How does a Detroit Diesel two stroke work? 

That is actually the clearest explanation I have seen as to what makes a Detroit Diesel so unique. Well done.

7:05 "This is the piston liner from a Detroit diesel..." from a guy in Australia wearing a Freddie Mercury T-shirt with chickens strutting and clucking in the background trying to steal the show. Yes, there are still things in life that I could never of imagined seeing even at near 60 yrs. How surreal. Love the experience and knowledge you pass on. thanks

We have a Detroit Diesel at work to supply backup power to the entire TV/Radio station. Each Detroit has its own 'personality'. Can't wait to see what your Detroit's got in store :)

That is the most concise explanation of a 2 stroke petrol engine I have ever heard; I learnt something!. The Detroit talk was equally as interesting too. Very cool engine.

You’re great at not wasting any time just getting to exactly what is in the title of the video! Thanks! I was curious what the differences were btwn the 2-stroke gas and Diesel engines and now I know

Great video, very clear explanation of how the DD works and by comparison to 4 stroke and “Traditional” 2 strokes. I’m puzzled why even 1 thumbs down?

I really enjoyed the video. Not only did I learn how a Detroit Diesel works, but I loved the scenery!

I saw this video last year and watched it as a refresher. It is still as good as the first time.

Yes well done Sir. That is one of the best explanations of a two stroke, four stroke and a Detroit engine mechanical process. I have taken a 1988 Yamaha 25 two-stroke under my wing that was not running and with your help it is now a smooth running reliable engine from top to bottom. Thank you sir

I worked on US military vehicles with these engines and although I understood the basics of how they worked, I never understood why they had a "Blower" and a turbo. Thank you for clearing that up.

When you say you're not an expert, your explanation is far more concise than I've ever gotten from a grade mechanics on this subject. ABSOLUTELY OUTSTANDING VID ON THE INNER WORKINGS..👍

I have no fuel gauge and ran out of diesel on my 8V71 so unlike the high pressure types no bleeding required to get her fired up again. Hope I did not damage any injectors! Excellent demonstration of a 2 stroke DD.

Thank you Stew, I learned something new this morning. I basically knew how a 2 stroke diesel engine worked but did not know about the low pressure feed for the injectors and that the injector itself created the high pressure. Yesterday I watched "Bus Grease Monkey" hold a frozen injector in his hand and tapped the top of the injector with a hammer to create fuel spray. Now I understand what he was doing and why.

Thank you - learned quite a bit and answered all the questions I was seeking answers to.

I like your informative videos, that was really cool. I like the ‘hybrid’ system the Detroit uses, seems to make sense.

Great explanation stu. Informed educated and entertain all-in-one video on a Sunday morning. Thanks a lot

Never knew how 2 stroke engines worked. Thanks. I have been educated. Keep them coming.

Excellent class, Stu!!! Hard to believe the 6-71 was introduced 81 years ago, and that almost all of the parts from a 1938 6-71 are interchangeable with todays 6-71.

I wish you'd bought a boat with a Napier Deltic... I'd love to have seen you explain a 3 crankshaft, 18 cylinder, opposed 2T diesel in layman's terms!

Spent meany a year sitting behind a 3-53 Detroit 664 Clark skidder, the 2 stroke Detroit is an awesome engine!

Those Detroits, they are really quite elegantly designed ! BUT there's MORE !!.......The head can be swung 180 degrees if you want the exhaust to come out on the same side as the blower to facilitate a turbo charger feeding the blower, (or some other reason...), with less plumbing involved and it saves space in the engine room. The camshaft, mounted high in the motor (hence: no pushrods!), is removed from one side and is installed on the other side to make this work. The bearing journals are already there!! Everything important is Gear Driven and the timing marks are already there, too. Also they can be made to turn in the opposite direction! This helps in marine applications with 2 motors to cancel torque reaction of the boat. In buses and coaches it is said you can get a million miles before major overhaul; these motors WANT to run..... P.S.(Might want to consider a flapper valve to fight runaway condition). Long Live The (Detroit) King!

Nicely explained Stu, lots of knowledge passed on that is greatly appreciated. Thanks for sharing.

