Pinging on acceleration.

[Witchboard]

Car idles fine and cruises fine, but pings when accelerating. I suspect timing. It's a 1973 225ci Slant 6 with a Carter BBD 2 barrel carb in a 1964 Barracuda. It has an electronic ignition installed, not sure if that makes any difference. I'm not trusting my timing light. It's one of those electronic ones that has a bunch of stuff built in. The light is rolling the timing marks and says it's idling at 800 RPM where I can connect a tach to the coil directly and says it's running 600 RPM.

So, I'm going to hit up my dad and use his old school light tomorrow. From what I can tell it's supposed to be 0 degrees TDC at 750 RPM for this year engine?

 

[Oldmanmopar]

Octane? I would poura higher octane race fuel in it and take it for a ride.

 

[Rug_Trucker]

Vacuum leak can cause a lean condition. Throttle shaft is one place. Check your hoses. Does your BBD have a sheet metal top on it? If so there is adjustment on the metering rods.

Non ethanol in my area is 90 octane. Love's may sell it. I know they did in Ada Ok.

What do you mean the timing light is "rolling?"

Distributor was new, or used?

Is the carb for a 6? BBD doesn't have the tin tab on it you usually can't identify it. However if the PCV connection is bent you have a super 6 carb.

 

[Demonic]

From what I can tell it's supposed to be 0 degrees TDC at 750 RPM for this year engine?

The factory specs are a bit too conservative. Even at 5 degrees before, you shouldn't ping. Carbon build up, leaking valves, and wrong plugs can cause ping. What do you mean by rolling? If you mean a varying timing mark, it sounds like you have a worn chain.

 

[Witchboard]

Octane? I would poura higher octane race fuel in it and take it for a ride.

Not sure I have access to high octane racing fuel. This is going to be a daily driver, not a track car, so I'd prefer to tune it to regular gas.

Vacuum leak can cause a lean condition. Throttle shaft is one place. Check your hoses. Does your BBD have a sheet metal top on it? If so there is adjustment on the metering rods.

Non ethanol in my area is 90 octane. Love's may sell it. I know they did in Ada Ok.

What do you mean the timing light is "rolling?"

Distributor was new, or used?

Is the carb for a 6? BBD doesn't have the tin tab on it you usually can't identify it. However if the PCV connection is bent you have a super 6 carb.

Not sure what a sheet metal top looks like. Distributor is original, but the hoses, cap, wires and gear are new. Carburetor has been rebuilt.

The factory specs are a bit too conservative. Even at 5 degrees before, you shouldn't ping. Carbon build up, leaking valves, and wrong plugs can cause ping. What do you mean by rolling? If you mean a varying timing mark, it sounds like you have a worn chain.

Rolling meaning that the lines looks like they are rotating in a clockwise pattern all the way around the crank. That's why I think my light is messed up. That and it's reporting an incorrect RPM.

 

[Rug_Trucker]

Okay, you have the old style toilet bowl BBD. That is intended for a 273, or 318. So it should have plenty of fuel. They run good on a slant. They are completely different on the internals that the newer BBD's. They are "air metered" don't ask me what that means. The metering rods are tiny diameter. I am not sure if they are adjustable.

There is ways to check the slack in your timing chain. One would involve pulling the valve cover. The other is popping off the distributor cap. Putting a breaker bar on the crank bolt. Checking for slack.

I actually had a 383 jump timing 25* on me back in the day with the nylon toothed cam gear. The teeth were gone and in the oil pan. It was eating into the aluminum gear.

 

[ESP47]

Your timing is most likely just too advanced. Factory sticker might call for 0 TDC but you should be perfectly safe at 5* BTDC without any pinging. I normally run about 10* just fine. Get yourself a timing light you can trust and go from there. If you feel like your timing lights aren't right, try this method and tune it old school style.

How do you adjust timing on a 273?

I have a 65 barracuda and I need help adjusting the timing. Thanks

www.forabodiesonly.com

 

[Rug_Trucker]

Your distributor could be a tooth or two advanced. Might want to double check.

 

[RustyRatRod]

Get the timing sorted out first. Get the good old light you said you were gonna get and double check the timing. Then report back.

 

[Mattax]

It has an electronic ignition installed, not sure if that makes any difference.

It means it might be the original distributor from '73.

From what I can tell it's supposed to be 0 degrees TDC at 750 RPM for this year engine?

IF that is the original distributor from '73 then there should be a tag on it. which I did not see in your photos but from the angles thats not surprising.

Which way does rotor turn in the distributor?

