mrmonk7663

iTrader: (9)

Sent a PM to you Sean. Thanks.

Gee Emm

Question about poly/bronze compliance bushings in the delrin kits. Short version: why only one?

We dunnunda have been having a discussion about polys in general (aka re-inventing this thread), and the subject of alignment of bushing housing (in arm), bushing surfaces, sleeves and alignment bolts has arisen. This has highlighted the 'misalignment' as the alignment bolt is adjusted back and forth in its slots - as the arm pivots to achieve the desired alignment specs, the axis of the bushing bore in the arm ceases to be the same as the axis of the alignment bolt/bushing sleeve, thereby raising the dreaded 'bind' bogeyman. Fit poly/bronze there, and the compliance of the poly solves the bind problem, the 'misalignment' of the two axes resolved in the flexing of the poly as the arm moves.

But there are two inner bushes at each LCA-I - why is only one poly/bronze sufficient? Surely when the arm pivots, it pivots at both locations: solving the bind at one leaves the bind at the other?

There may be several answers, but two that occur to me are:

1. The friction/other nasties have been halved, so that is sufficient win.
2. The suspension arm has sufficient flexibility that it bends in response to the 'misalignment', so that the theoretical misalignment is reduced in practice to acceptable levels (so why bother with poly at all?)

Be interested in seeing any discussion of this - the question never occurred to me when I installed the delrin+4 polys in the now-defunct racecar .

If I have missed an explanation up-thread, my apologies.

dleavitt

iTrader: (1)

Any reports on how the poly/bronze bushing setups are holding up? Going to be upgrading my bushings this coming off season and need to decide whether to go poly/bronze or delrin. Poly is a bit less expensive and looks to be easier to install, so I'm leaning that direction as long as there haven't been serious issues.

Gee Emm

Happy camper here! I haven't dismantled them them to inspect, AND my kms have been low, but a recent 1k+ kms tour two-up with luggage over B-roads was a success, passenger never commented on ride, though she found the corner speeds disconcerting at first.

If it is a hard-core racer, delrin would be the bushing of choice for me, but otherwise for dual duty, especially such as my recent trip, poly/bronze would be my preference.

dleavitt

iTrader: (1)

Finally getting around to installing my bushing retrofit kit, and have a quick clarification question on the installation instructions:

"If your bushings are grooved as shown in Fig 6 and 7 it is recommended that you seal the grooves with RTV when installing the bearings into the bushings."

I'm reading that as I should basically RTV the bearings into the bushing? I'm guessing this is to prevent grease from going down these grooves, and forcing it between the sleeve and the bearing?

Blkbrd69

Well went ahead and made some spacers while car is up in air for engine replacement.

Tribal knowledge says 1/8" is 1 degree, but calculation shows .145" is .923* degrees? We will see after alignment, would like 3.5*.

I went with .145" spacers (blue) using .172" washers to reduce the .033" gap/play in system which I felt was too loose.

The large washers could very nicely be added thickness on the delrin bushings or shorter sleeves.

Recommend an option on bushings to reduce caster for track guys without power steering.

FYI If doing this make sure you have new tight nuts . Loctite isn't a bad idea either.

jspadaro

iTrader: (1)

Definitely let us know how this worked for you.

I have the same issue, I was considering ditching my elbjs for normal ball joints and seeing where I can get. If spacers work I would do it though.

yho

Hello. For the NC miata what would you recommend (trackday weekend warrior car) delrin is not available I belive
Cheers

nickalltogether

Anyone got a pic of a FUCA poly bushing that's been drilled out to 7/8"? I tried getting started on mine last night, but they look pretty rough... trying to decide if I need to scrap them or not.

duthehustle93

I don't have a pic, but I tried drilling mine out at home and had results that were probably worse than yours. Ended up taking them to work and using a really sharp HSS boring bar to turn out the ID instead of drilling and it worked great.

