[urq] Re: UrQ's Head gasket progress

[Steve Eiche]

Mike,
While distributor to cam timing errors will still allow the car to run, 
the distributor to flywheel pin timing MUST line up for the car to start 
and run.  Basically, the signals from these sensors both go through the 
same AND gate inside the ECU that tells the processor that the engine is 
at 60 degree BTDC and on the compression stroke of #1 cylinder.  If 
these marks do not line up, the ECU will not know that the engine is 
spinning, so there will be no ignition.

One way that I can see the distributor being mistimed with the -0- mark 
on the flywheel, yet still run is if someone put in an MC flywheel.  The 
MC flywheel looks physically the same as the WX, but the timing pins are 
off by 2 degrees on the flywheel.  To make the car run reliably, they 
would probably have had to move the distributor (advance) slightly.   
Even with this, the cam should line up with the flywheel.  It sounds to 
me like the cam is a tooth retarded, which will kill the already weak 
bottom end.

Looking at the front of the engine, it turns clockwise.

Steve


>> What I noticed -- none of the timing marks lined up!   Not the distributor
>> rotor and corresponding mark, not cam wheel dimple and valve cover gasket and
>> not the "O" on the flywheel.   I couldn't get 2 of the 3 to line up???   OK the
>> 10 million dollar question, which way does the motor spin?   Standing at the
>> front and looking at the engine it would appear that the engine spins
>> clockwise.   If thats the case it would be my guess that the ignition is detonating
>> before TDC as the dimple in the cam is one notch counter-clockwise from its mark
>> when the distributor rotor is lined up with its mark...   Even so the flywheel
>> mark is no where to be seen.   FWIW it also appears that someone put a white
>> mark on the flywheel where the "O" is???   I checked through the old paper
>> work and sure enough the timing belt and water pump where changed 7k ago.
>  
>

The cam/distributor lineup is not that critical.  The engine is timed off the flywheel pegs -
the Hall sender in the distributor merely discriminates between TDC exhaust/induction and TDC
compression/power - so the ECU knows to fire on the latter.  Some ignition systems don't
bother and waste a spark on the former, too.  I think Harleys do that.