peejay

I know that at least one of the guys who would three-link or equal length four-length the car, would use shifter boots to seal the hole.

Sgt.Stinkfist

iTrader: (6)

good idea. I have 8x 1/2" aircraft strength heims and 4x adjustable equal length arms on order, and have been trying to think of how to seal the upper inner joints/mounts from the outside.


Im choosing to do the vintage Mazda race car design of custom upper mounts inboard , equal length 4 links and heim'd watts with a urethane bushing on the pivot mount (ill just hide the new upper mounts under the storage bins )

diyman25

put a Go pro hero3 on rear suspension ... look like i can get some stiff spring at back now !!

peejay

That's really weird, it says I posted this Oct. 4, 2013.

October 4th, I was in Tulsa at the SCCA Rallycross National Championship, not posting to RX-7 Club. And, furthermore, at 1:45am I was outside the hotel BS'ing with friends, since I was outside from about midnight to 2:30am.

Weird...

mustanghammer

iTrader: (3)

What size and brand is that heim? Interesting failure. In my experience, the brackets fail but not the heim.

j9fd3s

iTrader: (3)

i don't know about your settings but the default time setting is like Greenwich mean time, which is ~8hours different. for instance it is 10:34am here, and posting time says 5:34pm.

peejay

"All times are GMT -4" and current time is same as mine.

So that was posted at 1:45am "San Dimas time" which is actually 45 after midnight Tulsa time.

The thing is, I remember posting that, a looong time ago.

rk970

iTrader: (1)

I get a kick out of the muffler hanger as a side load g-force meter..

diyman25

another shot

i think my upper link move too much (L/R) wise

hows every one's idea

elron90sc5speed

iTrader: (4)

I think that much lateral movement is fine in a road car but a little much for a Race-car. Just my opinion and not backed by any actual facts.

elwood

iTrader: (1)

I see remote reservoirs. Which shocks are you using?

diyman25

Local brand( taiwan(Which I will never use it again on
Any of my race car

diyman25

JRZ double adjusable

j9fd3s

iTrader: (3)

that is probably the problem. the rod end is designed to move side to side, so until it binds it should be totally fine.

not to get too far into it, but the US made parts have quality control standards and are usually made out of the material they say they are

mustanghammer

iTrader: (3)

Aurora brand heims and bearings all the way

elwood

iTrader: (1)

I use Aurora too. The Teflon-lined versions have done track and street duty for me while remaining silent (no clunking).

themanicmechanic

iTrader: (1)

I know it's loud while on track; so you probably couldn't hear the failure.

But, I suspect you felt it immediately. Do you recall if it was under acceleration or deceleration and/or over bumpy section of the track?

diyman25

U don't need to hear it or feel it
Because car was not driving able

N hearing ur driving shaft bang on tunal is not fun

I think is the corner exit meaning I am on Gas

peejay

I get about two days worth of use from Summit's Black Magic rod ends (3/4" thread 5/8" hole) before they start to clunk.

Rod ends can move side to side but it still must not bottom out in the bracket. My 3-link was designed around the width of a stock rear upper/lower link bushing, so I have spacers on the sides of the rod end. The spacers are not equal in thickness, either... I was playing around with angling the upper link to compensate for driveshaft torque-over. No lifting the right tire under acceleration for me!

themanicmechanic

iTrader: (1)

My .02 is that it's impossible and undesirable to eliminate all lateral movement. Without using reinforcements much larger than needed; the chassis, frame rails/unibody, roll cage; etc. will always flex under load.

After looking at both of your vids; my concern would be the width of the bracket where the heim failed. If it's too narrow and/or too tight it will bind and fail. I believe it was MustangHammer ( my apologies -- it was peejay) who commented about using spacers on either side of the heim to take up the slack. This would allow the lateral movement without the binding and undue stress.

The only other logical cause for the failure would be massive amounts of torque being applied during acceleration/deceleration cause you're making too much power or have too much braking capabilities...;-) Nah, that couldn't be it.

Good luck with the fix! Looking forward to a follow-up post after it's figured out.

diyman25

Anoter Rod end fail..........................and is at final lap of race... That really sucks

luckyly i caught all the fail on the tape


that was my last race of the season

i think i might change the Tri link design to Lotus link or 4-link design

elron90sc5speed

iTrader: (4)

Use a heavier rod. That size is just too light weight for the track.

Sgt.Stinkfist

iTrader: (6)

agreed, that rod-end looks way too tiny (maybe a 1/2" or 12.7mm?). Also, you could be having binding issues by running such a narrow chassis mount bracket. I would try a larger, quality, heavier duty rod-end, like 5/8 or 3/4 (16mm or 19mm) and make the chassis mount wider and run some "high offset" spacers to allow for more useable articulation

elwood

iTrader: (1)

Your initial thought was that the failure occurred under power; the last video corroborates it. It failed right when you applied the shock load of an upshift. Under accel load, the lower links will be in compression, and the upper is likely to be in tension due to the reaction torque from the rear tire traction. That would explain your tensile failure.

I have a similar setup with a narrow clevis. If you have a heim-jointed panhard rod or Watts link, I doubt there's enough lateral movement to put that upper link into a bind. My upper link doesn't bind, and it has plenty of unneeded additional lateral range (I can move the rear end of the link about 8" from side-to-side).

My upper link does use 5/8" Aurora AM rod ends.

I would try up-sizing, as elron suggested, and/or getting a higher strength heim joint before making any drastic suspension changes.

notveryhappyjack

iTrader: (4)

Question,
I'm using the old re speed coil perch parts for my front. The handling has continued to be worse and worse. It almost feels like one side is blown out, when I go over speed bumps the car feels stiff on one side and squishy on the other. What parts need replaced? Iirc I have white tokico all 4 corners, 350 or 375 Springs front, 175 Springs rear

Also I found that the bushings in the stock rear end links are very worn & causing the car to make a bunch of rattle sounds, is replacing those with Mazda oe parts a good decision, or is there a better aftermarket part I don't know about