They get really brittle from heat and age. I have some new ones if needed PM me.

www.forabodiesonly.com

For an automatic it was p/n 3755042 it was TDC @ 750 rpm plus minus 2.5 degrees depending on conditions.

It probably had EGR. If you're not using the EGR valve then depending on the system the EGR may need to be blocked.
Whether this has bearing to the pinging depends on the circumstances pinging or gurgling is heard.
Most EGR systems worked only when the engine was warmed up, and warm or cold there was no EGR at idle and full throttle.
There is information in the Master Tech Series as well as the '73 Chassis Manual which should help figure out what is need to block off the EGR (based on what I see you don't want to make use of it for your car). Maybe its as simple as leaving an old EGR valve on the engine because its normally shut.

 

[Rug_Trucker]

don't remember seeing an egr on my '74 dart

 

[Mattax]

If its a mystory distributor, then the timing curve is a mystery too and you'll have to do some testing and measuring.
Its not the engine that caused the 750 idle rpm, its the emissions control setups used from the late 60s to mid 70s.
Then when cats came in they were able to split the difference to some extent.

Basically non-smog timing for '66 fell into this spec when set at 5*BTDC

And for comparison the '73 225 automatic with its original distribitor advance specs

Pinging is usually noticed up in the driving rpm range.
Setting a distributor with an advance curve like the '73 to the '67 initial of 5 * BTC could put the engine timing at 27 degrees at 2000 rpm. And if it pinged, that would be the cuase. The advance curve and the initial are tied together in terms of what the timing is at a given rpm. If we don't know the distributor, then we don't know the advance and initial becomes guess work resolved by measuring and testing.

 

[Witchboard]

Get the timing sorted out first. Get the good old light you said you were gonna get and double check the timing. Then report back.

Got the light. It's consistent now, but looks to be out of whack.

It means it might be the original distributor from '73.

IF that is the original distributor from '73 then there should be a tag on it. which I did not see in your photos but from the angles thats not surprising.

Which way does rotor turn in the distributor?

They get really brittle from heat and age. I have some new ones if needed PM me.

www.forabodiesonly.com

For an automatic it was p/n 3755042 it was TDC @ 750 rpm plus minus 2.5 degrees depending on conditions.

It probably had EGR. If you're not using the EGR valve then depending on the system the EGR may need to be blocked.
Whether this has bearing to the pinging depends on the circumstances pinging or gurgling is heard.
Most EGR systems worked only when the engine was warmed up, and warm or cold there was no EGR at idle and full throttle.
There is information in the Master Tech Series as well as the '73 Chassis Manual which should help figure out what is need to block off the EGR (based on what I see you don't want to make use of it for your car). Maybe its as simple as leaving an old EGR valve on the engine because its normally shut.

You found my old thread from when I was working on it the first time. Looks like the EGR has been blocked off already.

If its a mystory distributor, then the timing curve is a mystery too and you'll have to do some testing and measuring.

This is honestly above my head. I'll see if I can read it a few times and figure it out.

 

[Mattax]

This is honestly above my head. I'll see if I can read it a few times and figure it out.

Lets say you set the timing at TDC and measure the following:
750 rpm TDC
800 rpm TDC
1000 rpm 6* BTC
1200 rpm 10* BTC
1400 rpm 14*
1600 rpm 18*
1800 rpm 21*
2200 rpm 23*
2800 rpm 24* BTC

Plotting those on the graph, the timing looks the original '73 advance. Circles joined by heavy line.

Now lets turn distributor so the initial is now at 5* BTDC.

The entire timing curve shifts 5 degrees.

At 2600 rpm, instead of 24* the timing is 29*BTC.

That's 3* more than the factory spec for '67, and 5* more than the spec for 73. Would not be surprised if it pings, especially once the engine got heat soaked (long drive or steep uphills).

 

[RustyRatRod]

Got the light. It's consistent now, but looks to be out of whack.



You found my old thread from when I was working on it the first time. Looks like the EGR has been blocked off already.

View attachment 1716312527



This is honestly above my head. I'll see if I can read it a few times and figure it out.

Ok. So tell us WHERE the initial (idle) timing is. If I have to pull info out of you like teeth, I'm not gonna help.

 

[RustyRatRod]

Got the light. It's consistent now, but looks to be out of whack.



You found my old thread from when I was working on it the first time. Looks like the EGR has been blocked off already.

View attachment 1716312527



This is honestly above my head. I'll see if I can read it a few times and figure it out.

No, it's not. It's very simple and we can teach you how. If you let us.

