After reading a few posts, I'm seeing that HEI/DUI drive gears are tearing up cam gears. Is this inherent in all HEI type distributors? Do I need to panic or at least stop driving my Jeep till I replace the distributor drive gear? I still have the old distributor so I have parts, but how necessary is it? And, why would a new distributor have a gear that's not compatible with other engine parts? I sent an email to Performance Distributors asking them the same questions but I'm thinking the Jeep forum would know more about our specific engines and issues so I'll consider the responses here more thoroughly. Thanks.
My engine is a fairly new crate 304 with a mild cam.
The problem isn't with DUI brand HEI distributors. It's mainly with the cheaper HEI's that are using hardened gears.
__________________ '81 Scrambler w/ FI 360 AMC, 33x12.50 BFG M/T's, 5" of lift, ARB'd Dana 44's F & R, Dana 300 clocked & twin sticked w/4:1, Warn XD9000i, etc...
2002 Grand Cherokee Limited, 2008 Overland Grand Cherokee, a 1976 CJ-7 in pieces and 3 more off-brand 4x4s............... John N
"And, why would a new distributor have a gear that's not compatible with other engine parts?"
No NEW cam gear is compatible w/an old/used cam gear, already in your engine..
RDH said it best.
Search function "cam/dizzy gear" whoulda told ya that.
Sorry if that sounds harsh..no java yet.
Now if I can borrow a paint booth to lay down some Loden Green Metallic (w/a little extra metal flake).
I forget who had that sweet Green Golden Eagle that helped me decide to keep it the original color. Thanx guys!
The problem is that the HEI is out of a GM engine that had different specs. As stated by John it is the hardness of the gear that is a concern, if too hard it will eat the softer metal of the cam.
It has nothing to do with the specs of the HEI. These hardened gears aren't the stock HEI gears. The stock HEI gears have the cut going the opposite direction as AMC gears, so they can't be used to begin with.
The problem gears are cheapo AMC V8 gears that are installed on cheapo HEI units made offshore.
Depends... Ford had different gear materials for different engines (ie roller vs. mechanical). Regardless, you never EVER put new gears in with old ones. This goes for axle gearing, engine gears (diesels), distributors , etc. After a TON of miles racked up, the gears wear in together making them a matched set. There's no better way to destroy a perfectly good gear and littering your oil system with metal than to install old on new.
1978 CJ7: 304, 3Spd, AMC 20 Rear, Thrush Welded Mufflers W/ Turndowns, Unknown Front, Worn out Dana 20 case