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Collapsable spacer Question
Posted: Wed Jun 01, 2011 5:59 pm
by crankycruiser
heres the story.
Before I left fot the cape I got my diff FULLY rebuilt and I mean FULLY, the only part re-used was the airlocker.. we even used a new housing..
that diff made it around 2000k b4 the collapsible spacer collapsed more and got a heap of slop in it, I tightened it (only enough to take up the slop) in melb but by the time I got to ALbury it had done it again and was whining its head off!
So my good mate Dan (MUD000) in Albury pulled me out of the shit and let me put my airlocker in his spare diff. His mate set it up for me (a diff guru) and it was all good.. that one made it 6000k b4 the spacer did the same thing, I have tightened it again and it seems all good this time..
Now WTF is causing this? I am running a Blown LS1 thru it but its only mildly tuned and not a horsepower hero...
Will a solid spacer fix this??
thanks guys
Ray
Re: Collapsable spacer Question
Posted: Wed Jun 01, 2011 6:05 pm
by 91Mav
crankycruiser wrote:Will a solid spacer fix this??Ray
Yes.
Re: Collapsable spacer Question
Posted: Wed Jun 01, 2011 11:41 pm
by V.W.Dave
91Mav wrote:crankycruiser wrote:Will a solid spacer fix this??Ray
Yes.
Yes X2 but it will put more stress on the crown/pinion. I have seen a few third members crack open caused by a solid spacer but it was getting some curry through it.
Re: Collapsable spacer Question
Posted: Thu Jun 02, 2011 10:05 am
by hulsty
Are you sure its not some kind of other under lying issue? Has the spacer DEFINITELY shortened after installation? Could the bearings be failing due to some other issue.
IMO a solid pinion spacer is a good idea anyway, I have been running them front and rear now for a few years with no issues and it makes a pinion seal change out a breeze.
Re: Collapsable spacer Question
Posted: Thu Jun 02, 2011 10:46 am
by chimpboy
I like the logic of collapsible spacers but I've replaced them with solid ones in a few settings, in practice they often seem to have the kind of problem you've described.
Re: Collapsable spacer Question
Posted: Thu Jun 02, 2011 12:06 pm
by dogbreath_48
Can someone explain how a collapsible spacer fails and how a solid spacer remedies the situation? History has shown solid spacers to be beneficial but what's the theory behind it? Besides the housing or pinion shaft distorting I cant see any way the spacer could he further crushed.
Re: Collapsable spacer Question
Posted: Fri Jun 03, 2011 12:53 pm
by rockcrawler31
dogbreath_48 wrote:Can someone explain how a collapsible spacer fails and how a solid spacer remedies the situation? History has shown solid spacers to be beneficial but what's the theory behind it? Besides the housing or pinion shaft distorting I cant see any way the spacer could he further crushed.
From what i interpret from reading how to's on rebuilding a diff center, the pinion shim just behind the main pinion bearing is what sets the distances inside the diff with regards to mesh of the teeth and regardless of what the spacer does this will not change.\. The spacer, collapsible or otherwise simply sets the preload on the pinion bearings. I don't know how the collapsible spacers fail other than some monkey balls'ing up the torque on the pinion nut.
as for how it remedies it, it goes basically like this
The collapsible spacer is set up by tightening the pinion nut until the spacer STARTS collapsing then it is tightened up until the preload on the bearings (measured with a very small torque wrench - think inch/pounds) is correct and then the pinion nuts is "spiked" on to the pinion so it can't move. The solid spacer is set up with shims or by machining it down to the correct size so that when the pinion nut is tightened to a set torque (around 90ft/lbs from memory) the bearing preload is correct. It's more time consuming to do it this way and thus more expensive when being done by a shop.
I believe that with a crushable spacer should the spacer become loose for whatever reason, there can be some lateral slop (not axially or longitudinally as this is set by the rear shim) in how the pinion is held by the bearings/races which allows the pinion/ring gear mesh to alter.
At least that's how i interpret the documentation i've read.
Re: Collapsable spacer Question
Posted: Fri Jun 03, 2011 4:30 pm
by TheBigBoy
Sorry to here cranky. How was the cape anyway? I want pics...