I'm having some trouble with a dump truck I just bought. It had a cracked exhaust manifold when I bought it so I replaced them with a set of headers. Well in the process I dented the d/s valve cover. I removed the cover and used a block of wood and a hammer to straighten it all out. Looked pretty good so I reinstalled the cover. Started the truck and had a tap, tap, tap then shut off. Tried to start again and it would only run for 2 or 3 seconds then shut off. Did that a hand full of times then said screw it and pushed the truck outside. I figured from the rockers hittin the cover it wasnt letting the valves open all the way hense the stalling out right away. It sat for about 10-14 days until I got a new cover.

So today I pulled the old cover and replaced with a new used cover. New cover is straight and true. Put the new one on and tried to start it and it just cranks.

The old cover there were 2 light rub marks no deep gouges or anything just rubbed smooth a lil. I'm praying it isn't a bent valve.

Any and all info is greatly appreciated. Would like to get her going cause thy are calling for some snow.
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Check the basics first, spark fuel.ect. Pull the air cleaner, look down the carb and cycle the throttle plates, look for a shot of fuel from the accelerator nozzles .that will tell you if the fuel pump, and fuel bowl have fuel.

As for the rockers, if you bent a valve..usually you would have heard it hit the piston..maybe have bent a push rod..more likely.

You can check that by putting the corresponding cyl to tdc, and try spinning the push rod..of its taco' ed, you will see it as you spin.

Hope this helps.

 

But a v8 small block will light on 5 cyl s, so you would have to have bent a bunch of valves for it to not start.

 

 

Sounds like you knocked something lose. Air fuel spark. Your missing one.

 

I've been trying everything for the past 2 weeks. Replaced plugs, wires and coil. Dizzy was never removed so that has to still be correct. The only thing I didn't check was if the points are bad. I was getting spark at the plug but it wasn't very strong so I replaced the coil but haven't checked to see if the spark got stronger or not. I can see fuel shooting into the carb. The truck ran before I did the header install and bent the valve cover. It should still run on 7cyl just really crappy but it doesn't even sound like it wants to turn over. Just cranks.

 

There is 1 rocker on the driver side the 4th one from the fire wall. It would be the closest rocker to the front of the motor on cyl #5. When I am cranking the motor that rocker only moves 1/4" up and down and every other one moves like 3/4"-1". I wonder if i collapsed a lifter??

 

Set point gap with a match book, check condenser, make sure engine has a good ground.firing order is correct, and right direction. Firing order should be 18436572.
The collapsed lifter may pump up once lit.

 

A good forum for 67-72 (and 73-87) Chevy/GMC truck info is www.67-72Chevytrucks.com ...if you haven't already stumbled across it.