More on evaluating vacuum leaks

Question:

If the symptoms listed by Benny Gonzales in the September issue occurred on my Packard (288 cu. in. straight 8, solid lifters) I’d reset the tappet clearances. (The 1948 Ford Deluxe would backfire and miss after stopping for lights and stop signs.) These symptoms are classic for tight valve clearances on a flathead engine. Certainly the vacuum gauge indication should show this condition, but you’d have to catch it when it was happening. Also, tappet adjustments on the flathead Ford V-8 are not as easy as tappet adjustments on my Packard.

Answer:

You are quite right, Mike. Those little irregular puff sounds Benny Gonzales describes are typical of tight valve clearances. On an original Ford Flathead V-8 you would need to install new valves wherever the clearance was too tight because the valves are not adjustable on Ford flatheads. You just machine them to length when you install them and that’s it. Aftermarket adjustable valve kits are available and can certainly make things more convenient on a Ford, but installing them is a bigger job than just adjusting the valves on inline flatheads.