A poignant reminder that capital investment is no substitute for rigorous technical diagnostics and precision engineering. This case study perfectly illustrates how easily incompetence can turn a massive expenditure into a mechanical disaster.
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He Spent $30,000… And The Engine Got WORSEAdded:
Today we have one, this 8V71 Detroit, and this bus was just rebuilt. Uh, and it's coming in. It's running horribly.
The engine is shaking. It's smoking like crazy. It's got no power. He's invested over $30,000 in this engine in the last 2 years. And it's absolutely horrible.
He just took a long trip to Florida with it. The first trip since the engine rebuilt, and it used 4.5 gallons of oil on the trip. Uh, so it's leaking oil, smoking, running rough. We got to get into it and see what's going on with this thing.
>> Oil has been pouring out of it ever since. When I got it back from him, temperatures about like this, white smoke just rolled out of it of the morning when I fire it.
>> Huh.
>> Little hard to start.
And yesterday it bogged out for about 10 minutes.
>> Wow.
>> Yeah. When I kicked it up on fast idle, it was really fogging out.
I shut it down after I pulled it out of the drive to hook hook up.
And when I restarted it, it fired right up at that point. But it was hard to start to begin with.
>> Well, there's a lot of that blower.
>> Yeah.
>> You know, leaves. It's >> Yeah, I think it's coming from the valve cover in the backside or it's coming from under the blower, but Heat.
Heat.
Heat. Heat.
Heat.
Heat.
Yeah, this thing barely made it up the hill. He had that pedal floored. That was all it had. We could have dropped the toad, but the toad might have been able to help push it up the hill if we needed it. That's why I wanted to leave it. But it made it, but it barely did.
All right, good morning. We're going to get ready to pull this in the shop and take a look at it.
So, what do we know is going on with it?
Well, a few different things. We know it's way down on power. We know the engine was just rebuilt on it. We know that it's smoking. And we know that it's leaking oil. So, we got three completely different things. Are they all related, or are they three different things? We don't know. Uh, but we're going to get in the shop and take a look at it, start doing some diagon, and see what we got.
It's a cool morning here. It was in the 40s overnight. We're going to have a nice, beautiful, sunny day today. So, let's see how it starts on a cold start here. It's been sitting for uh two days.
So, we're I said we're going to start it up, get it pulled into the shop, start taking a look at it.
So, this is the date that they had the engine rebuild done on.
So, about a year and a half.
Um, then it had the had new injectors in it, inframe kit.
Okay. And then just before that rebuild, they had it in a shop and they had $10,000 worth of work done on the engine. This was some fuel line and they put new injectors in it. They replace all the injectors.
The engine is shaking so badly that you can see this see and hear the steering wheel in here.
See if I rev it up if it changes.
But it's it's definitely got a very bad vibration.
This coolant temperature gauge is a problem. It's very hard to accurately tell what temperature you're at. And the difference between 200 and 210, your engine is cooked. So that's could be a problem.
>> This is the 71 series firing order and this is a left hand rotation engine.
So it's one left, one right, two left, two right, four left, four right, three left, three right, and then they're numbered away from the flywheel. The flywheel's back here.
These stamp steel valve covers are notorious for leaking oil. And that's what looks like the top one is what was leaking a lot. But let's get these off here and start taking a look and check out the settings for the tuneup on it.
Looks new gasket.
>> Yeah.
It's still leaking though.
Tell by all the oil all over it.
I knew these felt loose, but look at that.
That's a 1517. So that's supposed to be the go and no go. The end is supposed to go. The other part is not supposed to go. But the whole thing goes in. No.
There's a lot of slack in there.
021 is not supposed to fit in there.
It's a little snug, but the 19.
No problem. Like better.
So this one I got that go no go. Right.
So the little part that shiny dull part on the end there is the 15 that's supposed to go and then it goes up to 17 on the thicker part there.
