 Beezerbob
Silver Supporting Member
Posts: 30
Loc: Georgetown
Reg: 01-21-10
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05-20-10 04:25 AM - Post#1917737
 As I remember there are 2 different sizes of pilot bearings for chevy trucks !? 1965 1/2 ton . Right!?
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brokenspoke
Forum Newbie
Posts: 21
Reg: 02-28-08
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05-20-10 07:33 PM - Post#1918148
In response to Beezerbob
I remember that if the engine came from factory with a automatic, the crank took a smaller bearing if adding a standard transmission
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 Vaughn
"11th Year" Gold Supporting Member
Posts: 13637
Loc: Colorado Springs, CO
Reg: 08-08-04
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05-21-10 08:52 AM - Post#1918346
In response to brokenspoke
As far as I know, there is only one pilot bearing DIAMETER, but there are two different types - bronze bushing or roller bearing. You can get either at a local parts store (provided the parts counter person knows what he is doing).
Most GM and other US domestic manual transmissions (car and truck) from late 50s up into the late 70s had a pilot bearing diameter of 1/2 inch.
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Vaughn
"11th Year" Gold Supporting Member
Posts: 13637
Loc: Colorado Springs, CO
Reg: 08-08-04
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05-21-10 09:11 AM - Post#1918363
In response to Vaughn
Correction:
Sidworks PM'ed me, Apparently there is a difference of .025 to .030 inch between the manual and AT trucks. I had not run across this before, but I am willing to take his word for it.
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 pctahlequah
"5th Year" Gold Supporting Member
Posts: 532
Loc: Tahlequah, Oklahoma
Reg: 08-03-08
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05-22-10 06:09 AM - Post#1918772
In response to Vaughn
Am I missing something? The pilot bearing slides along the input shaft to engage/disengage the clutch, right? So why would an automatic need a pilot bearing? Or are you talking about the crankshaft mains?
I don't understand what you are talking about, which isn't unusual for me. 
************* Preston
'66 Chevy 1/2 ton(conversion) LWB 454/TH400/3.08 rear
'68 Impala SS Fastback
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Edited by pctahlequah on 05-22-10 06:22 AM. Reason for edit: No reason given.
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Vaughn
"11th Year" Gold Supporting Member
Posts: 13637
Loc: Colorado Springs, CO
Reg: 08-08-04
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05-22-10 12:33 PM - Post#1918899
In response to pctahlequah
In the chevy motors - they didn't know when they were produced whether the motor would be put in front of a manual or an automatic - so all chevy cranks were drilled for a pilot bearing. Once they got to the main assembly plant, they were mated up to the flywheel/flexplate and the trans they were going to use, and then the identifying numbers were stamped into the block.
It isn't like the 472-500 Cadillac blocks, where only auto transmissions were used behind them - so these didn't have a pilot bearing drilled in these cranks at all - and it is also why it is difficult to set them up for manual transmissions.
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pctahlequah
"5th Year" Gold Supporting Member
Posts: 532
Loc: Tahlequah, Oklahoma
Reg: 08-03-08
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05-22-10 05:41 PM - Post#1919012
In response to Vaughn
Ok...I get it now. You're meaning the hole drilled in the back of the crank to accept the nose of the trans shaft.
Thanks
************* Preston
'66 Chevy 1/2 ton(conversion) LWB 454/TH400/3.08 rear
'68 Impala SS Fastback
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Beezerbob
Silver Supporting Member
Posts: 30
Loc: Georgetown
Reg: 01-21-10
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 05-28-10 04:48 AM - Post#1921781
In response to Beezerbob
As I remember there are 2 different sizes of pilot bearings for chevy trucks !? 1965 1/2 ton . Right!?
 Outside diameter , has to do with crank , forged , cast, ect.
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