Making Delrin Bushings
 

I am debating to either make delrin bushings or go with ebay poly control arm bushings. Keep in mind it is a full race car.

If I make my own delrin bushings I can offset some of them to get more camber. Currently I wear the outside of my tires and would like to get more life out of them. I can also use ultra wear resistant delrin. 2 questions

- Would I have binding issues setting toe in the rear? (no slop to skew the rear lower control arm away from parallel)
- what sleeve material/size would you guys recommend? (Just copy OEM?)

Or I go with poly?

Thanks

Binding issues both in toe in the rear and caster in the front. The $130 kit on amazon that has everything is a real fast way to fix a lot of the bushing deflection. BUT poly is a massive compromise and really shouldnt be used on a racecar since a lot of that deflection still remains. But with delrin you have to worry about the binding and also the pretty fast wear with them only seeming to last a couple seasons. Sphericals quickly gets you into thinking about how cheap delrin is, if you want them to last with $30-40 a piece for good sphericals.

If you've got a lathe and have time to kill making your own delrin can work out alright. sleeve wise, I would just go with whatever off the shelf tubing has the correct ID and cut it to length. I know some people do use poly in both lower control arm bushing to avoid the bind issue that you're worried about.

ISC Racing sells Delrin bushings with offsets already, if you want to avoid building them yourself.

I can't decide if the binding issues you might have with delrin are worse than the fact that poly is nearly the worst material in the world if you want your suspension to pivot freely without huge amounts of friction. the radial deflection is not nearly an issue as the amount of force it takes to move your a-arms after poly bushings have been on the car for a few months and all the grease becomes non functional.

Which is why you have to keep the grease from getting to be non-functional. Checking, and re-lubing mine is part of my in between race checks. Its just a hold out till I find the need to drop $1200 on sphericals.

Drill and zerk and relube?

--Ian

I can notice my poly bushings getting tight, so I add more grease :bigtu:

When I installed the polys, I added zerks. Some of the bushings in my kit (prothane?) weren't set to take grease, so I made them better...

https://www.miataturbo.net/attachmen...ine=1413864545

so lets assume the greasing is a non issue because mine will get zerks regardless of material. poly?

Performance wise delrin win. You got to make your choice, man. Poly can go a long time just needing greasing a few times a year. Delrin is like 4 times as expensive and is better than poly but only lasts a couple years. Cheap sphericals are better than delrin but are doubtful to last a year and are going to be a custom solution. Expensive sphericals are even slightly better and should last many years but again you're looking at like 10 times the price of the poly and custom. What matters to you? For me, poly is a cheap stop gap measure before getting quality sphericals.

Ive tried many different ways to zerk them. grease never goes where its needed unless you dissasemble it. grease zerks simply don't work on Poly bushings. freekin wast of time to put them in.

Agree to disagree, 95% of my polys are pre-split from the factory, and the zerk sits right over the void. Pre-cast grease channels bring it straight from the slit to where it needs to be. Mine can and will squeak, and immediately shut up once I grease them. Must be doing something...

The stock rubbers are ten times as stiff as even ungreased poly bushings. I'd bet a nickel my arms would drop under their own weight were I to remove the spindles/coils with the poly bushings. On stock rubbers, no way.

Lots of guys swear poly bushings lower their car 1/2" or so, because of the friction "spring rate" lost over stock.

can i ask how specifically you accomplished this? every implementation ive seen on a miata was set up to fail, and didnt direct the grease to where it needed to be. not saying you did it wrong, but im curious if even done correctly that its still an uphill battle.

looks like deezums answered my post in an offhand way.

did that still dosnt work. As a mater of fact Ive found much more consistant and lower friction with the surface between tha ARM and the bushing being the sliding surface instead of between the bushing and the pin. even with the slots and carfull handleing of how the zerks are installed thats where the grease ends up if using zerks anyway on 10 out of 14 of the bushings. And the greas might stay in place for a single autocross at best then it goes back to taking 40+ lbs of force just to get the A-arms to pivot. Ive measured up to 90 lbs if compleatly left alone for a season. That amount os stiction is a huge detrament to suspension performance. With the V8-roadster arms it seems to be better than stock arms but still sucks.

I don't think it’s possible to do correctly even if you think your scheme might work it won’t. Poly simply won’t stay greased and it has a high friction coefficient by itself. Makes a horrible bushing material if you desire low sliding friction. or at least an amount of friction that stays the same week to week.

