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Author: Subject: pushrod suspension almost done
datz510

posted on 18/6/06 at 04:30 PM Reply With Quote
pushrod suspension almost done

Night before last, I went to work on the problem of the front shock mounts. I had to figure out where the shocks are going to sit up front, yet allow the needed space for the mounting and motion of the pushrod and bellcrank... AND allow enough room for the rack and pinion and other needed items.

Here's what I came up with, along with some newer photos of what the frontend looks like now. Also got some photos of the new Woodward rack that showed up on my doorstep last week:

The frontend as it sits after the work night before last:


Suspension is starting to take shape. You can see one of the rockers on the right side of the chassis:


Details of the suspension. I have all the brackets tack welded to the chassis now.


Final placement of the lower coilover mounts.


I custom fabricated these brackets with a little beer-box prototyping work and the plasma cutter. Took 1 hour from start to finish for the set. They are different front and rear due to the chassis width changing, so it was a bit of a challenge to get them right.


Looks like it should work. I have room to change the rocker dimensions should I need to alter the motion ratio.


Top down view:


Top down (front of chassis is up in the photo). Lots of room between the shocks!


With new steering rack mocked up in place:


It'll probably sit just a hair lower than this photo:


End of rack looks good for bumpsteer.. I'll be running the steering link off the bottom of the rack end to allow it to drop down. This will let me orient the rack a little higher to clear the nitrogen canisters on the shocks.


Its snug, but I think its entirely doable!


The new rack is a real work of art:


You can see how the unit is opened up to change the steering ratios:


Woodward Precision, indeed..


[Edited on 18/6/06 by datz510]

[Edited on 18/6/06 by datz510]





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1972 Datsun 510 (1600) w/ 200hp 3.0L V6
1995 Nissan Pathfinder rock crawler

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datz510

posted on 18/6/06 at 04:31 PM Reply With Quote
The front suspension is done and it works!!!

Fabbed up the rocker mount brackets today and got the front suspension pretty much done.

Here are the brackets I made:



This side is actually sitting on its own after I got it all mocked up:


The rocker in place.. perfectly straight shot to the pushrod mount at the wheel.


Here you can see that at ride height (left), the shock is compressed about halfway, which is right where I wanted it.


A couple more views of the rocker assembly:



A shot of the whole frontend.


I have decided to change over to the 2003-2004 Yamaha R6 shocks in the front, which puts the nitrogen canister parallel to the shock body. I decided this after looking at the clearance between the pushrod and my tie rod with the rack and pinion set in place.. it looked way too tight of a fit. I figure that I can move the rack forward if I go with the later shocks, as the only thing in the way is the nitrogen canister, not to mention this will give me springs that are the same, left to right. The r6 shocks I have now have different springs on them for some reason.


Here is one of the 2003-2004 R6 shocks:






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1972 Datsun 510 (1600) w/ 200hp 3.0L V6
1995 Nissan Pathfinder rock crawler

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donut

posted on 18/6/06 at 04:35 PM Reply With Quote
Blimey!!!





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nitram38

posted on 18/6/06 at 05:20 PM Reply With Quote
Very, very nice job!
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datz510

posted on 18/6/06 at 05:30 PM Reply With Quote
Thanks for the kind words, guys!

The only thing I will really need to do on the front suspension is alter the rocker pivot to include an oillite bronze bearing. Right now, its just a 1/2" bolt going through the eyes of the rocker triangle, which works, but would probably get a bit sloppy over time.

FWIW, total cost for parts (including the coilovers) for this pushrod setup will come out to about $130. The rockers are from a 2001 Yamaha R6 motorcycle and can be had on ebay for $5-10 a set. The coilovers are second hand 1999-2001 Yamaha R6 shocks off Ebay for $20 each. The most expensive part is probably the heims for the pushrods at 4 @ $15 each and the misc nuts and bolts I needed (about $30 total).

It was a hell of a lot cheaper to go this route than with standard outboard coilovers.

[Edited on 18/6/06 by datz510]





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1972 Datsun 510 (1600) w/ 200hp 3.0L V6
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Megatron-UK

posted on 18/6/06 at 05:33 PM Reply With Quote
Thats just porn, that is.
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JoelP

posted on 18/6/06 at 05:34 PM Reply With Quote
looks good! i too noticed that r1 and r6 shocks change over the years, not sure what differences there are besides the angle of the canister. They are closer to £20-£30 in the uk.

[Edited on 18/6/06 by JoelP]

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ned

posted on 18/6/06 at 06:33 PM Reply With Quote
welding looks good on the frame, is that tig on the completed bits?

my only observation would be that where the tie rod on the top wishbones is on the outboard end i'd of sandwiched the rosejoint between two plates, not justed bolted the rod end to one plate.

but nice work.

