Alton Sheer Plugs

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been following this thread since it directly applies to my alton starter on-going issues. i sheared my 3 pins within about 20 starts. they were not OE alton pins, but some poly stock i bought at McMaster-Carr. really seems like the same material. i was able to measure out my original pins, and they came in less than 10mm and closer to 3/8th or .375 stock. i also had some 10mm poly stock - made pins and they seemed TOO tight - almost had to force the two halves of the assembly together. note the difference in diameter between .375 and 10mm is .0187". i think there lies the problem. when you first hit the starter, that play in the two part assembly is the weak link. seems to me, theres an initial shock when the starter first engages because of that free play. that initial shock plays hell with those pins. what i did, and NOT saying this is the solution, but i'm giving this a try. i installed three .375 pins, AND one 10mm pin. the one 10mm pin takes up the free play in the two haves of the assembly, and should take care of that initial shock when the starter motor is first engaged. the durometer rating of the 10mm pin is 80A, and the .375 pins is 95A - both considered "hard" on the A-scale. i have nothing scientific, or any engineering to back up what i'm trying, but it seems problematic to me to have any free movement in the assembly. anyway, wrapped things up today, and back on the road tomorrow.
 
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The Alton plugs do resemble sliced up glue sticks, but they obviously ain't :rolleyes:

I agree, I'm pretty sure that any play will increase with each operation of the starter until they shear, so zero play (or tight) is probably critical in this application.

I just measured all my spare Alton pucks, and they range from 9.71mm to 9.95. I've never had to change mine, so not sure how tight they would be.
 
Even to me: Less 20 starts, defect. So by the end od the day should be an assembling of 6 pins also solve that issue of backlash.
What is the material you use?
May you have a link? As I understood McMaster carr is a supllier for tooling andraw material.
I still wait for new pins, but France and Germany seems like Earth and Mars. Not arrived after 7 days by mail!
 
So out of interest, what primary are you running, belt or chain ?
 
Seems to me that unless you know exactly what the alton shear pin material is and can duplicate the exact dimensions, it would be best to get the pins directly from Alton. If my Alton (installed in 2012) has shear pins in it, they haven't sheared yet in uncounted starts! ;)
 
joe czech said:
been following this thread since it directly applies to my alton starter on-going issues. i sheared my 3 pins within about 20 starts. they were not OE alton pins, but some poly stock i bought at McMaster-Carr. really seems like the same material. i was able to measure out my original pins, and they came in less than 10mm and closer to 3/8th or .375 stock. i also had some 10mm poly stock - made pins and they seemed TOO tight - almost had to force the two halves of the assembly together. note the difference in diameter between .375 and 10mm is .0187". i think there lies the problem. when you first hit the starter, that play in the two part assembly is the weak link. seems to me, theres an initial shock when the starter first engages because of that free play. that initial shock plays hell with those pins. what i did, and NOT saying this is the solution, but i'm giving this a try. i installed three .375 pins, AND one 10mm pin. the one 10mm pin takes up the free play in the two haves of the assembly, and should take care of that initial shock when the starter motor is first engaged. the durometer rating of the 10mm pin is 80A, and the .375 pins is 95A - both considered "hard" on the A-scale. i have nothing scientific, or any engineering to back up what i'm trying, but it seems problematic to me to have any free movement in the assembly. anyway, wrapped things up today, and back on the road tomorrow.
Click to expand...

I measured my spare pins at a diameter of 0.384" - so they are about half way between 10mm and 3/8"... they fit snug when I put them in, not super tight.

And according to the RGM site, they list a durometer of 90.

My nylon 6/6 pins that I machined (x6) are holding up well so far, I likely have over 50 starts on them now.

FWIW
 
MexicoMike said:
Seems to me that unless you know exactly what the alton shear pin material is and can duplicate the exact dimensions, it would be best to get the pins directly from Alton. If my Alton (installed in 2012) has shear pins in it, they haven't sheared yet in uncounted starts! ;)
Click to expand...
Hey Mike - out of curiosity, what oil are you running in your primary?
 
just measured mt MMC stock. the 3/8 material averaged .368, and the 10mm measured in at .390 - both a little on the shy side. i tried four 10mm pins, and it seemed a little tight. wondering if three would make a difference? i'm sure i'll be tearing into this again down the road. next time, i'll try three 10mm pins. unfortunately, the only 10mm stock MMC has comes in at 80 on the durometer A-scale.
 
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