I've been wanting to create a set of sounds that describe a properly running engine ever since I first heard the John Muir Diagnostic Sounds a couple of years ago.
Unfortunately that site has been down for a long but recently a mirror of these useful sounds appeared and upon hearing them again it motivated me to make my own recordings especially since John's sounds are Type 1 oriented.
Muir provides a great list of sounds; my own list is much smaller and more oriented towards correct operation so you can determine if your bus or one you are about to buy is in proper tune/condition. This is a low mileage GE engine from 1978 that has had some repairs but not been rebuilt (crank, cam, rods, pistons, cylinders, heads all the original from the factory).
All files are in MP3 audio format for compatibility. If you have trouble playing any of the files please let me know. I tried to get the best sound quality I could without investing in better equipment: I used my old Sharp minidisc unit from 1999 for portability and a Sony stereo electret mic. I imported them to the Mac and converted from ATRAC3 (analog) -> AIFF -> MP3.
Actuated by AFM flap as heard from open engine lid (remove the air cleaner and move the flap with a chopstick). The click heard is the double relay being activated by the AFM. Notice the smoothness? Any grinding noises indicate that the pump is wearing out.
Tip: always prime the fuel system this way when resurrecting an engine that has been sitting for several years. Don't worry about fuel pressure buildup: the excess fuel will be recirculated back to the fuel tank by the fuel pressure regulator (PR) unless you have a fuel leak (another good reason to do this before firing up the engine).
Notice how quick the engine turns over? This is due to the cold start valve which gives the pump time to prime the fuel lines. The whine you can hear is the sound of the alternator kicking in. You can also hear the RPMs begin to rise and the engine speeds up because the auxiliary air regulator (AAR) is open. As it closes over the period of 90s or so, the engine rpms will drop. It is important when doing a tuneup to have a warmed up engine (closed AAR) because the high idle speed is enough to creep into the mechanic advance region of the distributor and when the engine truly returns to idle speeds your timing will be slightly off.
As heard when putting your ear next to the fresh air intakes. The lifters sound like a loud sewing machine when they are adjusted properly.
I took off the engine access hatch in this recording so you can hear the engine unmuffled. If you are buying a new bus I highly recommend you drive around like this so you can hear the engine better. If you have a Westfalia the rear cushion will greatly muffle the sound of the engine (which is normally a good thing).
Here's a very short recording shifting from 1st through 3rd and then decelerating. I removed the engine hatch on this recording also for clarity.
Notice how quick the engine stops? No run on, no struggling, just a peaceful ending.
My original 75-78 muffler rusted off in 1989 and the replacement rusted off in 2002. My current unit is a one piece "eliminator" muffler that bolts directly to the heat exchangers with triangular flanges (bypassing the need for a cross-over pipe). This is an unusually quiet and VW sounding aftermarket Mexican muffler. The stock muffler is indeed good but it's not so much better that you should replace a perfectly good extractor style muffler if you're heard how quiet the stock muffler sounds.
This engine has hydraulic lifters that are not correctly pre-loaded (the valves were adjusted to zero lash only) You can just hear the pounding. Some people describe this sounds as "booda-booda-booda" as heard from the driver's seat.
Air-bound Lifters (alternate)
Same symptom as above but recording from the view from the engine hatch. The engine has been running for a few minutes and all of the lifters have become air bound. The sound is clearly coming from the center of the engine. Notice how labored the idle has become because the valves aren't opening properly.
Slack Rocker Arm
Hydraulic lifters again; this time the valve adjusting screw had far too much lash (perhaps 5mm) and you can hear the components of the valve train (single push rod) clacking against each other.
Jackhammer (Really Dry)
My engine starting up for only the 2nd time after sitting for 4 years straight. Running the engine for 35mins will get rid of this sound. I took this low quality recording in 2002 with my digital camera.
Reverse makes a distinct sounds because the gears are straight cut instead of helical cut like the forward gears. You can hear me let off the gas pedal later in the recording. If your transmission sounds like this in the forward gears you probably have some serious ring and pinion wear.
Buses from some countries such as Canada and Australia and others received fresh air fans under the dash to aid with window defrosting and air circulation. They are highly sought after but after installing them some people are surprised how loud they are. In the recording you can hear the two speeds of the fan. This is how they normally sound.
In this clip you can hear the key unlock the sliding door, the door opening and locking at the rear catch then sliding closed again. The door should move effortlessly thanks to the roller running in greased tracks.
Get outa my way, bro! A lot of bus owners seem to have a broken horn. Well, this is what it really sounds like when it's working.
The clock was a dealer option and installed by the factory on Champagne Ed II buses. The earlier clocks make a faint humming sound. Obviously the clock is not this loud and I've amplified the recording a little (unless you've got a hangover maybe). OK, this is a stupid recording! :-)