When I was in diesel school we actually took one air box side cover off while a we had a 6-71 running. Very cool to watch the piston. Just don’t whack the throttle while it’s off because you’ll get a face full of oil. Another fun fact. Because Detroit are the type of two strokes they are. The upper crank bearings see almost no wear along with the lower rod bearings seeing almost no wear. I’ve heard of guys just replacing the worn half’s of the bearings of budget rebuilds. Great job explaining the combustion process. Teaching is cool! Cheers

I learned a long time ago about bleeding fuel lines of air, but I never understood why they didn't clear themselves until today. Thank you!

Very interesting, I'm glad the chickens allowed you to continue and finish your summary.

Good explanation. Just one more thing to add tho. If a Jimmy(nickname for Detroit Diesel) isn't leaking oil it's busted. The airbox drains always leak a little oil. If you don't put a catch can on, and regularly drain it, there will always be a puddle of thick black oil under the engine. It's even worse in a confined engine bay like the trawler. If you ignore the catch can then the BILGE MONSTER moves in with a vengeance and stinks the whole place out with oily sludge and all the other detritus that falls in with it. It's a unique smell that never really washes off, you or the boat. You'll stop noticing it, your friends and people you've just met won't.

that was a cool educational video Stu, been around engines al my life ,62 now, and EVERY day is a school day cheers fella

Probably my fav video from you so far. Love it.

I've been running a 1947 Allis-Chalmers Road grader for 30+ years. Now I understand a lot more about the Detroit Diesel that powers it. Antique engine but give it a shot of ether and engage the starter with ample juice and it still fires right up. Massive power.

A true work of art. Very much ahead of it’s time.

Wow, two drops in a week. Love it, and learned a little bit, too. Many thanks.

Every day is a learning day, thanks for that!

Wow I needed that. I've been looking at explanations and animations - but your straightforward summary was just what I wanted.

Excellent video... I have never owned a diesel car or truck but have owned two-stroke motorcycles and outboard motors so I understand their operation and being a car guy all my life I completely understand four stroke engine operation so this was very interesting and explained very well so now I completely understand how this works. Thanks much !! 👍👍

You should do a video on the versatility of setup for Detroits. You can put the blower on one side or the other, exhaust on either side, starter on either side, dipstick in multiple locations, etc to work for your setup. You can set your twin engine up identically or to be mirrors of each other, etc.

Great explanation with props of the operation of the Detroit Diesel.

Excellent description of these different engine types :)

Great explanation, thanks! Now the words you say during the restoration make a lot more sense to me.

great vid..just explained or simplified my common misconceptions when talking diesels & blowers!

Stu - Merry Christmas and happy new year from San Diego , Ca ..always enjoy watching the videos from the trawler & the workshop . Looking forward to seeing you cruising the Trawler .

Read valves and blowers, so the redundant air goes to the next cylinder from the blower. That's answered a lot of questions. Love your two way radio minute 10.16 behind you, best ever explanation, keep thinking about how to improve things on a two stroke, true blue Mate. Thanks again.

Loved the video, I had never thought about how a diesel works. Thank you very much.

Excellent explanation of the Detroit two stroke cycle, and basic engine architecture.🙂

Fine explanation. Maintained and repaired many of these when I had my dockside service company before I retired. These are a favorite among farmers for irrigation pump stations as well. They give them years and years of trouble free service. If properly maintained, they are pretty much a bullet proof engine.You are going to have about as close as you can get to a brand new engine. Used engines like the two I found for you up in the North can be a tricky thing if you don't send off oil samples and get a report. I know the cost was pretty large for all that machine work but, at least you know for sure what's been done to it. Can't wait to hear you crank it up. Keep up the good work.

The Detroits without turbos are referred to as naturals. Naturally aspirated means just the blower. 71 series naturally aspirated are legendary for their reliability.

Thumbs up. A refresher from high (secondary) school, engine and automotive courses.

Fantastic description. Thank you.

Just learned something new. Thank you for the great content.

Great explanation of how a Detroit 2 stroke works but you left out the most important part. The sound of a screaming jimmy is like no other sound a engine makes you have got to love that sound

Thanks for the lesson, Kim from Canada

Very informative thanks mate cheers from Florida

Outstandingly good explanation. Many thanks.

