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Underbody braces, turbos and more!

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PostPosted: Tue Mar 03, 2015 6:31 pm 
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Joined: Fri Sep 21, 2012 9:23 am
Posts: 178
Location: Mount Vernon, WA
WARNING THIS IS EXPERIMENTAL AND A GUIDE ONLY, DO AT YOUR ON RISK!

This is what I came up with for a replacement to the roughly 13/64 or roughly 5 mm differential spring pin. I used a Artu USA 01022 Multi-Purpose 7/32" or 5.56 mm by 3 3/4 " long, Rotary or Percussion Cobalt & Tungsten Carbide Tip Drill Bit. The tip is 7/32 but the body as best I could measure is 5.15 mm ish. The body fits inside the differential spring pin hole flawlessly (Snug tight, no wobble no room for anything wider. I ended up welding a 6 mm 1.25 narrow body nut onto one end, and a 5 mm .8 onto the other (I first thread a 5 mm .8 nut on the drive gear; I didn't like the width and ground it down and threaded a 6 mm 1.25 wide nut on). The top end I drilled out to fit the nut after rounding the corners. My drill press walked all over me, but the width should be smaller than what I drilled (1 cm max).

Potential benefits: The 5 mm or original spring pin has a double shear value of any where from 4,000 to 7,000 lbs. The solid pin I cannot determine the exact metal composition should in theory have a double shear value close to 12,000 lbs. The other benefit being that it does not slide out either.



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Before welding the nut
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After welding the nut
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This is where I messed up (it should not be wider the 1 cm, and only to the depth of the nut you use.
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This will get spot weld before installing the differential
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Last edited by Solerpower on Tue Mar 03, 2015 6:42 pm, edited 1 time in total.

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PostPosted: Tue Mar 03, 2015 6:40 pm 
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Joined: Tue Jul 03, 2012 12:19 pm
Posts: 344
Location: vancouver island, canada
one of the major issues i can happening is it will throw the diff out of balance. just something to keep in mind. i thought of doing something like this but because of the balance issue i never did. but let us know how it works.

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PostPosted: Tue Mar 03, 2015 7:00 pm 
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Joined: Fri Sep 21, 2012 9:23 am
Posts: 178
Location: Mount Vernon, WA
redneck racing wrote:
one of the major issues i can happening is it will throw the diff out of balance. just something to keep in mind. i thought of doing something like this but because of the balance issue i never did. but let us know how it works.


I thought about weight balance and it should be insignificant. It is not the same as a wheel where you have a single shaft that it rotates around. In the differential there are two bearings one on either side, plus a point of contact with another gear. When looking at both sides of the differential one having a hole and the other not I don't think they are balanced to begin with. I noticed a slight variation in the casing on each side, but I don't think this was for balancing. If they were going to balance I would imagine they would take it off a central axis point.


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PostPosted: Tue Mar 03, 2015 10:30 pm 
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Joined: Wed Jan 07, 2004 10:52 pm
Posts: 214
Location: Qc Canada
spring pin?
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PostPosted: Wed Mar 04, 2015 12:15 am 
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Joined: Fri Sep 21, 2012 9:23 am
Posts: 178
Location: Mount Vernon, WA
That is definitely another way to lock the differential pinion shaft in place. Is that braze? Didn't occur to me to try that. I still like being able to remove the parts more easily, but at the end of the day no one wants to take the transmission back apart.


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PostPosted: Wed Mar 04, 2015 9:49 am 
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Joined: Fri Sep 21, 2012 9:23 am
Posts: 178
Location: Mount Vernon, WA
Differential side comparisons
Here are two different designs for the same differential:

no hole indent on one side vs. two hole indents on both sides
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PostPosted: Tue Mar 10, 2015 9:44 am 
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Joined: Fri Sep 21, 2012 9:23 am
Posts: 178
Location: Mount Vernon, WA
If anything after viewing the differences between them adding the pin appears to balance the mass out left to right, essentially filling in the hole on one side balancing the already filled hole on the other side. Another thing to consider is that the rpm is already stepped down, it is not going as fast as the engine. Force=mass x acceleration; taking this into consideration the distance out from the center line of rotation is not relatively that great (the further out the greater the acceleration).

I test fitted today there is definitely no clearance issues with the bottom nut. I welded it and then ground it down to be continuous with the slant of the casing. This also reduces the mass of the nut on the end.


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PostPosted: Tue Apr 21, 2015 1:49 pm 
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Joined: Fri Sep 21, 2012 9:23 am
Posts: 178
Location: Mount Vernon, WA
Just to update. The pin is holding fine. There is no vibration, nothing to indicate an irregular or unbalanced differential. I will post back if anything goes wrong involving the pin. Hopefully I never will, knock on wood.


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