Real Fiero Tech

If you do another run of bearings shells, put me down for an 88 front set.

ericjon262 wrote: ↑Sat Jan 30, 2021 2:13 am I'm going to hang onto the control arms that will be removed from my car, and use them for development of a coilover for my car, so I'll need another set of these when that time comes. if you're planning another run, mark me down for a set of 84-87 front LCA bearings/shells.

ericjon262 wrote: ↑Tue Jul 27, 2021 2:40 am If you do another run of bearings shells, put me down for an 88 front set.

Do you want two sets?

The same parts work in '84-'87 and '88. That's not even the result of any effort on my part. GM used the same bushings.

handled in PM already, but yeah, I'll need two sets.

Will, do you plan to make a press-in version? Any reason something like this design wouldn't work with the Fiero arms?
https://www.speedwaymotors.com/1973-88- ... ,9021.html

Series8217 wrote: ↑Tue Jan 03, 2023 2:14 am Will, do you plan to make a press-in version? Any reason something like this design wouldn't work with the Fiero arms?
https://www.speedwaymotors.com/1973-88- ... ,9021.html

For a press-in version, I'd have to get the OD and tolerancing right... which is probably just a one-time thrash over a narrow range of finished dimensions to figure out what fits well. In the original fit, the control arm metal and the bushing shell are about the same thickness, which is well into "thin wall" territory in stress/strain calcs. Since they're about the same thickness, they both stretch/squeeze about the same amount. The spherical bearing shell wall is much thicker than both the original stamped (spun?) shell and the control arm stamping. If the spherical bearing shell had the same OD as the OE shell, then it would have almost no squeeze and all the stretch would be in the control arm metal, which may be enough to damage it. I would need to determine what a good OD and OD tolerance would be by "sneaking up on" a good press-fit via multiple fit-check mock up parts. This would only have to be done once per "K-number".

Another other factor with press-in shells is that they have to have the correct axial separation to engage the body attachment points. The front body attachments are all just cheeks that aren't very stiff longitudinally, so some mismatch is tolerable. The '84-'87 rear cradle is much less forgiving. The OE bushings being rubber just accommodate the mismatch. If there's mismatch with a spherical bearing, even if the body attachments flex, there's static axial load on the bearings. I don't know if this would be enough to be a factor in bearing life or not. I could probably solve this with a laser cut template; the installer would press one shell in all the way, then press the other one in until the template was a bare slip fit between the two shells. That would work on the '88 front and '84-'87 rear. It might not work on the '84-'87 front because the pivots are not coaxial.

Also pressing shells in and out of control arms without mangling the arms is somewhat fussy. I'd have to make a press fixture/mandrel kit that I'd rent with each shell kit sale in order to make sure the customer had the right tools to get it done... and then I'd risk becoming tech support for the ones who smash their control arms anyway.

It just seemed like it was a lot more trouble than the ability to install without a welder was worth.

Why? Is there a sanctioning body you'd like to run in that requires press-in bushings?

I hadn't considered the axial tolerance issue for a monolithic control arm with two bearings. Makes perfect sense. The ones from Afco above are for a single link rear control arm.

I suppose you could supply a kit with undersized spacers and a set of shims to align a control arm to a specific subframe.

The Dark Side of Will wrote: ↑Sat Jan 07, 2023 11:36 am Why? Is there a sanctioning body you'd like to run in that requires press-in bushings?

Nah, just for ease of installation.

The control arms are made of stamped metal, and I didn't want to bend them pressing out the stock bushings. This is the method I used to remove my stock bushings without much trouble.

First, I heated the outside of the stock bushing shells to heat the rubber and make it pop out, just as with a normal polyurethane bushing installation.

I made some thin cuts with a cutoff wheel in the flanged area, which otherwise makes the stock bushing shell stronger.

I applied heat to the inside of the stock bushing shell. I used a 40000 Btu/hour propane torch.

With the shell hot and softened, I bent (the area with cuts) the stock bushing shell flange flat.
Then, my objective was to deform the stock bushing shell into a heart shape.

Still with the aid of heat, I made the heart shape by using pliers to bend the ends of the stock bushing shell. I also used a chisel and hammer to smash the side of the stock bushing shell inwards.

A removed stock bushing shell:

Very interested in seeing how your setup comes out with drilling new mounting holes for the stock control arms with these spherical bearings. I may be interested in a set myself.

zok15 wrote: ↑Tue Mar 07, 2023 1:16 pm Very interested in seeing how your setup comes out with drilling new mounting holes for the stock control arms with these spherical bearings.

