Expert: Ben Deutschman - 3/11/2010

Question
We just picked up a 63 Dodge Dart Slant Six engine torqueflite trans.It has a slight knock in the engine.I dont know if this could be tooken care of through valve adjustments or if its a rod bearing or what.How do I go about troubleshooting this.Its a light knock while running than that settling knock as the engine cuts off.like the rods loose but not off the wheel.I would really appreciate some direction in this matter thank you.

Answer
Without having the car in front of me, I can only guess that this knock you are hearing is a pronounced knock, coming from down deep in the Engine. If that is that case, then nothing short of a complete Engine rebuild will cure the problem.

If it is just a tapping sound, that could be the Tappets having gone out of adjustment. If this is the case, then removing the Valve Cover, and on a fully warmed up Engine, adjusting the 'Air Gap' between the Tappets and the Valves, will quiet the Engine down. The settings are .010 Intake, and .020 Exhaust, and you can easily determine which Valve your are adjusting, by looking to see whether it is in front of an Intake Manifold Runner, or an Exhaust Manifold Runner. You will need either an assistant to bump the Ignition Switch to make sure the Valve you are adjusting is not under tension, or a Remote Starter Button (available at most Auto Parts Stores in their Tool aisle). You determine if the Valve is not under tension by first turning the motor over (Coil Wire from Coil to Distributor disconnected), and watching the Valve you intend to adjust. After the Valve has opened (moved downward), and closed (moved upward), check the Tappet by trying to wiggle it. The Tappet should be able to wiggle a bit. Then, once you are certain the Tappet is at rest, using a flat Feeler Gauge, check the clearance between the Tappet and the top of the Valve Stem. The Gauge should fit in between the Tappet and the Valve Stem with a slight amount of resistance. If the Gauge won't fit in (such as the .010 blade for the Intake Valve), then the Adjusting Nut on that Tappet would need to be turned counter clockwise to increase the clearance, until the Gauge fits in with a slight drag on it. If the Blade of the Feeler Gauge fits in too easily, the Adjusting Nut would need to be turned clockwise, until there is a slight drag on the Blade of the Feeler Gauge. The procedure is the same for all twelve Tappets. Once done, you can start the Engine with the Valve Cover off to listen to the Tappets, so you can determine if all the adjustments are correct, just keep the Engine at idle.  If the Tappets aren't clattering, then shut off the Engine, clean the surfaces where the old Valve Cover Gasket was, being careful on the Engine side to NOT get any of the debris in the Engine. Once both surfaces are clean, use a small amount of Gasket Sealer (my preference is silicone Gasket Sealer) on the Valve Cover side of the Gasket to hold it place, and reinstall the Valve Cover. The nuts get tightened to 10 foot pounds. If you don't have a Torque Wrench, then tighten the Bolts (front to back), a little at a time, until all are snugged down, then go back and carefully do your final tightening. The Bolts need not be tightened a lot, just mainly enough that they aren't loose enough to back out on their own, and after a week or so, you may want to recheck the Bolts, since heating, cooling, Engine Vibration, and Gasket compression, may cause the Bolts to become a little loose.