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Ring Gear for 4A

Posted: Tue Aug 15, 2017 1:48 am
by 2001f4s
I discovered that the ring gear on my fly wheel is just a mess and needs replacement. Is anyone aware of a source for a ring gear. Mine has 112 teeth.
Is there an alternative that will work well on the 4A.

Thanks for looking and for your input

Re: Ring Gear for 4A

Posted: Tue Aug 15, 2017 1:14 pm
by Paul Bouchard
Ring gear usually wear in two spots 180 degrees apart from each other. They are a press fit so you can try to take it off and rotate it by 90 degrees and/or flip it around front to back. Just check to see if the teeth are the same profile on the front and back.


Re: Ring Gear for 4A

Posted: Fri Aug 18, 2017 2:45 am
by bitsobrits

Um...I don't get the "remove the ring gear and rotate 180 degrees". Isn't that the same as just rotating the engine by 180? The starter pinion and ring gear do not engage at the same point, over and over, due to the large variance in diameter between the two. Every time the starter is engaged, the starter pinion will engage at essentially random points on the ring gear.

As for the "remove the ring gear and flip it around", that could work.

Re: Ring Gear for 4A

Posted: Fri Aug 18, 2017 2:51 pm
by mikeyr
you are right, the ring gears do wear all around. But they do tend to wear in a few spots as the engine when shut down tends to shut down in the same spot in the rotation. Not every time of course and but if you look closely as a well used ring gear you will see 2 or 3 spots that are more worn then the rest of the gear, trying to rotate the ring gear though I find is a waste of time (but I only tried it once) because the engine will stop where it wants to. I read about this in Skinned Knuckles magazine years and years ago and I tried it on my 4AD, it helped but it really was not a solution.

Flipping the ring gear around so the unused side of the gear is now facing the starter pinion is something I have had good luck with as in its worked everytime.

Re: Ring Gear for 4A

Posted: Fri Aug 18, 2017 3:51 pm
by indian301
The ring gear should tap off the flywheel, but You will need to heat it up to install it again.

Re: Ring Gear for 4A

Posted: Sat Aug 19, 2017 12:54 pm
by 2001f4s
Mine seems to show damage almost 270 degrees around, but I think what Paul describes with flipping it over will work for mine. Thank you

Re: Ring Gear for 4A

Posted: Wed Aug 23, 2017 7:53 am
by GuyBevan
I purchased the correct ring gear for my Singer 4a from Magnum performance Products. 35 Marni St. Dandenong South, Victoria Australia
Phone +6139706 6554

The sell on Ebay Australia for $A 195.00
Part number is 112TRG#226
112 teeth 288mm outer
267.3mm inner
Michael is the contact
They do not show this part no. on their online store but they have it
Hope this helps

Re: Ring Gear for 4A

Posted: Sun Sep 03, 2017 2:07 pm
by 2001f4s

Great information. Thank you much for that information. Sent an e-mail inquiry to them.

Thanks again. Not likely I would have found them without your work