My experience is with a TR3A where my goal was to put it into reliable
daily driver status... still it may be of some use to you...
> > Is it possible or a good idea to use oversize piston rings on standard
>pistons
> > and if it is yes, until which diverences between piston size and cylinder
>bores
> > is this reasonable? I can slid a 0,3 mm / 0,012" feeler gauge between
>piston and
> > cylinder walls.
This was about where my piston/cylinder clearance was... just beyond the
.010 max suggested by Haynes (for a TR3A) but I went with standard rings
and no "remedial actions" to the pistons or sleeves.
> > The Haynes manual says, when new piston rings are used on old cylinder
>bores,
> > the top ring should be stepped. I understand the problem, but how do I step
>a
> > piston ring?
> >
> > Is it possible to take away the ridge of the previous top ring in
> > the cylinders DIY without destroying everything?
I did not use a stepped ring, but instead rented a ridge reamer to
remove the ridge. I remember nothing about the actual using of it,
which tells me it was straight-forward and presented no problem.
Of course there may still be the question of roundness/ovality but I
didn't know about such things then and don't know now if TRs are
susceptible to these ailments.
All this was 17 years ago and as a daily driver (not concours or
competition) I am still satisified with the result.
Geo Hahn
59 TR3A
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