08-18-2023, 11:57 PM | #1 |
Junior Member
Join Date: May 2008
Location: spicer mn
Posts: 60
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72 c20 pinion angle
Does anybody have or could measure their pinion angle on their 1972 c20. I'm trying to get a reference so I can set mine up
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08-19-2023, 09:18 AM | #2 |
Post Whore
Join Date: Feb 2016
Location: Portland Oregon
Posts: 11,350
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Re: 72 c20 pinion angle
It's not really that simple.
Is your truck a coil or leaf spring truck? Two or four wheel drive? Is it lowered? Is it lifted? Does it still have the factory drive train? Two piece driveshaft? How old are the engine and transmission mounts? The pinion angle needs to be set up in relation to the transmission output yoke's angle (also known as the engine angle) So if I told you my pinion angle was up 2.5 degrees it is unlikely that would mean much when it came to your truck. Here is a current thread on the subject with links to further information to help understand the the physics involved. http://67-72chevytrucks.com/vboard/s...d.php?t=846700
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Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377 |
08-19-2023, 09:36 AM | #3 |
Senior Member
Join Date: Dec 2009
Location: TN.
Posts: 8,408
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Re: 72 c20 pinion angle
The answer you get most of the time is 3 degrees or less.
In a Truck this is sometimes not going to happen in the Real world. Especially with bigger tires and lift kits or lowering kits. Here is one link talking about it. Link: https://www.motortrend.com/how-to/pinion-angle-change/ Here is a Calculator that member HO455 shared a couple of years ago. link: https://spicerparts.com/calculators/...gle-calculator
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________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build |
08-19-2023, 10:27 AM | #4 |
Junior Member
Join Date: May 2008
Location: spicer mn
Posts: 60
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Re: 72 c20 pinion angle
I get the 3 degrees deal I'm just looking at stock coil C20
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08-21-2023, 09:42 PM | #5 |
Registered User
Join Date: Mar 2005
Location: Jurupa Valley, Ca
Posts: 1,210
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Re: 72 c20 pinion angle
If you have a 2 piece driveshaft, basically if the front driveline is 3 down make the pinion 3 up. so that they are parallel. Problem is that the pinion moves up on acceleration so some say to make the rear 1-2 up at most. as far as the engine/trans goes, the front driveshaft should be within 1 1.5 degrees the same slope as the engine trans combo. Are you having vibration issues?
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Terry 1970 Custom Camper/C20 , GM Crate 350/7004R, Dana 60, factory AC |
08-22-2023, 06:54 PM | #6 |
Senior Member
Join Date: Feb 2010
Location: Falls City, Nebraska "100 Miles From Nowhere"
Posts: 2,219
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Re: 72 c20 pinion angle
I just measured two of my trucks, they're both 3 degrees up and both 3/4 ton 2WD trucks. One is leaf sprung, the other is coil. One truck has a factory two piece drive shaft, the other has a factory one piece shaft, both trucks at factory suspension heights.This subject gets so blown out of proportion that the simple necessary facts get lost in the non-pertinent details, (BS)! HO-455 pretty well summed it up, we need more info! How many shafts? Automatic or stick? Motor and Trans on factory mounts and crossmembers? The bottom is, the crank centerline should be in the neighborhood of 3 degrees down. The pinion angle should match or closely match the same angle as the motor, only up not down. They should be looking at each other for the optimal set up... Two piece shafts are a little more detail oriented than one piece shafts. U-joints need to work in tandem, one counters the other. That goes out the window if that carrier bearing centerline is not inline with the crank centerline! Then the final two u-joints play in cancellation harmony...Why are you asking for pinion angles? Did you twist the trailing arm perches on the axle? I did that on Nasty Sally's 12-bolt when I put big block juice to the rusty factory mounts.
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Michael of the clan Hill, "Two Seventy Two's" 71 1-ton Dually 350 4-Speed 71 C/50 Grain Truck, 350 Split-Axle 4-Speed 02 3/4 ton Express 14 Indian Chief Vintage 1952 Ford 8N, "Only Ford Allowed On The Property" "Be American, Buy American" Last edited by Ironangel; 08-22-2023 at 07:11 PM. |
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