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Cam gear dilemma |
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6762 |
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So I did a little test to see if there is a difference between 1969 and late 1978 distributor and cam gears.
Just a small facing on the lathe; The distributor gears from these to eras are definitely cast iron. Likely ductile and good quality by the finish. Both, from my perspective, very close to being exactly the same. The camshaft gear from 1969 is slightly softer then 1978, but both are either a face hardened steel or tempered steel. Press with bullet firing pin to dimple, showed same size dimple at 2000 PSI. Hardness is close but cutting finish was slightly different. 1969 was definitely softer "skin". So 74 you are correct on the camshaft gear hardness changed as far as I can tell. But they are definitely different materials.
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304-dude
AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9081 |
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From past experience with bad wear on oem gears, it always ended up with distributor gears being replaced. The cam gear was worn but within good limits. These were post 72 engines. Ever since starting on the internet, the root cause for cam gear failure was either bad oiling flow from cam sprocket, cam end play from loose chain, or the use of hardened distributor gears. As for distributor gear issues with oem gears, is mostly due to distributor alignment (either out of spec from wear, or bad installation of timing cover) I have stated in the past, when bulltear stopped making sets, to use a bronze distributor gear, or MSD. I admit i am no engineer, but to me, with the type of gear mesh used, having both gears of near equal hardness or same material will allow a wear fit before failure. Again, this may be wrong in my reasoning, but this discussion has been inlightening, even though very strong stances have been made on both sides. Edited by 304-dude - Jun/19/2019 at 5:29am |
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71 Javelin SST body
390 69 crank, 70 block & heads NASCAR SB2 rods & pistons 78 Jeep TH400 w/ 2.76 Low 50/50 Ford-AMC Suspension 79 F150 rear & 8.8 axles Ford Racing 3.25 gears & 9" /w Detroit locker |
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74Bubblefender
AMC Addicted Charter Member Joined: Jun/29/2007 Location: The AMC form Status: Offline Points: 2589 |
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Yes I know I was right (pat, pat) but like I said there is a lot of speculation that will get you into trouble when your building an AMC or maintaining one.
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We are just about to forge new AMC V8 crankshafts.. please check here
http://www.bulltear.com/forums/showthread.php?19564 |
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