Delrin at least has a low sliding friction

im trying to find pics of how i did my truck. im curious what you think, although im not sure the miata bolt size affords the ability to do it that way.

I wish sombody made Delrin ones for my V8-roadster arms.

Give me dimensions and I'll make whatever you want.

Thoughts
http://www.s10forum.com/forum/showthread.php?p=7533641
86' s15 ext cab v8 corner carver, 56k beware

The V8R arent delrin? And they dont use normal miata bushings? Why the dick would he do that? Normal miata bushings fit perfectly in a common off the shelf tubing size (1.75x.065 I think).

The V8r use common off the shelf tubing size but I haven't found off the shelf bushing for them. something Im going to look at this winter.

I might even go back to stock arms and modify the front lower to get the Camber I need. Or convert the V8-r to run sphericals some how.

I still question the strengh of the V8-R front lowers. I've cracked one set. I think the replacements they sent me used a much thicker tube in one critical spot because they got heavyer even though the outboard end has been lightened.

So you're saying I should get off my ass and finish up my indestructible arms that use standard miata sized bushings and have an option for sphericals? I'm really just a couple finishing touches on the jigs and double checking that the roll center doesnt get fucked up with the chevy lbj away from starting to make things.

Gun drilling the camber bolts won’t work on a Miata to get grease to the bushing if that is what you are showing. Plus I already torque those things well beyond spec to the point of yield in an attempt to get them to slip on a car that has huge amounts of grip running 275 A6 tires. Don't want to compromise strength of them.

I may take you up on the bushings. I will measure tonight.

that was kind of my thoughts too on the strength. on an s10, its not a big deal as they are quite over sized to begin with, and when would an s10 ever see the same kind of loads on track; when does an s10 ever even go to the track lol. the UCA bolt wouldnt be very doable just because it so long anyway.

ignoring the issue of strength, why wouldn't gun drilling get grease to the bushing? did you see how i did the sleeves to facilitate the gun drilling?

just let me know on the bushings, im sure we can work something out.

I'm curious about the significance of the binding in the lower control arms using delrin. Is it enough that I should run delrin everywhere but the LCA's? Maybe poly instead

What problems will I run into using all Delrin? No control over caster/toe?

just caster on the front. toe in the rear

the issue is that the front and rear bushing in the lower arm are in line with each other. if the adjusters are indexed the same there is no issue (camber), but as soon as they are indexed differently from one another(caster, rear toe), you are trying to make the pivot run through the bushing at an angle. with rubber, it just deflects. no such luck with something as hard as delrin. so you get both binding and much more difficult (if not impossible at a certain point) catser adjustment.

my game plan was delrin uppers and outer rear lowers and upper knuckle, and poly everything else

https://www.miataturbo.net/attachmen...ine=1413915224

https://www.miataturbo.net/attachmen...ine=1413915224

https://www.miataturbo.net/attachmen...ine=1413915224


Miata Suspension

Why have noone made bronze sleeve bushings between the clamped sleeve and the plastic?

Needle bearings inside sphericals would be stiffer and more maintenance, but I assume there are low friction bronze that would go longer between lubes than the plastic.

Why have noone made bronze sleeve bushings between the clamped sleeve and the plastic?

Needle bearings inside sphericals would be stiffer and more maintenance, but I assume there are low friction bronze that would go longer between lubes than the plastic.

Huh?

1. thats too complex and doenst do anything

2. theres no needle bearings in sphericals.

the plastic(delrin) is the bearing, no need for bronze.

and what about needle bearings.....?

The grease would end up between the bolt and the inner sleeve not in the bushing and the holes on the chassis side are slotted for adjustability so the inner sleeve is not sealed on the ends when installed. Path of least resistance grease would just come out the ID of the sleeve between the bolt and the sleeve.

sounds kind of British. I use to have a 68 Jag XKE it had needle bearing pivots on all the A-arm bushings.

when one part would do why not use 50?

yup, forgot about the slots :loser:


by dirtbikes have needle bearings in every pivot. most wear out annually, some last a few years at best.

my wifes 95 kawasaki has 1 rubber bushing- the top shock mount... its original :)

1. Introduce a proper bearing surface instead of plastic scrapers continuously transporting grease elsewhere.
The complexity of a 1mm layer in-between is not huge, if you do delrins yourself it's just different diameters to make the gap (larger demands on surface finish of the inner sleeve though)

2. adding needles inside the sphericals to reduce the friction was common in ancient F1, similar thinking as in 1, separate rotation from deflection.
But needles are not perfect for small angles.