Great episode! This Build has become a Must see for Me and no doubt for all the rest of Your Subs. Beauty DM, unreal stuff thanks.

Best explanation I've seen. Thanks much

This is one of your best videos! Really clear explanation lovely to listen to and clear diagrams. Keep up the good work

That was a great vid! Thanks buddy stoked she is moving along. Watch every video

An excellent explanation. Thanks.

The things you learn every day :) Cheers as now I know.

...great info., the work is lookin' good...

Thanks for sharing that information.

This was so helpful. I learned what I wanted to know. Thank you

Fantastic video, enjoyed every minute

Thank you thank you Stu for explaining that. It cleared up a lot of questions i had about that ! Thank you !!

Thanks Stu, that was a great video. Learned something new.

Thanks for another interesting and informative video. See ya in the next one.

Good explanations. Thanks for the video.

Well done professor. 👍

Great simple explanation.

Good explanation!

Best video to sate my curiosity. Thanks mate, well done.

The screaming jimmys had a reputation of not being the most fuel efficient, but they are ultra reliable. Which is what is needed when out at sea. Good luck with the installation Stu.

Very educational. Thanks!

Very clear explanation. Good Work.

THANKS, I JUST WATCH A VIDEO A WAS CHANGING THE OIL ON A DETROIT AND IT GOT ME WONDERING, SO GOOGLED IT AND YOU ANSWERED ALL MY QUESTION . SORRY FOR THE CAPS.

Superb technical explanation.. thanks so much, learnt heaps.

A well done video. Thanks for the education!

Very good explanation thanks

Well done Stu, great explanation !! Seeya Rob

An excellent explanation, Stu! I've never worked on a Detroit but it seems very similar in principle to the large B+W two strokes I sailed with (980mm bore). Those had a central exhaust valve in the top of the head and three injectors spaced around it. The big difference (apart from the size) was that we had a crosshead and a very long piston rod which had a sliding seal around it as it passed through what we called the scavenge space, and you call the air box. This piston rod gives you the possibility of a much longer stroke/bore ratio and therefore higher efficiency. Because we burned heavy fuel, sometimes quite high in Sulphur, it was necessary to inject a highly alkaline cylinder oil through quills in the side of the liner to lubricate it and neutralise the acidity of the combustion products. This was a total loss system, so a lot of this oil and carbon ended up in the scavenge spaces (air box) and needed frequent cleaning. Fortunately it was large enough to send people in! What interests me is how the conventional lubrication system of the Detroit copes with the demands of keeping the piston, rings and liner lubricated, and what kind of state the air box gets into after a lot of short runs?

love the specifics, great video

Great explanations--I learned alot--many variations I wasn't aware of!

Thanks for the info 👍🏾

Thank you very much a great thought out explanation and easy to follow. Steve in Thailand.

At 7:40 i about lost my sh!# 😂 "im filming here dude" Good video man, i bought one of these and trying to learn more about it

So interesting. What a unique combination of ports and valves! Love it. Can't wait to see it come together. Good luck with the blower.

Thank you, I have wanting a video like this for awhile

Great episode, super interesting. Cheers!

Nice explanation, so interesting to hear how they operate. Thanks mate.

That was a really interesting video! The explanation was great, and the editing moved at a good pace to keep things interesting. Kudos!

Nicely done

Thanks for this vid Stu, Fascinating I think I learned something today. Merry Christmas.

I'm from BC Canada, out traditional industries are fishing and forestry. Those Detroit Diesels were used in fishing boats and logging machinery, and referred to as Screaming Jimmies. Detroit was a division of GM. Noisy, hard on fuel but very reliable.

That was awesome, made me finally understand how they work. Great audio and visual explanation. I need both. Lol. Thanks. 👍🏻👍🏻

I was just thinking that a Detroit diesel was just a Diesel from the city of Detroit. I'm feeling pretty stupid right now. Love the video again Stu! Keep it up!

Excellent explanation.

Awesome! Learnt so much in that 14 odd minutes!

Very good explanations. Ant, Cid & the Pooch crew.

Great explanation

I agree with one of the other comments it's a very good explanation, we had two or three Terex R17 Dumpers using the GM diesel engine with a blower box in 1971 in the Avoca Copper mines at that time

Great explainer.