What could pinging mean in terms of timing?

[pjoll84]

Appreciate all of the wisdom… you don’t learn unless you ask. Appreciate it!

I think what I’m going to do is clean up the remaining loose ends ie, double check the spark plug and points gap, recheck timing and bring it down to more factory spec and be happy with that… I mean it reaches 40mph on the flat in under 10 seconds and it’s a motorhome… can’t be upset with that lol

IRONICALLY… or maybe more hilariously, everything is dialed in and I still have a bit of a hesitation on acceleration if I stomp on it (more when warming up) I noticed the accelerator arm is connected to the inner hole up top instead of the outer hole.. just an observation, not saying that’s why… accelerator is a strong stream if I mash on it… so I don’t know, I’ve done everything else that’s been suggested and it just sounds like it’s being flooded and catching up or it’s choked out for a split second and it roars to life. If I feather or slowly depress the accelerator, it’ll be just fine.

 

[pjoll84]

One other thing…IF it only pings when you are already at highway speed and floor it, “maybe” your vacuum advance needs adjusting (Allen wrench inside hose connection nipple in distributor)

Hmm interesting. Is this Allen bolt simply a lefty loose eighth righty… quarter turns and go out for a rip? Or is there something I could or should be measuring?

 

[Geoff 2]

Many things cause pinging:
- ign timing
- engine too hot
- lean mixture.

Since this is happening at high[er] rpms, the springs for the centri weights in the dist might have stretched, allowing excessive advance at higher rpms. I would start there.....

 

[PurpleBeeper]

Hmm interesting. Is this Allen bolt simply a lefty loose eighth righty… quarter turns and go out for a rip? Or is there something I could or should be measuring?

That's roughly correct. I can't remember which direction you turn, but it adjusts "how high your vacuum needs to be to get vacuum advance" or in other words "what vacuum level cuts out the vacuum advance when you push down on the gas pedal while cruising". Like, if your vacuum at cruising is 18"Hg, then you'd want your vacuum advance to stop adding advance at maybe 13"Hg or less (?-total guess)...something lower than your cruising vacuum.

 

[PurpleBeeper]

Many things cause pinging:
- ign timing
- engine too hot
- lean mixture.

Since this is happening at high[er] rpms, the springs for the centri weights in the dist might have stretched, allowing excessive advance at higher rpms. I would start there.....

Your 3 points are correct, but I'm thinking "advance spring strech" would affect your mid-range ignition advance, not high rpm advance since the slots inside the distributor limit the maximum advance. The springs set the rate/rpm where you get to that maximum advance

 

[RJRENTON]

Or convert to the Chrysler electronic ignition system and eliminate the points.

WHY??.....Then your issues will be ECM failures, ballast resistor issues, coil issues......just leave well enough alone and re-jet the carb richer and re-curve the distributor and flush out the cooling system and install a 180° F thermostat.......just my opinion of course....
BOB RENTON

 

[pjoll84]

WHY??.....Then your issues will be ECM failures, ballast resistor issues, coil issues......just leave well enough alone and re-jet the carb richer and re-curve the distributor and flush out the cooling system and install a 180° F thermostat.......just my opinion of course....
BOB RENTON

I’m a bit confused as to which system I have as I have a ballast resister in the front, points and a condenser. I also seem to have that chrome box with the two plugs.

Already flushed the coolant when I picked it up and replaced the tstat with a 180 few weeks ago… runs 175 on the gauge all day

Messing with the vacuum advance seems to be out of my league unless I can find an uncle Tony’s garage video on the step by step process.

I took the cap off the dizzy and looked inside.. it seems there’s points/condenser and then some sort of plate and the springs underneath. Do I unscrew the nut (the rotor sits on) and then remove the plate? UTG suggests eliminating the heavier spring altogether…

 

[toolmanmike]

I’m a bit confused as to which system I have as I have a ballast resister in the front, points and a condenser. I also seem to have that chrome box with the two plugs.

Already flushed the coolant when I picked it up and replaced the tstat with a 180 few weeks ago… runs 175 on the gauge all day

Messing with the vacuum advance seems to be out of my league unless I can find an uncle Tony’s garage video on the step by step process.

I took the cap off the dizzy and looked inside.. it seems there’s points/condenser and then some sort of plate and the springs underneath. Do I unscrew the nut (the rotor sits on) and then remove the plate? UTG suggests eliminating the heavier spring altogether…

Do yourself a favor and stay away from Tony's videos. They can lead you in the wrong direction. Halifaxhops, Mattax and others on this site are very knowledgeable about ignition systems.

