Russo Loco Wrote:
========================================
> Bruce, Tom et al -
>
> #484 has been 'out of square' to some extent
> for more than five years - see [
ngdiscussion.net].
>
> I vaguely remember someone CONJECTURING that
> during one of her major overhauls a valve spool
> from a K-37 was used to replace one of #484's
> own spools that had been damaged, and that -
> even though the K-37's were "reverse engineered"
> from the K-36's - there is enough of a difference
> in these parts to cause a timing problem.
Earl Wrote:
========================================
> K28's, K36's & K-37's all use the same valve
> spools. There was an urban legend that #473
> used to pull better than the other two 470's
> because it had "K-37 Valves in it". Doesn't
> matter. They are all 11" piston valves.
Thanks, Earl -
Apparently the person who CONJECTURED the cause of #484's problems had heard a similar urban legend. Is it reasonable to conjecture that, because setting the valve timing correctly - though tedious - is a relatively straightforward process, that #484 is 'out of square' for other reasons (like maybe some worn parts) that would be more difficult to repair or replace?
OTOH, even though all the spools are 11" diameter (otherwise it would be impossible to substitute one for another), is it possible that they are slightly different in length or at least in the spacing of the rings? IIRC, a difference of as little as ¼ inch between the innermost rings at each end of a K-36 spool vs a K-37 spool could cause a significant difference in the lead and also affect the cutoff, and - less important - a difference in the spacing of the outermost rings would affect the timing of the exhaust.
- Russ
p.s. I understand why she sounds worse in reverse - that has to do with the geometry of the valve gear - but she doesn't sound a whole lot better running forward.
Edited 1 time(s). Last edit at 11/20/2014 01:44PM by Russo Loco.
