MSD Distributor gears

[jeepmonster]

Are MSD distributor gears now the cause of cam gear failure? Seems like every year or 2 some new "latest reason" for gear failure appears on the net. I dont quite get it. FWIW I bought an MSD billet distributor about 10 years ago, dint install it until 4 years ago used the supplied lube and original cam gear and installed the distributor with the suupplied gear from MSD as installed out of the box. Never had a problem lots of burnouts and highway driving.

[jeepsr4ever]

I have heard about people having issues with their bronze gear and other makers bronze gears. I would suspect the material integrity its enough to support the AMC oil pump. For some bronze works well but for others using various high viscosity oils and different styles of oil modifications they are plagued by these issues. One of the main issues is that AMC camshaft gears do not allow a smooth operation and a "no break in" condition. Both gears must find a pattern for wear. Using a very soft distributor gear and a "new" or unused camshaft gear will cause damage to the distributor gear. To run a soft gear you must have a good OEM or aftermarket camshaft gear that has been run and has a nice wear pattern (Hard to do!) Then you can switch to a softer gear.


Bronze gears for the AMC V8 came from Chevy development when the roller camshafts were used the camshaft material was so hard it would chew up the stock chevy steel distributor gear. This was because they couldnt find a wear pattern and the roller cam gear (Which is integrated into a chevy camshaft) was often a rough cut gear. It didnt take long for camshaft mfgs to realize they needed to do something quick. I cant rmember his name but he worked for a small company that helped develop the roller camshaft. Well needless to say the gear hobbing got better and as a fix they made the distributor gear a sacrificial parts of the system and by MATCHING the tooth profile of the helical gear they were able to obtain a large load on the bronze without tearing it apart.


AMC oil pumps are larger than a Chevy SB and require a gear set that can take a greater load. Alot of gear engineering and info is needed to make a matched set that will last. I remember some from the mid ninties when we had a gear engineer working with us here in our shop. Their is alot more to gears than I had ever thought and he even made a computer program for gear design. We now have 7 different distributor gears and 3 different camshaft gears being made out there that I know of and finding a good matched set is critical. Some claim that the bronze gear allows them to take their distributor out and reinstall without a gear failure. I have seen and have done unistalling and reinstalling of the distributor using different clocking and as long as the set is matched your in good shape. It has been my experience that their simply is no sacrificial part in a AMC V8.

[jeepmonster]

Good Info, the wear pattern on the MSD gear and the gear on my original delco distributor are EXACTLY the same, I am reusing the original cam gear for my rebuild and going to just drop in the MSD again, but I WILL use the MSD gear lube again. The MSD instructions are IMPLICIT that their gear lube be used when Removing and reinstalling a distributor, its stucky stuff and byt the time its washed off by engine oil it has protected the gears, I am sure there is a % of people that ignore the instuctuins and ruin gears from not using lube.

[donwag]

I have an MSD dizzy with the MSD gear in my 401. I tried to install the matched original gear on the MSD dizzy and found out the MSD gear is slightly different than than the OEM in the distance from the pin hole to the gear.

To make a long story short, used the MSD gear, about 3K miles now and on inspection the gear looks fine.