JD's "Mallock Tribute" Build

[a.moore]

Bummer JD. I hope you get it sorted.

You're on the right track though making sure the shaft isn't too short. On one of our FSAE cars, the joint exploded much like you are describing (except in ours, the boot held together and contained the parts). Under full bump the CV was riding on the very edge of the housing and eventually it slipped out, bound, and the rest is history.

[horchoha]

Remember w hat I say JD,"If man built it, man can fix it"

Minor set back.

[GonzoRacer]

Remember w hat I say JD,"If man built it, man can fix it"

Yo, Perry-
Yep, you're absolutely right. I can fix it, won't take all that much time/effort or even money.

Cleaning up the black goo out of the back of the car... Well....... Can I borrow one of those robot vacuum cleaner things from somebody? I'll give it back in a few days. It'll never need lubrication again...


JDK

[GonzoRacer]

Hi Andrew-
I think you're right, it just pulled apart The CV bits aren't broken/shattered. The end of the big housing is a little bit scarred, where (I think) the two ends banged together after separating. The other end isn't marked much at all. We found two of the three "rollers" but they're still wrapped in a towel in my truck... I don't think they're banged up much either.

It's a puzzlement... I can advance several theories:

1) Bubba didn't take the measurements right when he figgered out how long the shaft needed to be to begin with.
2) The machine shop that shortened the shaft screwed up.
3) When the first weld broke, and the axle spun on itself, it ground off some length.
4) When Harold repaired the broken axle, he inadvertently shortened it.
5) The ghost of Sir Arthur Mallock or that damn lizard did it.

Those are listed in "order of likelihood" in my mind, although #5 is gaining in popularity.


JDK

[Trochu]

I don't know Harold, but I'm going with No. 4. Maybe he just cut the two ends off to make them square and then welded them together without adding the extra 3/4" he cut off?

[GonzoRacer]

I don't know Harold, but I'm going with No. 4. Maybe he just cut the two ends off to make them square and then welded them together without adding the extra 3/4" he cut off?

Yo, Trochu!
Hey Buddy! How's it goin' waaaa-aaay up Nawth there??? Good to hear from you!

If you knew Harold, you wouldn't think that. He's very good at stuff like that. Add to the mix that he didn't actually cut the axles, that first machine shop did. It broke cleanly at the cut, because of lousy welding the first time around. Harold just cleaned up the first welds, beveled the edges back more than they had, and re-welded.

I'm not saying it's impossible that Harold messed up, or at least contributed to the "too short" problem. He is (mostly) human... Just that I'd blame Bubba before I would Harold... I KNOW Bubba is capable of that kind of screw up. I've seen him do it...

Hey, you don't happen to own one of those self propelled robot vacuum things, do ya??? Heehee...

JDK

[laserracer]

[PooPoo] bad luck JD..Lovn my live axle now ..sorry haven't replied earlier been crook with the man flu..Hope hamdip didnt take it to hard..not that it was her fault anyway ..we here at slotus all know it was the ghost of Sir Arthur Mallock and that damned lizard..we shall rebuild

KIWI DAVE cough ..cough sneeze..puke cough

[GonzoRacer]

Kiwi Dave!
Good to hear from you! Yep, I'm blaming the lizard... All his fault...

Sorry you're a sickie these days, hope it passes soon, you gots a Slocost to finish!!! Now that you're all skinny, you'll fit into the car better, maybe won't need all that "personal lubricant" to get in the seat. Not sure what else you could do with the stuff, but I feel certain you (and the sheep) will find something to do with it...


JDK

[1970manxsr]

Don't think of it as 'CV grease on the chassis'.

Think of it as 'poor-man's undercoating'...

bryan

[john hennessy]

JD, was it the ball type or the three pronged type?

the ball type rely on the shaft moving in and out for the length thing and the three pronged tripod type rely on the joint moving in the case/outer, this type must be fixed to the shaft with circlips so that it doesn't move.

if this was not done, then the shaft could move in to the joint and when it moves out, it brings the joint with it and bang.

[laserracer]

...LOL..LOL All skinny...LOL...

[GonzoRacer]

JD, was it the ball type or the three pronged type?

the ball type rely on the shaft moving in and out for the length thing and the three pronged tripod type rely on the joint moving in the case/outer, this type must be fixed to the shaft with circlips so that it doesn't move.

if this was not done, then the shaft could move in to the joint and when it moves out, it brings the joint with it and bang.

