Nasty noise

[Art Bailey]

Hey All,

 

I hate to bother you all with this, but this is not a good noise. 

 

Happens when I give it a quick rev. I can't tell where it's coming from, front or back or what. It doesn't happen if I pull the throttle gradually and increase the engine speed. I don't want to do it too much and push my luck, so I'm hoping maybe this is a familiar noise to someone? I thought it might be belt slippage, but it doesn't appear to be, seems mechanical. Thanks...

[Sniper]

sounds like your accelerator pump isn't squirting and the engine bogs. 

[plymouthcranbrook]

Or maybe the vacuum advance isn’t working

[keithb7]

Agree with Sniper. Sounds like a vacuum whoosh.
 

Shut down the engine. Take your oil bath filter off.  Ensure choke is wide open. Look down carb Venturi with a flashlight. 
cycle the throttle linkage wide open a couple times fairly briskly.  Observe a raw stream of fuel squirting into the Venturi. If not, you may have a carb accelerator pump issue. Leather cups wear out and don’t like to push fuel. 
 

Do you experience a brief stumble when you drive the car, at initial acceleration?

 

You can witness this pump action in my video here:

 

 

Edited October 20, 2021 by keithb7

[Booger]

19 minutes ago, keithb7 said:

Agree with Sniper. Sounds like a vacuum whoosh.
 

Shut down the engine. Take your oil bath filter off.  Ensure choke is wide open. Look down carb Venturi with a flashlight. 
cycle the throttle linkage wide open a couple times fairly briskly.  Observe a raw stream of fuel squirting into the Venturi. If not, you may have a carb accelerator pump issue. Leather cups wear out and don’t like to push fuel. 
 

Do you experience a brief stumble when you drive the car, at initial acceleration?

 

You can witness this pump action in my video here:

 

 

thats an awesome lecture professor. Carter 101!

Edited October 20, 2021 by Booger
spelling

[Art Bailey]

Thanks guys. I'll look into vacuum advance and accelerator pump. Couple things, though---if you're listening on the speakers on your laptop, you might not hear how it sounds like metallic parts rubbing against each other, and only hear a whoosh. If you can, check it out with decent speakers or headphones, it sounds like a New Year's Eve noisemaker. 

 

The car's not on the road, I'm only able to test this out in my driveway by manually operating the throttle, so I don't know if there's a stumble when the engine's under strain, in addition to the nerve wracking noise. I rebuilt the carb with a kit from Then and Now, it starts very well, and I've looked down the venturi and observed squirts, so I think I can rule that out. This happens when I "gun" or rev the engine quickly, only. Otherwise, the rpms can be increased to what I'd imagine would be in the 50 mph range and beyond, and stay there, with no stumbles or noises.

 

Vacuum advance is a possibility. I got from Bernbaum what I assumed would be a rebuilt vac advance, since they ask for a core. I let it sit unopened past the 30 or 90 days they allow to return it, opened it to discover it was NOS from 1950-something, and doesn't quite hold vacuum pressure....it all leaks out, slowly. I put it in, because I thought it was better than nothing. Maybe the diaphragm ripped, and it's flapping in the breeze? I bought a brand new vac advance unit on a whim, on ebay, that looked very close in size and general dimensions to mine, that I thought I might try to adapt. I'll report back and see what I can figure out. At the very least, I could pull the old vac advance and see if it's even worse at holding a vacuum now. 

Edited October 20, 2021 by ratbailey

[Bryan]

Make sure fan isn't rubbing against radiator lightly.  

[Kilgore47]

Looks like a new water pump so those bearings should be good.  Check the generator drive end bearing for play.  It could be going bad.

[Dodgeb4ya]

The engine will run fine with out the vacuum advance for testing.

Disconnect and plug the line...run it and see.

[47 dodge 1.5 ton]

Maybe spray a little carb cleaner around gasket areas and bottom of the intake looking for a leak. I had a repaired crack in the intake manifold that I thought was bearings in the pump. Ending up being a vacuum leak.

[JerseyHarold]

A mechanic's stethoscope may help track down the source of the noise.  Just be careful when poking around a running engine.

[Bryan]

1 hour ago, JerseyHarold said:

A mechanic's stethoscope may help track down the source of the noise.  Just be careful when poking around a running engine.

Ask my brother that had his hand pulled in alternator by long loose sleeves. Lost a finger.  

[Art Bailey]

1 hour ago, Bryan said:

Ask my brother that had his hand pulled in alternator by long loose sleeves. Lost a finger.  

