308 won't fire

[Vombil]

Thanks Sandaro. Yeah that makes sense as I've got it wrong before and timing Mark has been aligned

[wbute]

Sorry to correct you WB, but timing marks will line up twice, both times with piston at top, trick is one is compression stroke and the other is exhaust stroke. That's why you could be 180 deg out with dizzy.

Vom, on the compression stroke at TD both valves will be at rest (easy to tell if you've got the rocker cover off)

No worries. That is correct.

[axistr]

Don't use a tissue not accurate they can pop even on the exhaust stroke, put your thumb over number 1 spark plug hole firm. When its cranked and the person operating the key hears the compression trying to escape past your thumb let the key go, the engine normally stops very close to Top dead centre. Check the timing marks on the timing cover and harmonic balancer. Move the crankshaft to around 8 degrees before TDC. Make sure your checking number 1 cylinder and not #2 (not on the wrong bank.) ensure you know how to read the timing cover marks. Looking from the front the harmonic balancer mark should line up on the second mark on the timing cover rotating in the clockwise direction. Check your distributors 8 reluctor teeth they will perfectly line up if the timing is correct and the rotor is in the correct cap lead position. This will be close enough to get it started if its a timing problem.

I like to check the piston at TDC with a screwdriver down #1. Rock the engine by hand around TDC and feel with the screwdriver to ensure the marks line up simultaneously. Its not uncommon for the harmonic balancers to move on the rubber, over the years I have come across around a dozen that have been out by more than 30 degrees.

1)Double check you have a good blue spark that can jump at lest 10mm should be easy for electronic ignition.
2)Yes still should start with 100 p.s.i compression, but do get a bit harder to start and can easily foul plugs at low compressions.
3)do you have manifold vacuum?
4) Do you have engine oil pressure, When the cam lifters have no oil to them or not pumped up they don't lift very high and the duration is dramatically reduced, makes starting harder and again fouls plugs quickly.
5) If the mixture is 12-1 or lower the engine is two rich to fire and will not start. Plugs will be wet when checked after an attempt to start.

I once had a V8 that I rebuilt that would not start, checked everything 10 times over. Took 3 days to work it out. it was 8 brand new dud Champion spark plugs. I earthed out the plugs on the head but wouldn't ignite when placed into the combustion chamber. New set of Bosch plugs and started first pop.

Has the fuel gone off, they are very hard to start if the fuel is old. You can smell if the fuel is off it smells like varnish.

Hope this helps.

[Vombil]

thanks Sandaro. i took rocker cover off and checked valves and i've set timing up correctly so i must've got lucky!

Update: turns out when a Holley is over-fueling then some AIR helps ! Sprayed some start ya bastard without any fuel line attached and it fired. re attached fuel line and opened throttle and it jumped back to life!

the last owner was never going to get it running with timing out 180 and both pos and neg at dizzy connected to the neg of the coil! ill run it again and then re-test the compression

thanks everyone for the help!

[Vombil]

thanks for the great tips axistr.

i'm always solo when working on a car so need a system for finding TDC on my own mate.
plugs were very wet after multiple failed attempts to start yesterday and look to have been running way too rich.
Once I held the throttle open today it jumped to life straight away. Is this a sign that there is possibly an issue with the heads?

not sure about oil pressure. there is plenty of oil on the rockers so it's pumping up the pushrods I guess. i'd like to check vaccum but don't have a gauge. fuel is fresh from a bottle. thanks again