Have spark and fuel, can't get the rebuilt engine to start

[Theom]

Are we positive the camshaft is timed correctly to the crankshaft and # 1 piston at TDC ?

How would I check this? The machine shop installed the camshaft and crankshaft

 

[Scott06]

How would I check this? The machine shop installed the camshaft and crankshaft

Normally onky seen when timing cover is off. Google degreeing camshaft you likely can tell off the intake centerline.
have you run a compression test? See if any cylinders may have valves set too tight. Id do this and verify timing again before taking engine apart.

also had a engine with massive vacuum leak due to carb gasket. Could only keep it running by dribble fuel down carb. If yiu dribble fuel down does it start?

the fact that it tried to run when off basically a plug makes me think timing is way off might turn distributor while cranking

 

[cyclops222]

The first step is always setting the crankshaft to camshaft correctly. Or at least checking it accurately.

 

[flashback]

I'm leaning to the ignition timing 180 out as well, rarely would an accredited rebuilder mess up the valve timing.

 

[cyclops222]

I have met a couple with helpers.

 

[Theom]

I bought an inspection camera so there is no doubt about if I'm on the compression stroke. Both valves were closed as the piston came up for the compression stroke. I marked the range where the piston isn't moving at the top of the stroke to make sure my timing mark is in the right place and it is (see attached picture)

I then lined up the distributor cap so the rotor was pointing at plug #1 while at TDC for cylinder #1 on the now-confirmed compression stroke.

There are no signs of trying to start, including with starter fluid.

 

[Theom]

I removed all the sparkplugs and checked compression:
Cylinder: PSI Plug Condition
1: 115 black
3: 125 clean
5: 113 clean
7: 150 clean
2: 120 black
4: 110 mostly clean
6: 118 black
8: 120 black

 

[cyclops222]

4 1/2 cylinders are not working well ? You have serious cylinder problems.
Regular oil changes ? Non working hydraulic lifters ? Rocker arms failing ?
Or... They did NOTHING. And charged you. They did not change the plugs ??
They are dirt bags.

 

[Scott Danforth]

Both valves will be closed one revolution later too. However only for a brief moment as compared to the compression stroke where the valves would be closed for about 45 degrees of crankshaft revolution

Out of those compression numbers , only cylinder 7 is in spec

 

[ttownthomas]

I removed all the sparkplugs and checked compression:
Cylinder: PSI Plug Condition
1: 115 black
3: 125 clean
5: 113 clean
7: 150 clean
2: 120 black
4: 110 mostly clean
6: 118 black
8: 120 black

#7 seems like a lot of variance but overall compression will be lower since you cant warm it up before running the test.

 

[Candy Gramformongo]

#7 seems like a lot of variance but overall compression will be lower since you cant warm it up before running the test.

Unless I have lost the plot, the compression testing was to indirectly confirm that the crankshaft and cam were timed properly, without disassembling the timing chain cover.

 

[Scott06]

Unless I have lost the plot, the compression testing was to indirectly confirm that the crankshaft and cam were timed properly, without disassembling the timing chain cover.

more for if the valves are adjusted correctly. Common mistake can be to overtighten nuts on rockers arms, valves don't close.

Have also heard that if one intake hangs open can prevent firing but never seen it myself.

To the op might be worth checking the rockers on those low cylinder loosening them and see if compression comes up.

Considering the engine is cold and not broken in would expect it to be lower but this seems excessive. if you paid for a rebuild you may want to discuss the compression numbers with the builder

 

[alldodge]

Is anyone able to see the vid of the spark?
I keep getting an error of file is corrupt

 

[Scott06]

Is anyone able to see the vid of the spark?
I keep getting an error of file is corrupt

yes I could see it. it looks good but its a video shot in the dark obvious blueish white spark jumping a good size gap and snaping noise. Seems to be in decent time but also seems battery is weak

 

[Scott Danforth]

If it wants to fire turning the dizzy 45 degrees, the distributor is not inserted correctly

 

[Scott06]

If it wants to fire turning the dizzy 45 degrees, the distributor is not inserted correctly

is he using the correct bank for cyl 1 . If I recall last cyl in firing order is 2 then dizzy goes back to 1- which sort of matches the offset to where it kind of runs?