I have an '80 L48. Nicely warmed over with about 224rwhp. Not a 10-12 second car by any means but lots of fun.

Paul's Machine Shop, Springdale, AR, refreshed my DART Iron Eagle heads for $612 "out the door" for the machining, hot-tank, resurface, painting, all-new DART-spec guides, all-new steel valve seats, shims and my k-kit dual valve-spring kit installed and checked). Just bolted and torqued the heads back on the short block today. I've been cleaning and painting parts today after the head install and decided to drive the dizzy gear off of my Accel Performance replacement unit.

The $129 (import) Accel unit has a nice performance re-curve laid down by a long since out-of-business tuner in Tampa that, save for his destroying my primary metering rods back in my early search for performance improvement, did a fine job of adding 40hp to a 160rwhp baseline.

I put a drift to the pin in the dizzy gear and as I prepared to install, discovered that Comp did not set the 'composite carbon' gear up for 'stock' install. The 'hole' is not only too small but there is no hole opposite it on the other side of the gear.

Question: Did Comp tap the piece on one side due to integrity issues? This looks like a glorified 'plastic, carbon, composite' dizzy gear. I'm guessing I need to carefully enlarge the ONE hole in the gear and shorten and debur the dizzy gear pin to fit.

Correct?

 

Should I just use my stock iron distributor gear?

I am installing comp retro roller camshaft 'k-kit'.

They require the '12200' composite dizzy gear for the cam gear.

I've read a few 'grenade' stories about the composite dizzy gear but that was with a lot of spirited driving and the gears were re-drilled (weakened).

 

You have to drill it. That's what I did, I put put the gear on and ran a drill bit through it, the hole in mine was the right size, but only drilled on one side, I know that they make two different shaft sizes and don't know but maybe the roll pin in the accel distributor is larger. The three times I've pulled my distributor since I built the engine, the composite gear looks brand new.

 

Just think for a moment about what puts a load on the gear. The oil pump. I only went to the Comp cams Resin gear because they screwed me by delivering a non sleaved billet cam weeks late. Their fix was to send the poly gear overnight.

I built a non bypass oiling system 427 that would run 80 psi at higher rpm. So I'm out driving around the track and I had just shifted from 4-5th gear on the main straight and the motor went silent. The tach and the oil pressure went to zero, so I whipped into "N" and coasted off on to a return road.

The poly gear lost it's teeth and screwed me out of weekend of racing. I do not think that it is a good product. You shouldn't have to be drilling holes if it was made right. On a stock lower pressure oiling system they might work fine. I now carry a spare one in my Vette for when it fails.

 

Try a Lunati everwear gear on there forget those plastic gears

 

The gear has one undersized hole intentionally: You align the undersized hole with your mainshaft hole, and then match drill all the way through. Although most GM gears are provided pre-drilled, this match-drilling is common: all Ford distributor gears (from Ford or from NAPA & others) come with only one undersized hole with the intent to match drill the gear to the shaft. This assures that the holes are exactly in-line so that the pin does not put a twisting load on the composite gear. Drill the hole all the way through - do not shorten your pin and install it though only one wall of the gear - that will result in certain failure.

Lars

 

Good info. Thanks Lars.