Datsun Roadster Forum-311s.org

What are the dimensions needed for the right bushing?

This is a picture of seven of the 8 bushings sent by Flex-Form:


And a closer shot of just 2 of them:


A shot of the 'narrowed' 1 1/2" 'eyes':


On the bushings, none of the dimensions are consistent. Length, shoulder thickness, and diameter vary quite a bit. They are rough. Some can be forced into the eyes by hand, some will drop in, and some might be able to be forced in with a vice or press........Not my idea of quality machining for a custom made part.
These bushings are solid. I didn't have the centres bored out because Mark said they didn't have a bit for a 15mm hole. Probably just as well........

I'm not sure if you can tell from the picture but the machining on the eyes is also inconsistent. More taken off on one side than the other, and different side on the other end. also not even as far as the distance to clear the bushing shoulder, and again quite rough.

What needs to be done?

1) Make new bushings.......I will do up a drawing, to be posted later, of the dimensions I use. I will drill a 15mm hole for use at the back, 15mm or 5/8" at the front of the spring. I will also make new bushings for the shackle to frame mount which will have a different OD because it is smaller than the eye of the new spring.

2) Make a 'sleeve' for the front bushings. This will be a 12mm ID by 5/8" OD (maybe machined to 15mm.....) sleeve that will install between the bushings and the bolt at the front mount of each spring. If I could find some 15mm steel rod locally I would use that.

3) Drill and install grease nipples at the eyes of the springs so they can be easily greased down the road. Searches on the internet have frequently brought up comments of noisy urethane and delrin bushings if they are not kept lubricated.
The Delrin is quite a hard material, and I am concerned about it as a bushing material, but I am going to run with it for now.

4) Because of the awkwardness of getting the whole spring up on the milling machine, I am going to hand file the narrowing of the eyes to clear the bushings. Yes the eyes could be removed, and that is what I will recommend anyone else to do, but these have already been apart and modified once (at Flex-Form), I'm not comfortable taking them apart again.

5) install............

Looks like craptacular quality to me...

I just checked McMaster-Carr. You mean the guys that made the springs couldn't cough up $20 for a 15mm drill bit? That being said, judging by the "quality" of the machining done to the bushings, you are probably best off that they couldn't drill the holes...

Ican't believe any decent maching shop would turn out that crap - perhaps they have some reasoning behind all the mismatch. I'm with Spl310 on the $20 drill bit - lame way to do business.

Daryl, I am very sorry you have had this experience, especially after all the work, time and delay you have delt with. I don't know what your recourse is, other than to contact them and ask "what gives?" I continue to be interested in the concept, if not the springs themselves, because from what I have read people really like them, and so far I have not been able to find another supplier on the internet for composite springs that might do a Roadster. I think I would contact them and say "Look, this is crap. Is this the reputation you want? What are you going to do to make it right?" Those springs never should have left the shop like that, and your contact there needs to know it quite clearly. And while we Roadsters may not be a big group, I believe our blogs are searchable via search engines, and info on the net spreads fast. Don't take this lying down: A company's reputation is everything, and they need to know that you won't be silent. If they want to prosper, let alone eat and pay their bills in the near future, they better get their act together.

Again, thanks for all your work. Sorry for your disappointment. It sucks.

I don't know about anyone else, but my view of installing these springs on your car is to improve handling and allow you to drive round corners faster.

I've driven in a car with the Volvo springs installed, by one of the guys who developed the upgrade. It handles better than anything I've ever driven in. But the lateral forces applied when cornering to the limits of these springs are significant.

There's no way in the world I'd be applying the same force to something that is intended to be one piece, is now effectively held together by two bolts. You're putting an awful lot of faith in those two little bolts.

Not for this little black duck.

"is now effectively held together by two bolts. You're putting an awful lot of faith in those two little bolts."

Ruth,
I might be a little concerned if it was just 2 little bolts. Fortunately there is also a very strong construction glue in there also.
These springs are primarily used on race cars, with larger tires and forces than you'll typically generate on a street car, for longer periods. I have no concerns about those 2 little bolts.

Greg,
I will be writing to Mark at Flex-Form, but my gut tells me they are not overly concerned about the machining side of their business, and would rather not be involved. All three of us that got the springs and bushings from them have tossed the bushings and sourced our own.
Scott's springs were 2" wide and he had to make up some spring pads to be able to clamp the rear end on. The ones I had made were the stock width, which means the eyes have to be narrowed........no easy way to do this it seems, when the 'extras' by the manufacturer are unusable. The springs themselves seem to be well done.

"Scott's springs were 2" wide and he had to make up some spring pads to be able to clamp the rear end on. The ones I had made were the stock width, which means the eyes have to be narrowed..."

What is stock Roadster width? When you say "the ones I had made were the stock width" are you referring to Roadster stock spring width, or a standard width that FAF uses for their springs? I have also read that you MUST make sure you don't have any U-bolt or metal to spring contact, as it can damange the spring, and that most suppliers provide sleaves to cover the bolts... did FAF, or are you going to make your own? You mention Scott's spring pads... I assume FAF provides some kind of pad between the metal mounting plates and the spring? FAF also says "we generally make two arch sizes in varying rates." This sets ride height, does it not? Did they offer any ability to adjust that other than lowering blocks? Which arch did you choose? As I recall, Roadster comp springs have almost no arch to them at all (and now mine are reverse arched!). What weight/rate of spring did you get... 190lbs?

