Author Topic: Strange Noise  (Read 3235 times)

Offline Beekeeper

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Re: Strange Noise
« Reply #15 on: November 20, 2018 - 02:05:14 pm »
Definitely have a whine there, try removing or changing out the air cleaner; I know it sounds weird but my first impression was that it was coming from the carb. I agree that if it is a vacuum leak it would be running like crap. It could be the AT pump or a bearing in the front of the trans. I would drive it until the problem shows itself more (as in something gets louder, breaks or stops working).

I agree. Id drive it a bit more




Offline cv70chall

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Re: Strange Noise
« Reply #16 on: November 22, 2018 - 10:08:49 am »
So, first off.

HAPPY THANKSGIVING EVERYONE!!!!

After some investigation, we've discovered it to be a vacuum leak- which seems to be coming from the carb.
Replaced gaskets on the intake, carb and some o-rings as well.
We did also notice that a second factor was a vacuum hose that went from the back of the engine into the firewall- which I suspected was an AC related hose. (I have the stock AC system)
Any ideas on this hose?

Lastly, I have a Comp CAM (268/280 and .477/.480) installed and want to know if I would be better off upgrading the stall- which is currently stock?
The CAM is a Comp Extreme Energy CRB XE268H-10.
« Last Edit: November 22, 2018 - 10:18:54 am by cv70chall »

Offline 70chall440

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Re: Strange Noise
« Reply #17 on: November 22, 2018 - 11:28:21 am »
Happy T day to you and yours.

Makes complete sense.

I believe the hose you are referring to is to run your AC/heater controls which is vacuum actuated.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline cv70chall

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Re: Strange Noise
« Reply #18 on: November 22, 2018 - 03:07:11 pm »
Sounds right. I won't really need that hose operational unless I decide to switch from cold to heat, right?
Any thoughts on the CAM and if I should upgrade from a stock stall converter?

Offline Beekeeper

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Re: Strange Noise
« Reply #19 on: November 22, 2018 - 04:09:46 pm »
Inside the car, on the heater/ac box, there are vacuum operated doors and the vacuum hose you see in the engine compartment supplies a vacuum source to actuate them. The simple solution if you dont care about heat or ac would be to plug the nipple at the fitting on the intake manifold and leave that hose going through the dash disconnected. You could also rig it easily to have heat but no ac if you wanted.

Im curious how you determined the high pitch noise to be a vacuum leak at the manifold and carbs.


Offline cv70chall

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Re: Strange Noise
« Reply #20 on: November 22, 2018 - 11:04:38 pm »
Understood. I want to keep the look- and my AC working. Don't need the heat.
As for the noise- basically took water and sprayed down the suspected area- replaced gaskets on the intake manifold and carb- and checked each vacuum hose.
Part of the problem was the vacuum secondary on the carb (some loose screws internally) and lack of good seal between the carb, aluminum cooling plate and intake and leak inthe hose leading into the heater box.
Sounded like a turbine at one point!

Offline Beekeeper

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Re: Strange Noise
« Reply #21 on: November 23, 2018 - 12:59:45 am »
Understood. I want to keep the look- and my AC working. Don't need the heat.
As for the noise- basically took water and sprayed down the suspected area- replaced gaskets on the intake manifold and carb- and checked each vacuum hose.
Part of the problem was the vacuum secondary on the carb (some loose screws internally) and lack of good seal between the carb, aluminum cooling plate and intake and leak inthe hose leading into the heater box.
Sounded like a turbine at one point!

Interesting...never heard a vacuum leak noise like that so good to learn something new.

If youre ac is working, Id just replace vacuum hoses as needed. There should be another vacuum hose to a heater valve at the firewall on the engine side. If it is all hooked up properly, the valve is naturally in a closed position keeping hot coolant from entering the heater box but when the ac is off, vacuum is applied to the valve opening it up in case you want to turn on the heater. The only ac cars I have owned were GM but Im guessing Mopar is similar in that the vacuum source goes through the firewall to a control under the dash. When the heater valve needs to be opened, vacuum is applied to a specific hose that goes back into the engine compartment to the valve. Sounds more complicated than it really is. The important part here is there are several small vacuum lines as part of the system that are hidden and capable of causing small leaks which can be a nuisance.

Offline cv70chall

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Re: Strange Noise
« Reply #22 on: November 23, 2018 - 12:11:08 pm »
Thanks
I actually plugged both heater valve hoses as I do not plan on ever using heat. That being said, I will bock off the vacuum hoses as well, but keep the stock appearance.

On the subject of my CAM, I have a Comp CAM (268/280 and .477/.480) installed and want to know if I would be better off upgrading the stall- which is currently stock?
The CAM is a Comp Extreme Energy CRB XE268H-10.

Offline cv70chall

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Re: Strange Noise
« Reply #23 on: January 11, 2019 - 08:18:50 am »
So...Thanks too my good Mopar friend John, the source of the noise has been discovered and corrected. Turns out there was a tear on the Intake gasket! Replaced and fixed.
Thank You John!

Offline 70chall440

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Re: Strange Noise
« Reply #24 on: January 11, 2019 - 01:38:57 pm »
i.e. a vacuum leak... glad you found it.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)