 

[pjoll84]

Do yourself a favor and stay away from Tony's videos. They can lead you in the wrong direction. Halifaxhops, Mattax and others on this site are very knowledgeable about ignition systems.

Appreciate it…

Here’s the plan today:
-check the gap on my points and adjust if nexessary
-check the gap on my plugs as that’s the last thing I haven’t checked (just house keeping really)
-return the accelerator pump to the factory hole
-warm it up and reset timing to book spec

See what happens.

 

[pjoll84]

These points don’t look great… should the two points that meet and seperate be lined up?

 

[pjoll84]

Never mind, bent them back and gapped to .018… sure lit off a lot quicker… on to the plug gaps hope everyone’s enjoying their Saturday

PS: what is the name of this spring and where can I get a proper one?

 

[toolmanmike]

These points don’t look great… should the two points that meet and seperate be lined up?

View attachment 1676206

View attachment 1676207

Not good at all. Get with @HALIFAXHOPS and purchase some quality ignition parts. You won't regret it. I would buy a proper cap and rotor from him to make sure everything is correct.

 

[toolmanmike]

Never mind, bent them back and gapped to .018… sure lit off a lot quicker… on to the plug gaps hope everyone’s enjoying their Saturday

PS: what is the name of this spring and where can I get a proper one?

View attachment 1676209

Try Mega Parts USA and look for "spring" or "kickdown" in the search box.

 

[pjoll84]

Try Mega Parts USA and look for "spring" or "kickdown" in the search box.

Well,

-I adjusted the point gap to .018, bent it back so they touched square.

-re-gapped the spark plugs to .35… some were as far as .45 but nice and clean

-re-oiled by evap canister

-dialed back the timing to shop manual spec (roughly 2.5 +-)

-returned the arm of the accelrator pump back to the factory hole

Purrs like a kitten, no bog… not a lotta guts but runs a heck of a lot better!

I am curious about the vac advance Allen wrench comment… it seems that everything was hastily put on this engine (everything’s new) and then something happened and they sold it before dialing it in. The distributor looks brand new with paint marks etc on different screws from the rebuild. If I turned it all the way clockwise… theoretically… how many turns out should it be for bone stock?

 

[HALIFAXHOPS]

Varies by the motors corved. No one setting. FSM timing light and vac guage and you can do it.

 

[HALIFAXHOPS]

 

[Don Gould]

It takes 2 conditions to make an engine detonate too much HEAT and PRESSURE if either one of these conditions is not present then it wont detonate.
The lower the fuel octane, higher the combustion chamber temps the more susceptible to detonation.
I believe you said this was a 69 engine?
Do you know what the fuel octane level was in 1969? Regular was about 92, premium was around 104-108 LEADED no ethanol, no fuel additives just plain old GAS.
Now your trying to burn weed killer 87 or 93 at best at $8 plus a gallon in California.
You need to think about these two detonation causing conditions when you are tuning these old engines.
2.5 to 5* of timing may have been OK in 69 but now 55 years later your going to have to tune to the fuel that's readily available.
Start out with a good electronic Ignition System like the HRR688 computer controlled Box and Coil Kit. You've got to get a good hot spark and it's got to get the plug at the exact optimum moment to fire the flame front to optimize the pressure in the combustion chamber.
The timing numbers need to match the fuel.
On this engine considering the load (Vehicle weight) I would set it up with about 12* initial timing 34* total timing, a Vacuum Canister that can be adjusted to bring the timing up to about 30* at Idle, about 40* at cruise and connected to a CONSTANT manifold vacuum source.
Keeping in mind that a lean A/F ratio takes longer to burn than a rich A/F ratio the timing will be high under Idle and Part throttle conditions and under hard load it the vacuum timing will drop back as manifold vacuum decreases.
Its also important on this type of application that springs in the distributor are set to hold back the total mechanical advance to not fully advance until the engine is in its peak power band.
These numbers can only be achieved using a Distributor machine with adjustable RPM and vacuum levels simulated to engine load and the screwdriver in the hands of a very experienced technician with decades of experience.
The ignition timing is the heart beat of your engine, don't take your heart issues to a Proctologist even tho it may be cheaper.
FBO Ignition has the people, the parts, the equipment and over 5 decades of doing this correctly.
I've been retired now for nearly 4 years but I'm still on call whenever Dana needs me as a consultant and Jim is still in the shop everyday custom curving and modifying distributors for engines used in every application imaginable from performance hot rods to farm equipment.
Its good to be back I've missed all you guys