Tuning help, please

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Beams

Beams

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Hi all, having some issues getting my 1965 with recently installed 273 tuned.

Details:
- HIPO 273. Domed pistons. Unknown if it’s ever been taken apart. Assuming 10.5:1 compression. A833 behind it.
- Original Carter AFB
- Fresh gas (pretty certain I went with 87 octane though) and new fuel filter
- Verified TDC and timing mark on balancer.
New Champion RC12YC plugs
- Using harbor freight basic timing light

Tuning story:
- Started with Mopar Electronic Ignition, but I had some bad misfiring and car quit starting. Checked through components and grounds, and although not confirmed, I’m pretty certain it was the Used - Like New cardone distributor I got from Amazon. Ultimately couldn’t get car to start at all.

Swapped in spare points distributor. Fired right up, but rattled on throttle blips. Finally got it to rarely rattle, but timing was set in the ballpark of 25 ATDC. Drove round the block, and had zero get up and go.

Coworker had an MSD ready to run unit. Dropped that in with new wires and coil. Much happier. Idled at 8btdc. Took it for a drive, and the rattle showed up again. Adjusted distributor throughout the drive and ended at about 5 atdc, and still some rattling under normal/mid to heavy acceleration. Idle mixture screws currently 2.5 turns out.

My gameplan is to:
-confirm balancer shows correct at TDC
-confirm that it has enough fuel through pump and filter
- put in higher octane gas
- keep tuning

I’m really thrown off by the timing wanting to be atdc. At 5 atdc it’s still responsive, didn’t notice any bogging.I thought the rattling was pinging, but maybe it’s something else. Oiling problem?

Here’s a clip of the sound under acceleration. Shows up at about 5 seconds in:

Apologies for the long post. Just trying to be detailed.

View recent photos.jpg
 
Adding:
-timing set with vacuum advance disconnected and plugged at carb

I’ll add driving without vacuum advance to the list of to-do’s
 
I can't tell much from the video. Start with higher octane fuel or add octane booster then retune. My 340 with iron heads and 10.5 compression will ping bad on 87. I'm running 94 octane.
 
Beams said:
put in higher octane gas
Click to expand...
Yes, Just like Woody said.
I looked in my 66 service manual and it has 3 different timing settings for 2bbl,4bbl,auto and manual.
2bbl manual shows 5* BTC .2bbl auto shows 10* before. Now get this,cars with cleaner air package ,2bbl manual or auto
its 5* ATC.

The 4 bbl auto or manual shows 10* BTC if it has the cleaner air package auto or manual its 5* BTC
 
Darter6 said:
Yes, Just like Woody said.
I looked in my 66 service manual and it has 3 different timing settings for 2bbl,4bbl,auto and manual.
2bbl manual shows 5* BTC .2bbl auto shows 10* before. Now get this,cars with cleaner air package ,2bbl manual or auto
its 5* ATC.

The 4 bbl auto or manual shows 10* BTC if it has the cleaner air package auto or manual its 5* BTC
Click to expand...
Thank you. I saw that when I was looking for potential solutions. Just out of curiosity, any idea why manual would be lower than automatic?
 
The sound in your video is not pinging. That’s the exhaust banging or something like that. Secondly, to get the timing sorted out you’re going to have to learn how to tune a distributor. You need to know how to limit the mechanical advance before you start adding initial advance in to it. And you should start by verifying that the balancer timing mark is accurate or everything else you do will be worthless.
 
TT5.9mag said:
The sound in your video is not pinging. That’s the exhaust banging or something like that. Secondly, to get the timing sorted out you’re going to have to learn how to tune a distributor. You need to know how to limit the mechanical advance before you start adding initial advance in to it. And you should start by verifying that the balancer timing mark is accurate or everything else you do will be worthless.
Click to expand...
Thank you. Appreciate the first point, for sure. Helps to narrow focus.

