I wish my engine would quit eating the distributor gear.....

[jaredgoodwin]

Engine: 1969 351W
So over the last month and a half I have had ongoing problem with my distributor gear(s). For some reason, my distributor gear is wearing badly. The first time this happened, I replaced the distributor (still under warranty), and within two weeks I had the same problem. After two distributors, the cam gear was shot. So two weeks ago, I tore the engine apart. I replaced the high volume oil pump with a standard volume in an attempt to reduce the load on the gears (Tightend the bolts with distributor installed to ensure everything was lined up). I installed an ARP driveshaft (and I checked for block to shaft clearance as well as shaft to distributor). I replaced the camshaft (Summit cam flat tappet SUM-3601). I am using a (third new one) duraspark II distributor from a mid 70's truck. I used moly lube on both the cam gear and the distributor gear. After a little over a week and a half, I checked my ignition timing (indicator that the gear is wearing, timing backs off as gear wears), and it was off by 5 degrees. I pulled the distributor and the gear is showing some significant signs of wear. The gear had oil on it when I pulled it out.

Any ideas? The wear pattern on the gear looks fine (as far as teeth engagement depth). I think that insufficient oil is getting to the gear. I have heard you can drill a .030" hole in the plug under the cam sprocket to increase the oiling. I am using a cast iron gear on a hydraulic flat tappet camshaft. The engine has approx 8K on it, for the first 6k I had no problems. Around 6K I took it to school to dyno it and it overheated, blew a head gasket. Before I figured out the head gasket was blown, I tried a different distributor, didn't make a difference so I just left the new one in (kind of regret that now, but hey it was free). That distributor lasted maybe 1000-1500 miles before the gear ate all the way through. I replaced it and drove it for a week. After pulling it to check it, it was not good, I parked the car to pull the motor. Replaced everything listed above, and here I sit with another chewed up gear.

Any thoughts or ideas will be appreciated. Let me know if you need more info.

 

[helix007]

get a steel gear

 

[jrichker]

get a steel gear

The camshaft and distributor gear must be made of the same material. Steel distributor gears mate with roller tappet camshafts, and iron distributor gears mate with cast iron flat tappet camshafts.

 

[bluevenom867]

The camshaft and distributor gear must be made of the same material. Steel distributor gears mate with roller tappet camshafts, and iron distributor gears mate with cast iron flat tappet camshafts.

Thats why you get a brozne gear, they work with both.

 

[ratrapp]

how much oil pressure are you running?i had a similar problem with a 304 jeep engine i had built years back.my motor would eat up a dis. and cam gear in about 1k miles.i had a new edelbrock cam,it didn't matter because the cam gear bolts to the cam.i had plenty of oul pressure,apparently too much.the gear was wet but not wet enough,all of the oil was being pushed to the top of the motor and burning up my gears.i eventually found an old hotrod article about splicing into the oil sendind unit line and drilling a hole in my timing chain cover and suppling oil to the gears like this.it never ate up a set of gears again.

 

[QDRHRSE]

I have seen this problem with really hipo 351's. I've been told that a really big set of oil lines and external filters will help by upping the oil volume and reducing the pressure at the same time. I can't remember why....I was at last years Shelby event at California Speedway and one of the racers was talking about the same problem. He put on some mongo extrnal filter and also installed a bronze gear. He said that it helped.

 

[jrichker]

Thats why you get a brozne gear, they work with both.

Bronze is softer than either cast iron or steel. He needs to fix the problem, not make it wear faster because he's using a gear made of softer material.