So it's supposed to just go in just a little bit and then stop and not go the way. And that one is correct. But the same cylinder here. The whole thing's going no problem. There's a lot of lot of slack there. That 19 will probably fit in there.
So, very inconsistent settings.
1.460 is what it's supposed to be set at.
1.490 is what it is at.
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Because this engine's an automatic, there's no easy way for us to bar the engine over. So, we disconnect the muffler on here and move it over slightly so we can get to this inch and a half nut here on the cam drive. Um, and that's how we bar it over. We put a ratchet on there and we can turn the engine over. Then, a manual transmission is a little easier. We can put a bar in the flywheel, the teeth for the flywheel. But, this is an enclosed wet flywheel on this automatic. That whole flywheel is all closed off. And again, it's a wet flywheel. So, there's actually transmission fluid in with that flywheel on here.
Okay. Can I stop right there?
>> That's no good.
>> She's This one won't even go in the So, this one This one goes in all the way past the go. No go. And this one, the go won't even go in.
So, we have three rockers on each cylinder that we need to adjust. The outer two rockers, this one and this one way over here. The outer two are both exhaust valves. Remember, this is a two-stroke, so there's no intake valves on it. There's holes in the middle of the cylinder liners that do the intake.
So, the exhaust valves are the outer two. There's a jam nut that's on here.
We loosen the jam nut, and then the shaft of the push rod is what we adjust there to change it up or down. And then the center one in the middle, that is the fuel injector timing. So, exhaust valve timing, fuel injector timing right there. So, we're going to go through and adjust all those. But you can see there's that little square drive shaft there with this jam nut. Those jam nuts are super tight on here for some reason.
Okay, here's another one. The go no goes the whole way.
It's going away.
This is only the second valve on the entire engine where the the no the go no-go is actually going in and then stopping.
Can we have two on the same? No. And then this one just flops in like nothing.
Crazy. So, two valves are actually set right on the whole engine.
Another thing to get it to run smoothly that we're going to need to do is go through and you see that little fuel injector lever there that's coming off of this rod. We need to make sure that all those injectors are giving the exact amount of fuel every time they fire. If that little push rod is pushed in a little too much or pulled out a little too much, then that that monitors the amount of fuel that comes out of there.
So, if one of these is is backed off considerably like like that, that's less fuel. That's full fuel. So, if they're not all right, then each cylinder is giving a different amount of fuel and the amount of power per cylinder is is all over the place. So, to run smoothly, all of those need to be set exactly the same. And we also need to confirm that they're all getting full fuel. You can set that governor wrong and set these wrong. So, the fuel injector never actually gives its full amount of fuel, which will affect the great greatly the amount of power that the engine's getting.
Got a whole lot of permiteex on that valve cover gasket that was leaking.
Kind of might have been leaking right there.
It's awful lot of Permiteex, though.
So, only two valves out of the 16 that get set on there. There's 16 bridges.
So, there's 32 valves, but 16 of them that you set. Only two of them were actually correct. All the other ones were bad. Uh, and then the fuel injectors, none of them were even close.
They were I think they obviously they're shooting for the wrong thing, but they just did it all wrong. That would have definitely affected some some smoking on the engine a little bit. Not not as much as it was smoking, but it would have made it harder to start and it wouldn't have run as smooth with those settings all over the place. So, uh, let's see what happens.
Okay. So, tighten it just a tiny bit.
So, if you do it where the fat part is what you adjust it for, that's a little too snug. Right.
Tighten it just a little bit.
Right there. And then hold it down while you snug it.
So yeah, we're go no go. That's perfect.
Actually stops. Okay, so this one here.
This one you got to loosen it. All right. Too much right there. Okay.
Tighten it down.
The engine's a little hard to get to on here. And if you can get wrap your head around how it's sitting in this bus, it's actually tipped over on its side.
this flat part right here. That would be the very top. If the motor was sitting up and that was flat this way, that would be the top middle of the engine.
