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Engine Noise
Posted by: MoxyRamone ()
Date: October 07, 2018 01:07PM

I am moving in a few weeks, so I thought I would get the Corvair going again. We had been out of commission for a while with carb issues. I found out that the idle mixture screws on both carbs were more than 4 full turns out from seated. No wonder it was running rich!

Once all was sorted, I let it warm up and took it for a little drive. While the engine is warm and at idle speeds, there is a rhythmic "pssst" sound. It is consistent with engine speed. It reminds me of an old tractor. The exhaust seals are shot, and I currently have the air cleaner off. Is this a normal sound that is usually quieter? I am thinking that it is the sound of air somewhere and not mechanical in nature.

Any thoughts are appreciated.

John Carver
Landrum, South Carolina

1964 Monza Convertible

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Re: Engine Noise
Posted by: Lane66m ()
Date: October 07, 2018 03:17PM

Can you identify the noise to one cylinder bank or the other?

Al Lane
Ellabell GA

1966 Monza Coupe, 110 hp, 4 Spd
1968 Camaro SS Coupe 350 CI 295+ HP PG
1964 Greenbrier Deluxe, 6 dr, 80 hp car engine, PG
2015 Chevrolet Malibu 2LT
2018 Chevrolet Silverado LTZ Z71 Centennial Edition
1947 Farmall A tractor 15 hp


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Re: Engine Noise
Posted by: MoxyRamone ()
Date: October 07, 2018 03:25PM

Honestly, it sounds like it's coming from the top center of the engine. Is there a possibility this could be crankcase breather tube or oil dipstick tube?

John Carver
Landrum, South Carolina

1964 Monza Convertible

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Re: Engine Noise
Posted by: Lane66m ()
Date: October 07, 2018 03:38PM

I have heard people say a rhythmic sound like a pffft is usually a cylinder gasket leaking. I hope someone else has some other ideas.

Al Lane
Ellabell GA

1966 Monza Coupe, 110 hp, 4 Spd
1968 Camaro SS Coupe 350 CI 295+ HP PG
1964 Greenbrier Deluxe, 6 dr, 80 hp car engine, PG
2015 Chevrolet Malibu 2LT
2018 Chevrolet Silverado LTZ Z71 Centennial Edition
1947 Farmall A tractor 15 hp


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Re: Engine Noise
Posted by: MoxyRamone ()
Date: October 07, 2018 03:51PM

That would actually make sense. It does sound like compressed air escaping.

John Carver
Landrum, South Carolina

1964 Monza Convertible

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Re: Engine Noise
Posted by: Spectre ()
Date: October 07, 2018 03:55PM

Often, a cylinder head gasket will make a chirping noise.

David Clamp


1965 Corsa convertible - 140 4spd/3.55/AM-FM

2013 Mustang GT convertible - 5.0, 6spd auto, Procharger i-1

2003 Miata SE - 6spd manual (wife's toy)

"Victory is mine!" - SG

Oklahoma City, OK

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Re: Engine Noise
Posted by: Lane66m ()
Date: October 07, 2018 03:57PM

Now the question is, do you have time to pull fan shroud and lower shrouds off to check for leaks?

Might have to crank the engine while someone checks cylinders for leaks to determine which side is leaking. Maybe a pressure check of each cylinder with valves closed to make sure it is not a head gasket, but probably not if it is center of engine.

Al Lane
Ellabell GA

1966 Monza Coupe, 110 hp, 4 Spd
1968 Camaro SS Coupe 350 CI 295+ HP PG
1964 Greenbrier Deluxe, 6 dr, 80 hp car engine, PG
2015 Chevrolet Malibu 2LT
2018 Chevrolet Silverado LTZ Z71 Centennial Edition
1947 Farmall A tractor 15 hp


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Re: Engine Noise
Posted by: MoxyRamone ()
Date: October 07, 2018 04:13PM

Sounds are sometimes difficult to isolate. I'm also slightly deaf on my right side (28 years of rock&roll bass! Hell yeah!). I will get a second opinion tomorrow and probably post a video so you all can hear it.

John Carver
Landrum, South Carolina

1964 Monza Convertible

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Re: Engine Noise
Posted by: moomba32 ()
Date: October 07, 2018 05:55PM

If you have time and can get it to Maggie Valley next weekend you'll have 20 mechanics wanting to look at it. They seem to be attracted to misbehaving Vairs and almost push each other away so they can touch it.

Don Marlowe
66 Monza 2Dr 140/pg
64 Spyder convertible now, 110/pg
Eutawville SC

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Re: Engine Noise
Posted by: MattNall ()
Date: October 07, 2018 06:17PM

Moxey... very easy to just retorque head nuts / rock studs to just 30 ft/ lb.... then you'll know if / when you feel a loose one! Then drive on!





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Engine Noise
Posted by: RKF ()
Date: October 08, 2018 02:57AM

I would do a compression test on all cylinders. A leaky head gasket will result in low compression in the affected cylinder.

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Re: Engine Noise
Posted by: MoxyRamone ()
Date: October 08, 2018 05:58AM

#6- 155 #5- 160
#4- 148 #3- 140
#2- 120 #1- 110

A little squirt of oil in #1 and #2 boosted the reading to 145(#2) and 130(#1).

These results were from the last time I ran a compression check back in April. The engine made the same sound then as it does now, and was not run at all between them and yesterday.

John Carver
Landrum, South Carolina

1964 Monza Convertible

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Re: Engine Noise
Posted by: MattNall ()
Date: October 08, 2018 07:12AM

Drive it! 50 psi is a big difference though...





MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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