15 year old OEM rubber is not that bad, no greasing needed and stable enough to keep alignment (which is not always true for generic poly). But the torsion spring function are often confused with friction...

I think the torsion spring effect is a much less problamatic problem than the friction level of Poly in terms of suspension performance. I think just straight mazdaspeed rubber bushings are probably better than poly for performance. fancy $4,700 set of shocks are kind of usless if it takes 40-90 lbs of bump force before thay start to move and do their magic.

Oh jesus bob, I'm rolling over here. Thank you for that :bowrofl:

I will say the only lube I have ever gotten to partially work ok for longer than a short drive around the block with poly bushings is Permatex Copper anti seize. Poly seems to repel any and all forms of grease and any movement or force squishes it away from where it needs to be. If you re-lube enough times with Copper anti seize the copper particles eventually begins to impregnate into the surface of the Poly and the friction level goes down a bit even with the absence of any grease.

I have poly on the lower arms of my Subaru. Whitelines I believe. 45k with no issues, greased once when installed. They came with a black graphite(iirc, it's in their sales literature) impregnated grease and they had relatively larger retention pockets cast into them. The rear isn't comparable to anything on a miata but the front is of the same design. Maybe it's the graphite? Maybe we should all start mixing tubes of graphite with our pivot grease lol.

Edit- I assume no issues as they havn't made a squeak. I havn't actually taken a strut off and checked for binding. Maybe I should.

<<<@!1!@>>>

I was actually thinking the same thing. But why mix when you can buy? Any lithium based grease with graphite added should work, like this

* for some reason it put that shit at the top of my post rather than quoting your post, no idea why.

Sarcasm.

That's the exact stuff I'm going to buy to lube my s10.

<<<@!1!@>>>

I’ve tried that. Takes a couple months to for the stuff remaining in areas where it might help lubricate to turn the consistency and effectiveness of caked together black dirt. I’ve had better luck with this. Mix it with Lucas Red n’ Tacky makes it real slippery for a short period of time but use it straight and it gives marginally acceptable consistent performance for a full season. It also dries out but the contact surfaces remain copper color and slide a bit more freely even after most all the gooey stuff has squished out between mating surfaces. It basically becomes a dry lube.
All my sliding surfaces on my V8r A-arms are between the pouder coated surface on the arms and the bushings. bout half the friction force I was ever able to get between the bushings and the inner sleeves and the chassis. The bushings don’t slide that well on the front and back against the chassis either.

The bushing tubes on the V8R arms are 1.5" X.095" wall. they measure a tad thicker than that I'm guessing because of powder coat thickness. all the inner sleeves I believe are 3/4" OD.

In.

This is a very interesting thread. About 6 months ago a friend and I installed Delrin bushings though-out his FD and noticed a massive improvement in car feel/feedback. We did quite a few things to the car so giving all the credit to the bushings may be a bit brash, but the NHV of the car was pretty apparent from a before and after perspective.

Can any of you all point me into more literature comparing the various types of bushings in a Miata. I am currently building an NA miata and just installed some poly rear diff bushings and it has really payed dividends in conveying information on what is happening to the rear axle to the driver, but these are not a pivotal point in the geometry of the suspension, such as LCA bushings. I would love to find a compromise in cost to performance for replacement of my 20+ year old bushings, but this thread has me second guessing my poly preference, and I would like to read any data you all may have on the subject.

i need a little more info than that
length? flanges, no flanges? flange dimensions? quantity? are you comfortable just ball parking the OD like that? figure 0.098" for wall, OD would be 1.304", or would you want to add a few thou for press fit? best bet would be to take one out and measure it.

edit- looking at the pics. there are 2 different sizes(lengths), you would need 4 of the smaller and 2 of the larger for just the lowers, they all have flanges. common sense says the flange od would be at least 1.5", they look a little larger in the pics. whats the flange thickness?

did you want uppers too?

these are the ones you have?
http://cdn6.bigcommerce.com/s-hbv2qi...00.659.JPG?c=2

maybe we should take this to PMs

Yea Id want all of them. I have a lot more measurments to take yet. iteresting thats about the 7th different design I have seen for the front lower. Different than the replacements I got a few months ago. I think they finallygot them so they dont bend at least I wish I was a little more comfortable obout them not cracking near a weld like my first set.

just send me a pm when you get all the data.

must be doing something right bending those:party:

where do they crack?

