75 Twinspark timing variator stripdown info (dont)

[jonathan coates <alfa@xxxxxxxxxxxxxxxxx>]

This afternoon I had the time available to take my timing variator off
with the intake cam for investigation. I think it's great that taking
camshafts out is a part-day job, but on to how it went.
I got the camshaft out and stuck in the soft jaws on the bench, fresh
from the parts washer (new toy). Blowing compressed air into the hole
found in the front bearing surface moved the variator as it is supposed
to, though with less than 2.5bar (35ish psi) the thing wouldnt move.
In an attempt to find out if there are any seals which could have gone
bad, I foolishly took it apart. I found the seals in the form of tiny
piston ring type rings fitted in grooves. When I had cleaned it all up I
found that just pushing the thing back together wouldnt work, even
though there is a taper lead for the smaller ring seal which lives
inside the unit. Finding there was no way to get at it to compress the
ring I assumed that a small amount of force was required to push it
together.
To cut a long story short I broke the ring and now the variator doesnt
variate at all.
The moral, if there is one, is that if the thing works, dont mess with
it.
Final diagnosis, I havent enough oil pressure to make it work, so it
wouldnt work. I should get some new crank plugs and rip the sump (oil
pan) off to check these.
Now for the question, are the crankshafts regrindable, or can I be sure
I get the right size big end shells, as I may as well change these while
I'm in there, right?
TIA
- -- 
Jonathan Coates
75 Tspark etc

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