Bushing Sizes?

[emcdonald]

Hi Everyone,

Just picked up my next E30 and am getting the suspension all set up for doing track days. I have access to a nice machine shop and was just going to make the bushings (control arms, trailing arms) myself, but am having trouble finding the dimensions. Anyone know them or can measure theirs for me before they install some new ones?

Also, I was looking at the Turner MS RTAB and they don't have equal widths on the sides of the bushings, so that dimension would be needed too.

Thanks!

Erik

[jlevie]

Even very high durometer polyurethane does not machine worth a dam, which is why bushings are mostly molded rather than machined. Just buy bushings from AKG.

[TobyB]

muh- haa haaa.... says he who's been dicking with this recently:

Actually, acetal machines beautifully. That's Delrin(tm) in generic terms.
I was amazed- you need a lot of relief and a sharp tool, but it will finish mirror-
smooth at high feed and speed rates.

I've been using UHMW for the lower- stress bushings (shift tower, etc) and it's
a bit more squirrley. But once you account for its springiness, it'll do what you want.

That said, you'd do better to just buy them- the material cost is significant, and by
the time you pay for someone to set up and machine them, you won't save any real money.
AND if even one or 2 go wrong, you're behind.

I'm doing it simply because I want to- it's fun. And yes, acetal is probably not the
best thing in the world for trailing arm bushings, but it worked in a 160 hp 2002 for
the better part of a decade, so I don't figure it'll kill me immediately in an e30.

SOME dimensions- inside trailing arm's 27mm, end of the front 'wishbone's as near to .800"
as makes no nevermind, (.793, I think) ....

Others I don't remember- my notes were only as good as "you need 1.5" stock for
the trailing arms, 2.5" for the subframe, 3.5" for the diff.

I actually don't like the AKG 'bolt through' design bushings for personal prejudice
reasons (first and foremost, they don't 'bush' in both directions)
but yeah,

What Jim Said!

t

ps, if I find more dimensions, I'll post them. And guarantee them to 1 digit of accuracy....

[emcdonald]

Thanks for the replies.

Toby- I don't think the material is all that expensive, plus I like to machine (I'll be doing all of it) so the time spent will be for fun.

McMasterCarr has 2.75" Delrin rod for about $30/ft. Pretty much any bushings I've seen have been about $80-90, so I figure for a little bit of time I can just make all of them and have some extras around.