The ones he had been selling as his upgraded strength arms look like this, and they crack right next to the weld where the diagonal tube meets the cross tube.

https://www.miataturbo.net/attachmen...ine=1413998296

The last set I got as a replacement has the cutouts in the plates on the outbord ball joint end like their current pictures but they were nearly 1/2 lb heavyer I assume the tube that runs logitudinal with the car was made a lot thicker also the fishmouth of the mating tubes at the aft end was done oposite with the fishmouth put in the logitudinal tube. First set cracked in the logitudinal tube in the middle at the edge of the weld where it is welded to the short diagonal.

Whats the best material to use? The Acetal blend with 13% PTFE sounds like it would be a good choice. Slightly less stiff and lower friction?

https://www.interstateplastics.com/a...01410221158-2p

Delrin 500TL is probably what you really want, it has one of the highest strengths of the delrin options while still having some teflon in it for low surface friction, and it the strongest of the teflon impregnated delrins.

i think either one of those is a great choice.

i think we have some of that ptfe blended stuff here at work, its super silky.

delrin properties. good stuff starts on pg 7
http://plastics.dupont.com/plastics/...rin/H76836.pdf

Anybody ever played with Nyloil (https://www.interstateplastics.com/N...410221158-2p)?

From looking at the specs, I think it would be a good candidate. Plus, I have some sitting around. Looks like I might have another project to add to the list...

--Ferdi

im going to make a few bushings for myself and found this during my research
http://plastics.dupont.com/plastics/...rin/H81093.pdf

i would put us in the - delrin against metal - steel - wear - high PV - category.

100af and 500af are unicorns, and mere mortals cant get it.
"Note:
The large majority of Delrin 100AF shapes commercially available today are actually blended down to a 13% PTFE known as Delrin AF Blend. For this reason, when customers require a full 20% PTFE filler, we ask that they request material as "Full-Strength Delrin 100AF".
Full-Strength Delrin 100AF is available as a Custom-Order Only, as no domestic extruders manufacture this grade as standard. "

Delrin® 100AF - 20% PTFE (Full-Strength) Sheets & Rods - Order Online

so bob it appears the blend you chose is the best thing we are going to get without buying a large quantity of exotic acetal.

500AL seem like a good second choice with TL as third. i cant seem to find any of these. most places just sell "white" or "black" or 13% blend.

I am not a fan of poly bushings for the reasons previously mentioned but I just installed a set of these on a Porsche 993 and was impressed by the minimum stiction. The bushings seem to have an almost octagon shape inside. If you're going with poly this design works well. I would be tempted to try the same with Delrin. Less surface area creates less drag but enough to support the load.

Those are the same style as came with the v8r arms. the grooves seem to just provide an escape path for the grease to vacate from where it will do any good. I get much lower friction with the bushings sliding against the A-arm surface than the bushing sliding on the inner sleeve and against the chassis.

I've kind of measured everything as best I could without taking everything apart but I haven’t drawn everything up yet. The inner sleeves are actually 7/8" to do all the A-arms excluding the rear upper upright which I intend on using a spherical on it takes 30 bushings and there are 4 configurations used in various locations. The current bushings are about 1.8" diameter at the flange but I think 1.75" rod would work good. I figure it will take about 4 feet of material.

Still interested? I’m not sure I can make good guess on tolerance to make them work good I was kind of thinking maybe taking the A-arms existing bushings and material to a local machinist and tell him to make them so they fit right and work.

I haven't had any firsthand experience with them, but was seriously considering the superpro bushings. Not only am I a fan of MotoIQ, and they seem to have nothing but good things to say about them, I've also seen that the insides have a knurl that supposedly helps keep in the grease. Either way the article seems relevant because they're taking out Delrin to put these in.

Project V8 RX-7: Part 15 - Major Suspension Overhaul with KW Suspension, SuperPro and Improved Racing Components

In my machining experience with Delrin, I'd never consider them for a bushing, it just seems way too harsh. If you do end up making some, make sure you use sharp tools and keep them sharp. Instead of getting dull and work hardening the material like with metal, with Delrin the tool gets dull and then melts the delrin into one god awful mess.

I do think the knurls do work better than the spline groves. I've had both though and neither design was that good. The sliding friction properties of urethane just suck and when applying grease the grease quickly propagates to where it is the least useful.

did you mean to quote me bob?