Author Topic: T35 big end rollers  (Read 317 times)

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Offline douglas1947

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T35 big end rollers
« on: 03 Jun 2022 at 05:49 »
For a T35 crankshaft overhaul I need standard size 3/16 x 1/2" big end rollers.
The rollers are worn, other parts are still usable.
I would like to get help, do anyone know a source?

Michael

Offline eddie

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Re: T35 big end rollers
« Reply #1 on: 03 Jun 2022 at 06:45 »
Michael,
               If your crankshaft has 3/16" x 1/2" rollers, it has already been reconditioned/modified. The T35/Mark series engines all had 2 rows of 1/4" x 1/4" rollers (but in various designs of cage). The 3/16" x 1/2" rollers were used by firms like Alpha Bearings in their reconditioned crankshafts (these rollers are the same as used in the Dragonfly cranks) (but in a different dia cage). If you look at your con-rods, you will probably find that they have thin liners pressed into the big-end eyes - this is the weak point with the reconditioned cranks - the machining of the con-rods (to accept the liners) is often poorly done, allowing the liners to flex under load, and start cracking. Attached is a photo to illustrate the poor machining of the con-rods - being machined, rather than ground, the bores were also barrel shaped.

   Hope this is of some help,
                                             Regards,
                                                            Eddie.
« Last Edit: 03 Jun 2022 at 08:01 by eddie »

Offline cardan

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Re: T35 big end rollers
« Reply #2 on: 04 Jun 2022 at 05:00 »
Hi Michael,

I've looked in the bearing box, and I have some 3/16 x 7/8, but unfortunately only 16 in total. I've bought loose rollers from Vintage Bearings in the UK before: https://www.vintagebearings.co.uk/

Nice grinding Eddie - it's good to get the finish you're looking for. I'm not equipped, or qualified, but I once did some hardened FN fork links using the Dremel on the tool post of the lathe. Not exactly big-end quality, but it was satisfying none-the-less.

Leon

Offline douglas1947

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Re: T35 big end rollers
« Reply #3 on: 08 Jun 2022 at 04:58 »
Eddie,

thanks for the interesting informations about the roller variants.
I had in the past refurbished a MK1 crank (with 3/16 x 1/2 rollers) and 90+ crank (with 1/4 x 1/4 rollers); also dismantled stationary cranks (all in bad condition, with 1/4 x 1/4 rollers). I wonder about the different rollers, now I know the reason.
On my 80+ crank the surface of crankpin and conrod are okay, so it will be easy to change only the rollers - and save a lot of money?

I believe to change to INA needle bearings it is also necessary to make speciial crank pins with bigger dia for the needles?

Leon,

thanks for the link to vintagebearing.

Michael

 

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