High all any help on this issue would be greatly appreciated.
I have a 1981 f350 with a 351 modified /400 newly rebuilt with many problems from the guy who did it. Problem one 60 over pistons with matching edelbrock cam intake and carb all new. But the idiot did not replace the springs. So fist start up all my pushrods bent. Took the motor back and he fixed it? Then stated up with problem 2 smoked like a chimney. Took it back and the idiot hade to replaced bade seat and guides that were already supposed to have been replaced. I got the motor back and it ran great for about 40 miles then as I was driving down the road bang the motor seized. Apparently a valve separated from the stem and logged into the head and piston. Took back to the guy and he installed a sleeve new piston and head. Never ran right.
Now the problem the truck will not run! It will not idle the only way to get the thing to run is to play with the gas. It back fires through the carb and fouls out the plugs. I have checked almost everything. This is my thought. I pulled the front of the motor apart , I still need to pull the balancer to get to the gears but I took out plug turned it over by hand until I felt pressure on my finger covering hole one. When the pressure stopped I played with it back and forth trying to get TDC. The rotor seems to be pointing at number 8. If I rotate the motor to the exhaust stroke it seems to be pointing at 5. So the question is could I set all the wires back one to get to try and get it to run or should I just change the gears. Also it seems like number 1 on the cap is facing the center of the truck. Should it be turned more towards the driver side? Did the guy install the distributor wrong and the timing is on? It seems that there is more than ½ inch of play on the chain but I cannot measure it until I get the cover completely off. Can I get some thoughts please?

 

have you had a timing light on it since you got it back? might try tweaking the timing if not you may just have to pull the dist and re-time it

 

#8 should be right next to #1 in the firing order #1 is first and #8 is last. Have you had a timing light on it? It doesn't really matter what way the distributor points as long as you can get the timing right, if it weren't for the vacuum advance you could spin it a complete turn and it would be fine. If it were me I would pull that motor and get your money back and get a different one from a rebuilder who knows what he is doing, it doesn't sound like he did any thing. Oh yeah and .040 over bore is pretty accepted as the maximum over bore on these engines you could have over heating problems due to thin cylinder walls. The way I get a baseline timing is to find TDC when #1 is on the power stroke (intake valve closes as you near it and then both valves are closed), next turn the engine over by hand until your timing pointer is pointing at the desired timing mark on the dampner, then pull #1 plug and wire and hold it against the block, finally slowly rotate the distributor until your plug sparks and you will have it pretty dang close. If you engine has been run recently you will want to pull the other seven plug wires too because the motor can start if you are sparking other cyls. Well I hope that gives you a starting point.
-Johnboy

 

thanks I understand the guy messed it up. It was a local machine shop. But here is the question I am pretty sure I have found tdc I know 8 is next to 1 should I reset all the plugs wires in order according to where they sit in the dist just to see if it will run right first. Then put in a new chain and gears along with moving the dist.

 

That would work if you get it right.
-Johnboy

 

also by looking at pictures it shows the distributor number one stamp slightly facing the driver side of the vehicle. In this it is more directly facing the center of the truck. By advancing or retarding this does not move the placemnet of the number one stamped on the cap. So if by putting the wires on one plug off and it runs, do I replace the timing chain and gears or do I take out the dist and move it. Where is the proper facing of the stamped one supposed to be. Center or too the right?

 

Sorry I misread your first post, You really need to set the timing with light. If you chain is bad enough to get an entire cylinder off then there is no point in messing with it until it has a new chain. I thought you were asking if you could move the wires to where #1 was not on the #1 spot on the cap. You can do that but you have to keep the firing order and the timing correct. Just to let you know it doesn't matter what way the rotor is facing in relation to the truck, engine, or anything else it only matter in relation to the cap.
-Johnboy

 

thanks here is another question. How critical is the adjustment of the rockers? I believe that when I put them on all I did was tighten them down where they were. Meaning I did not set it at tdc and adjust intake 1,4,8 and exaust 1,3,7 rotate 180 and so on. Being that it is one plug off would that alone make the thing not run. Or do the adjustment on the rocker need to be done following the adjustmnet pattern?

 

You need to get the rockers (valve lash) right, but they will always open and close at the right time no matter what order you adjust them in as long as you timing chain is installed correctly. You most likely have the non adjustable type rocker arms, which I am not too familiar with. I think there is a torque spec and you just turn the engine over untill both valves are closed and then torque them down. Not positive on this and you need to be sure which style you have, but like I said most likely non adjustable.
-Johnboy