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Distributor Gear / Cam Gear issues. As experienced by Randal Needham 31 Jan 2009 Let me start by saying I will not name manufacturers as this seems to be an issue with any after market distributor when mixing original and replacement gears. My experience is as follows. I had rebuilt my 304 and wanted to make it look a bit more impressive so I purchased an inexpensive HEI and installed it without any problems. Drove it for a while and then went to pick up parts from Craig another AMC owner with a very hot 74 AMX. He had a stock duel point distributor so I mentioned the HEI I installed in my car. He Then related his issues with a name brand distributor eating up his cam gear after only a few hundred miles. Well I had almost 800 or 900 miles on mine so I figured I was okay. Then one day it decided to backfire (carb issues) and quite running. A tow truck and home it went. I knew by the sound it was making it had jumped time but I was confused since I knew I had new timing gears, and chain. Next step it to verify pulling number 1 plug, setting to top dead center and pulling distributor cap verified it had jumped time. Pulled distributor and upon inspection I could tell cam gear had jagged edges (big problem). So pulled timing cover and discovered cam gear was chewed up (another frightening light bulb went off, METAL SHAVINGS ALL THROUGH MY LESS THAN 1200 MILE REBUILD). My next step was to jump on the internet to see if any one else had this issue. To my amazement many have, some due to poor machining of cam and distributor gears not having the needed holes or flashing blocking those holes preventing oiling of the cam and distributor gear. I checked all my equipment and did not find any oiling issues. More searching finally revealed issues with the gears themselves, from not having chamfered gear edges, to different machining of gear widths. I forget the web site that finally noted there are 3 different type of cam gears and 2 different types of distributor gears. The thing to do is to remove your old distributor gear and put it on the new distributor which should result in a better result than I and many others have experienced. I have purchased a match gear set and in the process of putting it back together. I will update the note later after I get some miles on it. By the way I rinsed motor out with mineral spirits, and did not get many shavings out and did not see to many others in the oil pump housing or in the timing cover. I figure if the shavings did manage to get to the cam, main, or rod bearings the damage has already been done and I am going to run it till it drops then it will be 401 time. |
