"Islander" wrote: ( 76 E250 460 CID )
I replaced the stock ignition with an MSD wire set, billet distributor, blaster 2 coil and 6Al module. It runs fine at idle but coughs and splutters and surges under load. The instructions say to start by setting the timing to the factory specs but I can't find the specs.
This is the latest change. Previous was Hooker headers, planed heads, Edelbrock intake and Edelbrock carb. All ran super until I screwed up the timing. With my timing light I can see a timing mark but no reference point. I expected to see a plate marked off in degrees?? I don't know where to start. Can someone help?? _______________________________________________
Some engines have a timing mark on the vibration damper and a graduated plate bolted to the front of the engine. Some engines have a timing mark on the vibration damper with graduations also on the vibration damper and a pointer sticking out of the front of the engine. Examine the front of the engine until you find which arrangement you have. Look up your timing specs on the internet.
The engine is nearly at the right timing because it idles okay. It may be becoming too far retarded when the vacuum drops under load. If that is the case, here is a way to set the timing without the specs and without a light:
1.) Loosen the distributor holddown bolt just enough to be able to rotate the distributor by hand.
2.) Apply the throttle (by hand of foot) until the engine is running fast and smooth at about 1500 RPM. Snap the throttle wide open for one second, then let it drop to idle.
3.) If the engine breaks up at wide open throttle, then rotate the distributor to add a little advance (turn it the opposite direction of the rotor travel).
4.) Repeat Steps 2 and 3 until the engine no longer breaks up, then repeat some more until you hear the RPMs rise the fastest under full throttle.
5.) Tighten the holddown bolt.
Note:
This method provides the maximum power timing you will get from the engine, but you may have to ease it back:
a.) During the full throttle condition, if you hear gas knock (preignition) back off the advance until it just disappears.
b.) When returning to idle, if the engine runs rough, back off the advance until the roughness just disappears.
Good luck.
Rodan.