Dizzy gear

I bought a Mallory Dizzy gear from a member on here a while ago, well I'm ready to install it onto my MSD 8580 Dizzy and it fits ok but the role pin is twice the size of the MSD shaft, so do I just drill out the Dizzy shaft for the bigger role pin or will that make the shaft week with the hole being twice as big???? or do I just order the MSD gear??? thanks for any input guys

I'd drill it! or you could redrill the gear just turn it 1/4...

butterbean wrote:I bought a Mallory Dizzy gear from a member on here a while ago, well I'm ready to install it onto my MSD 8580 Dizzy and it fits ok but the role pin is twice the size of the MSD shaft, so do I just drill out the Dizzy shaft for the bigger role pin or will that make the shaft week with the hole being twice as big???? or do I just order the MSD gear??? thanks for any input guys

I am a little confused here so I am going to include a few pictures, pictured is a MSD #8580 which has a bigger roll pin than the Mallory #5756701 I believe they both have the same shaft size .531

I would not just drill it out unless I knew exactly what I had, and the correct size of hole required, as I would be more worried about the hole size being incorrect and the roll pin falling out than I would be about the shaft failure.

Unfortunately I do not have a caliper here so these photos are far from technical but for demonstration purposes they show the 2-distributors with the shaft on the MSD being slightly longer, with a BIGGER roll pin.

IMO - Buy the gear for the #8580 don't risk the failure.



MSD



Mallory



MSD on top




MSD on top

cool40 wrote:I'd drill it! or you could redrill the gear just turn it 1/4...

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cool40 wrote:I'd drill it! or you could redrill the gear just turn it 1/4...

redrilling the gear is the smart thing to do. what is there is a need for a 3rd gear change? more holes drilled in the shaft a good thing

thanks guys, I drilled the dizzy gear and turned it 1/4 before doing so, the 8580 dizzy had a much smaller role pin than the mallory gear, I thought if I drilled the dizzy shaft it would have made the shaft weaker due to a larger hole in the shaft so thanks again

FWIW I have drilled the shaft bigger for the next size up roll key without any issue.

If you drill the shaft out will when you install the gear will it be set right if not I would just turn it 1/4 turn and drill the gear where the hole need to be when the dizzy is installed.