Librislt

Hi everyone,

new user here. My car is non-turbo, does that mean I will be stoned to death?
I was wondering if anyone has access to the file OP posted. I have tried to access it, but it redirects me to the homepage.
I would love to buy a kit from sadfab themselves, but I am on the other side of the planet, and I have access to a lathe. Plus, you know, DIY.
I have emailed sadfab, but (so far) have not received a reply. Could you guys look through your old files, maybe someone has it saved?

Thanks a million!

aidandj

iTrader: (5)

Some links probably got lost in a website transition. Everything is here on GitHub at least. https://github.com/sadfab/sadfab.github.io

KitsBeach

What are people doing nowadays for this.?

Any idea how long the SadFab waiting list is.?

And any thoughts on this competing kit.?

A1 Ground Control Nylatron control arm bushing kits

https://miataroadster.com/products/o...m-bushing-kits

Also curious about opinions on how Nylatron compares to Delrin.?

I'm leaning towards a full set, similar to the SadFab, and the spherical on the rear upper outside.

I currently have offset Delrin in my FUCA, but even one of those is binding a bit (possible installed awkwardly.?). I'm about to take it off and inspect it and see if I can get it moving better. Then I will look at all four corners and check for bind.

LeoNA

There is also the Supermiata kit. I’m running their upgrade kit with Energy Suspension bushings. I don’t have many miles on them so far, but it is better then plain urethane.

Delrin and acetal have low friction properties, are easy to machine and inexpensive. They are not exactly the same material, homopolymer vs copolymer. Nylatron is a polyamide which is your typical nylon type of material. Compared to the Acetal and Delrin it is more difficult to machine, similar frictional properties and is much better with shock loading. For this application nylon materials are better. I did not want to use offset bushings and went with adjustable upper control arms.

Roda

I recently finished installing a set, and got the car aligned, but haven't been back on track yet. Have an event in a couple of weeks.

Best thing to do is just get on the list and Sean will get ahold of you when he's ready to make them. He's a one man show, so you need to be patient. IIRC it took ~ 6 months to get mine.

KitsBeach

Is Nylon/Nylatrol better because it has a bit of give.?

I think the A1 kit has Nylatron all around, as compared to SadFab which uses a combination of bushed poly and Delrin.

KitsBeach

Your cleanup job looks nice.!

Are you doing grease zerks as discussed above in the thread.? I'm looking specifically at your front uppers.

I've taken one of mine apart (right front upper) and it appears lack of grease is part of my binding problem. Not binding badly, but not slick. I do grease them regularly and grease stops the noise. But I cannot turn the sleeve inside the delrin by hand. I'm about to pop off the ball joint and take a good good look.

Also for front uppers the placement of the grease zerk on mine is to one side and does not seem like it would get enough grease in there, given that the sleeve and bushing are say 3" long and the zerk is off to one side. Just my thought but I'll be able to check it out better once my control arm is out and on my bench.

KitsBeach

OK...I've popped off my right FUCA and ya I don't like the placement of my zerks, which seem to also be doing double-duty as set screws for my offset bushings:



I've seen this placement elsewhere on the internet (possibly from the seller of the offset bushings.?). The placement also makes it very hard to get the grease gun to stay on because it rubs up against the strengthening rib of the control arm.

Also the only movement of my control arm is between the bolt and the sleeve (metal on metal and with no grease lol). As I understand it, the sleeve should rotate in the delrin (I think that's why the delrin piece is called a bushing.!).

I'm going to try and press the sleeves out and see if I can get them moving and also check if grease is getting in to the right place. Extended zerks would be helpful (I haven't been able to find any). But I think I'll add zerks in the suggested place (which I think is pointing straight down on the FUCA...but I need to go back up the thread and check).

KitsBeach

Couple more pics to show my offset bushings (this is still right FUCA)

LeoNA

It is a bit more elastic which makes it less prone to cracking. Tough vs hard is a good way to look at it. Nylon is still much harder then urethane. Acetal/delrin crack fairly easy, I would not spec them for lower control arms.