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Old 10-14-2019, 10:21 AM   #1
smurph
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Default Engine Noise

My 1929 engine has developed a disturbing noise which I can best describe as a rattle, or a “clack, clack, clack” (not a clank). The noise usually does not occur at idle, but appears once revs increase (maybe 1500 rpm) and then will usually , but not always, stop as rpm’s increase above 2000(?).
When driving under load there is usually no noise, but when I take my foot off the accelerator the “clack, clack, clack” frequently appears.
I think the problem may be coming from cylinder #2 because when I short out the plugs one by one, I get the expected decrease in revs from #’s 1,
3, and 4 but in addition I hear a definite but more subdued rattle or chatter or clack coming from #2.
Any thoughts about what’s going on would be much appreciated.
Thanks,
smurph
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Old 10-14-2019, 10:31 AM   #2
30 Closed Cab PU
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Default Re: Engine Noise

Valve issue, MMO treatment needed?
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Old 10-14-2019, 11:15 AM   #3
WHN
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Default Re: Engine Noise

Quote:
Originally Posted by 30 Closed Cab PU View Post
Valve issue, MMO treatment needed?
I agree. Try the simple things first. Enjoy.
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Old 10-14-2019, 11:32 AM   #4
Ernie Vitucci
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Default Re: Engine Noise

You might take a look at the Distributor body and see if it has a crack in it. Also the distance from the rotor to the tit on the distributor body should be 0.025. I have occasionally seen these things warp a bit and one gap will be way too close or too far. Also, you might try a different spark plug in number 2. Ernie in Arizona
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Old 10-14-2019, 11:54 AM   #5
Patrick L.
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Default Re: Engine Noise

I think I would try to determine a bit better as to where the noise is coming from. A stethoscope, screwdriver, long dowel, hose, etc can be used. Does it sound louder from top, bottom, left or right ?
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Old 10-14-2019, 02:04 PM   #6
smurph
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Default Re: Engine Noise

Thanks for your thoughts. I use MMO regularly in every gas fill up. I have also used a stethoscope which hasnt helped much. Things sound pretty normal through the stethoscope when the clacking isnt happening.
The noise seems to be a top end noise, about in the middle of the head.
Good idea to change #2 spark plug which I will try. And Ill closely inspect the distributor body and rotor contact points.
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Old 10-14-2019, 02:51 PM   #7
30 Closed Cab PU
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Default Re: Engine Noise

Just to absolutely rule out the generator/alternator/water pump - remove the fan belt. I prefer not to assume anything and like to rule out things even if they do not make sense.
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Old 10-14-2019, 03:17 PM   #8
Bulligen
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Default Re: Engine Noise

How about slop in the fiber timing gear. It can make some weird racket!
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Old 10-14-2019, 09:07 PM   #9
w.michael
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Default Re: Engine Noise

Loose valve insert?

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Old 10-15-2019, 02:58 AM   #10
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Default Re: Engine Noise

How about exhaust manifold gasket.
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Old 10-15-2019, 08:28 AM   #11
BRENT in 10-uh-C
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Default Re: Engine Noise

I am going to say it likely is NOT valve related simply because you are not describing a miss. If you had a sticking valve or tappet, you would likely hear a backfire or miss in the engine as the valve stuck in the open position. A timing gear noise, -or an oil pump drive noise will not be affected by cancelling cylinders as you described.

I am wondering if you are hearing a piston slap or a loose wrist pin?
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Old 10-15-2019, 11:02 AM   #12
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Default Re: Engine Noise

Easy things first, as EJ suggested I would check the exhaust/intake bolts for proper torque. I believe they are 30ft pounds... A leak in the gasket seal here can really expose some "clatter"... Chap
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Old 10-15-2019, 11:34 AM   #13
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Default Re: Engine Noise

I agree with Brent and I’d go to the drivers side below the water jacket and use a stethoscope. Set your rpm where you hear the noise. Don’t keep driving it thinking the noise will go away.
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Old 10-16-2019, 07:57 AM   #14
George Miller
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Default Re: Engine Noise

with out hearing it, it is hard to say, but if it changes when you short it out to a faster noise my guess would be a rod. I would pull the pan and check the rod, piston rings wrist pin in that cylinder. Most likely a loose rod.
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