In article <v01510100accf5a94fcb1@[130.123.73.26]>, Liquid@massey.ac.nz wrote:
> Having reassembled and fitted the head, the car was taken for a
> test run, with the hope that the embarassing smoke problem had been laid to
> rest.
I don't remember your symptoms, but let me mention:
Blue smoke: Burnt oil
Black smoke: Excessive fuel
Blue smoke, mostly on overrun: Probably valve guide
General blue smoke (?): Piston oil control rings
> If so, are they intended to be used with valve seals?- the machinist
> said they would be OK without. I can't remember what the original guides
> were like, but these new ones are not smooth, but rather, have equally
> spaced circular grooves along their length.
I would assume that valve guides with grooves would be designed for use
with a seal? I imagine that oil would be sucked along the grooves and
into the cumbostion chamber.
Another thing: It is really on the inlet where the seal is needed the
most, due to the high vacuum present.
> Should I reset the timing back to original specifiction?
I would have tried it.
> How
> can I tell if I advance the timing too much? - I'm not really sure what
> pinking sounds like (is it unmistakable?)
The sound is unmistakable. It is not a good thing, it will harm the
pistons and rings in the long run.
If you advance the timing beyond the origial spec (max. 5 degrees, say), and
go up hill with a hot engine, low speed, high gear and throttle open,
you'll sure enough hear it. A short test like this will not damage
anything, just educate you!
> and have also read somewhere
> that modern petrol has additives that prevent it .
Yes, but those additives are accounted for in the octane rating.
> Does setting the timing
> statically and dynamically yeild different results?
No, in case a number of conditions are met (we've covered those recently).
> Also, as the problem
> is intermittent, could the advance mechanism be sticking? i.e. maybe it
> has been stuck when I set the timing, but has subsequently been
> intermittently settling back to a more retarded position.
Use the ignition strobe lamp to verify that it is advancing properly at
higher RPM. Just remember that advance is often stated as camshaft
degrees - double those values to get crankshaft degrees.
Egil
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