Camshaft crankshaft correlation problem
 

I have 2002 blazer 4.3 4x4
the gear on the bottom of distrib.
Wears out and eventulaly causes ignition problems
this is third one i put in, be lucky to get it to run this time
very bad design. Too bad was a nice truck
selling for $5,000 needs new cam

Cam gear was probably junked at the time you installed the first new distibutor drive gear. Time to replace the cam and lifter as you said. I havent heard/seen too many examples of this problem.

I bought the suv new . And you should of seen the first distributer i replaced.
I belive that chevy trys to get too much horse power out of standard oem parts and the result is parts internal parts that will fail. So i guess chevy manufacuter put the thing in wrong when it was built on assemblely line.
Either way the motor is junk.
Its for sale if interested 2g all leather power everything 4x4 new tires / brakes
oh well gotta find a job down hill both ways

There may be a TSB or something along those lines for it. I havent seen one. It is a junky pos plastic distributor. First time I pulled it off, I was like, Holy sh!t, why is my distributor plastic! A steel shaft inside of a plastic body, another great idea Chevrolet. There has to be some deflection in the distributor at higher RPM's. Mine still feels loose even after being securely tightened down. Maybe kyle ,hanr3 or one of the smarter guys has read something about it.


Where is your location? NE? I wanna buy your blazer for 2G's..

2g, what color is it ? Miles ? I think it will sell QUICK.

There is virtually no load on the top part of the distributor so why would there be deflection? All of the load is at the bottom where it drives the oil pump which is very close to the gear and to the support point in the block (just above the gear). About the only things that are problematic on these distributors is the vents in the base under the cap and the gear at the bottom which is likely caused by defects in the base metal.

As already said, if you have replaced three gears, your cam is likely chewed up and causing the new gears to go bad. Remove the distributor and have a look down through the hole that it came out of. Look for sharp teeth on the cam gear.

Again, there is VERY little wrong with the design of this distributor, a design that basically goes back to the first small block and beyond. Many of these plastic distributors go far beyond 100,000 miles. And the view point that plastic is not better than metal is quite a misunderstanding. If designed right, plastic can be stronger and cheaper to manufacture than a metal counterpart.