2 Stroke Supercharged Detroit Diesel V8 GM 8v71T Truck Engine Revival Pt 1
ฝัง
- เผยแพร่เมื่อ 30 ก.ย. 2023
- In this video, I retrieve this old 8v71T Detroit Turbo Diesel Supercharged 2 Stroke truck motor which has been left in the end of this farm shed for about 19 years and would have likely ended up in the scrapyard. Little information is known about its exact condition so we start to go through the motions in preparation to see if it will start and run.
If you’ve had experience with these engines and have any tips, please leave a comment. Thanks very much for watching, Bruce. - ยานยนต์และพาหนะ
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One of the all time great engines.
Can't wait to hear it run. you can't beat the sound of those dirty old Detroit 2 strokes.
Its Wabco scraper spec engine 8v71t very reliable and tough as nails ,use correct oil and service clean oil and fuel live long life .
beautiful turbo diesel
Good on ya mate for trying to bring a DD back to life! 👍👍👍👍👍
I always wondered what happened to old DDs, looks like a bunch went *Down Under* !!!
I used to work on DDs and the dry-sleeve, common-rail setup was *so much* easier to repair. Everything in one of these is HEAVY-took two of us to lift a head off of a 12-71! 🥵🥵🥵
For setting the rockers you’ll need. “Go-No go” feeler gauge to get the spacing right. (Been 40+ years since I last did one of these, so don’t remember the exact number of 1/1000” gradations for spacings, but you’ll need one to get max performance to help reduce “Slobber.”
My best to you from an old “Cranky Yank!”
❤ ya videos n stories Bruce, sadly i lost ny pop when i was 3 but from what nan told us i think he was like you. Always look forward to your videos n stories mate
The sound will be great
Looking forward to it
🪖
Lots of good stuff in that shed.
What a glorious thing that is, supercharged with a turbo 2 stroke v8. I'd want to do some mad max stuff with it. Good stuff man.
Great save ...!
I’m buzzing you guys Bruce I’m going to put one in my old Chevy Viking truck
Steve's place down under did a start up on a Detroit diesel recently in a giant tractor, you can find him on youtube, another great aussie channel
Yes I know of Steve from TH-cam, he’s a great mechanic and has a great channel, thanks for watching, Bruce
Nice work Bruce
Brought back some old memories went you whipped out that speed brace
Thanks Andy, now that you mention it, I don’t see a lot of people using them these days, Bruce
G,day Bruce, great video mate looking forwards to more of this 871gm content
Thanks very much,Bruce
I love these things
Standard 8V71 was 304HP and 800 Torque. The 8V71T with the boost from the turbo system was 350HP and 965 torque. The roots blower is a requirement for these engine to run at all, and it provides no boost. All the boost is from the turbocharging.
Thanks for the Help Bill, Bruce
Nissan did some 2 strokes and there's a guy with a UD5 2 stroke, the UD8 was 600 CID, 345 hp w/o turbo and with turbo over 550 HP
8v71t and 8v92t are two of my favorite diesel motors . Thanks for sharing
Bruce, I don’t know how these old engines find you but I’m sure pleased they do, this will be an interesting diagnosis and troubleshooting exercise, hopefully she’ll be a goer. I’ve just watched a video on Diesel Creek and he’s just done one up. Anyway, looking forward to this little series.
Morning Gordon, hope your well. I’ll do a video in the next few days on the bottom end to see what surprises await. I’ll check out diesel creeks rebuild, I’m sure it will be good. Thanks for watching, Bruce
Bruce
Love your fairdinkum Aussie approach looking forward to next episode
Thanks very much Chris, best wishes, Bruce
A quick and dirty method that I have had work on those injectors is to remove the rockers and take a brass hammer and manually actuate the injector while attempting the run the fuel pin in and out, if the plunger goes down and stays down, you may have to soak it before disassembly. Big thing is do not hammer on the fuel pin itself.
Thanks very much for the help, Bruce
I love those Wurth spray bottles
Looking forward to see if you can get this making that sweet Detroit music bro. Safe travels. Ken.
Thanks Ken
Detroit usually painted their motors green, Caterpillar must have sprayed them yellow for the dozers and scrapers. That Leyland Boxer/Mastiff truck in the background would be a good resto project Bruce. Overall it's in fairly good nick Bruce, should be a goer, Detroit made a quality product. I wonder hour many hours it has clocked up? Great video, awaiting part-2, thanks Bruce.😉
Hi Dave, some parts of it are the green colour under the yellow like the intake but other parts don’t look like they’ve ever been green so it’s hard to say. It wasn’t super dirty outside and I was shocked to see how clean it was inside the rocker covers- almost too clean. Part two will involve a closer bottom end inspection before I try to run it so stay tuned.
That Leyland was in a rear end fire. It otherwise looked complete, like it might start and strangely was fitted with some kind of ford v8 diesel?
Thanks for watching, Bruce!
Used these on seismic vibrator trucks. We used four operational and one on standby.
