Hey, thanks folks, so many replies, and 'cos I get easily confused as to who
suggested what, I will not reply to each in turn, but to the "list" in
general. Thanks to each and everyone though.
David Vizard sort of suggests the plexiglas idea, but dosn't go into
sufficient detail.
I tried it but never thought of using either an "O" ring or vasaline (sounds
better, I like the idea of vasaline, it is always easier with
vasaline.....oops, sorry getting carried away again). My attempt at this,
without sealing meant that (a) the head had to be absolutetly level to get the
air bubble out, and (b) even then the liquid (I used parrafin) sort of seeped
between the plexiglas and the head (cappiliary action at work).
So, sand won't give an accurate figure because the sand grains will absorb
moisture.
Should have thought of this. There is an old pub trick where you add dry sand
to a full glass of water (or beer if its not yours !) you are supposed to be
able to add about 1/3 pint dry sand to a 1 pint glass of beer without it
overflowing. Supposed to work with sawdust also.
Like the plasticine idea, noted the use of oil to stop the plasticine sticking
to the cylinder head. You would also want pretty soft plasticine so that you
could slice off the excess with a straight edge accurately.
The method of then displacing liquid in a measuring cylinder is because this
is the most accurate way of measuing the volume of your irregular lump of
plasticine.
Oh, the reason for all this is because I have shaped and ported my head (well.
alright, the car's head) and now need to raise the CR. As David V says, there
is no absolutely optimum CR to go for, he advises a "gut feeling" approach.
Fuel on sale in the UK is generally 95 octane.
I thought I would go for a CR of 9.5 or 10.0, this with a Kent 276 Megadyne
camshaft, and a total capacity of 1320cc. Road use. Any views on this ?
This is all to go in my "other" car, which is a 1971 Austin Sprite (post
Healey) which is nearing the end of a 6 (or is it 8 ?) year restoration.
Total, and I mean absolutely total strip down, bare metal grinding welding
phosphate dip etch primer 12 coat paint recondition everything new nut and
bolt rebuild. And yes. I do intend to use it! The main thing to keep me sane
('though on second thoughts perhaps I am not the best judge of sanity) has
been driving my "other" other Midget, 1500 O/D gearbox conversion, as my
everyday car around the English Lake District where I live and work (a bit ).
Spent some time thisevening filling the brake hydraulic system for the first
time. All new seals, pipes, pistons and stuff, but, although I doubt if I have
yet got all the air out, it didn't pose any problems. No use of pressurised
mastercylinders or anything like that, just started with the nearest valve and
bled through each one in turn. Leave it to stand overnight then bleed again
in the normal sequence tomorrow. Am I just too much of an optimist to think it
is as easy as that !!
Thanks again to all, will let you know how the measuring turns out for real,
idc.
Sorry this has ended up a bit long,
Guy
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