I don't really know what I'll be able to conclude about that.

I'm doing a bunch of things at once (wheels, tires, bigger brakes, rear coilovers, stiffer front springs, sluppy123 front hubs, poly for front UCAs, Will's spherical bearings, front LCAs and steering rack moved a bit, RD zero-lash sway bar links), so I'll only really have general driving impressions of the new car, without being able to isolate the effect of a specific modification. Right now it's nearly bone stock (except for poly in rear control arms) 85 SE suspension, complete with cracked rubber bushings and 215/60R14 Radial T/A tires.

There is some logic to incrementally modifying a car and seeing what each mod does, but I think you can get stuck in a local maximum of performance doing things that way, versus jumping right to where you think you want to be.

I mostly mean that I am curious to see if you can dial out the pro-dive geometry and control bumpsteer with the stock control arm geometries. Because my other option is to make some custom control arms, and I was planning to do this to use heim joints, which being a smaller size allows more anti-dive to get dialed in, especially when it comes to limitations raising the rear pivot.

But if I can get away with spherical bearings in the stock lower control arms and simultaneously not rotating the entire crossmember (which I do not want to do) then it seems like a good direction to go in. This is assuming that I could still get a set of these spherical bearing shells from Will.

I don' t think Will has any available, pretty sure he only made enough for the people in the group buy, I have them in my car, but the front end also has anti-dive spacers installed to rotate the front subframe. I'd kinda like to redo the front end, and make a custom setup, and incorporate better (lighter) brakes, and better front bearings.

zok15 wrote: ↑Thu Mar 09, 2023 2:04 pm This is assuming that I could still get a set of these spherical bearing shells from Will.

ericjon262 wrote: ↑Thu Mar 09, 2023 2:16 pm I don' t think Will has any available, pretty sure he only made enough for the people in the group buy, I have them in my car, but the front end also has anti-dive spacers installed to rotate the front subframe. I'd kinda like to redo the front end, and make a custom setup, and incorporate better (lighter) brakes, and better front bearings.

I have every intention of doing another run this summer.

When I install my set in The Mule, I'll remove the crossmember wedges and assemble with stock geometry. I'll do this in order to try to measure the eccentricity that these run in that suspension in order to have a number to use when looking for seals that can handle that eccentricity.

Once I get that, I'm going to try spacing the crossmember "flat" rather than rotating it. That will increase the eccentricity in the spherical bearings, but... they're spherical. As long as the spacers don't hit the shells, they'll be fine.

The big problem with rotating the crossmember is that pretty much all the caster goes away. The mod is very effective at what it's supposed to do, which is reduce pro-dive. The car feels MUCH more confident under hard braking. Steering feel is trash, though. Getting caster back requires custom and/or fully adjustable upper arms, which are difficult to package elegantly around the spring perch.

Spacing the crossmember down "flat" will keep caster intact and reduce pro-dive. I'm not sure how the reduction in pro-dive between rotating and spacing will compare, but I'll try it and see.

That is an interesting concept, I have more of an inclination to chop into the frame to allow moving the rear pivot up as much as possible, but I guess lowering the subframe without pivoting it would maybe prevent you from having to do anything with the steering rack for bumpsteer reasons. I do want to make new pivots for the upper arm as well to help with camber gain/roll center, this may cause enough change to require repositioning the rack anyways for bumpsteer reasons.

So I am interested to see how Patrick's setup goes even with all the additional mods.

I have 2" Street Dreams lowering knuckles, so raising the car an inch with anti-dive spacers, then lowering it 2" with knuckles should put it at a fairly sane ride height.

I'm thinking that once I get my '88 knuckles in the Storm Trooper for testing, I'll set up a version for the early cars. The '88 tie rod end is in the wrong place for the early car rack, but I should be able to make a version that would both reduce the scrub radius and set the kingpin angle to what the '88's use, while moving the tie rod end to work with the early car's rack placement. Of course that will move the hub flange inboard like 2 inches, so I'll need to make +2" control arms. That extra 2" will make packaging coil overs outboard of the original spring perch/bump stop without cutting the crossmember much easier. I'll have to noodle how to implement an adjustable upper arm for a bit, though.

