The Napier Deltic engine had a totally unique sound to its exhaust because of the very unusual firing sequence of its 18 cylinders (more info after the jump). Here’s a few Class 55 Deltic locomotives at work; the best sound happens at round 3:00.
Cylinder firing order of the 18 cylinder Napier Deltic diesel engine: The grid represents triangular cylinder arrangement (banks A, B, C) and rows 1 to 6
The Deltic’s unique sound is not just because of the firing order though. Here’s an explanation from Wikipedia:
Being an opposed-piston design with no inlet or exhaust valves, and no ability to vary the port positions, the Deltic design arranged each crankshaft to connect two adjacent pistons operating in different cylinders in the same plane, using “fork and blade” connecting rods, the latter an “inlet” piston used to open and close the inlet port, and the former an “exhaust” piston in the adjacent cylinder to open and close the exhaust port. This would have led the firing in each bank of cylinders to be 60 degrees apart. However, it was decided to arrange that each cylinder’s exhaust piston would lead its inlet piston by 20 degrees of crankshaft rotation. This allowed the exhaust port to be opened well before the inlet port, and allowed the inlet port to be closed after the exhaust port, which led to both good scavenging of exhaust gas, and good volumetric efficiency for the fresh air charge. This required the firing events for adjacent cylinders to be 40 degrees apart. For the 18 cylinder design, it was possible for firing events to be interlaced over all six banks. This led to the even, buzzing exhaust note of the Deltic, with a charge ignition every 20 degrees of crankshaft revolution, and a lack of torsional vibration, ideal for use in mine-hunting vessels.
A bit complicated, but it’s what gives the Deltic the “edge” to its already unique sound. I can only imaging what the Superpumper sounded like at full chat.
So what’s your favorite engine sound? If you want to embed a YouTube video, just copy its url (from the browser) and paste it into your comment.
Subaru’s 4 cylinder boxers, especially the Impreza STI even in standard form a very distinctive sound, let alone when it has a slightly modified exhaust system and dump valve.
Maybe I’m weird but there’s something pleasant about the rumbly “gur-gur-gur” school bus diesel noise. It’s a very growly and powerful sound.
Also the noises that lawnmowers make, both the buzzy noise of older two-stroke mowers and the deep, slappy noise that the four-strokes make.
Memorex reminds me I need to add one near the top of my do-not-like list: the PowerStroke diesel. The rhythmic gap out of its idle noise, like the Olds blubber, makes it sound to me as though a cylinder is missing in action. That, and earlier versions—made when Ford were still bleating and whining that they couldn’t make ’em any quieter—sound at idle as though they’re taking a particularly wet and messy metallic ѕhit.
(It is possible Memorex and I are talking about the same engines.)
Scania: 11 liters in line 6 from the 90’s 113 model tractor truck, also used on buses. This one’s a CMA body over Scania 113 frame and powertrain.
https://youtu.be/QljV-EzcFsg
The Alco 539 straight 6, turbo version. 1000 hp at 675 rpm. 12 1/2 x 13 bore and stroke.
https://youtu.be/72dd6SMe08M
Best action starts around 4:45
Auto Union V16 is hard to beat. 911 in 3 litre trim is very nice too.
The engine in any vehicle that’s paid for.
Cummins 5.9, in stock form
(particularly the old 12 valve)
Special mention goes to:
Chrysler LH 3.5
Hemi 5.7
Chrysler K 2.2
Pentastar 3.6
225 Slant 6
Don’t like:
Subcompact imports (Honda/Subaru/etc), especially and particularly with obnoxiously loud exhausts
Ford Powerstrokes (the turbo spool sounds like an industrial washing machine with bad bearings on a spin cycle)
Subaru Boxer (sounds like a motorcycle)
I would love to hear one of those Deltics in person.
Overall favorite:
Any big block wedge Mopar, musclecar or not, including the starter and the Torqueflite whine.
Second:
Any Oldsmobile V8
Honorable mention:
almost any inline 6 but the AMC 242/258 I6 might be my favorite
Gen3 Hemis, especially Hellcats
Diesels:
Cummins VT903
Detroit 6V-53
Dislike:
Any 4 cylinder except for 2 stroke outboards
HST with a Paxman Valenta engine?
Quite the sound from the Deltic – much different from the low throb of a North American diesel locomotive. I like it. I have a few other favourites…
– A BMW M3 with the V10. I see and (better) hear one a couple of times a week when I bike to work along Richmond Street in downtown Toronto. The howl echoing off the buildings is unreal.
– Any well-tuned Detroit V8 will a good exhaust system, but preferably one from the ‘60’s.
– A Merlin, of course. I’ve heard (and seen) Spitfires and Mustangs flying over Toronto during the CNE air shows – always great to hear.
– Any classic radial engine.
A supercharged Hemi running a full load of nitromethane.
Racing engine: A hemi on 90+% nitro. Nothing like it, needs to be heard in person.
Street car: My friend’s Bullitt Mustang is pretty much perfect, with my own Challenger 6.4’s sound in sport mode is not far behind.
Locomotive: EMD 567 NA on hundreds on old F and Geeps. I miss the old GP10 (rebuilt GP9) Conrail 7592 which hung on at Stanley yard forever, tied with the 645 in original form with the spaceship sounding idle and the old style transition. I heard and saw them hundreds of times going back and forth on the tracks along the back of our yard when they were first released and later on as veterans in back of our rental property. I loved that transition at 9MPH(I think). The turbo whistle always got me. A new EMD or GE at full throttle isn’t bad either.
Lanz Bulldog 😀
Some of my favorites are the Detroit 12V71, the TVR Speed 8, and the Honda 250cc 6 cylinder Moto GP engine.
I’m with Mads on the Alfa Busso, had a 3 litre 75 (a Milano to you Nth Americans) best V6 ever, no sense of strain as it hits the limiter, oh and the all alloy twin cam twin carb alfa two litre my Alfetta had. Air cooled 911s of course, twin carb BMW six 1971 2800 a friend had, redline in third = 100 MPH, triple carb 240Z we have in the family(38 0r 40 Dellortos), and my cousin’s L34 Torana the ultimate version of the Aussie 308 CI V8, 780 CFM dp Holley, engine internals upgraded by repco parts associated with the Brambam F1 V8 I believe, tall Bathurst gears in the M21 4spd gives 70MPH in first. And finally the Mazda 787 quad rotor at Le Mans https://www.youtube.com/watch?v=az39eqLIbyU