Pinging

Synchro909

Synchro909

Well-known member
I have an electronic distributor from FS with auto advance on my tourer and while towing, the motor pings like a depth sounder one moment, then nothing the next. Today, I was doing 50 mph at one stage and it was pinging badly, the next hill and I was down to 40 with my foot into it and no pinging. It seems to come and go as it pleases. Any suggestions as to the cause? I'm thinking that the worn bushings may be responsible.The shaft has a lot of play in it.
 
I suspect the auto-advance curve itself. You may have less advance at 40 mph than you do at 50 mph. Do you have a timing light and a tach? About the bushing play- several thousanths will create havoc with a mechanical points cam but a reluctor and Hall sensor like you have will see virtually no timing drift from shaft play because the gap is not the critical timing element.

What you really need for varying loads and hills is a vacuum adv/retard in addition to the centrifugal advance.
 
Thanks for the quick response, Mike. I have towed for tens of thousands of miles with this setup and no problems before. Is it possible for the advance curve to change?
I don't have timing light and tach with me (I'm several hundred miles from home on tour at the moment)
Maybe I should ditch the auto advance and go back to doing it myself?
 
You could try a bottle of octane booster from a servo as a quick fix to get home.

Not sure how good that stuff works.
 
I considered a shandy of ordinary 91 octane and a higher octane fuel. I need to fill in the morning so I think I will try it.
 
Advance springs can go soft, or break. If it has vacuum advance, the diaphram can get a hole or perish. I've had both problems on various 70's cars that I've owned.
 
I think you may got some crap fuel there seams to be lot around our area lately
I have 2 lots in my mustang in the last 3 months so bad it would hardly run
 
Synchro909 said:
I considered a shandy of ordinary 91 octane and a higher octane fuel. I need to fill in the morning so I think I will try it.
Click to expand...

Yep, that will help. Even half and half or less will make a difference.

A quick look at the FS web site says the weights advance quickly. So it must have soft springs to begin with.
Maybe the weight stop has moved or broken. Not sure how you adjust the throw to shorten the advance for a higher compression head, if that has been done.
 
Higher octane fuel might stop the pinging, but if the advance is too much, then the rod bearings will still be getting a pounding.
 
Speaking of ruptured vacuum advance diaphragms, Chief had one on a '49 Plymouth, on warm shut down, it would allow fuel vapors to get into the distributor. The first time the points opened, A BIG BANG & it would BLOW off the distributor cap!!! NEVER broke anything, just put it back on & we were OFF & GOING!!
Bill Scared
 
It's tomorrow here now (???) and I thank all of the respondents. I'm going to run 98 octane till I get home, then get in touch with FS for advice and maybe new springs. If that is the trouble,it started very suddenly but it's worth a look. Going back to manual advance might be the way to go.
This distributor has been almost impossible to time righ from the start. I'm sure I got one of those faulty triggers (the aluminum thingy that goes on the shaft). There was a batch that were all over the place. Something also to speak to FS about!
All that said though, doesn't explain how the engine can be pinging while cruising at 50mph one moment, then not when I,m at 40 lugging on a hill.
I'll be seeking all the wise counsel I can when I get home (on Sunday).
 
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I would retard the timing before I ruined the bearings. I use a Ford B distributor and it has + - 10 degree slide on the body, does yours have any means of adjustment?
 
Sounds like the advance mechanism is sticking sometimes, not always retarding when it should. Using higher octane may not be needed in your car if the advance works right.
 
J Franklin, as I have said, this distributor is a dog to time but I have taken all of the retard I can get - no help.
Rich, I believe you are correct although I have kept it well lubricated all the time I have had it. All part of what I want to talk to FS about.
 
You need some time to make some small adjustments relative timing. You probably need to find the "sweet spot" for your set of running conditions. I am assuming you have a zipper distributor which is very sensitive to small changes in rotor position. My guess is you are too advanced and need to try repositioning the rotor so you are slightly retarded. Another thing to check is to see if the distrubutor has unknowingly moved. This is a problem I had with mine which Mel at FS said to grind a point on the end of the locking screw. This seems to help but I plan to remove the set screw, spot the location with a marker, remove the distributor , and spot drill a small dimple in the base. This should prevent any rotation.
 
Have you cleaned and checked the auto-advance for smooth operation?

Back in the 60's a broken spring gave me similar symptoms.
 
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The motor didn't make it home. It will arrive back on a truck next Wednesday week. Once it arrives, I'll dismantle the engine and go through everything.
I suspect that by retarding the ignition, I have burnt a valve. That's an easy fix but I want to get to the cause of the problem before I reinstall the motor
Does electronic ignition give more power or just better running? I'm thinking of going back to points and condenser and manual control of the timing like Henry did it.
 
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