newto440

A MOPAR mechanic just finished looking a my 440. Everything checks out i.e. fuel, spark, rocker movement. He replaced the plug wire and it's the same, still missing on ole no. 8. End result: drive it, he did suggest a "leak down" test.

Thanks to everyone for your input.

TVLynn

What did the plug look like ? did he replace the plug ? What happens when you disconnect the plug wire ? Do a compression test !

newto440

Changed wires and plug. He put a timing light on it, timed it. The compression is 115 on 8, which is within 15 pounds of all the cylinders. The plug was slightly dark, not wet, not white. The plug fired when removed and grounded. We took off the valve cover and he checked out the rocker lifts. Then removed the carb and ran a scope down the runner for no 8, all clear. What next?

newto440

With the engine running and the plug wire removed the RPM's don't change.

Mr.4spd

Intermittent or never fires at all? Has it ever run right since you've owned it? Is that header tube smashed flat? Fuel distribution problem? 115 psi sounds low, that's like less than 8:1...either way I guess the point is all cylinders are in this range and fire just fine. Real mystery.

newto440

It seems like it doesn't fire at all, it has never run right since I've owned it. I have never had it on the road yet (not counting two trips around the block). It sure seems like a fuel problem, I really can't tell you if it starts firing when the RPM's pick up, I don't have the equipment. It has cast iron exhaust manifolds. This truck has not been on the road or completely assembled in 18 years. Thanks for the interest.

Mr.4spd

Maybe the exh manifold is plugged with carbon? Pull the plug and rotate the engine by hand, do both strokes push air out the hole like it's the compression stroke? Or drop a spare working carb on it? Very curious about this.

RacerHog