Always good to have a spare, Bruce
Special application just means it's not a normal GM arrangement, if it was a genset drive or an industrial pack the number would indicate that. Tin sumps are common truck items which could be fitted to industrial engines if space was tight. It's normal for 71's to show some wear on the big ends with a lot of hours so seeing a bit of copper on the inserts while not good doesn't mean it's trash. Another worthwhile check on an unknown engine is to remove the small rectangular covers on each side of the block, these are the air box covers, once off you can see into the cylinder through the liner inlet ports and see the state of the bores, if the rings are broken or stuck, if the piston crowns are damaged and with a small mirror or a boroscope look up and get an idea of the condition of the valves. As you have found someone has been into the governor, these are fairly simple but very delicate to set up, get your hands on workshop manual or on old bloke familiar with them to make sure it's assembled properly a runaway 2 stroke is not much fun they will valve float for a while at massive revs before usually the blower binds up or it drops a valve and it all stops . Having a CO2 fire extinguisher (red bottle with black band) handy is a good idea when starting an unknown engine, a good shot straight into the turbo inlet puts it out almost instantly with no damage to the engine or mess to clean up.
The old Detroit Diesel is still the most efficient engine ever built for turning diesel fuel into noise 🙂
Thanks so much for all this information Ray, I’ve taken it all into account in my bottom end inspection video posted this morning, best wishes, Bruce
No that would be easily (and I do mean easily) surpassed by the Commer Knocker opposed piston Uniflow Diesel. The noise they make is beyond belief.
That's a jewel you got there mate
Funny seeing a Detroit in CAT yellow! Looking forward to hearing her buzz ..
Yes your not wrong, as another commenter pointed out, this one should been a mint green/blue colour, Bruce
Hey Jax ! G'Day mate !
Yes he was out here getting amongst it, checking the new yard item for rats as they do! 😅
They're not supercharged by the Roots blower. In fact if it didn't have the turbo, Detroit Diesel would designate the blower only types as N for natural. The turbo variants get the T designation from Detroit. On the N variants, when new the blower pressurizes the air gallery to .7 psi over standard pressure. On the N variants, the blower output is carefully sized to the NA volume of the cylinders at all rpm - the .7psi over atmospheric to compensate for blower wear and tear, and hot, high barometric pressure drop in order to make rated power. Since it is technically a Uniflow Diesel the blower is needed to aspirate the cylinders because it wouldn't run without it.
On the T variants the blower is retained for starting, idling and low power. Unfortunately when on turbo boost the blower becomes redundant but consumes considerable engine power that still has to be paid for in fuel.
Bypass blowers save 30% in blower pumping losses when on turbo boost which is better than nothing but far from ideal.
Mid sized GM-EMD Uniflows (645/710 series) have a hybrid centrifugal blower/turbo where the compressor is driven mechanically at low speed and by exhaust at higher speed via an overrun clutch. This was proposed by GM-Detroit Diesel in the development phase of their small size Silver Series 92 (6V & 8V) engines since it was in the family so to speak but development costs combined with better turbocharger technology being applied to inline 6 engines that produced more torque (although over a narrower powerband than a Detroit Diesel Uniflow) and saved fuel by having no blower and 2x fewer cylinders to substantially reduce pumping losses thereby freeing up power and on top of that improving fuel economy again at low boost, put an end to that good idea.
Interestingly, Commer Knocker opposed piston 2 stroke Uniflow Diesels do actually have true supercharging although the boost is rather low perhaps ~4psi or less.
Right, it's a uniflow design. No actual supercharging from the blower. To get boost, they have to have a turbocharger.
Thanks very much for this info, Bruce
Hiya Bruce greetings from the UK amazing video that sure is one hec of a beast of an engine, Will be great as someone has been in and touched it it probably would be a good idea to go through it with a fine tooth comb, I'm sure you will your attention to detail is legendary is it going in the Bedford? Keep up the great work my friend love the channel ♥️👍
Hi Dean, thanks again for your support and kind words, no not at this stage it won’t go in the Bedford. I have seen a couple of TK bedfords here in aus used as single drive prime movers with 6v53 detroits fitted and I thought that might have been a factory option? A 6v53 is a much smaller engine in physical size compared to this one though, but it would sure wake the old fire truck up compared to the 300. I’ll do another video on the bottom end, possibly next weekend. Best wishes, Bruce
The marine version weighs 1420 kg. I've never seen an aluminum sump, just cast iron.
This is going to be a good series , coming to this engine after another mechanic has been in it makes it more of a puzzle . Was hoping you would explain that the stuck injector rod would result in an engine run away when started , just for the veiwers that don't know GM's . Also can you add your history with this engine , it appears you have been around them in the past . I'm thinking someone in the past was going to buy this lump , checked the rack and found it was not safe to start up then went to see the condition of the bottom end . Hoping all was good and that the asking price was too high at the time .
