Rebuilt engine, cranks, wont start

[Brian Moseti]

Hi,
I overhauled my 4TL engine but cant get it to start. Checked everything. There's a spark, timing is ok, fuel pump working well, starter cranks well and at great speed. I have tried to reverse the firing order just to see what would happen and it backfires...but no sign of engine coming on with proper firing sequence. I am at my wits end... Please, please help.

 

[AdamWilkes]

Hi Brian - sounds like you have checked most of the areas!
Just in case:
Are you sure of the firing order (number one cylinder being the front of the engine, probably) and distributor rotation direction? Assume nothing !
Sound like fuel is going in (backfired) - possibly double check that all the 'plugs smell of petrol after trying to start it.
Hopefully the camshaft is correctly timed to the crank (timing chain) ?
Best of luck!

 

[Brian Moseti]

Thanks for the fast response AdamWilkes...I have checked that the firing order is with the No.1 cylinder at the front and I have also confirmed that the camshaft is correcly timed. But I have noticed that none of the plugs have the smell of petrol after trying to start. Could it be that I tightened the valves too much.

 

[mojobaby]

Hello Brian
It's quite likely that your timing is 180 degrees out.

The flywheel turns around twice for every one revolution of the distributer.

in one complete cycle, number 1 piston reaches the top of the cylinder twice. Once at the top of the compression stroke and again at the top of the exhaust stroke. any fuel that's in the cylinder gets sucked out of the exhaust valve.

number 1 and 4 piston move together, so a good way to check your timing is to remove your rocker cover and observe the movement of the rockers./valves.
As number 1 piston gets to the top(on the compression stroke) the spark plug fires and pushes it down. both valves remain closed.
Number 4 piston is also moving with no.1 but as it goes down, the inlet valve is opening to let fuel mixture in.

so you might have set number 1 piston timing on the exhaust stroke, thats why its not firing.
Do a search for "4 stroke animation" under my name and you'll see what I mean

 

[Piet]

There's an even simpler way of checking- with No 1 cylinder supposedly at TDC remove the spark plug from no 1 cylinder and with ignition OFF, hold your thumb over it, then turn the engine over slowly either by turning the fanbelt pulley, fan hub, or having it in gear and pushing the car forward very slowly in top gear, or get someone else to do same/help. If you are at TDC and all well, you will feel pressure- if not you are 180 deg out. Just don't run yourself over or get pulled into engine.... what could possibly go wrong?!?

 

[Piet]

Or, if we think this is what is going on, move the four outer (plug) ignition leads around on the dizzy by 180 degrees, which means swap each opposite pair of leads...

 

[Brian Moseti]

Hi guys... was at it again, whole day today... followed your directions, and true, I was 180 degrees out...but even after setting the timing properly and ensuring that fuel gets to the plugs and a spark too still got nothing...someone now suggests I need a more powerful battery, because the one I am using is struggling to get the starter moving and the starter doesnt pick great pace afterwards too... sigh...tomorrow is another day