bbundy

<<<@!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.

bbundy

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.

ericwh

iTrader: (1)

In.

90civichhb

iTrader: (5)

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.

hi_im_sean

iTrader: (3)

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?


maybe we should take this to PMs

bbundy

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.

hi_im_sean

iTrader: (3)

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

must be doing something right bending those

where do they crack?

Leafy

iTrader: (1)

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.

bbundy

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.

bbundy

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

Leafy

iTrader: (1)

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.

hi_im_sean

iTrader: (3)

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

ftjandra

iTrader: (6)

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

hi_im_sean

iTrader: (3)

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.

k24madness

iTrader: (6)

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.

bbundy

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.

bbundy

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.

Zissou

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.

bbundy

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.

hi_im_sean

iTrader: (3)

did you mean to quote me bob?