Hello Steve, I agree with you on both points. It will be interesting to get that sump off and see what awaits and I did wonder if that’s what’s happened with a possible previous purchaser. It feels okay barring it over making me think everything is still connected in the bottom end but time will tell. I’m by no means an expert on GMs but I might do an explainer on how they can run away as I’m getting the injectors unstuck. I’ve had a bit to do with the v12s and v16s in rail applications but not a heap with these smaller ones. The loco engines did huge hours but never sat around. I’ll do a video on the sump and throttle plate, side covers ect in due course. Thanks for watching, Bruce
Can find old rusty top fuel dragster engine or monster truck engine
Pull the airbox covers and check piston rings and bores thru the liner ports.
Thanks Larry, yes we do plan to do that, thanks for the comment, Bruce
😎👍
Is there a part 2 to this engine ?
Cheers Bruce still lighter than a Cat or Cummins. Did that GM come out of a scraper or something. What are you doing with the engine and how much would you sell it for?
Hi Andrew, yes a 621 cat scraper. We are not certain this was fitted from new. I’m not sure what I’m going to do with it yet but you would have to watch my latest video before you made any offer 😂 thanks again, Bruce
@@bruceinaus Thanks. My first comment was a bit abrupt as you hadn't got to that stage. Just a rush of blood on my part . But the old 318 with turbo sure could get up and go. Cheers for the upload.
Yea . A big lump go iron there mate ! It will prolly run though , Those GM's are pretty reliable .
Thanks Scott, it will be interesting to see why all the rack rods are disconnected and why the sump has been with those 6 stuck injectors so cross your fingers and toes for me! I can feel any huge clunks baring it over so that’s a positive sign I hope, Bruce
@@bruceinaus It sure looks like someone else was attempting to repair it , then gave up ! Good luck with it mate . Scott 🌵
I like my silver 8v92 2 stroke turbo to tinker with but some folks have them Nissan UD 2 strokes and the power is just nutty on those.
A couple of REAL men could have just picked up that piece of junk and carried it out!
A tone 😯 that's crazy how on earth do you find these things
Morning Shane, yes it feels every bit of a tonne much to my initial surprise. A lot of the time I hear about or come across these things on farms ect, I’ve lived in the same region for a very long time. Bruce
@@bruceinaus lucky you I'd like to be able to get some smaller stuff to make repair videos on.
👍👍🤩
👋🥖🇫🇷
Thanks Peter, I hope it was interesting, best wishes, Bruce
Just wondering, you seem like a guy that's probably dealt with a lot of Snakes in your life. Have you had to dispatch many a Snake in your time?
Hello, there’s quite a lot of snakes where I live. I try to avoid them, act with caution and if I see one I move back until I know I’m well out of it’s way and it has moved on. A man died earlier this month in a town north of here from a suspected brown snake bite at a school anniversary. Very tragic. Bruce
@@bruceinaus Thank you for the reply Bruce, you seem to live a honest life, I guess that's why I keep watching your videos. You seem like a Genuinely good guy. I'm sorry to hear about the man that died from a Snake a month ago, that's a hell of a way to go. I hope his family is doing alright.
Wondering, what is your favorite Australian Engine? Thank you for the videos and your reply!
know enough to stay away
GM in a cat scraper..........it must have been a repower to replace something like a 1673? The old skool turbo's were very inefficient compared to the modern designs......hence their large size. The turbo's on CAT dozers from the 1950's were twice as large again.....for about the same hp. For some context, the 318hp rated 8V71T from the late 70's is not that much stronger than say todays 6.7 Cummins, 24 valve 6BT.
Hi Wazza, thanks for the comment. It was fitted to a 621 cat scraper, I’m not sure if it was a repower or not and it looked to have a 3306 fitted into it after the gm was removed. It’s seems it’s the way of the world, modern technology, power levels increasing in smaller engines ect. Someone seemed to think this one was 350hp but I have no way of verifying that. Thanks for watching, Bruce.
@@bruceinaus Terex used GM engines in their earth moving machines, but I am 99% sure that Cat never did. Still, thanks for saving it, there are fortunately some great GM 2 stroke enthusiast channels on youtube ))
GM turboes were never intended for high boost, the intent was to recover the power lost to driving the blower, they were a fairly relaxed low stress engine.
@@raygale4198 there is a guy who has a channel here on youtube who has a 4-53 twin turbo in a Ford F-350 who is getting really good results. He uses his pickup as a daily driver and also rescues other GM's. Also check out the 8V-92 "Joyride" which has been fully modernized..........600hp and not a trace of smoke. Low boost in any diesel only does one thing......waste fuel
G'day, 8V71T is usually 350hpwith N75, 335hp withN70, and 8V71TT 305-308hp, 318is Na with N65 290hp with N60& 270hpwith N55 obviously there is then red tag, brown tag, white tag etc, there will be people with far more knowledge about them👍
Love the screaming demons
Me too, Bruce
Be careful, I have seen them run backwards, your have job stopping it, lol.
Part of me worries this one may have already done that with the rack rods disconnected, 6 stuck injectors and loose sump! Bruce
it is NOT supercharged
Doh...
your not a Detroit Diesel Fitter I am from Mitchell power uk