Detroit diesels

[queen of spades]

Why are Detroits so loud? Is it just that they didn't come with a good enough muffler, or something else with the design?

http://www.youtube.com/watch?v=97r0NXNT8LA

 

[mitch504]

They are 2-stroke engines, like a chainsaw.

 

[Zed]

Cause they are Awesome! ha ha now seriously... like Mitch said, two stroke diesels... Louder if they are aturaly aspirated. turbo jimmy's are a little quieter...

 

[queen of spades]

They are 2-stroke engines, like a chainsaw.

Well I knew they are two stroke diesels. I've owned a few two stroke dirt bikes and it wasn't that hard to silence them for woods riding. Never owned a Detroit -- do they use straight pipes on them?

 

[willie59]

It's not just the exhaust noise alone, you're also hearing noise from the engine that you don't hear from typical 4 stroke liquid cooled engine. First of all you have a roots blower making noise as it spins. Second, you're hearing combustion chamber noise because of the open "air box" design of the Detroit two stroke, noise that is typically muffled by coolant and engine block on other engine designs.

 

[wornout wrench]

As one of my friends used to say
"Detroit Diesel... The only engine in the world that can take perfectly good diesel and turn it into noise"

They are a bit noisier then some of the others but the silver series were not that bad.

As far as running straight pipes, you better have some very good hearing protection.

 

[randy448]

In the '80,s worked at asphalt plant with Roots blower for baghouse. That's where the Detroit noise comes from, the blower sucking air. Don't ever want to be around one with straight pipe, even on back of green scraper!

 

[grandpa]

Makes one wonder if they still aren't the most popular..... thousands of the bugger's still running in boats around the world.

 

[Steve Frazier]

I was driving an old White 9000 tractor/trailer with a 8V71 and 13 speed hauling asphalt. Half way through the morning the exhaust pipe blew off the muffler right under the cab. Words can not describe how noisy that thing was!!! Fortunately I found a pair of ear muffs behind the seat, it wasn't my regular truck. I had to work the remainder of the day with it like that.

 

[Dickjr.]

A lot of people hate the old GM Diesels , if you think about it they were the ones hauling parts to cat and cummins while they were building they're names in the truck engine business. A little lack of modernization killed them until they came out with the series 60. Always said they had no power , they had a funny power curve on or off. I had a 3-71 and a 4-53 in Oliver tractors and they would hold there own against any other 120hp tractor. The 3-71 would over heat if you pushed it but it was pulling 125 pto hp. Injectors were a little to big.

 

[Showpony]

This is an interesting question with an unexpected answer. What is the function of the blower on a Detroit Diesel??!!

 

[Dickjr.]

The DD does not have intake valves. there is a box around the lower portion of the cylinders that the blower charges with air. The liners of these engines have a series of holes in them that mate up to the air box. When the engine is running the air is pushed into the cylinder goes up for ignition , has power stroke then the exhaust valves in the head open as the cylinder goes back down to BDC the blower pushes the exhaust out then charges the cylinder with fresh air for combustion again. On a straight piped engine you can here the blower working. The blower doesn't work to actually build pressure like a turbo or super charger. ( If your building a pulling tractor engine you can overdrive the blower for an actual super charger effect. AKA cheating ).

 

[tuney443]

I still have a baby Detroit in my 59' JD 440 track loader-a 2-53. Runs like a top,but loud of course.

 

[truckdoctor]

I ran an "A" model Terex TS 24 scraper with a non turboed V12 and it was insane loud. The sound would go right through you. The muffler wouldn't even help. The same company had "B" model TS 24's and they were much quieter.

 

[Nige]

A lot of people hate the old GM Diesels , if you think about it they were the ones hauling parts to cat and cummins while they were building their names in the truck engine business.

The problem with GM IMHO was that they spectacularly failed to see the writing on the wall that 2-strokes diesels were going the way of the dodo ..........

 

[Cat_man320]

Apart from being the loudest SOB on the block, I think it was one of the most engineered engines ever built . What other engine can you build from a pile of parts 8 different ways . reverse rotation , switch the block front to back , put cam on each side , switch head front to back , etc etc . The 71 series i think came out in 1938 for the military tanks and everything was basically the same right up into the 80s or there abouts. After running DDs for the last 40 years and now half deaf LOL , I have nothing bad to say about the 71 series DD other than the noise and the oil leaks . Now as for the 53 series ( unless its in a compressor or something with a constant speed) , I'll call it a poor mans engine ............you'll always be poor while you own it LOL . The 92 series is worse !!!

 

[John C.]

Boats are where the Detroits really excelled. With a wet exhaust they mumbled at low idle. Bring them up to half throttle and they bring a feeling that some women compare to sitting on an idling well tuned shovel head Harley at bar closing time. Full throttle and they bark like a Rottweiler defending a litter of pups.

I know the noise comes from the blower and such, but I always figured it was more because every stroke of the piston is a power stroke. So two, four, six, eight or more cylinders hit on every revolution which makes for twice the noise of any four stroke with the same number of pistons.

I haven't worked on one for years so I sold all my special tools for these monsters yesterday. There are younger people looking to keep the faith. Also makes me see the gray on skull in a different light.

 

[boaterri]

John C.
I wish I had known you were selling your special tools. I have a pair of 6-71TIs in my boat and I try to do all my own maintenance. Any manuals or service documents left?

Rick

 

[John C.]

I think all I have left is an old 71 series book. I'll have to look to find it.

 

[RMXR]

Here's a bit of a write-up on the Detroit.

http://www.dieselduck.ca/historical/01 diesel engine/detroit diesel/index.html#.US2YgTdf2z8