Ned.

ps looking closer is that rod end i mentioned some sort of clevis? if so disregard the above the contact area on the front top wishbone bracket looks 'ish' with the angle the bracket is aligned at, are you going to just weld round it as is or fillet it or something to strengthen the weld area?

[Edited on 18/6/06 by ned]





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DIY Si

posted on 18/6/06 at 06:43 PM Reply With Quote
I thought that's how those clevis pin type things were supposed to attach? Hence the slot in them? Could be wrong, it's been known to happen....
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datz510

posted on 18/6/06 at 06:50 PM Reply With Quote
quote:
Originally posted by ned
welding looks good on the frame, is that tig on the completed bits?

my only observation would be that where the tie rod on the top wishbones is on the outboard end i'd of sandwiched the rosejoint between two plates, not justed bolted the rod end to one plate.

but nice work.

Ned.

ps looking closer is that rod end i mentioned some sort of clevis? if so disregard the above the contact area on the front top wishbone bracket looks 'ish' with the angle the bracket is aligned at, are you going to just weld round it as is or fillet it or something to strengthen the weld area?

[Edited on 18/6/06 by ned]


The welding is all MIG using a Millermatic 175 w/ CO2/Argon gas and .030" wire. Makes for an extremely clean weld with excellent penetration. On some of the suspension bits, I put down some welds nearly 1/2" wide that look just as good. I'd recommend it to anyone looking for a good welder.

Yep, the castor adjuster (front part of the upper A arm) has a clevis end with a 3/8" plate welded to the rear part of the upper A arm. It is overbuilt pretty excessively. Here is a photo of the assembly:


Yep, as it sits, the front top wishbone bracket is iffy. I tacked them in place only to get the positioning right. I'll follow up with some steel plate to reinforce it heavily on the front side where you see the gap.
There is still a lot of finish welding to do on my chassis.

[Edited on 18/6/06 by datz510]





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1972 Datsun 510 (1600) w/ 200hp 3.0L V6
1995 Nissan Pathfinder rock crawler

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indykid

posted on 18/6/06 at 08:32 PM Reply With Quote
istr last time mig welding like that was showcased, it was said to be a really bad idea. was it due to cold spots or something like that?

i could be completely wrong, but i'd probably be happier with a nice seam.
tom






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datz510

posted on 19/6/06 at 12:34 AM Reply With Quote
I'm not a pro welder... but I have built quite a few offroad rigs, rock crawler suspensions, and other parts that get abused heavily and none of them have ever broken a weld. Having said that, I'm really not too worried about my welds.

The problem with laying a solid bead on some of these parts is that the intense heat can warp the part fairly badly.. at least thats what I've run into. So, I lay a row of dimes, stop, wait a while, and then continue on.

BTW, I was not showcasing the weld on my upper A arm there.. that was posted in response the question regarding the clevis attachment. I know its not ultra-pretty, but it will work just fine.

IMO, it is just personal preference how the final weld should look:

quote:

While moving the gun forward consistently produces a sound weld with decent appearance, some people like the appearance of an overlapping bead profile, which is sometimes referred to as the "stack of dimes" look. This takes practice.

The "stack of dimes" look can be achieved a couple of ways. One is through a forward or push movement of the gun, then a slight back step or hesitation, and then moving forward again. Another method is using an overlapping "C" motion of the gun. This produces the "CCCCC" look of stacked dimes. Remember to make your individual beads close together. If they are too far apart, to the point where the toes of the weld become widely separated, the weld can fracture at any of those indent points (stress risers and/or crater cracking). Note that on 0.120-in.-wall tubing, melt-through and/or warping may occur if you make too long of a weld bead using this technique. To minimize heat input, make several short welds rather than one long one. Also, consider skipping around a frame, making a short, partial weld on one joint and then moving to a different part of the frame. This gives the weld a chance to cool.


Source: http://www.millerwelds.com/education/articles/articles70.html


[Edited on 19/6/06 by datz510]





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1972 Datsun 510 (1600) w/ 200hp 3.0L V6
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gazza285

posted on 19/6/06 at 05:25 AM Reply With Quote
The shockers are upside down. I don't know if this will affect the damping, but they run the other way up on the bike.





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Peteff

posted on 19/6/06 at 08:22 AM Reply With Quote
Get ready for some spring swapping as well, the original bike springs are 540lb ish so they will be a bit on the stiff side for the front of a car unless you change the linkage ratio.





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I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.

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datz510

posted on 19/6/06 at 04:36 PM Reply With Quote
Thanks for the info on the shocks. Only problem is that I dont know if they can be turned around right way up, as they only have a bearing on one end.

I seem to remember a discussion over on one of the other locost boards mentioning that they will work either way. They seem to work ok when I jump on the front of the car.

As far as the spring rate goes, it will be a little stiff for now. It will definitely require some fine tuning once I get it on the road, so I'll deal with that aspect when I get there. It is set up now with enough room to allow me to change the rocker out to alter its ratio.





