined, but to meet NZ approvals they cannot have a grease nipple hole in them.
Regds
 

0neoffive

Gold forum user
CAT Member
Messages
2,853
I am not sure of the brand of the rod ends I got, they are teflon lined, but to meet NZ approvals they cannot have a grease nipple hole in them.
Regds

OK, I'm curious! Why can't you have a grease pip in NZ ??
 

66TigerMK1A

Gold forum user
Messages
1,129
I'm using the Pinto ones from Speedway... they are 7° and I had to turn them on the lathe to adjust the taper a bit as it's closer to 6° as stated above...
They're actually quite long although I'd hate to get too far away from the steering arm as the stress on it would go up big time!!

Pretty reasonable at $9.99 per .. I'd hate to have something made from scratch $$$


Jim
B382000446
 

grelley

Silver forum user
Messages
70
Re the grease point, I am not sure, but perhaps a weak point? We have plenty of people in New Zealand to look after those of us they perceive unable to look after ourselves. We have very strict rules and how vehicles can be modified. It almost came to be that you were not able to modify any road registered vehicle, similar to Australia.
Those bump steer kits would be good, but need to fit the other way round in my case. That is basically what I have made up.
Regds
 
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