Right, my little rechargable light has run out of juice so I thought I'd report back.
Charged Battery, bought a compression tester, plugged into number 4, cranked her round an on the starter for 10 seconds and
absolutely no pressure registered on the guage.
I presume this is incorrect valve clearences or else there should be some sign of comression even if it was pretty poor?
I set the timing by pushing her in gear but I can't do that and keep an eye on the valves (I had a helper before).
Took the plugs out, rocker off and attempted to turn the crank by hand, absolutely no joy, won't budge. She turns fine on the
starter but the starter obviously has a bit more oomph than I. I have a socket that will fit but doesn't leave me enough space
to get a bar on with the radiator in the way, so it's off to the tool factor tommorrow to buy a giant spanner unless someone
knows a trick?
many thanks
Andrew
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Posted By : Paul
Mason, 13-May-2007, 06:02pm
It is now time to go back to basics. If it was running when the head came off it must run now. So it is something you have
done or not done! Get a good manual, Haynes is fine and go throught the rebuild and replacement of the head and make sure
you have done everytthing by the book. If you have checked the timing as the head is replaced (timing chain linking cam
shaft and crankshaft in the correct postion) then the engine will be set correctly. Turn the engine over in gear and watch
for the valves rocking on number 1 cylinder, go through a complete cycle to be sure. Exhaust valve closes after emitting
exhaust gases (finger over plug hole as piston rises and you will feel some compression as the exhaust gases are pushed
out). Then the inlet opens and admits a fresh petrol/air mix as the piston decends and then the piston rises on the
compression stroke as the inlet valve closes the rotor arm must point to number 1 cylinder with the timimng marks aligned
at whatever the timing is for the spitfire (8 BTDC ?). Thats it, now leave the timing alone and check for other causes. All
leads connected correctly, in the corect firing order, HT, LT, coil, points, etc, etc.
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Posted By : Steve
Abbott, 13-May-2007, 07:36pm
Andrew, the easy trick to turn the engine to do valve timing. Get a firm grip on the tyre and, with the car in gear, roll
the car using the road wheel. Easiest cars I have set are Triumphs and Mini's. With the Mini you are pushing the front of
the car with your head under the bonnet and eyes right over the valve gear!
Steve.
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Posted By : Steve
Abbott, 13-May-2007, 07:37pm
Also helps if you remove plugs to ease up the compression!! Nearly forgot that bit.
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Posted By : Steve Cureton, 13-May-2007, 08:45pm
If you remove the plugs you should be able to turn it over using the cooling fan.
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Posted By : Chris
Taylor, 13-May-2007, 11:23pm
Do you have a "proper" starter solenoid with a button on the end you can push to operate the starter motor? If so, use this
to motor the engine round for setting the rockers. If you don't have this type of solenoid, you could fit one (always
useful for this type of job) or even buy a remote switch that energises the solenoid (like a remote ignition switch) to
operate the starter motor. Just remember not to have the ignition switched on (or disconnect the coil) unless you ARE
trying to start the engine.
I am surprised you cannot turn the engine by hand with the plugs out. Try tightening the fanbelt and turning the engine
over by pulling on the belt. Just make sure the plugs are out, and the car is not in gear!
If any of the other cylinders are like no.4, that is why your engine won't start. Theoretically, to get a true compression
pressure, the throttle should be wide open when you turn the engine over, but if you are regsitering zero, that will have
made no practical difference; the problem lies with the valves (or, dare I say it, the headgasket).