Ok, I believe I know what this is but I want second (or third) opinions on it. Engine starts and runs but backfires quite a bit. Backfires primarily coming out the exhaust. Now if I remember correctly, this is most likely from the timing chain being worn out (I got the truck about a month before I left the country so haven't had time to fix). To the best of my knowledge, the timing chain is original. Is there anything else that could cause the backfire? Also, whenever it backfires, it kicks black smoke out the exhaust. Only smokes when backfiring.. Any thoughts? Has new battery, cables, sparkplugs and wires, distributor cab and rotor. Planning on replacing the Timing chain and gears, fuel pump, ignition control module. Is there anything I'm forgetting that could cause this? Smoke also blows right after starting from priming carb. My wife is having her cousin do some of the work for me while I'm out of the country so I need to make sure I give her good info.

 

black smoke='s rich mixture. My truck backfired through the carb and it was bent pushrods, collapsed lifters, and bad piston rings. Try resetting the timing on the dizzy. advance the timing. advancing it will ignite the fuel earlier, hopefully early enough that it will ignite before the exhaust valve is about to open. If that doesn't work, try moving the spark plug wires all (1 at a time or you will be in deep crap) to the left one spot. If that doesn't work, move them all back to normal. take your belts loose. turn your crank by ratchet to the right. take spark plug #1 out. hold your thumb over the plug hole, and turn the crank. when your thumb is blown off it is on the compression stroke. look at your crank, you should see some markings. Clean them off, check to see what it is on. You should be on 10-16 degrees of timing BTDC. Take your oil dipstick out, rub a lil oil on your finger, smell it. If it smells like gas and oil mix, then you're running rich, if it smells badly burnt, time for rebuild. if it smells like oil, leave it alone. If your timing is off, it is better for you to take out the radiator, fan, fan shroud, and A/C if installed. Google or search my threads for more info.

 

gray smoke='s need new rings.

 

Exactly the info I was needing.. Thanks.... a/c....thats another story...truck came from the factory with it but po removed the compressor...whole nother can of worms there

 

Have you had the distributor out of the motor? If so, it could be off a tooth.

 

No I haven't. Bought the truck specifically to move my families from one town to another and barely got that done before I had to leave to come overseas.. Didn't have much time to do very much with it. But all ideas and info is appreciated as I may be able to fix some parts of the truck by proxy (wife's cousin). Or I'll just fix it when I get home in 8 months..

I believe it still has the original timing chain and sprockets. With those obviously having gotten worn cause the distributor to jump a tooth? Or would it even matter at that point? I do believe it has jumped time.

 

If the timing set is original, then the timing chain could have stretched enough/ or the timing sprockets could have ground a tooth off. A new timing set isn't that much, and the gaskets for the water pump and thermostat housing aint that much either. Worth the two days of casual work to see. and a side question: where overseas are you?

 

That is what I was figuring. My wife's cousin says he'll do some of the engine work for me while I'm away.

I am currently running a chow hall in Kuwait. Was supposed to go to Afghanistan but my unit received a last minute change of mission.

 

Thanks for serving our country. One of my grandfathers was in the army in WWII as a cook. One of my uncles was in the army during 'Nam, he toured two times( I think) in '64 and '65.

 

as stated, checking the timing and replacing parts if needed will be not only the right step, but the cheapest

 

If that doesn't help, then it might be something internal.