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EVfun Samba Member
Joined: April 01, 2012 Posts: 5445 Location: Seattle
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Posted: Tue Mar 09, 2021 4:25 pm Post subject: Sudden new engine sound help |
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I can't figure out what it is but it started suddenly today when I started the car to head home from work. Others didn't notice it, it's not loud but a sudden new sound is concerning. The engine is a stock 36 horse. Making the sound harder to track is that the pea shooter on the right blew its guts out earlier this winter (not the heat riser exit side.) I also have a small exhaust leak at one of the j-pipe clamps. Things to fix when it's more fun to work in the driveway.
The sound happens when I let off the throttle, and is kinda a growling sound. Perhaps a little of a metallic growl. I shut the engine off and verified the oil pressure light was on before cranking and off after starting. When I got home I grabbed the pulley to check end play, unchanged at about 6 thou. The engine seemed to start and drive fine. I'm pretty sure it was worse when cold an quieter when I got off the freeway (but still present) but might be more about being a sudden change and in a quieter place. Your ideas are appreciated. _________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
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Zundfolge1432 Samba Member
Joined: June 13, 2004 Posts: 12452
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Posted: Tue Mar 09, 2021 6:13 pm Post subject: Re: Sudden new engine sound help |
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I had something similar, just a different tone. It ended up being leaves in cooling fan. Just a few changed the normal sound. Also check the integrity of the cooling fan nut, sometimes right before a fan lets go it makes a noise |
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earthquake Samba Member
Joined: January 10, 2008 Posts: 3984 Location: SANDY VALLEY, NEVADA
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Posted: Tue Mar 09, 2021 10:14 pm Post subject: Re: Sudden new engine sound help |
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Check the nuts holding the rocker on, I have seen that make a weird noise.
eQ _________________ 74 CLASS 11 LOOK-A-LIKE
69 DUNE BUGGY
79 INTERNATIONAL SCOUT II
05 SCION XB SERIES RELEASE 2[#437]
95 Chevy C3500 dually
98 Ford E150
Link to Kelly J. Nolte 3/20/53 - 11/6/08
https://time-zonelabs.blogspot.com/p/about-kelly.html
DEATH TO CHINGERS!
[From a military recruitment poster in the novel "The Stainless Steel Rat" By Harry Harrison] |
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anthracitedub Samba Member
Joined: June 20, 2007 Posts: 3241 Location: Michigan
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Posted: Wed Mar 10, 2021 5:31 am Post subject: Re: Sudden new engine sound help |
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These “Sound” threads always remind me of a book that I used to read to my kids called ‘I See A Sound’. 😊 |
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EVfun Samba Member
Joined: April 01, 2012 Posts: 5445 Location: Seattle
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Posted: Fri Mar 12, 2021 3:37 pm Post subject: Re: Sudden new engine sound help |
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anthracitedub wrote: |
These �Sound� threads always remind me of a book that I used to read to my kids called �I See A Sound�. 😊 |
Searching for sound threads is no fun either. Everyone describes it differently, making searches mostly futile. I did find a John Muir collection on the internet. _________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
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KTPhil Samba Member
Joined: April 06, 2006 Posts: 33875 Location: Conejo Valley, CA
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Posted: Fri Mar 12, 2021 4:19 pm Post subject: Re: Sudden new engine sound help |
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If you can get it to make the sounds in your driveway, use a "redneck stethoscope" (hose in your ear) to localize it. It's actually amazingly useful! |
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MrGoodtunes Samba Member
Joined: May 14, 2012 Posts: 849 Location: South Florida
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Posted: Sat Mar 13, 2021 5:57 pm Post subject: Re: Sudden new engine sound help |
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EVfun wrote: |
... sound happens when I let off the throttle ... |
So, RPMs would presumably be decreasing; does the sound's pitch also decrease? If you downshift, then letting out clutch would increase RPM's; does the sound's pitch also increase or maybe dissappear?
If the sound changes pitch with engine RPMs, then fan and shroud are suspects, and they're easy to investigate. With engine set on high idle, grab the shroud and sort of muscle it around. Should be able to rule it out or nail it as being the culprit. Hope it's the latter, 'cuz that's easy to fix. |
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EVfun Samba Member
Joined: April 01, 2012 Posts: 5445 Location: Seattle
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Posted: Sat Apr 10, 2021 3:22 pm Post subject: Re: Sudden new engine sound help |
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I got a chance to replace the exhaust tips so sounds were not drowned out by the pea shooter on the right side. Its guts were rattling around inside making enough noise up close that I couldn't pick anything else out. I got some new stainless pea shooters from CIP1 and they sound nice. Not much "freem" but quiet with just a light exhaust note in that higher frequency range. With that, and better light, the tacky exhaust leak took seconds to find.
That leaves with with 1 "new" (not likely, now I can pick it out) sound of concern. It sounds a lot like lightly tapping a knuckle on a countertop. It seems more likely at idle or as the engine is losing rpm. It is almost random and sometimes may be twice back to back, or may not happen for several seconds. It is not crank end play, that's about 6 thou. Could it be camshaft end play in a 36 horse?
When I grabbed my phone I accidentally shot this picture of the '66 Pigalle seats in my '57 oval. Included just for fun.
