Posted by Jack Smith on April 25, 1998 at 01:25:53:
In Reply to: 231 Tuning Questions posted by Henry Jacobs on April 24, 1998 at 00:20:31:
Henry,
First, be sure your distributor is tight and the drive from the oil pump is not worn. Check the breaker plate for wear too. Set the points dead on, put a new condenser in just for precision, and be sure the plugs are set on the smaller side of the tolerance range. Make sure the valves are all set to the hot clearance recommended, and the timing chain & gears are in good shape. (Alan's post in previous forum) You can start with tdc, using the best gasoline you can find. Advance a degree at a time, and take her out for a high speed
degree or two. At the low compression ratio this engine runs, you can get away with murder. Watch the temperature tho, as too much initial advance=overheating and hard starting. Tip: leave off the hood to hear the engine better. I think 5 or 6 before tdc is as far as you want to go, for everyday driving. You better have good gas too, for that much initial advance. When pump gas was 90++ octane, 8 or even 10 btdc was not unusual. Today's best gas is marginal for cleaning wheel bearings in my opinion. Redline for these engines seems to be around 3000 rpm's. The marine version is propped to run at a wide open throttle at 2800-2950 rpm. Industrials are often governed a bit lower. Some books have 3400-3600 as a top rpm, but I've never seen a dodge flathead under load go that fast. (shudder!) If you have the sodium-cooled valves, (big thick stems) look for a lower redline, as the heavier valves begin to float at about 2900. Listen closely at the exhaust while loaded and underway for a muffled high-pitched cracking sound...it is sometimes accompanied by a slight hesitation. That's the beginning of valve float. And no, henry, the manifold is not hot..it's a post-hypnotic suggestion! Let us know how far advanced you get when you're done!
Regards,
Jack