I am going through stock bushings in about a year doing DE's so I got delrin front bushings and the Welt red rear bushings based on reccomendation from Jason at Paragon for my 83 '44. Has anyone run this combination and what kind of wear did you get? Any issues with installation, they seem like they would be easier to install than stock.

 

The hard part is taking the original front bushings out...what a pain. Welt red front's slide right in; I dont know about the other bushings.

 

I personally wouldn't use Delrin for the front control arms. Because they are so hard they are very sensitive to aligment of the control arm's pivot axis. If it's not perfect the bushing and control arm will bind.

 

I use them and love them. I have though about it and binding issue not problem for steel arm cars.

Here is why.

When you install the control arm its location is set by front bushing not the rear block. the rear block allows slip front to back on shaft and also side to side given the large holes in the block where it bolts down. Thus if you install the bolt in to the crossmember first then tigthen down the rear it will self align. If you attempt adjust it then there will be some misaligment. This is also the reason some say there is no caster adjusment on the early cars.

Aluminum arm cars have caster adjustment there and could bind, but loose fit of the block to the chassis on early cars means no binding can occur if you install it from cross member first.

PS... they work 1000 time better than stock rubber as they actually keep the location on the crossmember and don't deform or shift.


Did you also in stall new control arms and ball joints? I always advise doing this as these steel arms are cheap and can crack with age. I know my originals were cracked. The stock replacements have not cracked after a couple years of hard track use. I inspect them every track day and have spare just incase, but never needed them.

 

Actually, it is an issue. While you may be able to bolt the up easily enough with the slop build into the mounting parts, as the arms pivot, if the pivot axis of the front and rear are not exactly the same they will bind. With the Delrin fronts you HAVE to use stock in the rear so the slop of the rubber bushing takes up the misalignment of the pivot axis.

This is where spherical bearings have a huge advantage. They can cope with a certain about of misalignment due to their ability to pivot seamlessly about 3 axis, all at once.

I have not purchased control arms yet for my car, but rest assured it will get new control arms and balljoints along with spherical bearings.

 

But if you use derlin front bushings
how do you go about adjusting castor
without causing the a-arm to bind ?

 

J Chen, You simply don't asjust it.

When I had my car check by Chris Cervelli of Technodyne a few years back caster came to 2 degrees on both sides. He said it was fine and NOT adjustable.

George.... If force a misaligment then there is a problem, but if you put the front crossmembe bolt in first the location rear block will shift to one that is in aligment with front and will not bind. There is something like +/- 0.5" of side to side movement in rear block not matter what you use back there. This not bushing slop, but slop in the mounting. Once locked down it will not move anymore. The pin in the control arm can also slide front to back in the weltmesiter bushing 1/4" easily.

So my point is that given the freedom in the rear mount on the steel arm front bushing does all the centering and defines the aligment axis. It is rather simple system. If you don't believe me then go to the car and look at the rear caster block and how much movement you have.

 

Joe, unless the rear mount is loosely bolted and moves around when the control arm moves up and down it absolutely CAN bind. What you are describing is simply mounting it w/o bind, but if the front and rear pivot points are not on the exact same axis you will introduce bind as soon as the control arm moves up and down. With a stock rear mount the rubber bushing allows the movement of the pivot axis itself, but that is a result of bind.

Take a bar and put a bend in it so that the front of the bar and the rear of the bar are no longer on the same axis. Now place each end in a conventional bearing (not spherical) and bolt the assembly to a bench. Now try to rotate the bar. You can't. It binds instantly. Now replace one bearing with a piece of rubber. You will be able to rotate the bar some because of compliance in the rubber.

As for the caster blocks, they won't do much because the upper location of the suspension does not move. It would be much more effective to adjust caster using camber/caster plates.

 

True... but why do you assume the pivot axis on the steel control arm it not lined up? Are you saying the tolerances are so far off that rear pin and front hole are never in static alignment? If you are right then the system could bind. If for example the rear pin for the caster block and front hole are in perfect aligment then the pivot axis is just fine. I know they won't perfect to .0001 or anything like that, but I'd bet they are close enough given the small amount of play between the cross member bolt and delrin bushing's steel sleeve.

 

Geo wrote:
exactly how are you going to get spherical bearings in a stock steel a-arm?

 

Easy peasy.

You make a cassette that holds the spherical bearing and the cassette replaces the bushing. See those produced by Weltmeister and Elephant Racing for an example. Both of those are a bit fancier than they need to be for racing.

 

Bingo!

I think if you assume they are in line you could be open for disappointment. I'm sure they are close, but are they close enough for rigid bushings? That is the big question. Also, just normal bumping and curb hopping can throw them off on a race car.

 

George,
I will not argue that sphericals are not better. They infact are better.

I do disagree that delrin's are not improved overstock. They are much better than stock and any binding is minor. It is certainly not enough for me to worry about given my suspension.

If you are shelling out for $5000 dampers then a little binding may cause issues.
If however you are using delring front and weltmeister reds in the rear then... it will work. Remember the rears do allow some slop since the reds are not "that stiff".

I still feel that level mis-aligment is minor enough to be considered a non-issue.

Let me ask you how much experience do you have racing with delrin fronts and welt rears.

I would venture to guess I have close to the most experience with these as I have first set in my car. Remember I had to move away from stock or welt reds since they did not stand up to the abuse I put them through. Sure sphericals are better, but given my class limitations and the cost of sphericals. I am quite content with delrin and consider it good intermediate step between stock and sphericals.

 

Joe, I'm not questioning your choice. It's the best choice you have available. Given other choices however I would choose differently. That is all.

 

They sure are.
http://www.srsvw.com/parts/partdetail.asp?pid=124

Been racing hard on them for 4 years now.