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489 case solid spacer woes making me angry

Posted By: jamesc

489 case solid spacer woes making me angry - 10/31/14 01:08 AM

doing a 489 with a solid spacer, parts were given to me the spacer is from richmond (just spoke with owner)

spacer was too long (normal) so i surface ground (vertical spindle surface grinder) both ends to make them square. the spacer was binding on the pinion so blue the spacer to see where it's hitting, relieve the ID some (very little). put it together, check it again with indicator, needs .025" off it to start with. chuck it in lathe, trim the 25 off, put it in surface grinder take a couple more off and make sure square. put pinion together torque to 200# get 5inlb of drag. take it apart put spacer in grinder to take some more off.

here's where it starts to make me curse. when i put it in the grinder i had to drop the stone about 3-5 thou iirc which can only mean the "solid" spacer is collapsing. trim some more off mock it up 200# torque and get 20inlb drag.

clean things up, assemble pinion, tighten nut didn't get to 200# and it's tight. didn't want to ruin my low torque wrench but it was over 40inlb and i know that's not all the seal.

so now i'm making up new swear words. this "solid" spacer does NOT look like the Ratech spacers i have used in the past for all i know it could be what Ratech is selling now.

anyone have this problem before? it looks like the spacer is distorting and collapsing.
Posted By: CHAPPER

Re: 489 case solid spacer woes making me angry - 10/31/14 01:19 AM

Are the bearing races still not 'seated' or moving...???
Posted By: jamesc

Re: 489 case solid spacer woes making me angry - 10/31/14 01:37 AM

no they're firmly seated, if they weren't it would get looser not tighter.
Posted By: CMcAllister

Re: 489 case solid spacer woes making me angry - 10/31/14 02:15 AM

I've tried to use the solid spacers in any number of different units. None were the right size and trying to get them right ended up just like it ended up for you. Now I only use the ones that include a shim pack to dial it in. I've found that .001" difference in the shim pack can make as much as 10 in.lb. difference in turning torque.

Available most rear end parts places. The Ratech # is 4102.

ETA...It's been a little while since I've done a 489, but I remember the Ratech pieces to be pretty heavy walled. Not going to crush the one's I've used in the past.
Posted By: CHAPPER

Re: 489 case solid spacer woes making me angry - 10/31/14 03:16 AM

Quote:

I've tried to use the solid spacers in any number of different units. None were the right size and trying to get them right ended up just like it ended up for you. Now I only use the ones that include a shim pack to dial it in. I've found that .001" difference in the shim pack can make as much as 10 in.lb. difference in turning torque.

Available most rear end parts places. The Ratech # is 4102.

ETA...It's been a little while since I've done a 489, but I remember the Ratech pieces to be pretty heavy walled. Not going to crush the one's I've used in the past.





My bad,,,I 'assumed' he was using shims and still having problems. If not using the shims, I can see that it could be hard to dial it in.
Posted By: GTX MATT

Re: 489 case solid spacer woes making me angry - 10/31/14 02:43 PM

I recently did one with an ratech spacer, I wasn't impressed. It came with a shim pack, which I also wasn't very impressed with. I had to reduce the size of the spacer also. I used a lapping table and just ran it in a figure 8 pattern by hand, which took a noticeable amount off quickly. I don't think that this would collapse easy at all, but I also wasn't impressed with the instructions which told me to tighten the pinion nut to 125 ft lbs, which seemed too low to me.
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