So, right now, you've got one head up here and the other head's down here. The engine is totally tipped over on its side. Um, yeah, nothing is straight up and down on here. So, it's a V, but it's it's tipped over on its side because the way they the GM bus, they wanted to be able to get an extra row of passengers in here. So, the engine is tipped sideways. And this is a left-hand rotation that spins backwards because the transmission is a goes in at a V drive angle into the rear end there. So it's not a T drive like what we were used to seeing.
Get the angle right. Yeah, it's perfect.
It's going right to the go.
So we're shooting for 1.460. We're almost 1.490 right now. So we're going to bring it about way down over here.
I got to hold it.
Good.
>> Yeah. Keep going.
Go a little past it for when we tighten it down.
>> Yeah. I don't remember which way it moves when you tighten it.
>> Yeah. I'll be pulling backwards. So, it'll get back to if we go a little bit over 5'9 or whatever.
460 is way down here.
>> Oh, yeah.
>> Okay. Now, that's that would be right on the money if that's where it tightens at.
>> Um I think I think you back it off like 2000s and then tighten it down. I think that'll be pretty close.
That's right on the money.
Okay. Start start snug in from there.
This Snap-on dial caliper gauge is a great way to set the fuel injector timing on it. Super easy to use. Um, we can also use the pins very successfully and we'll go through and check things with this little timing height pin. Each pin is a different height and the standard timing on this engine is 1.460, which is the pin that we have right here. It goes in a little hole in the injector and then the follower height gets set to the bottom of this. So, when this is correct, it just glides the oil right off the top of the injector, but it's a little bit more accurate with the timing gauge. So, here we're using a timing pin just to confirm the settings there. And it's perfect. You just It just wipes the oil right off the top of the follower there. It's a 1.460.
You might have to use that pin on the top if it's easier for him because it's the way this engine's tipped over sideways. This side is almost vertical back then. There's not a lot of room.
Having the timing set right on the engine is so important. Uh imagine yourself running like a two-legged race with somebody. You ever done that like in grade school where you tie your leg together and you try and run like that?
Um, this engine's trying to run an eight-legged race, and if everything's not timed perfectly, it's just going to stumble and fall all over the place, which is exactly what it was doing.
Okay, so making those adjustments on the tuneup, that should make it run smoother, and then we'll diagnose some more issues with it. But that let me know what kind of quality the rebuilt got done on it, too, because if those settings were so all over the place, it was never finely tuned. I mean, this thing should run like a sewing machine, and obviously it wasn't. It never has since he had it rebuilt. He said it never ran so good, never had good power or anything since the rebuild. So that was just giving us an idea of what we were looking at. But now we got to figure out what mechanically is going on with the engine, too.
>> Yeah.
Heat.
Heat.
What the So, we're taking off the exhaust manifold here to see if we can figure out which cylinder down here is smoking.
If it's one of these on the bottom or one of them on the top or more than one.
I think it's more than one, but this will tell us. I don't see any signs of oil or anything crazy.
We'll see.
We're going to use this Teslong Boris scope camera here. This is the one that has that articulating end on it there.
We're going to stick it up in the cylinders and see if we can see what's going on. So, we're going to remove the inspection covers on here on the bottom side so we can get up in there and see what's going on.
>> Yeah, there's not supposed to be that's not supposed to be full of oil in that airbox.
>> You see it just leaking?
>> Yeah. Don't get it in your face.
Yeah, they clearly didn't take those off.
>> You got to inspect it if you're just rebuilding it.
>> Yeah.
This isn't going to be in the way, is it?
That might be in the way.
Why is there such a big ring gap right there?
Pull it back just a little bit.
That's crazy.
Looks like the side of that piston's a little scored, too.
Yeah, right there.
I mean, there's so much oil dripping down the sides of that liner. That oil should not be there.
>> And the rings broke or something.
>> Yeah, we're going to have to turn Both those pistons, unfortunately, are up right now. So, we'll need to turn it over so I can get in the liners. So, yeah, there's a lot of oil on the side of the piston there.
How did I not get glare on the camera?
Okay, go ahead and bar the engine a little if you can. Keep going. That's why it's smoking because the oil in there.
Keep going.
Keep going.
One more time.
That's it right there. I'm going to go in the cylinder. Now, the cylinder liner walls are extremely scored.
See all those scrape marks?
Oh, I popped out, Jonathan. I came out.
I got to straighten up my thing. It's It's bent over like on itself or something. There we go. I can move.
Okay, go back in the hole.
I want to try to see the uh boy, the scoring is crazy in there.
I'd like to see the ports of the cylinder, the the round parts.
>> Yeah. Down. Yeah. Come down a little bit more. I'm looking for a crack in one of those.
Can you come down just a hair more or is that Let me Oh, hold on.
I can't I can't specifically identify easily a crack on any of them, but the the scoring in the liner is crazy. So, let's go ahead and pull out and try and go in the other one. Is the piston down enough on the other one or >> I can't see it. So, >> slide it in a little more and I'll let you know.
move it back and forth.
>> Yeah.
>> Yeah.
>> Okay. Yeah, that piston is still up.
>> Okay.
>> So, I'll if you hold it there.
Give me a second. I can see it.
And if I can hold it. Okay.
>> You want to give me the camera? Oh, I got it right there. And if you want to bar the engine over. Okay.
Just a tiny bit more.
That's it right there. Okay.
Can I get it in the hole? Can I get it in the hole? Cannot get it in the hole.
Grab Grab that camera thing.
Wiggle it out just a little bit.
Yeah.
Look at all that scoring.
>> Mhm.
>> Move the Move the camera around. Keep Oh my gosh.
Okay, keep going.
Is the brightness all the way up on it?
>> Um, probably not.
>> Yeah.
>> Okay.
Move the camera.
You >> see? Are you trying to see the bounds? I was trying to see if there was a a crack in one of those liners, but that's scoring. I mean, there's no way it's going to run good like that. That's just down on compression. And that's should probably go and check the other four that are down on this side or two cylinders.
A little oil on the airbox cover. Ice cube tray number four.
Yeah, there's oil all over the sides of it.
I don't know if my light's helping it or not.
>> It's I think your light's hurting.
Okay, so let me see the other one.
Yeah, there's oil in there, too, though.
I think the whole engine's going to need to be rebuilt.
Let's go ahead and turn it over so we can get in in the liners there.
It's all scored.
Pull it down just a little bit.
A little bit more there.
Turn the light on.
>> No.
>> No. Good.
Okay.
Pull it back just a little bit.
Yeah, I'm seeing almost no cross-hatching in there. Everything is just vertical scoring.
This one has a little cross-hatching showing through, but okay.
So, the engine rebuild wasn't done right, but that's not what the failure problem is here. I really think this engine has been overheated. Uh, you know, he didn't have all the power that he had. It's got the automatic transmission which adds heat to that already taxed cooling system on there.
The inaccuracy of the gauge up front.
Um, you know, all that just went together. But the engine should have been running better. It should have been tuned better, but I can't put the failure of the engine on the guy that rebuilt it. Uh, he can take some of the blame for a few of the things, but I really think it was overheated or oil starvation is what scored up all those liners. It's that's hard to say, too.
Um, but I know that gauge is so inaccurate and it's hard to pay attention to. I really think that it got overheated. the the cylinder liners look like they've been overheated. Uh and it's unfortunate because it was a brand new engine. It's only been on that one big trip and a couple tiny little trips around town and stuff. So, uh that just sucks. Uh if if we do rebuild it for him, we're going to make sure we put a a more accurate digital gauge in there so he knows exactly what temperatures at.
We could put an alarm on it, too, or something, too, so it's easier to pay attention to. But, uh I can't throw the original mechanic all under the bus for everything for the failure on it because I I don't think that that's fair. Uh even though the tuning was terrible. Uh but that that's not what caused the failure.
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