New to me 78 NYB on its way but please Don't tell my wife

commando1

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Vibration is a fucker. It diminishes under part throttle. But definitely directly tied to rpm. Just barely perceptible under engine idle/coasting with mild engine braking.

At times it thrums a bit….. which is really weird…. Under very light throttle.

Could my converter be out of balance with engine?

I wonder…. Need to read up on that.
Had the same vibration. Drove me bonkers. You'll never guess where it came from. I happened to do an A-Z brake job on the rears.
POOF. Vibration gone.
Don't ask me why.
And this was after I had the drives shaft balanced which did nothing.
 

73 T&C

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Still throwing rocks at the gremlin.

Mile 329 of 500 and it’s better.

Someone at the shop “adjusted” the carb to death. Bent the choke bar to keep it on. Set rich as hell even after I know I leaned it out when I initially brought it back to the shop.

Think it’s the new guy trying to help.

Miss is still gone. Vibration continues but less so.

At least it looks beautiful.

moving back into the house.
 
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Mr C

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My heavens this thing is beautiful. The Forged aluminum Cordoba rims look great and right at home on it.

I hope you get it running the way you want...glad it's improving.
 

73 T&C

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Note on the alum rims…..

Just so everyone knows. You need to up the studs to 3” to mount the alum rims. Other than careful placement of taped balancing weights to avoid calipers, they bolt right in.
 
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73 T&C

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Mile 495 on new engine. Better but still not right. More methodical rock throwing and insights.

Timing set at 18 degrees BTDC. Starts right up every time. No pinging.

Choke set and working fine. Two good pumps cold and I’m golden.

Vibration bad cold but diminishes with temp. Always there…… SHIT!

Final temp fine at center or just above center of gauge….. depending on fan mode.

All plugs appear to be firing fine. Rpm set at 850 no load. Engaging drive drops it about 75 rpm. With addition of A/C on, rpm drops another 50rpm warm and is at edge of instability cold and when choke comes off. No Bueno

The lean burn advance program is a real drag on the engine with the slowed return to advance built into it.

I spoke with Holley about the ignition system I should use. I can go either way with replacing the lean burn with standard Chrysler electronic ignition or stick with the Lean Burn distributor and index it with the Holley computer. The Holley would be taking over the timing tasks from the Lean Burn. That allows me to program in advance more precisely and will add some fun and life to the project.

Obviously, I would prefer the most complicated install. It keeps the car looking stock upon initial examination but would be loads more fun to dial in.

But for now, I figured I would keep it simple to start and ordered the Mopar kit for $150 bucks. It is plug and play with the Holley Sniper.

Put in a zinc additive to the oil (STP) as I continue my search for that gremlin. Couldn’t hurt.

All moved in to the refurbished house….so I can focus on it a bit more. Just some sorting, cleaning and planning for the next steps to go on the exterior rehab. It looks ok but it needs some love.

I’m going to run a full compression check on engine myself next. Then a leak down test… again doing it myself.

Even if I end up junking the engine, all the new parts will be reusable.

I’m driven purely by curiosity at this point so frustration is waning. Perhaps Spartacus has gotten his second wind….
 
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73 T&C

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Ignition arrived today.

Some of you may remember to had a similar rough idle on the 440 in my wagon. It had a rough idle that cleared up under a bit of throttle under load. It was a bad exhaust valve. Number 3 cylinder was just weak.

That’s what this feels like….. only a bit worse.

It’s definitely something but also definitely a bit better.

But first, I swap in the new ignition. The one I used for testing was cobbled together from spares.

I’ll mount this new one temporarily on a removable panel until I’m ready for the Sniper.

Of course, lots of pictures to follow.
 

cantflip

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Ignition arrived today.

Some of you may remember to had a similar rough idle on the 440 in my wagon. It had a rough idle that cleared up under a bit of throttle under load. It was a bad exhaust valve. Number 3 cylinder was just weak.

That’s what this feels like….. only a bit worse.

It’s definitely something but also definitely a bit better.

But first, I swap in the new ignition. The one I used for testing was cobbled together from spares.

I’ll mount this new one temporarily on a removable panel until I’m ready for the Sniper.

Of course, lots of pictures to follow.
Glad you are getting progress... I'm still here if you need to call me, for whatever...

Food for thought... or just my random thoughts. If you like, remove all drive belts and see what happens to the vibration to quickly eliminate all accessory drive items... can't drive or run long without a w/p though. Bumping the belts off/on cuts the time for this dramatically.

Does the scope provide easy access to power balance testing? Try doing it in gear for additional load.

Don't recall if that's been done before.
 

73 T&C

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Glad you are getting progress... I'm still here if you need to call me, for whatever...

Food for thought... or just my random thoughts. If you like, remove all drive belts and see what happens to the vibration to quickly eliminate all accessory drive items... can't drive or run long without a w/p though. Bumping the belts off/on cuts the time for this dramatically.

Does the scope provide easy access to power balance testing? Try doing it in gear for additional load.

Don't recall if that's been done before.

great minds….

I was going to do a load test next. See if I can identify weak cylinder.
 

73 T&C

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< sits quietly thinking about possible solution and drives himself nuts by another man's problem >
:BangHead:

Thanks, I’ll keep you posted and, for god’s sake, don’t worry about it. Meantime, any suggestions that don’t involve junking the Thermoquad are welcome.
 

73 T&C

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Well gentlemen…….

Been a while…. Had to finish up house and then came move in and take oldest to grad school in Gainesville… then a huge kidney stone plugged up my works but I’m recovering…. Well at least not dead.

I did manage to do an idle running test of each cylinder just before the stone struck.

Brought her to lowest possible idle and then pulled out each plug wire one at a time and checked rpm drop.

result: number 4 shows lowest drop. Almost 0 actually. Rest are between 40 and 50 rpm

I’ll repeat with car blocked in drive and raised idle to 900 to confirm.

listened around with my stethoscope and the #4 exhaust has slight tick. Bent?

Getting the camera ready for when I can do it without seeing stars.

But right now , and for the next few weeks, I’m still in healing mode with only light household sorting duties allowed and 1/2 time in the office.


hope you’ve all had a good summer.
 
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