I just replaced the points, rotor, and condenser on my '53 Chevy 3600 216 c.i. engine (which I have done at least 30 times in my 35 years of owning it). This time however there is a distinct knocking sound like something is hitting inside or below the distributor when it is running. It started right up but the noise was not normal. I opened the cap and all looked good, I reseated the rotor and it seated on the tab like it should. I did notice when I pull up on the distributor while the engine is running the sound almost completely goes away. When I push down slightly it gets louder and I can feel like something is hitting something when it is running. Any ideas?
Did you by chance change one of the screws holding the points or condenser? If so it may be hitting the counterweights, springs or other items below the point plate. It’s a easy thing to remove two screws that hold the plate in place and have a look.
Please keep in mind it’s been a while since I’ve looked below the points if my info is a bit off. I do know it’s not a challenging job.
There are 3 screws, not 2, that hold the plate in. Two of them also attach the spring clips for the distributor cap. You'll also need to remove the insulator block that goes through the side of the housing. I just rebuilt a Delco distributor yesterday. Giving the centrifugal advance system a good cleanup and lubrication is part of doing the job correctly. Look for a polished spot on the bottom of the screws that hold the points down, and score marks on the advance assembly from rubbing on the screws. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Take out the points, condenser, insulator and point plate as HRL suggested. Its pretty common for one of the springs that holds tension for the advance weights to break or fly off, or for the spring anchor pins to get loose or break of entirely. Take a peek and lets see what you have going on here.
Did you replace the rotor at the same time? I've discovered that some new rotors are too big and wack the cap instead of just brushing by. Put the old one back in and see what happens.
1950 Chevrolet 3100 (Ol' Roy) 1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1956 Cadillac Sixty Special Fleetwood (The Godfather) | 1966 Oldsmobile Toronado (The Purple Knif) | 1966 Ford Mustang (Little Red) | 1964 Ford Galaxie 500 coupe | 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
1950 Chevrolet 3100 (Ol' Roy) 1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1956 Cadillac Sixty Special Fleetwood (The Godfather) | 1966 Oldsmobile Toronado (The Purple Knif) | 1966 Ford Mustang (Little Red) | 1964 Ford Galaxie 500 coupe | 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
Will take out the points plate tomorrow and see what's going on below. May pull the distributor and see if anything is going on below deck. Thanks for all the suggestions.Sad thing is that it was running pretty good, just a tiny bit of misfire so I though I would do a tuneup since it has been a couple of years. This is a new one for me. 35 years and only 28K miles, it has always run like a champ.
A couple of months ago I had an NOS 2403 on my Sun machine. Brand new never run distributor. did not come up to specification. I had to take it completely apart, clean it from top to bottom, polish the advance weights and relubricate all the moving parts , before it would come up to specification.
After all these years, your distributor may be at the end of its service life. Time to check the condition of the gear, and the advance mechanism. Also look carefully at the lobes for really rough, rusty or uneven wear.
Finally, make sure there is not excessive clearance between the top of the gear and the bottom of the distributor casting. To much clearance can allow the shaft to move up and down changing the dwell and point clearance.
Mystery solved, I pulled the distributor and the breaker plate. I could see a fresh cut groove in each of the nuts holding the advance weights plate. Nothing on the bottom of the breaker plate was scratched though. Hmm, strange but all looked good. When I spun the distributor shaft and the oil pump shaft all was fine. Then I looked at the condenser and the points screws and yep there it was. The bottom of the condenser screw had a nice matching worn down end. Either I was missing a washer or I had replaced the screw in the past (looked newer) or both but I added a flat and lock washer to raise the screw and all is well. After adjusting the ignition timing it runs like new.
"I love it when a plan comes together!" Kudos to you for finding and fixing the problem! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
