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Re: Starter Ring Gear

To: Triumphs Mailing List <triumphs@autox.team.net>
Subject: Re: Starter Ring Gear
From: Pete & Aprille Chadwell <pandachadwell@mac.com>
Date: Mon, 29 May 2000 19:49:45 -0700
Michael Graham wrote:

>>I know this has been discussed over the years having searched through the
>>archives. But here is my question: The ring gear on the TR6 definitely
>>looks backwards to me, and several people in the archive stated that they
>>had "reversed" it and reinstalled it with the bevel toward the starter. I
>>am getting my flywheel resurfaced and am inclined to reverse the ring gear
>>at the same time to have a "clean surface" next to the starter. Has anyone
>>on the list done this reversal and what have been the long-term effects?
>>Any good reasons for not doing it? Any starter engagement problems?
>>
>>As usual, thanks very much for any assistance.
>
>
>I realize that there's been some controversy on this topic, and I 
>can't explain how some people apparently have had success with 
>putting the ring gear on with the bevel AWAY from the starter.  That 
>boggles my mind.
>
>The DPO of my car didn't have the brains God gave an artichoke. 
>When he replaced the clutch, one of the many things he screwed up 
>beyond belief was this:  He made the keen observation that one side 
>of the ring gear was beveled.  In fact, he mistook this bevel as a 
>sign of WEAR.  So, he removed the ring gear and flipped it around so 
>that the starter would have 'fresh' teeth to bite on.  He TOLD us 
>this... this isn't just what my dad and I surmised at the time. 
>(this was in 1986)  And in fact, he had been going through starters 
>left and right... so much so that the day we took it home there 
>actually was NO STARTER on the car.  We had to push-start it.  The 
>starters that he had taken OFF of the car had damaged bendix drives 
>and the DPO couldn't figure out why.  Obviously, the starter was 
>having great difficulty slipping into mesh with the ring gear, even 
>to the extent that it was damaging the bendix drive.  It wasn't long 
>after bringing the car home that dad and I had to tear into the 
>clutch.  (it barely worked at all) and in the course of that 
>endeavor, we removed the ring gear and had it re-installed 
>bevel-side TOWARD the starter.  In 1988 & '89, when I rebuilt my 
>engine, I had NEW ring gear put on, just as a matter of course, and 
>when I picked it up at the machine shop I immediately noticed that 
>they had installed it bevel-side AWAY from the starter.  I demanded 
>that they reverse it and when my engine and newly rebuilt gearbox 
>went back in, it had a brand-new ring gear with the bevel facing the 
>starter. Since I've owned the car (and that's 14 years) I've 
>replaced the starter exactly ONCE.  And that was simply due to 
>normal wear and tear... nothing unusual in the least about that 
>repair.
>
>The other thing I'd like to point out is that if you give the matter 
>some serious thought, there cannot possibly be ANY reason, on a TR6, 
>to put the ring gear on backwards.  On a GT-6, however, the starter 
>engages from the REAR so in THAT case it IS logical.  But I ask you 
>this:  The engineers at the factory spent a certain amount of effort 
>to design a bevel into that ring gear and the machinists who 
>manufactured the ring gears put effort into MACHINING the bevel into 
>the ring gear.  On a TR6, what would be the purpose of installing 
>the gear backwards?  Whatever purpose that bevel is supposed to 
>serve cannot POSSIBLY be served with the bevel on the back side 
>where it doesn't interact with any other parts.  In other words, if 
>it was SUPPOSED to be installed facing AWAY from the starter, then 
>the factory engineers would have been wise to omit the bevel 
>altogether... wouldn't you think?  Why would it be necessary at all?
>
>Conversely, there obviously IS a benefit and purpose to installing 
>it toward the starter.  It makes it much easier for the bendix gear 
>to engage the ring gear.  The same thing is done to the dog teeth in 
>your gearbox... the dog teeth have to fit into the synchro hub 
>splines in order for the gear to be engaged.  And each and every one 
>of those dog teeth has a bevel and those bevels face the synchro 
>hub, not away from it!!  This makes it much easier for the synchro 
>hub to "find" the dog teeth and leaves virtually NO surface area 
>with which to clash... the bevels on the teeth guide the hub into 
>mesh with the teeth when you engage a gear, after the synchros have 
>equalized the speeds of the hub and gear.  It's the same principle.
>
>If someone else has some logical explanation as to what purpose the 
>bevel serves when faced away from the starter, please step forward 
>and make yourselves heard.  I'd love to hear it.
>
>Perhaps the angle of the bevel creates a particular air current 
>within the bellhousing while the engine is running that is useful in 
>some way?
>
>'Nuff said.
>
>Best of luck!!

-- 
Pete Chadwell
1973 TR6

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