L31MaxExpress
I'm Awesome
I noticed my distributor making some weird noises. The rotor tip was contacting the cap electrodes, causing a clicking/tapping sound. I pulled it out and discovered I had 0.055" end play and cracked distributor cap mounting bolt holes despite the thing being aluminum. The gear had some wear too. I pulled a new distributor out of the box and it had greater than 0.040" end play. I shimmed the new distributor down to 0.017", closest I could get to my target of 0.015". I ended up having to shim the distributor body with a 0.060" nylon shim to prevent it from bottoming out on the oil pump drive shaft. When I shimmed the drive gear down, it stacked the oil pump drive shaft solid and the base would not seat in the intake fully without the gasket in place. Oil pump drive shaft needs ~0.050" clearence gap to allow for heat expansion to prevent from shoving the oil pump gear into the housing. Distributor is nearly silent now. That is a 0.015" feeler gauge relative to the end gap of the old distributor. I checked a low mileage OEM GM plastic distributor and it had even more end play. I cannot believe they let these roll out of the factory as loose as they are. No wonder the CMR dances all over the place relative to RPM change and the gears wear as quickly as they do. Straight garbage tolerances, especially the OEM distributors. My CMR does not even vary 1° now snapping the throttle, reving the engine from 1,000 to 6,000 and coasting back down to 1,000. The engine seems to run more smoothly as well, could be placebo, but it seems to none the less.
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