Delrin bushings : good idea?

[DarioStraightSix]

My E30's suspension are really tired,and bushings too.
I've got a mechanical shop (i work with CNC milling machines and lathes) and i've got some delrin in my warehouse. I've seen a lot of cars with delrin bushings.So i'd like to make my own bushings. Could it be a good idea?
Have you got some experience with bushings made in this material? Could it be better than polyurethane?

[jimmyspeed]

Hey Dario

Like you I have access to a good cnc and have been thinking about making some engine and tranny mounts for my turbo build. I think Delrin might be a bit stiff for a road car though and was thinking about a polyurethane. - this link had a rough grade. - http://www.akgmotorsport.com/catalog/ca ... ans+Mounts

I have a specific link which has a variety off materials and suggested uses from a nylon track bush to a softer poly. Will get the link off my other computer

My design aims were minimise the roll in the bay as I have a big manifold and turbo as well as a possible engine drop to lower the center of Gravity but haven't mocked or drawn anything yet

Found the spec 75a for daily 90a for track

http://www.r3vlimited.com/board/showthread.php?t=193979

[HairyScreech]

They only really work on the front wishbone rear bushes and the rear trailing arm bushes.
The track m3 compact uses delrin eccentric front wishbones and they do work.

[DarioStraightSix]

Thank you Jimmy!!
So you're a machinist too!
I thought about Delrin not just because i've got it in the warehouse but also because i read of several people that have had bad result with polyurethane. I've seen pics of bushings destroyed after few kms (sorry,maybe you prefer to say miles). Delrin should last more and has the advantage of being a selflubricating material. But you're observation about the stiffness is interesting. I've got to check the material data to know its hardness.

You said you want to make them in polyurethane : do you think to machine it? I think it's possible,the trick is to find the correct cutting parameters. Probably you should have a better quality than the moulded ones. I think that the ones that cracks after few use could broke due to air inclusions.

[DanThe]

I wouldnt use delrin for a road car, the proper rubber bushes are cheap enough
The only place for poly on a road car is ARB and trailing arms

[jimmyspeed]

I do a bit off cnc on the hurco mills, some manual lathe stuff too but primarily stainless tig fabrication work. Are you a programmer ?


Looks like delrin will be good for some parts then so should save you some money. As for what tolerances you need for afirm grip on suspension parts I'm not sure. The standard rubbers ones are relatively flexible and therefore grip well when installed. You might have to make a test section to see what you can press in. All the parts I plan to make will just be bolted down so not as critical

The acetal we use cuts beautifully to very fine detail so I can't see other firm plastics causing much of a problem

[DarioStraightSix]

Yes,i'm also a programmer. I can say i can do more or less everything about mechanical parts. Together with my Brother and my father i own a little mechanical shop,it's a family company,so i've got to do every operation . I not only make the parts with the machines,i do quotes,i order the materials,i package the parts.......and,yes,i even clean the bathroom
We are a typical North east Italy little family company.
I'm more pratical with cnc machines but i can use traditionals too,in fact i've got some old school stuff into the shop. Until two years ago i had a wire edm but we sold it because it hadn't enough work. I can use a welder too,but i'm not a pro.

Going back in topic......i think i could even do the differential Mount in delrin,mine is a bit worn.