Tuning Still struggling on valve timing

[sporting chap]

Hello again.
Hopefully the last time i will need to run this past you peeps.
R reg fiat punto sporting 16v.I have the tools to set the cams and pistons.
When rebuilding the engine , does it matter which piston 1 or 4 is on its compression stroke. I set the pistons 1&4 on the up stroke to the mid point and fitted the head extension with cams locked.Next fitted cam belt with pully loose . tightened belt by tensioner , torqued up pulley, then set tensioner.
Refitted every thing else but engine has lost compression and wont run / back fires. sparking at plugs . New coils . There is something that i am missing. It just does not make sense. Last week had 1,2,3 at 200psi,4 at almost zero.The head looks ok and the valves were re-seated.

 

[fingers99]

Backfire through throttle body suggests that ignition timing is out. Guessing that these engines have a pip on the crankshaft timing pulley (the inner pulley, as it were) which must engage with the hole on the alternator pulley (from which the ignition takes its timing).

How do you know that the compressions are down? Did you find the cause of the low compression on no.4 last time? (Very unlikely to be just the valves needing cutting in or there would be no running Puntos out there!)

 

[sporting chap]

Re seated the valves when i de-coked the head etc.Did notice the pip on the crankshaft pully and would have located the two unless i took my eye off the ball which would possibly explain any mis alignement of the timing. I carried out compression tests as i went. I will check the pully position.That sounds promising thanks . So the answer to my question , does it matter if 1 or 4 is on its compression stroke is no.

 

[fingers99]

It shouldn't -- wasted spark engine. It will if yours is coil per cylinder.

 

[fingers99]

It shouldn't -- wasted spark engine. It will if yours is coil per cylinder.