Hi Ed,
I am also currently chasing a bottom end rattle. My engine is fresh with
only about 3500 miles on it so I am not concerned about rods/mains/wrist
pins, timing chain, etc. I do currently have the distributor and oil
pump drive out of it, since I did not replace these parts when I rebuilt
the engine.
I am also considering replacement of the oil pump drive shaft and
bushing. I think the durability of an after-market bushing is probably
low risk just so long as it's machined to the proper tolerances. I do
think that I would take the new drive shaft and have it Rockwell
hardness tested at a machine shop.
My rattle is only when hot and very distinct. It only occurs at a slow
idle (500 rpm) and very narrow rpm range. A minor change in rpm and it
disappears. In fact if I set the rpm to 800, I never hear it. If I don't
resolve it with the oil pump shaft, I am just going to drive it and not
worry. It runs great otherwise with no strange noises.
I would be interested to hear your results when finished.
Thanks,
Mike
popnglo@gmail.com wrote:
> Hello List,
>
> After a number of years I am making a return to the list, in search of the
> sage advice. In the interim (I think its been maybe 2-3 years hiatis, maybe
> more). I have been driving the TR3A and generally neglecting the
> maintenance as I diverted to motorcycle interests. I now have 2 Yamaha
> XS650' s (a 1979 and a 1980). The '79 I completely tore apart and I guess
> you'd say a frame off... but that's another list. These are the 2 cylinder
> air cooled vertical twins, of the British Triumph, BSA, Norton, etc style.
> OHC instead of pushrod.
>
> Back to the TR3 ... I decided this winter to follow a sound that's been
> bothering me, seemingly originating at the bottom end. I did find the
> starter dog bolt loose and I have found the crank end float to be .012"
> (spec is (.004" - .006"). I had in the past (I think 3-4 years ago, maybe
> more) changed the main bearings and con bearings when I did the sleeves and
> pistons, but for some reason not the thrust washers, maybe not the con
> bearings either. I'ma little fuzzy there.
>
> My question, what may be the recommended source for the bearings and thrust
> washers. I would prefer to go this time with the tri-metal type. I am
> almost positive that I got the (County?)bearings I did change before are
> from MOSS and they were the bi-metal type. I see that BFE and Brit Parts NW
> (maybe TRF too) carry the tri-metal bearings. I will probably go with
> standard size, I'll measure the journals, but I am not the least bit
> thrilled to pull the crank unless I find something there that really
> justifies that.
>
> Also, I have been thinking to replace the oil pump drive shaft and bush.
> These aren't cheap though and I am wondering whether they are worth it. Any
> experiance out there? Also I do recall that there had been problems in the
> past with "soft metal" shafts where the tang would fail after replacement.
> Just wondering whether this is worth the bother. Is that little woodruff
> key as difficult to seat as I imagine it could be?
>
> In any case the apron, radiator, fan, hub, sump, etc, are all off and the
> bottom end innards exposed, just sitting there waiting for their respective
> maintenance interval.
>
> I have been lurking on the list for the past 2 weeks, I see some familiar
> listers and some new and some (to me) missing. I hope all has been well
> with all and I hope going forward I will be able to contribute some. TIA
> for any reply.
>
> Best Regards,
>
> Ed(1958 TR3A - Hudson Valley, NY)
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