Hi John-
I'm not sure I follow your description of the process. There was a snap ring on either side of the outer CV. The outer one of those came off a few weeks ago, and had to be replaced when the CV pulled apart. The car was on jacks at the time, and the CV came undone when the suspension went to full droop. James replaced the snap ring, put it all back together and we're good.

In this recent case, it was the inner CV that gave up, which looks a lot like the one pictured:

cv-joint.gif

The picture is actually a Honda CV, I think. In my case, the CV looks a lot like the drawing with the exception of the snap rings on either side of the spider. Mine has a snap ring on the outside of the spider, which is in place. On the inside, the stub end of the shaft, there is no snap ring, nor is there a groove for one that I can see. The spider presses onto the splined shaft until it rests against that one snap ring.

I'm thinking the CV was good, just pulled apart when the too-short axle flexed a bit too much. It's past my bedtime now (I'm in Eastern time!) but I'll look at that axle and CV again tomorrow and maybe even take a picture or three.

Thanks for the info John, I'll check on snap rings and such in the morning!
'Preciate you looking in on us, Sir! Come back any ol' time!

JD

[GonzoRacer]

Don't think of it as 'CV grease on the chassis'.
Think of it as 'poor-man's undercoating'...

Good concept... Except the Slotus has a full belly-pan, so it's "undercoating on the pan where I put my hand to lean in and adjust things."

But you got the "poor-man" part perr-zackly right!

JDK

[GonzoRacer]

Welcome to Forensic Slotus Class for this Wednesday evening...

Tonight we will be studying the differential mount of the Slotus. You know, the one that let the diff rotate enough to dis-combobulate the CV joint and sling goo and small parts all over the place? Yeah, that one...

So, the suspect:

4 16 13 Diff Mount.jpg

The upright bit, gussetted to the frame, was pretty strong. However, the fit of the br*cket that fit down over the upright and over the mounting tab on the diff cover was too loose for its own good. It was also too flexible for its own good. Looking at it now, it looks like the left side had gotten warped waaa-aaay outta shape since it was installed not-so-long-ago. Bad JuJu, B'wana...

Playing with the diff, trying to get it to sit level so I could measure the length for the new axle, I noticed that there sure was a great deal of flex in the diff. Too much flex... (Think John Wayne saying, "Yeah, Pilgrim, those Indians are TOO quiet.") A little more exploration showed that one of the two tabs on the frame that the front of the diff mounted to had broken off at the weld. It's the one on the passenger side, near the center of this picture:

11 20 11 Fuel Cell Mount, Lft Side.jpg

So, net result, the diff was actually attached to the car by one tab at the front and the one rear mount that didn't work so hot. It's a wonder the damned thing stayed in the car at all.

I'm thinking the axle was a bit too short, but the flex in the diff was what allowed it to totally separate and tear up the boot and scatter innards all about.

So, next chapter in the saga, a new diff mounting system and re-build those frame tabs!
Stay tuned, Friends and Neighbors, we'll be a-doin' stuff shortly!


JD "Floppy Differential" Kemp

[geek49203]

(edited twice, wish I could edit verbal comments in "real life"....)

***DISCLAIMER -- if I'm telling you stuff you've already thought about, and discarded as "silly" then I apologize. As you can see by my build, I'm not exactly Colin Chapman when it comes to car design and construction.... ***END DISCLAIMER***

Which means that, basically, you have many of the same issues as the original Champion chassis, with their use of the Miata rear diff? Seems to me that the IRS pumpkin wants to rotate, HARD, everywhichway? (A bit of Hoosier lingo there, which once was used to build Indy cars...)

slotus Diff Mount.jpg

I see that the front of the diff has some mounts meant to resist torque -- but those have rubber mounts, correct? And the rear mount is "solid"? So that means that the rear mount would be bearing all of the torque, at least until the squishy parts are fully compressed?

Ripping off an idea from the Miata et al -- would it be possible to have "wings" sticking out from the sides of the diff to control the lateral (side to side) action? Cause using the "That looks about right" engineering, I'd guess that the system you have won't have enough leverage to resist that twisting motion, even if you triple the metal thickness, due to the narrow nature of the mount? I'm thinking of something attached to, say, the bolts holding on the rear cover, extending a couple of inches either direction, etc?

(LATER EDIT- after seeing the post about the Explorer diff cover, I'm in love with that idea)

slotus front diff mounts.jpg

Am I correct that these are the front mounts?

I am thinking that "Equal but opposite forces" thingy applies here. Simply put, the rotational forces that move the tires (and the car forward) have an equal-but-opposite forces here, right? So, these nice little 1/8" tabs are basically holding up the torque of the system, both up-down and "twisting" side to side?