John Middlesworth wrote:
>
> I finally got down to the casting on my old 4A engine. It was as bad as I
> expected: all 4 thrust washers lying in the pan and the surfaces where the
> washers usually sit considerably ground down (think about having a quarter
> inch of crankshaft end play!).
>
> Has anyone out there tried to fix this problem by welding and machining,
> or is it just not worth it?
Alternatively, John, what is the availability of TR4-4A blocks? The
liners and pistons can be transported from one block to another, but can
the block be fixed? I think this depends to a very large extent on the
skills of your local artisans.
> The block is what I'd particularly like to
> salvage, it has overbored liners and relatively new pistons. I figure the
> only surface in the block needing work would be the upper rear thrust
> face, since I could find a replacement bearing cap and have the whole
> thing line bored.
Still and all, that would mean having the block portion of the saddle
built up and resized. I'd suggest you talk to a few machine shops in
your area about the problem. Some shops won't touch such work, but some
have contacts with excellent welders who will do contract work for them.
I recall seeing a Cat D4 block in Michigan which had been cracked from
crank breakage and been repaired by a local welder. Using a special
Eutectic cast-iron rod (and plenty of experience) this shop's contract
welder had repaired the crack so well that, after bead blasting, the
only sign of a repair was a slightly different coloration in the
repaired area. As well, a really good welder may be able to find the
correct rod to apply a hard facing to the area, minimizing the potential
damage if and when the thrust washers poop out again.
This brings up another question. After reading here about all the
difficulties with thrust washers in these engines, why is it that no one
has, to my knowledge, offered oversized thrust washers to compensate for
wear and the inevitable thousandth or two taken off when having the
crank thrust surfaces trued and polished during crank grinding and
refurbishing? I last rebuilt a TR4 engine in 1974, and don't recall
oversized thrust washers being available then. It seems like a part
waiting to happen. <g>
Cheers.
--
My other Triumph doesn't run, either....
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