To the second point—it’s a good point. I do need to figure that out too. The points distributor was on the motor when I bought it. Theoretically, it should have been in the ballpark. I verified balancer timing mark already, but plan on checking again, in case I was too distracted by the screaming kid pulling on my leg.
 
Once you do, take a white marker and draw a line from the center all the way out to the edge. That way if it ever slips you’ll have a visual reference.
 
Either you're using the wrong timing mark, the balancer has slipped or "something else" is going on. The engine will not perform well if the timing is set ATDC. Is it remotely possible you're reading it backwards? Some timing lights have the inductive clamp with an arrow on it that's supposed to point toward the plug. If that's flipped around wrong, that can affect your reading. Something is not right with what you're doing. I would double and triple check everything, starting with finding TDC for #1 with a piston stop and verify you're using the correct timing mark. Sometimes there are multiple hash marks on the balancer.
 
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My buddy bought a 340 (1970 model with a aluminum water pump) But the engine had the 68 cast pump balancer.That ment the timing marks were on the wrong side. Just a thought.
 
I agree that the random banging noise in audio is not pinging. Something is hitting something.
 
Thanks @RedFish. Maybe I should clarify the video too. It was taken from inside the car. There’s a very clear metallic banging noise coming from clutch pedal linkage. The rattle lasts for maybe a second, starting at 5 seconds. I’ll admit that it’s subtle in the video.

I’ll don’t know if I’ll have a chance to wrench on it tonight, but will definitely give an update this weekend.
 
Only a month later… just want to give an update.

The old distributor was definitely toast. New distributor in from Halifaxhops. Back to the initial mopar electronic ignition setup. I got to drive it around for a few minutes this week. Verified TDC timing mark, filled up with fresh 91 octane, and topped off oil too. Rattle seems to be gone. Could use some more tuning—timing light still shows about 5 ATDC. I’ll just tune off of feel, I guess.

Only drove for a few minutes because rear drums were screaming. Right rear is dragging bad. Parking brake cable was pulled tight to fit the new exhaust, but still drags even when the adjustment is backed all the way out (and cable is loose).

I guess the saying is true… Drive them, and they’ll tell you what they want.

I’ve got a lot to learn with these old cars. Appreciate everyone’s help with the rattle!
 
Darter6 said:
I looked in my 66 service manual and it has 3 different timing settings for 2bbl,4bbl,auto and manual.
2bbl manual shows 5* BTC .2bbl auto shows 10* before. Now get this,cars with cleaner air package ,2bbl manual or auto
its 5* ATC.

The 4 bbl auto or manual shows 10* BTC if it has the cleaner air package auto or manual its 5* BTC
Click to expand...
Cleaner Air Package vehicles got distributors with mechanical advances that compensated for retarded initial.
The retarded initial put more heat into the cylinder walls, insured more HC was burned up, and reduced CO.
A graph illustrating the 273 CAP vs non-CAP timing in this post.
 
Beams said:
The old distributor was definitely toast. New distributor in from Halifaxhops. Back to the initial mopar electronic ignition setup. I got to drive it around for a few minutes this week. Verified TDC timing mark, filled up with fresh 91 octane, and topped off oil too. Rattle seems to be gone. Could use some more tuning—timing light still shows about 5 ATDC. I’ll just tune off of feel, I guess.
Click to expand...
Is 91 the highest youy can buy?
If so, and depending on altitude, the timing should be on the low side.
That said, depending on how Halifaxhops set the distributor up, initial should be 8 to 12*.
Initial timing MUST be measured at a known RPM. If this requires buying or borrowing a tachometer, then so be it.
Timing at 650 rpm will not be the same as timing at 850 rpm, never mind 1200 rpm.
 
Following along, hoping to learn lol. With the older AFB's they only have the one port for VA, which is ported vac(my 67 273 4295S) is anyway.
Good luck, it can be frustrating (1st hand knowledge)
 
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