So I've been shopping around for seals, and I came across these (they look like they fit the bill):

American High Performance Seals
HRO
High misalignment, single-lip oil seal
https://ahpseals.com/product/hro/

I might want to request a quote, but I would like the design dimensions if possible, as the fill form requires that. Of course, I have measured the parts of my kit, but that is not as accurate as knowing the original design intent.

Will, can you share the housing ID and shaft OD dimensions+tolerances?

Maybe you would like to do the inquiry instead if you don't want me intruding in your project?

pmbrunelle wrote: ↑Thu Apr 20, 2023 5:24 am So I've been shopping around for seals, and I came across these (they look like they fit the bill):

American High Performance Seals
HRO
High misalignment, single-lip oil seal
https://ahpseals.com/product/hro/

I might want to request a quote, but I would like the design dimensions if possible, as the fill form requires that. Of course, I have measured the parts of my kit, but that is not as accurate as knowing the original design intent.

Will, can you share the housing ID and shaft OD dimensions+tolerances?

Maybe you would like to do the inquiry instead if you don't want me intruding in your project?

Installation bore: 1.375 +/- 0.005
Shaft OD: 0.750 +/- 0.005

I did find a place to ask about eccentric seals. I don't recall if AHP was the place and my GMail-Fu must be drained from working with Google Sheets this week.

The big question they asked that I couldn't answer is how much eccentricity the seal needs to deal with.
I was expecting to install the shells in my control arms and reassemble The Mule's front suspension withOUT anti-dive blocks--that is, with stock geometry--to measure the eccentricity the design requires.

If your front suspension is assembled with stock geometry and you have the shells installed, you should be able to take the measurement.
Eric could too, for that matter.

Shaft OD was pretty bang-on, around 0.7495".

Installation bores measured between 1.375" to 1.377". The wall of these parts is thinner, so less solid than the shafts, so I am not surprised that there is more variation here (some out-of-roundness).

If you took measurements of these dimensions, do my measurements agree with yours? I was using a slide caliper (new enough with little use/wear), so while OK, not the best of measuring tools. I had shells 9 thru 12.

I think that +/- 0.005" is perhaps a lot of variation for a seal with a pressed-in steel outer ring.

If we order a seal, perhaps we can have one made that is just 0.001" bigger than the largest installation bore that was actually produced, assuming that the produced variation was less than the drawing tolerance.

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Right now the crossmember is out of my Fiero, but I haven't hacked it up yet with modified pivot positions, so in principle, I could put it back into the car, and then measure the misalignment.

I guess I'll focus on getting this measurement for the stock 84-87 Fiero first.

It wouldn't make much sense for us to open parallel inquiries for the same item at a given vendor.

I'm not sure my car is a good basis for comparison, mainly due to the anti dive modifications.

pmbrunelle wrote: ↑Thu Apr 20, 2023 10:25 am Shaft OD was pretty bang-on, around 0.7495".

Installation bores measured between 1.375" to 1.377". The wall of these parts is thinner, so less solid than the shafts, so I am not surprised that there is more variation here (some out-of-roundness).

The shaft was just 303 SS bar stock.

I didn't have any problems installing seals in the shells in my '88, despite not checking installation bore any more precisely than with calipers. Seals are made from formed sheet metal. Per the measurements, they have a lot of 'interference" but because the seal rim is formed sheet metal, it squeezes a LOT more than a solid ring would... Unless the MFGs documentation with the seal gives installation bore tolerances, +/-0.005" should be fine.

pmbrunelle wrote: ↑Thu Apr 20, 2023 10:25 am
If we order a seal, perhaps we can have one made that is just 0.001" bigger than the largest installation bore that was actually produced, assuming that the produced variation was less than the drawing tolerance.

********************************************************************************

Right now the crossmember is out of my Fiero, but I haven't hacked it up yet with modified pivot positions, so in principle, I could put it back into the car, and then measure the misalignment.

I guess I'll focus on getting this measurement for the stock 84-87 Fiero first.

It wouldn't make much sense for us to open parallel inquiries for the same item at a given vendor.

I don't think ordering a custom seal would be a good idea.

I don't recall if AHP was the vendor I asked or not. It's also been >2 years since I was asking that question. YTF can't I find that email chain?

ericjon262 wrote: ↑Fri Apr 21, 2023 9:47 pm I'm not sure my car is a good basis for comparison, mainly due to the anti dive modifications.

I'm expecting that I will temporarily remove mine to make the eccentricity measurements, then either put the wedges back or try flat spacers.