Engine and Transmission Tech

tips, technology, tools and techniques related to vehicle driveline components

Go to Thread: PreviousNext
Go to: Forum ListMessage ListNew TopicLog In


coolmg
Mark Cooley

(15 posts)

Registered:
06/22/2008 08:02AM

Main British Car:


pinion gear
Posted by: coolmg
Date: May 07, 2010 07:11AM

Just checking, am I correct in that the pinion gear and ring gear are matched as a pair. Case in point I have a 3:07 ring from a MGC but the pinion gear is not to be found, I was told that a stock B gear would work, is this true?


ex-tyke
Graham Creswick
Chatham, Ontario, Canada
(1165 posts)

Registered:
10/25/2007 11:17AM

Main British Car:
1976 MGB Ford 302

authors avatar
Re: pinion gear
Posted by: ex-tyke
Date: May 07, 2010 09:31AM

"Matched ring & pinion set" is the correct statement and are usually sold as such. Even if you find another MGC correct pinion for your 3.07 ring gear, that doesn't make it a matched set.


tr6turbo
Dale Knapke
Sidney, Ohio
(169 posts)

Registered:
08/24/2008 09:44PM

Main British Car:
1972 Triumph TR6 Ford 2300, 4 Cyl Turbo

Re: pinion gear
Posted by: tr6turbo
Date: May 07, 2010 05:52PM

The last operation in manufacturing a ring and pinion set is to run them together in a bath of lapping compound. This process provides the final finish to the surface and defines the contact pattern. If you run an unmatched set I would think you are looking at a lot of gear noise.


roverman
Art Gertz
Winchester, CA.
(3188 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: pinion gear-up for learning
Posted by: roverman
Date: May 07, 2010 06:50PM

Mark, I suppose if you "really" want education, you could try a test fit? If you you have concise manual, follow it explicitly on how to "read" pattern and adjust accordingly ? Perhaps even "best effort" , may require, lapping in. If that produces usable match, (unlikely), you could flush meticulously, and put in new bearings ? roverman.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6468 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: pinion gear
Posted by: BlownMGB-V8
Date: May 13, 2010 08:42AM

Odds are your pattern will be less than perfect. But, these parts are cut to precise tolerances so the real reason for running them in is to smooth out tooling marks and minor warpage from heat treat. The processes are very uniform from part to part so the chances of an acceptable match might be quite a bit better than you think. At any rate, the "print" on the contact pattern is the final arbiter. A decent pattern at good clearances and you're good to go. Something odd... well that'll probably make noise. But it could still hold up reasonably well in some cases.

JB


Bill Young
Bill Young
Kansas City, MO
(1337 posts)

Registered:
10/23/2007 09:23AM

Main British Car:
'73 MG Midget V6 , '59 MGA I6 2.8 GM, 4.0 Jeep

authors avatar
Re: pinion gear
Posted by: Bill Young
Date: May 13, 2010 10:27AM

As to the question about the stock MGB 3.9:1 pinion gear working with the MGC 3.07:1 ring gear, no way! The pinion gear angle and diameter for a set of helical bevel gears is different for every ratio and the ring gear thickness also varies. You'll definitely need the correct MGC 3.07 pinion and then you'd have to check the gear mesh pattern very closely when assembling.


Sorry, only registered users may post in this forum.