I just replaced the 250 inline six cylinder engine in my 1969 C10 and made a mistake in the timing and being a carpenter not a mechanic I am not sure how to coorect it. Help would be appreciated. I do not know how to set the distributor so the timing is correct? I have the firing order and know how to get the number one piston to TDC but that is about it and it does not run very well and backfires through the carburetor. Any guidance or where I could find exact instructions would really be appreciated. The car manuals I have do not give the information. HELP!!!!!!
Two ways to do this. Unhook the negative battery cable. Remove the number one plug and turn the engine over to put number one at TDC on the compression stroke. Move the engine so that the timing mark on the damper is at about 10 degrees BTDC. Now you have two options. One requires you to pull the distributor out and the other will just make you turn it a bit one way or the other.
One : Find the number one plug tower. If I remember right it is the tower to the left of the vacuum advance pot. (been a while). Make a mark below that plug tower on the distributor base (piece the cap sets on). Now pull the cap and see where the rotor tip is actually pointing. Since it probably won't be pointing at that tower, remove the clamp and pull the distributor out. Watch how it rotates back as you pull it up. Now set the rotor tip to that mark you made and back it up like you saw it rotate when you pulled it out. (usually 1-2 teeth different) Set the distributor back in and see if the oil pump drive will go in OK. It probably won't so use a long screwdriver to rotate the oil pump shaft to a position so that it will. (look at the bottom of the distributor and move the shaft to match that position as close as possible. Now put the distributor back in and let it drop all the way down. You should now have the distributor in the engine, The engine should be at about 10 degrees BTDC, and the rotor tip should be pointing at the mark you made on the distributor base. Lock it down, Reinstall the cap and check the firing order on the cap.
Two : Follow the number one plug wire back to the distributor cap. Pull it off. Remove the distributor cap. Look at where the rotor points. Make a temporary mark on the distributor base in line with the rotor tip. Put the cap back on. Look at the mark and see which tower it is closest to. Mark the center of that tower on the distributor base and take the cap back off. Loosen the clamp and turn the distributor so the mark you made is in line with the center of the rotor tip. Lock the clamp back down. Put the cap back on. If that tower had a plug wire on it take it out and put the number one plug wire in it's place, that tower is now number one plug. Pull the rest of the wires and reinstall them following the firing order using the one you marked and put the number one wire on as the starting point.
Myself I would use the second method and tag the wire as No. 1. Same result and easier.
If you followed the steps your engine should now be timed real close to
10 degrees BTDC. It should start and run OK unless there are other problems. (worn points, bad condenser, bad coil, bad cap)
Use a timing light (with the vacuum line off the advance pot) to set it exactly. (some were 6 degrees BTDC and others were 10 - 12). To get it really dialed in get it running good. Fill the tank with whatever grade gas you intend to use most of the time. Now take it out on the road and find a hill. Drive up the hill and listen for the engine to start pinging. No ping is OK but to get the best mileage, loosen the base clamp and adjust the timing to be 2 degrees more advanced. Try the hill again, hear any pinging? If no repeat the adjustment of the base advance. Now hit the hill again. Hear it pinging? If yes you can now retard the distributor one degree and call it a day. You engine will now run with the best power and mileage for that grade of fuel.
Oh IF the new engine was installed using an older points distributor I would suggest finding an HEI unit to fit it. Makes them run much better and no messing with points. BUT if you install the HEI make sure you install a new power feed wire to the distributor from the keyswitch. The factory wire has a resistor wire built in that reduces the voltage to the points to reduce the amount of power they switch (it helps make the points last longer) That resistor will also limit the HEI to lower rpm since it will not be running at full power, that will burn it out quick.
I saw an old Ford straight 6 run in school (I remember now what I was thinking) with the timing WAY off. For some reason I thought it was 180 out, but this happend over 15 years ago now so the facts are skewed... instructor was a nut job and he was able to start his thing up (it was on a stand that we used to test carburators that we rebuilt) and then short this bad boy WITH HIS FINGERS touching all 6 plugs to shut it off. The man taught Auto electrics too and had a perpetual twitch.....
I hope your instructor put his thumb on the block first. I have seen people do this on model T's but that was a low voltage magneto ignition. On having the spark 180 out, think about what is happening when the spark goes off. You are into the charge part of the cycle. Unless you are very lucky the intake valve will be open and instant backfire.
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