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1972 Datsun 510 (1600) w/ 200hp 3.0L V6
1995 Nissan Pathfinder rock crawler

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JoelP

posted on 19/6/06 at 05:26 PM Reply With Quote
you can just turn the rocker around to improve it somewhat, currently it appears to increase effective spring rate by 1.5 (ie, to 750lbs/inch), switching it round would reduce it to roughly 450ish?
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datz510

posted on 19/6/06 at 06:00 PM Reply With Quote
I'll have to take a look at it. I dont think I have enough room to just flip the rocker. I'd have to make new ones from scratch. Not that big of a deal, but there may be other solutions. I believe the current ratio is closer to 1.2:1 than 1.5:1.

One other thing, Keep in mind that I'm running about a 40 degree angle on the pushrod, which gives a much greater reduction in spring rate. If the shocks are currently 540 lb/in, with a 1.2:1 ratio, that gives about 416 lb/in at the wheel.

I've been looking at coilover springs. I can get 8" coils for about $40 each in any spring rate from 200-500 lb/in, so I might go that route. need to pull one of these springs off and see if it is close to 8" free length.





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1972 Datsun 510 (1600) w/ 200hp 3.0L V6
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datz510

posted on 19/6/06 at 06:09 PM Reply With Quote
Found a place called Hyperco that sells any coilover spring imaginable:

http://www.hypercoils.com/Catalog.aspx

They carry everything from 1.4" to 3" ID and from 4" to 12" in free length. Prices are around $50 each.





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JoelP

posted on 19/6/06 at 06:33 PM Reply With Quote
well, on the plus side, with the shock that way up you have minimal unspring weight as its the light end you are moving. And you are right, the push rod is at a fair angle to help the spring rate down.

You could try sticking weights on the front to measure the overall effective rate?

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datz510

posted on 19/6/06 at 08:08 PM Reply With Quote
When I let the car down onto the suspension, you can see in the photos that it compressed the shock about 1". The engine and tranny combinaton in the car weighs around 490lb, and mabye half of that weight plus the weight of the chassis for that corner was on that wheel. So, mabye 300lb on that corner, compressed the shock halfway. It is a bit stiff, but since it has compressed the shock and spring so far, the rate at the wheel doesnt appear to be too terribly high.

Once I get the other rocker assembly and get the whole frontend on the ground, it'll be a little easier to measure the wheel rate.





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1972 Datsun 510 (1600) w/ 200hp 3.0L V6
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Syd Bridge

posted on 20/6/06 at 09:48 AM Reply With Quote
I'm always bemused when I see these cars with 'pushrod' suspension. Why do it? If only to say that you can?

It adds cost, weight, complexity, and stresses that are unnecessary in a car of this type.

Reengineer the front wishbones and damper pickups to be as they should, and the job is done.

Cheers,
Syd.

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gazza285

posted on 20/6/06 at 03:01 PM Reply With Quote
Noticed that your shock mountings do not look to be parallel, with most shocks this is not a problem, but you will need them parasllel if using the R6 shocks due to the use of a needle roller bearing in one end. The shock is only designed to move in one plane, and by not having the eyes parallel it will be introducing stress into the mountings.


Syd, it's to prevent the paint on the shocker getting chipped.





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DIY Si

posted on 20/6/06 at 03:34 PM Reply With Quote
I don't see how it can add cost. He's said it's cost him pennies so far, but he has made many pf the bits himself. However, much less than a new set of shocks would be. And it does make the front end look a bit 'cleaner'.
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datz510

posted on 20/6/06 at 04:05 PM Reply With Quote
Gaza, the shock ends are a slightly off. The end mounted to the chassis has a rubber bushing in it, so it should be fine. If it was a roller bearing on that end, I'd definitely have them in line.
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datz510

posted on 20/6/06 at 04:08 PM Reply With Quote
quote:
Originally posted by Syd Bridge
I'm always bemused when I see these cars with 'pushrod' suspension. Why do it? If only to say that you can?

It adds cost, weight, complexity, and stresses that are unnecessary in a car of this type.

Reengineer the front wishbones and damper pickups to be as they should, and the job is done.

Cheers,
Syd.


"Because I can" is the answer... The old adage of "to each his own" comes to mind. All of our cars are unique and built the way we wanted to build them. Some go the simple route, others choose to take on a little more challenge. I enjoy a challenge and want to make it work. And I dont want my car to be just like all the others...

Not to mention, it costs a heck of a lot less than buying a full set of standard coilovers. I have $130 in my whole front suspension. I could spend twice that on just one coilover.

[Edited on 20/6/06 by datz510]

[Edited on 20/6/06 by datz510]





Hang on, we're goin for a ride!

1972 Datsun 510 (1600) w/ 200hp 3.0L V6
1995 Nissan Pathfinder rock crawler

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