I'm hyper aware of that stuff. I had a few close calls working for my old man, and witnessed some ugly accidents, too.

Edited October 20, 2021 by ratbailey

[Art Bailey]

So, it's not the vac advance---I disconnected it, still makes the noise. Carb is squirting away, so it's not the accelerator pump. I just rebuilt the generator, so it better not be that, but I'll double check. I did some vacuum leak hunting last week, and found a big vacuum leak around the throttle shaft, but I really think it's a mechanical noise. I'll do some more hunting around the intake manifold. Mechanic's stethoscope is a great idea, I'm going to get one of those, or use some pipe or tubing.

 

Any chance it could be clutch related? It has a tough time shifting into reverse without the gears grinding, but only sometimes. I've learned to put it in gear slowly and carefully. 

 

I'll have some time this weekend to goof with it, I'll report back. Thanks, all!

Edited October 20, 2021 by ratbailey

[Sniper]

Pulling the belt will tell you if it's the engine or an accessory.

[Art Bailey]

3 minutes ago, Sniper said:

Pulling the belt will tell you if it's the engine or an accessory.

Good advice, thanks. I'll try it.

[oldodge41]

Could it be a harmonic balancer issue? If it has one. Just trying to think of anything that could " slip" under quick acceleration. Pulley on the generator, bad impeller in the water pump. Shots in the dark because I can't discern anything from the clip.

[Sniper]

Might try it with the clutch in and the clutch out, could be a throw out bearing.

[Art Bailey]

1 hour ago, oldodge41 said:

Could it be a harmonic balancer issue? If it has one. Just trying to think of anything that could " slip" under quick acceleration. Pulley on the generator, bad impeller in the water pump. Shots in the dark because I can't discern anything from the clip.

Ugh. You know what? I've been watching the harmonic balancer, or damper, as it idles, and somehow, it looked like it might be bent or crooked. I glossed over it in my mind, thinking that it wasn't possible, or an optical illusion. I'm going to look into that. Whether or not that's the source of the noise, I should take care of that before running it too much. Crap, I don't wanna pull the rad again ? 

Edited October 21, 2021 by ratbailey

[Dodgeb4ya]

Make sure crankshaft end play is less than .010".

[Sniper]

24 minutes ago, Dodgeb4ya said:

Make sure crankshaft end play is less than .010".

 

Oh geez, that's a bad thought there.

[Art Bailey]

22 minutes ago, Sniper said:

 

Oh geez, that's a bad thought there.

Just read some posts about checking crankshaft play, gonna be a big boy and do it. What do I expect from a car that's 73 years old?! This is the fun part, right? Right? ?

[Dodgeb4ya]

Generally if it's really over the limit pulling and pushing on the flywheel hard you will hear and feel a heavy clunk.

And you will easily see the crank and flywheel move forward and backward.

A proper end play of approximately .005" would not show any movement or sounding clunk to say a novice mechanic. A dial indicator is the accurate way to see the exact crankshaft end play clearance.

Also end play would have to be way way out of spec to cause a serious engine issues, difficult to achieve proper clutch adjustment, crank pulley moving, timing chain rubbing timing cover with clutch pushed in of course while running.

Just something that probably should be checked.

[Art Bailey]

I had a few minutes to goof with the car this morning. It appears that the damper is sitting crooked on the crankshaft pulley by a noticable amount, maybe 1/8" or a little more. I turned the engine over slowly by hand, with the fan, and gauged the gap between the pulley and damper with a mess of feeler gauges. Looks like we're pulling the rad again. I know little about the damper on this thing and how it's put together, but Don Coatney mentioned in a post that there's rubber in there that can deteriorate and cause it to "freewheel." Might or might not be the source of the noise, but either way, it's gotta get fixed. The car was hit in the front left at some point, the engine may have taken a hit, but I kind of doubt it. What I can see of the half-assed repairs done to it, it didn't look like a major hit, just a minor fender bender. When I have more time, I'll check the crankshaft play.

 

Question: is there any great danger in running the engine a few times to get it in and out of the garage with the damper sitting crooked like this? I was really hoping to get the brakes and cylinders pulled and sent out before the weather gets lousy, which I can only do in the driveway. 

 

Good call on the damper and crankshaft, guys...thanks!

Edited October 21, 2021 by ratbailey

[greg g]

Check Damper Doctor.com. if they are still in business they can rebuild yours or sell you one on an exchange basis.  Several folks have mentioned good results working withem for rebuilding original or swapping for a refurbished unit.