Your donations help keep this valuable resource free and growing. Thank you.
|
Cam gear for distributor |
Post Reply | Page 123 4> |
Author | |
Nor Cal CJ5
AMC Apprentice Joined: Dec/03/2019 Location: Nor Cal Status: Offline Points: 126 |
Post Options
Thanks(0)
Posted: Sep/14/2020 at 11:00am |
Here is a picture of the original cam gear.
I replaced the distributor with a Pertonix unit 5 years ago and no issues. I recently rebuilt the motor (no short block) and after about 8 hours of running time, the original distributor drive gear on the cam wore to a knife edge and eventually jumped a tooth. During the rebuild I replaced the timing cover, rebuilt the oil pump, installed the distributor and clearances were checked. I followed Rick Jones' advice and aligned the cam oiling hole with the new timing gear, fuel eccentric, and distributor gear. I used a good conventional 5w-30 oil and an additional zinc additive. With the wearing of the cam distributor gear, the cam wore into the timing cover a bit. What is the consensus on the reason for the issue? Should I just replace both cam gear and distributor gear (Pertronix gear looks fine) or is there something else that needs to be done? Thanks in advance. |
|
1972 CJ5 304 2 barrel 3 speed
|
|
304-dude
AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082 |
Post Options
Thanks(1)
|
From what I gather most distributor drive gears on aftermarket distributors are hardened. Never mix different harnesses. Mallory and MSD have good gears, both in brass and iron. Their distributors come with the proper gear. I obtained a newer (2018) iron gear that has proper hole locations and depth. No guarantees just be sure with any gear obtained to check thoroughly.
|
|
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 |
|
SC397
AMC Addicted Joined: Apr/30/2009 Location: Michigan Status: Offline Points: 5480 |
Post Options
Thanks(1)
|
Did you replace the timing cover with a OE part or a aftermarket one?
|
|
Nor Cal CJ5
AMC Apprentice Joined: Dec/03/2019 Location: Nor Cal Status: Offline Points: 126 |
Post Options
Thanks(0)
|
It was a used OEM cover from a member here. My first thought was some sort of alignment issue - the distributor is bolted to the timing cover and the cam gear can move back and forth. However, these two gears have been working well and have had no significant wear when pulled for rebuilt. The only difference is the timing cover. I don't know what the original cam gear is made from, but I know that Pertronix makes good quality parts. Is a hardened cam timing gear available? I'll definitely get both gears new this time.
Edited by Nor Cal CJ5 - Sep/14/2020 at 1:17pm |
|
1972 CJ5 304 2 barrel 3 speed
|
|
Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6916 |
Post Options
Thanks(1)
|
That gear in the picture is worn on the inboard side on each gear tooth face and the outboard side of the opposite side of the gear tooth face.
This indicates that the gears were not a matched set, or at least not cut correctly. If this was oil or even different hardness issues, the gear teeth should be worn equally on each face. If it was the cam had walked, the teeth should be worn on the inboard. Next gear set, mesh them by hand so they roll nicely and use a good square to ensure you have a 90 degree angle between gear faces.
|
|
Nor Cal CJ5
AMC Apprentice Joined: Dec/03/2019 Location: Nor Cal Status: Offline Points: 126 |
Post Options
Thanks(0)
|
The gear is worn on both sides of the tooth - to a knife edge. EDIT - Sorry - you are right, The gear is mainly worn on one side, just where it wore thru and jumped the tooth is it worn on both sides.
Where can I get a good matched set of gears?
Edited by Nor Cal CJ5 - Sep/14/2020 at 12:33pm |
|
1972 CJ5 304 2 barrel 3 speed
|
|
Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6916 |
Post Options
Thanks(0)
|
I still reuse factory gears so cannot help with new sets.
If you know a wrecker with a few 304's or 360's - that's were I would shop.
|
|
Nor Cal CJ5
AMC Apprentice Joined: Dec/03/2019 Location: Nor Cal Status: Offline Points: 126 |
Post Options
Thanks(0)
|
Here are some better pictures:
Outboard side: Inboard side: When the timing cover was removed, oil was apparent on the gear. The depth of the groove shows approximately 1/2 of the cam gear was engaged. One thin gasket at distributor base. |
|
1972 CJ5 304 2 barrel 3 speed
|
|
304-dude
AMC Addicted Joined: Sep/29/2008 Location: Central Illinoi Status: Offline Points: 9082 |
Post Options
Thanks(1)
|
To me it looks like the distributor gear is too hard, if it is in near perfect condition. Like others stated, could be gear meshing issues, due to not being matched.
|
|
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 |
|
Nor Cal CJ5
AMC Apprentice Joined: Dec/03/2019 Location: Nor Cal Status: Offline Points: 126 |
Post Options
Thanks(0)
|
The distributer is a PerTronix with a steel gear on it. It is pretty much flawless. I've used the Pertronix and the original Cam gear since 2016 and the cam gear was ok when tore down for rebuilding the top end recently. I've looked around for a new set and all I see is the Crown and Omix-ADA stuff. I did see that MSD has an iron cam & dist. gear set 8005 & 8007 that seems to work for people with AMC motors. I'm trying to figure if that is the route to go right now. Checking with MSD... The distributor gear on the PerTronix shaft is .500 where a standard AMC distributor shaft is .491.
|
|
1972 CJ5 304 2 barrel 3 speed
|
|
Post Reply | Page 123 4> |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |