Runaway 2 Stroke Detroit Diesel and Ethered Cummins Engine Tear Down

i know most of you remember the old runaway detroit video this is that truck it's been slightly reduced over the last few months but this is it [Music] so i told you that we would uh tear this thing down someday and see exactly where things went wrong and i believe that day has finally come so let me get this thing drug over there closer to where the tools are and i'll get started on it well i've been giving her all the amps all night long somehow nothing burnt down in the middle of the night but i bet it still won't start [Music] i was wrong [Music] [Music] so [Music] so [Music] um well she's just not wanting to come out of there [Music] [Music] that wasn't nearly as much fun but it sure did work a whole lot better let me get this motor and transmission snatched out of here and then maybe i'll get it in the shop and start tearing it apart [Applause] there's the oil [Music] well i finally got this greasy old piece drug in here before i proceed with tearing this apart i'm going to address two or three of the most common comments that i saw in the detroit runaway video there were a bunch of people who seemed to think that this wasn't a runaway engine or that what we did was or was the same as just throwing a brick on the gas pedal and that's absolutely not correct so let me try to explain how this works and i'm no two stroke detroit diesel expert or any detroit diesel expert but i understand basically how these work so this is the throttle input to the governor so this rod right here is what connects to the throttle pedal in the truck cab so that input goes through the governor and there's a series of flyweights and stuff in there that spins around does a bunch of crazy [ __ ] and then the output from the governor is these two rods here there's one on each side one there and one right there and you can see that those are supposed to be connected to this shaft right here i don't know what the proper term for that shaft is i'd call it the rack shaft and it moves like this so off the bottom of this shaft there's a linkage that goes to each one of the unit injectors and what that does is controls the rack on each injector which in turn controls the amount of fuel that that injector is injecting into the engine so you can see that with this rod that's coming out of the governor disconnected from this shaft the governor no longer has any control over the engine whatsoever and then when you take bail and wire and you tie this rack shaft in the full fuel position like that that all four of those injectors on that bank of cylinders are going to be in the full fuel position they're going to be putting the maximum amount of fuel into the engine that they can and the engine is going to run away when you do that same thing on both sides then you have all eight cylinders in the full fuel position again there's no governor involved whatsoever the engine's running away this is a common thing that happens i mean obviously not with baylen wire but these engines do run away like that anybody that knows anything about two-stroke detroit diesels knows what a hung rack or stuck injector runaway is and then there were some people who seemed to think that it would have went faster or turned more rpms if it was running on its own crankcase oil and that's really not the case as evidenced by all the smoke that it was putting out it was being supplied more than enough fuel to go even faster than what it was valve float is the limiting factor so it was floating the valves and at that point the engine's not going to go any faster it doesn't matter how much fuel you put into it or what kind of fuel it is so we knew it was going to float the valve somewhere we just didn't know where that's why i was in such a hurry to get away from it i didn't know if it was going to float the valves at 4 500 rpms like it did or if it was going to turn 8 000 and catastrophically fly apart before it floated the valves now i know at that time i didn't never done this before until then there were also a bunch of people who had a problem with the comment i made about this being a naturally aspirated engine that's a totally true right and correct statement it is considered naturally aspirated yes of course it has a blower it's a two-stroke detroit diesel they won't run without a blower i mean there's third graders that know that but the purpose of this blower is not the same as like when you put a blower on a race car to cram a bunch of extra air in the engine so you can burn more fuel and make more horsepower that's not why this blower is here the two-stroke diesel cycle requires a blower you've got to have a slight positive pressure on the intake side to push the clean air into the cylinders and the exhaust gas is out without that blower without that positive pressure on the intake to do that they won't even run so any of these two stroke detroit diesels that are not turbocharged are considered naturally aspirated by the manufacturer well first impression from my first time going into one of these two stroke detroits a lot of you have probably seen that show engineering disasters this is one of them i mean the old boys in the engineering department obviously didn't have a whole lot of fun to give they just drilled holes right through into the cylinder head to mount wiring harnesses and pipes and little stuff like that no need to cast extra material in and make them a dead hole i guess so they won't leak just drill her straight through and let her leak everywhere apparently you're supposed to use a lot of copper washers on these they obviously didn't seal up very well judging by the three or four inches of gunk that's built up in here everywhere there's the emergency shutdown flapper see if that works nope she's stuck that's to be expected that's a steel shaft going through an aluminum housing don't have much use for those anyway usually i'm trying to cause an emergency when i'm dealing with one of these not prevent one so no big deal okay i got the cylinder head pulled off the driver's side and i found the problem there's one valve laying in there and then it's obvious that the pistons hit these two valves right here and bent them that one appears to be okay and the rest of the head appears to be okay so i'm assuming what happened was the piston got into the valves and then sometime after that is when the piston actually failed looks like we had some meltage too but that's why she quit running the other three cylinders on this side are okay i mean they're scuffed pretty bad but no major failures you can see the ports in the bottom of this liner where the intake air comes in i'm going to go ahead and tear this on down to the bare block so i'll show you some more of it as i go along good got quite a bit more deconstruction done here nothing failed catastrophically on this side it looks okay too here's the blower drive so that gear right there drives off this gear right here that whole assembly would be sitting in this hole from the back side and that's what drives the blower blower drive shaft these engines don't really have a head gasket which is kind of interesting to me they've just got these little rings here if i can get one loose i guess they call those fire rings i'm not really sure and then other than that they've just got some o-rings up here some pretty suspicious looking chunks laying in here not entirely sure if those are chunks of block or not but i think they probably are that liner has failed down there somewhere below where we can see right now so i'm gonna find some more carnage when i get there the flywheel housing came right off no problem i got this junk pulled off the side of the block and they have these flat screwdriver headed screws that hold these cam retainers in i ended up having to drill four of the six of those out that was fun here's what the rear gear train looks like all right i brought the thing outside to finish getting it apart got the crank out of it as you can see in all seven of the other rods and pistons out except for this one which is the failure piston as you can see she's pretty well screwed that's not even connected to anything anymore and what you're looking at here hanging out at the bottom right here that's the bottom of the piston the bottom of the liner is uh it broke off and fell into the oil pan so those chunks that i found laying in the valley those were chunks of piston not block but all that's moving separately from the crown of the piston that's not moving at all so that's what failed crankshaft looks fine it wasn't hurt at all well i managed to get this rod and piston out of there we didn't get a rod to come out of the blog but we got pretty damn close well i guess that's pretty much it for the runaway 8v71 teardown show you this liner real quick this is the failure cylinder you can see that the ports in the liner where the intake air comes in are all busted out most of that fell into the oil pan some of it ended up in the valley of the block too these 71 series detroits are dry liner engines so that means the coolant doesn't flow directly around the liners the 92 series detroits are also two-stroke pretty well the same design as these but the 92 series are a wetliner engine and then of course the 92 series are 92 cubic inches per cylinder where the 71 series is 71. the original 71 series came out in the late 1930s so for an engine design that's as old as these are they're not too bad you got to give them some credit and then the v70 ones like this came out about 20 years later in the late 50s i believe so from a diesel engine standpoint i'm not a big fan of these they don't make a lot of power they burn a lot of fuel and they leak everywhere but there aren't many engines out there that have as much history as these do and from a cool factor standpoint there's really nothing else that compares i mean nothing's as cool as the two-stroke detroit this took me two or three days i just worked on it as i had time but i guess while i'm going let me go get a hold of that 855 cummins that we sprayed ether into [Music] and start tearing it apart and see what went wrong with it another one of these 8v71s here just put this 8d battery on here let's see if she'll go it's been several months since i had this one running [Music] oh yeah [Music] um so so [Music] [Music] so so [Music] well i guess i'm gonna have to do it the boring way again i'll probably do a hood and radiator delete first and then i'm hoping i'll be able to sneak this motor out of here without having to mess with the transmission at all that bell housing's busted all the way around so maybe i'll get away with that so [Music] [Music] well needless to say i wasn't able to sneak that out of there like i wanted to but i got it out so let me drag it over here and start tearing it apart [Applause] uh got the rocker boxes off and there's nothing obviously wrong yet does not appear to have dropped any valves so i don't know what we're fixing to find out there's the injectors out of the cummins and the rocker boxes so this is pretty much all that happened this valve and valve seat failed and then pieces of that clanged around on top of number two piston number one doesn't look very good either but it stayed together and then the other two heads look fine here's number two number one and then three through six look okay i mean the liners are polished up pretty bad but as far as the pistons go there's nothing wrong with them so there you go there's the runaway detroit and the ether doubt cummins tear down i guess that's all i've got for this one so i'll see you next time

Channel: KT3406E

Views: 503,940

Rating: 4.7275219 out of 5

Keywords: kt3406e, diesel, engine, runaway, run away diesel, run away engine, runaway detroit, run away detroit, 2 stroke detroit, two stroke detroit, 2 stroke diesel, two stroke diesel, detroit diesel, cummins, N14, cummins diesel, cummins N14, runaway diesel, engine rebuild, engine overhaul, diesel rebuild, diesel overhaul

Id: fsCgUJ9nP54

Length: 26min 57sec (1617 seconds)

Published: Fri Aug 21 2020