_________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
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66brm Samba Member
Joined: January 25, 2010 Posts: 3676 Location: Perth Western Australia
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Posted: Sat Apr 10, 2021 3:36 pm Post subject: Re: Sudden new engine sound help |
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Get the exhaust leaks sorted then listen again, I'm betting you are hearing decell backfiring due to the leaks _________________ Aust. RHD 66 Type 1
Aust. RHD 57 Type 1 Oval
modok wrote: |
I am an expert at fitting things in holes, been doing it a long time |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Sun Apr 11, 2021 3:56 am Post subject: Re: Sudden new engine sound help |
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Release bearing? How much peddle free play do you have? _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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EVfun Samba Member
Joined: April 01, 2012 Posts: 5445 Location: Seattle
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Posted: Tue Apr 13, 2021 3:20 pm Post subject: Re: Sudden new engine sound help |
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Since changing a j-tube on a stale air heat engine is a bit involved I wrapped the leak loosely in fiberglass and managed to get a decent recording from the drivers seat. It was pretty loud this morning. Here is a link to a less than 20 second video where the metallic tapping can be heard coming and going. Pushing in the clutch doesn't seem to effect the sound, maybe a slight reduction.
[underlined link] _________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
Last edited by EVfun on Wed Apr 14, 2021 4:19 am; edited 1 time in total |
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66brm Samba Member
Joined: January 25, 2010 Posts: 3676 Location: Perth Western Australia
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Posted: Tue Apr 13, 2021 3:49 pm Post subject: Re: Sudden new engine sound help |
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Have you checked with the generator disconnected? While the belts off check the fan, pulley and bearings _________________ Aust. RHD 66 Type 1
Aust. RHD 57 Type 1 Oval
modok wrote: |
I am an expert at fitting things in holes, been doing it a long time |
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EVfun Samba Member
Joined: April 01, 2012 Posts: 5445 Location: Seattle
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Posted: Tue Apr 13, 2021 5:26 pm Post subject: Re: Sudden new engine sound help |
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66brm wrote: |
Have you checked with the generator disconnected? While the belts off check the fan, pulley and bearings |
Thank you for the test. Unfortunately, removing the fan belt results in no change in engine racket. That tap-tap-tap continues, and like before it doesn't happen in all conditions. It seems to show up for idle, when the engine rpm is declining, and at higher rpms with light load.
I supposed I could just run it and let her blow, but it seems a shame to do that to a Feb. 1957 36 horse engine. It runs pretty strong (as it I think I can match the Road and Track test results of 0-60 mph on 42 seconds.) If I can't fix that sound I don't think it will run long! _________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
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66brm Samba Member
Joined: January 25, 2010 Posts: 3676 Location: Perth Western Australia
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Posted: Tue Apr 13, 2021 11:40 pm Post subject: Re: Sudden new engine sound help |
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Might be time to pull the engine and have a look, check end play _________________ Aust. RHD 66 Type 1
Aust. RHD 57 Type 1 Oval
modok wrote: |
I am an expert at fitting things in holes, been doing it a long time |
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mukluk Samba Member
Joined: October 18, 2012 Posts: 6985 Location: Clyde, TX
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Posted: Wed Apr 14, 2021 12:27 am Post subject: Re: Sudden new engine sound help |
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Are you certain the noise is coming from the engine? It sounds like it could be something else loose that's responding to the vibration of the running engine, say, maybe the shifter rod, coupler, or a loose transaxle mount. _________________ 1960 Ragtop w/Semaphores "Inga" |
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raydog Samba Member
Joined: February 09, 2006 Posts: 1157 Location: Cape Cod
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Posted: Wed Apr 14, 2021 5:15 am Post subject: Re: Sudden new engine sound help |
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Unfortunately it sounds like a loose flywheel. _________________ Come on, It's not rocket science. KISS |
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oprn Samba Member
Joined: November 13, 2016 Posts: 12632 Location: Western Canada
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Posted: Wed Apr 14, 2021 6:15 am Post subject: Re: Sudden new engine sound help |
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I'm with Raydog on this one!
Fix it NOW! _________________ We had the stone age, the bronze age, the industrial age and now we are in the age of mass deception and mind control for corporate profit. (The mass media age) |
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EVfun Samba Member
Joined: April 01, 2012 Posts: 5445 Location: Seattle
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Posted: Wed Apr 14, 2021 6:52 pm Post subject: Re: Sudden new engine sound help |
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The old Bug is off the road! I have other priorities so I suspect it will remain off the road until this winter. As I fixed the other 2 sounds, and as this sound grew louder, I suspected it was a loose flywheel -- it was the best sound match (but still quite different) to the loose flywheel recording from Muir. I linked to his sound recordings above. I've never experienced that one before so I want to thank "raydog" and "oprn."
Since this thing already has the '66 Pigalle interior and a 40 horse gearbox perhaps the best use of it is to update it and drive it. It already has a well done color change from diamond green to black by an earlier owner (well done meaning the repaint includes the trunk, engine compartment, and interior.) Maybe I should update the engine and go 12 volt and toss in some old school custom with wheels, T-bars in place of bumpers, and a mild front lowering. Not necessarily a fast old Bug but a driver updated in looks and drive train with some Cal-look attitude. _________________
Wildthings wrote: |
As a general rule, cheap parts are the most expensive parts you can buy. |
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