If I go this route, I would ask that they send me the unattached eyes first so I can have them properly machined, then send them back for their attachment to the spring to ensure strength as addressed above. Also, would it be possible to have a metal insert made to press fit inside the eye so that you could then use new stock Datsun bushings like what Dean at Fairlady offers instead of trying to source and machine some other material? If FAF has bushings they use that fit in their eyes, why didn't they just use those, cut the length to fit in the new narrowed eye and drill or insert the hole to fit a Roadster bolt/mount?

Thanks Daryl...

Like I said before,I havent broken anything yet.I know that we are generating more force and load than any street driven roadster will ever do and I can assure you that if they will fail Ill be the first to post here.If by June nothing has broken,id say they are good for lots of street driven miles.I will be testing them over the next month with 15 x10 wheels and will let you guys know.

Hopefully yours don't fail because I could envision that could be very catastrophic.

LOL Hey everything else has failed,comes with using 40 year old parts.It can be real exciting when suspension parts break at speed,dont ask how I know.Beware of front spindles,swaybars and rear axles to name a few breakable parts that dont like high g force.

New bushings and steel sleeve:


Close up:


There are three sets of 4 bushings there.
1st set is for the front eye of the spring and has the steel sleeve go through 5/8" ID (this would be the same as the 2nd set IF I could find 15mm steel rod locally ).
2nd set is for the back eye of the spring and goes directly onto the shackle 15mm ID.
3rd set is for the top shackle mount and is urethane from Dean @ Fairlady parts.

They are all a very snug fit, and will get a liberal coating of silicone grease when installed.

What is stock Roadster width? When you say "the ones I had made were the stock width" are you referring to Roadster stock spring width, or a standard width that FAF uses for their springs? Same as the roadster springs - 2 3/8"

I have also read that you MUST make sure you don't have any U-bolt or metal to spring contact, as it can damange the spring, and that most suppliers provide sleaves to cover the bolts... did FAF, or are you going to make your own?Haven't looked at that yet....FAF does not supply them.

You mention Scott's spring pads... I assume FAF provides some kind of pad between the metal mounting plates and the spring? Nope. There is a stock rubber pad between the leaf springs and the plates. that can be used or a urethane pad can be purchased.

FAF also says "we generally make two arch sizes in varying rates." This sets ride height, does it not? Did they offer any ability to adjust that other than lowering blocks? Which arch did you choose?
I knew nothing of any choice. I simply filled out the dimensions on their form and sent it to them. There is one option that will lower the ride hieght some and that is to install the eyes in the reverse or upside down position. drop another 1/2 - 3/4" iirc.

As I recall, Roadster comp springs have almost no arch to them at all (and now mine are reverse arched!). What weight/rate of spring did you get... 190lbs?
I can't find my paperwork now, but pretty sure I ordered 180 lbs/in.......

If I go this route, I would ask that they send me the unattached eyes first so I can have them properly machined, then send them back for their attachment to the spring to ensure strength as addressed above.Would probably be quicker/easier to have them sent to you complete and assembled without the glue, have the machine work done and assemble/glue them yourself.....but I don't know how that would affect the warranty........

Also, would it be possible to have a metal insert made to press fit inside the eye so that you could then use new stock Datsun bushings like what Dean at Fairlady offers instead of trying to source and machine some other material? Didn't think about that....better question for FAF or your freindly machinist......

If FAF has bushings they use that fit in their eyes, why didn't they just use those, cut the length to fit in the new narrowed eye and drill or insert the hole to fit a Roadster bolt/mount? I discussed drilling a 15mm hole in the bushings with Mark @ FAF, his response was that they didn't have a 15mm bit, but if there was enough demand he would buy one. You saw the pictures of the bushings they sent me? Considering there have been three roadster owners who have bought the springs from FAF, 2 of us have ordered the Delrin bushings, and all of us have turfed the supplied bushings as garbage .......well what else is there to say??

And I've probably killed any chance of a warranty claim for myself by posting all this.........

Wow, that was fast Daryl! Man on a mission! Looks like you have done all the hard work... now, how can I get your bushing set up? What will it cost me? I bought Dean's complete high end bushing set up years ago, installed now except for the front ones as I recall. I need to decide between your set up which looks great and bolt in vs having my machinest make a sleeve to press fit into the eye so I can run Dean's stuff ($160 for the complete kit with new spring pads too). Thanks!

Update: Well, just got off the phone with FAF and got started. They are moving the shop so there may be some delay in production (3-4 weeks vs 2). He suggested I have the springs made w/o the glue first, I will remove the eyes and have them machined and re-assemble myself with their suggested glue. We have not discussed bushings, so I am waiting on what you have to say. Decided to go with a 200lb spring, as he said it would feel like a 190lb, which is what I wanted based on weight calculations from "How to make your car handle" book. Regarding ride height, he said we can get pretty close to comp height. This is done by changing the thickness of the mounting pad on the spring when they are made and is based on weight, spring rate and some other dimension that we will discuss. The part about the "two different archs" is not relevant in this case.

Hmmmmm define close.If close is within a half inch I will take a few sets at that ride height.Still havent inverted the eyes on mine but the ride height without lowering blocks is taller than the factory ride height and I dont mean with sagging springs.I will be interested to see how car sits when you get them.Please post picture and check ride height to rocker panel before and after with compostite springs.