 

[Witchboard]

Ok. So tell us WHERE the initial (idle) timing is. If I have to pull info out of you like teeth, I'm not gonna help.

I didn't think it was worth mentioning since I wasn't sure which mark was for top dead center. I plan on pulling plug one and going through the process again to verify what's what, but after getting the engine up to temp and pulling the vacuum advance, 0 degrees is below at 750 RPM.

No, it's not. It's very simple and we can teach you how. If you let us.

I guess I'm misunderstanding where the EGR valve is located. I thought it was under the carburetor on the intake manifold where that plate is in my picture, but I'll refer back to the documentation.

Please be patient with me. I'm diving back into this car after a while and have forgotten most of what I learned when I first started working on it. I'm relying on my notes and my history of threads on this forum to re-familiarize myself.

I'm honestly not trying to be difficult, I just don't want to waste anybody's time on stuff I feel I should know, so if it's not explained, I try and look it up.

 

[Ricks70Duster340]

I didn't think it was worth mentioning since I wasn't sure which mark was for top dead center. I plan on pulling plug one and going through the process again to verify what's what, but after getting the engine up to temp and pulling the vacuum advance, 0 degrees is below at 750 RPM.

View attachment 1716312898



I guess I'm misunderstanding where the EGR valve is located. I thought it was under the carburetor on the intake manifold where that plate is in my picture, but I'll refer back to the documentation.

Please be patient with me. I'm diving back into this car after a while and have forgotten most of what I learned when I first started working on it. I'm relying on my notes and my history of threads on this forum to re-familiarize myself.

I'm honestly not trying to be difficult, I just don't want to waste anybody's time on stuff I feel I should know, so if it's not explained, I try and look it up.

If that arrow is pointing to your TDC mark, then you're running almost 12* before... way too much.

 

[Witchboard]

If that arrow is pointing to your TDC mark, then you're running almost 12* before... way too much.

The arrow pointing at the harmonic balancer is where the timing cover shows 0 degrees. I'll see about trying to pull it to the yellow mark and see what happens, but if I recall, doing that made the car run like trash.

 

[RustyRatRod]

I see two timing marks clear as day on the balancer. You need to verify which one is correct.

 

[Killer6]

The arrow pointing at the harmonic balancer is where the timing cover shows 0 degrees. I'll see about trying to pull it to the yellow mark and see what happens, but if I recall, doing that made the car run like trash.

Dude, that's about 30°BTDC, that would be about the total power timing You'd shoot for....initial°+mechanical adv.°. Check the advance mechanism by popping off the cap & twisting the rotor back & forth against the advance springs, if it's stuck/frozen, it's like running a dizzy locked-out.....not for You Young Jedi....

 

[RustyRatRod]

Dude, that's about 30°BTDC, that would be about the total power timing You'd shoot for....initial°+mechanical adv.°. Check the advance mechanism by popping off the cap & twisting the rotor back & forth against the advance springs, if it's stuck/frozen, it's like running a dizzy locked-out.....not for You Young Jedi....

It's not that high. Look closely at the last number on the timing tab. It's 10 degrees BTDC. So where the arrow is represents about 12 degrees.

 

[Killer6]

It's not that high. Look closely at the last number on the timing tab. It's 10 degrees BTDC. So where the arrow is represents about 12 degrees.

But the yellow marked double-notch on the *dampener* is the TDC mark......

 

[RustyRatRod]

But the yellow marked double-notch on the balancer is the TDC mark......

Look REAL close on the balancer where the arrow is pointing. There's a hash mark. I'm almost positive that's the correct mark. If the balancer has been replaced, it will have two marks. All of them I have seen do. One mark for each timing tab position. Of course he won't know for sure which is correct until he checks TDC as he's been told. If he'll do it. You know how that goes around here.

 

[Killer6]

Look REAL close on the balancer where the arrow is pointing. There's a hash mark. I'm almost positive that's the correct mark. If the balancer has been replaced, it will have two marks. All of them I have seen do. One mark for each timing tab position. Of course he won't know for sure which is correct until he checks TDC as he's been told. If he'll do it. You know how that goes around here.

The yellow paint is at the most retarded position, and has two distinct notches, there are multiple hashes...all in an advanced position, and none doubled that I can see. It'd make sense if one is marking the dampener to keep track of the advance curve, all the additional marks would be in the advanced position. It would also square that if the mech.timing were stuck advanced, that setting the base timing to -0-° w/o any further advance would make the car almost undriveable, just sayin'...