The class 66 - what are these sounds for?

[heart-of-wessex]

Hi all,

I have been meaning to try and find out for a whilst now, but a few questions about the class 66 that would be appreciated if anyone can clear this up:

1. Why do the class 66's ying? is it something in the engine?

2. I don't remember wholly what this is about, but is it right that they move only using the turbocharger when pullin off from a stand? (is that the higher pitch sound?)

3. why do they (and their sister class 67s) hiss alot? it sounds like they are releasing alot of air for some reason sometimes like 'ying ying ying..hiss..ying..pssssssssst..ying ying..pssst..ying ying.hisssssss...ying ying ying'


cheers,

James.

 

[Turbostar]

Might have something to do with both 66's & 67's (and 59's as a matter of fact) have 2-stroke engines. Also, don't forget the 59's and 66's are derived from SD40-2s, hence why you'll find both sound similar (SD40-2's in case you don't know, are US locos built between early 70's and late 80's. They are very popular, or were in their day, and are one of the best-selling diesel locomotives of all time.)

 

[P156KWJ]

think it's to do with the fuel injector timing, they are checked during F6 exams

 

[heart-of-wessex]

oh so its the injectors making a 'ying' sort of sound

 

[TheSlash]

Not the injectors i would think. I think the ying might be the compressor?
A turbo charger just pushes compressed air into the cylinders of the engine. This can allow you to create a lean fuel/air mixture and still retain the power, or restore the balance of the fuel/air mixture and get more power. Basically the latter can boost the performance of a medium engine, to that of larger engine.
Not sure about the hissing.
66's can put on a good show at night, with a fully loaded liner or ballast train, running on greens.
It might be the turbo yinging at idle and the hiss is the wastegate {dump valve} opening when the turbo reaches over charge

 

[class 313]

I think the turbo is the kind of grrrrrrrrrrrring sound you hear when the 66 is on full power. A bit like a 92 when the blowers are running.

 

[support-uk-rail]

I heard that combined with some sort of turbocharger, a special filter made it make that sound!?

 

[hairyhandedfool]

Compressors should never 'ying' or 'hiss', not ever, if they do something is wrong. (I used to drive trains)

A 'leaner' fuel mixture REDUCES power, not increase it. (I learnt that watching Indycar on TV).

Beyond that I don't know about the yings and hisses.

 

[Nym]

I't somthing to do with 2srokeness, we had similar engines on one of the boats in the harbor back when I was on the coast, Gardner V8s from 1955ish

Anyway, the yinging from what I can tell is somthing to do with the compression in the fact that it exhausts and injects at the same time, it could be somthing to do with the FA mixture timings if it's all on a computer, which I suspect it will be...

In honestly, ask a GE engineer, I don't know their engines...

Perkins or Gardeners I can help on, aswell as some Cummins and Car ones, but not GE, sorry . but the above is what I suspect...

 

[O L Leigh]

I've no technical knowledge of these things, but had the "yinging" down to a harmonic in the exhaust.

As to the hissing, it could be something to do with the air system. When compressed, the water vapour in air condenses out and will collect in the bottom of the air reservoir tanks. Our Cl317's have a device known as a doughnut on the bottom of the main air res to allow the water out, but the Cl315's don't. Instead, they've been modified with an electrical system that periodically opens the drain cock on the underside of the main air res so that the water is forced out under the pressure of the air in the tank with a brief but loud hiss. Maybe Sheds have something similar.

O L Leigh

 

[Nym]

Most air brake systems have the valve systems you discribed, it could be a requirement of bleeding the brakes if the hiss is in a set pattern

 

[Sir_Clagalot]

whatever causes the sounds, they're awful sounding things!! Give me an EE powerplant anyday!

 

[Nym]

Nothing wrong with a big gardner

I am sort of wondering why no-one has gone for a big cummins in anything yet, such as the HST engine replacments...?

 

[heart-of-wessex]

ahhh yes ive seen hissing on a 67 and what looked like a small spray of water wooshed out, yhat explains that.

any ideas if the turbocharger does move the train first when the engine is still idling? I thought a turbocharger worked with the engine to increase power...thus the engine shouldnt be idling...

 

[class 313]

ahhh yes ive seen hissing on a 67 and what looked like a small spray of water wooshed out, yhat explains that.

any ideas if the turbocharger does move the train first when the engine is still idling? I thought a turbocharger worked with the engine to increase power...thus the engine shouldnt be idling...

The turbo does not get the loco running. The engine starts to power then the turbo kicks in.

Also if you notice on 67s. The idle is faster when supplying ETH.

 

[Turbostar]

I've no technical knowledge of these things, but had the "yinging" down to a harmonic in the exhaust.

EXHAUST????????

 

[TheSlash]

ahhh yes ive seen hissing on a 67 and what looked like a small spray of water wooshed out, yhat explains that.

any ideas if the turbocharger does move the train first when the engine is still idling? I thought a turbocharger worked with the engine to increase power...thus the engine shouldnt be idling...

We will try this once more;
A Turbo Charger forces compressed air into the cylinders {via a cooler} of an engine {as opposed to air at atmospheric pressure}. This allows you to experiment with the mixture of air and diesel.
You can reduce the amount of Diesel and replace it with compressed air to still achieve the same power {compressed air burns}
Alternatively you can increase the diesel to match the air mixture and so burn more in the cylinder, producing more force on the piston.
Also the engines work on the 2 stroke cycle as opposed to the 4 stroke cycle.
The four stroke cycle is suck, squeeze, bang, blow. Draw in the mixture {suck}, compress it {squeeze}, ignite it {bang] and then exhaust the waste gas {blow}.
2 stroke cycle

 

[Turbostar]

Might have something to do with both 66's & 67's (and 59's as a matter of fact) have 2-stroke engines. Also, don't forget the 59's and 66's are derived from SD40-2s, hence why you'll find both sound similar (SD40-2's in case you don't know, are US locos built between early 70's and late 80's. They are very popular, or were in their day, and are one of the best-selling diesel locomotives of all time.)

I already told heart-of-wessex at the start they were 2-stroke, & might have something to do with the 'ying ying' sound, but I think people have other ideas... :roll:

 

[TDK]

The turbo does not get the loco running. The engine starts to power then the turbo kicks in.

Also if you notice on 67s. The idle is faster when supplying ETH.

The 67 is in the equivalent of notch 2 to 3 on the power controller when the HEP/ETH is on. You will also find when the ETH is off the engine revs at it's own accord, this is due to air supply etc. Has given many a shunter a missed heartbeat when coupling.

 

[class 313]

You will also find when the ETH is off the engine revs at it's own accord, this is due to air supply etc. Has given many a shunter a missed heartbeat when coupling.

That's the same as 66s is it not?