#1  
Old 02-14-2019, 08:04 PM
mtnbktrek mtnbktrek is offline
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Default 70 Gto pinion race housing issue

70 got 10 bolt modular rear was just tearing it apart for a rebuild bc the dude I bout it from off this forum lied to me. Anyway I knocked out the outter pinion race and noticed he had put in 15 or so punch marks- if you understand why the punch marks are there please reply if not please don’t.! Is there any saving this housing? Should I rebuild it bc the pinion race I just knocked out didn’t spin and was tight in there. Can it be bored out and do they make oversized OD races for this problem?

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1968 LeMans Convertible - 462 w hydo roller comp cam forged flat tops- 6x-4 heads- performer intake - 800 cfm QJ- edelbrock 110 gph mech fuel pump- 4 row copper rad- followed by a Th400 w/2300rpm stall then a nodular 10 bolt posi w 3:90 gears ( need 3:55 bad
  #2  
Old 02-14-2019, 08:27 PM
68azbird 68azbird is offline
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A good locktite will work to hold that race so it never spins.
Just make sure you clean out where the race sits really good with solvent

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Old 02-14-2019, 08:36 PM
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lust4speed lust4speed is offline
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Punch divots inside the housing bore are used to tighten up the diameter. They effectively reduce the size allowing the bearing race to fit tight where it might otherwise have some slop. With today's questionable quality of bearings, the race just removed could have been undersized, and another make bearing might not have needed the peening process. I wouldn't be afraid to go ahead with the rebuild if the bearing race is tight.

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Old 02-14-2019, 08:46 PM
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Have you posted in the business exchange section about it?

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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule.
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Old 02-14-2019, 08:50 PM
mtnbktrek mtnbktrek is offline
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Nice - it looks as if the pinion bearing locked up and spun in the housing and that’s y they put the punch marks in it. I’m worried it might not be square. The guy told me it was rebuilt and only ran like 1k miles before I bought it. He also said it was a 3:55 but turned out to be a 3:90. He wouldn’t let me open it up but everything was tight and he seemed like an alright guy so I bought it but before I knocked it apart the pinion bearings were shot the pinion moved in and out of the housing like 1/8”.

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1968 LeMans Convertible - 462 w hydo roller comp cam forged flat tops- 6x-4 heads- performer intake - 800 cfm QJ- edelbrock 110 gph mech fuel pump- 4 row copper rad- followed by a Th400 w/2300rpm stall then a nodular 10 bolt posi w 3:90 gears ( need 3:55 bad
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Old 02-14-2019, 08:50 PM
mtnbktrek mtnbktrek is offline
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No this is first place I posted about it

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1968 LeMans Convertible - 462 w hydo roller comp cam forged flat tops- 6x-4 heads- performer intake - 800 cfm QJ- edelbrock 110 gph mech fuel pump- 4 row copper rad- followed by a Th400 w/2300rpm stall then a nodular 10 bolt posi w 3:90 gears ( need 3:55 bad
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Old 02-14-2019, 09:09 PM
mgarblik mgarblik is offline
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The race needs to fit tightly in the housing. I would try to source SKF, bearings for the rebuild. Timkin is still decent, but made in China now. The punch marks were to tighten the fit of the cup in the housing. I would use a liberal coating of Locktite 290 (green) on the OD of the cup and put it in. It must be absolutely clean with brake clean or lacquer thinner. Solvent, won't get it clean enough and leaves an oily film. The pinion moving in and out 1/8" means the pinion bearing pre-load is all screwed-up. You need a new crush sleeve and a new drive pinion nut. The rotating torque with new pinion bearings all lubed-up with an inch lb. torque wrench is 25-30 in. lbs. rotating with a beam wrench.

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Old 02-14-2019, 09:12 PM
mtnbktrek mtnbktrek is offline
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Ok so thoughts are rebuild it then? I have a new Yukon posi gears and install kit ready to go in. The install kit has USA made Timkins

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1968 LeMans Convertible - 462 w hydo roller comp cam forged flat tops- 6x-4 heads- performer intake - 800 cfm QJ- edelbrock 110 gph mech fuel pump- 4 row copper rad- followed by a Th400 w/2300rpm stall then a nodular 10 bolt posi w 3:90 gears ( need 3:55 bad
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Old 02-14-2019, 09:21 PM
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Is the posi tight? Do you have pics?

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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule.
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Old 02-14-2019, 09:35 PM
mtnbktrek mtnbktrek is offline
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Posi was tight only pinion loose

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1968 LeMans Convertible - 462 w hydo roller comp cam forged flat tops- 6x-4 heads- performer intake - 800 cfm QJ- edelbrock 110 gph mech fuel pump- 4 row copper rad- followed by a Th400 w/2300rpm stall then a nodular 10 bolt posi w 3:90 gears ( need 3:55 bad
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Old 02-14-2019, 09:54 PM
mtnbktrek mtnbktrek is offline
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Here is the pic
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1968 LeMans Convertible - 462 w hydo roller comp cam forged flat tops- 6x-4 heads- performer intake - 800 cfm QJ- edelbrock 110 gph mech fuel pump- 4 row copper rad- followed by a Th400 w/2300rpm stall then a nodular 10 bolt posi w 3:90 gears ( need 3:55 bad
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Old 02-15-2019, 06:58 AM
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Did the pinion have fore and aft play or was the bearing race spinning?

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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule.
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Old 02-15-2019, 01:22 PM
mtnbktrek mtnbktrek is offline
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This last race I just pulled out didn’t spin. If you grab the yoke and pullout it’ll go 1/8” while you are pulling on it it will move left and right a tiny bit

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1968 LeMans Convertible - 462 w hydo roller comp cam forged flat tops- 6x-4 heads- performer intake - 800 cfm QJ- edelbrock 110 gph mech fuel pump- 4 row copper rad- followed by a Th400 w/2300rpm stall then a nodular 10 bolt posi w 3:90 gears ( need 3:55 bad
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Old 02-15-2019, 01:37 PM
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Was the pinion nut torqued appropriately and was the crush collar in it when it moved in and out 1/8"? Was this supposed to be a ready to use rear?

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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule.
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Old 02-15-2019, 02:35 PM
mtnbktrek mtnbktrek is offline
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Crush collar was in I didn’t check the nut bc I didn’t think the core housing was “repaired” I put like 500 miles on it but the 3:90’s were stupid

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1968 LeMans Convertible - 462 w hydo roller comp cam forged flat tops- 6x-4 heads- performer intake - 800 cfm QJ- edelbrock 110 gph mech fuel pump- 4 row copper rad- followed by a Th400 w/2300rpm stall then a nodular 10 bolt posi w 3:90 gears ( need 3:55 bad
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Old 02-15-2019, 10:37 PM
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You put 500 miles on the rear with an 1/8" play in the pinion? If you ever went in reverse you would have had a big surprise.

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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule.
  #17  
Old 02-15-2019, 11:08 PM
mtnbktrek mtnbktrek is offline
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Yep - didn’t have an issue backing and I have a pypes system and never noticed noise. But anyway I re punched all those punch marks and added a few and presses in the race - felt ok going in so we will see if it holds.

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1968 LeMans Convertible - 462 w hydo roller comp cam forged flat tops- 6x-4 heads- performer intake - 800 cfm QJ- edelbrock 110 gph mech fuel pump- 4 row copper rad- followed by a Th400 w/2300rpm stall then a nodular 10 bolt posi w 3:90 gears ( need 3:55 bad
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