noise."Mechanic: 6.4L saga part 3 · 10:51am Jun 3rd, 2021
This Blog Post is a Sequel
Y’all know the drill by now. Everybody grab your favorite beverage.
In fact, for this tale of woe you might want a second. . . .
That’s right, we’re finally giving the full saga of the Ford 6.4 and its engine replacement.
I’ll get y’all up to speed first, just in case you haven’t read prior blog posts about this truck. It’s a 2008 F350 Super Duty Crew Cab Dually with a 6.4L diesel engine and about 700,000 miles on the odometer (give or take 1 million km for you metric folks). Customer’s initial complaint is an occasional misfire/runs rough, and the check engine light is on.
I determined it’s cylinder number 2 that’s got the problem; for those of you who are following along with the diagnostic songbook that’s the front cylinder on the driver’s side.
In a gas engine, you can have a misfire for lack of spark (ignition), fuel, compression, or airflow. A diesel engine doesn’t have spark plugs, so one of those things can be eliminated from the list. Not a whole lot you can get to to test. Fuel injector passes an electrical test, but that doesn’t mean it’s flowing. I said we needed to do a compression test next, that didn’t get done. Instead it got eight fuel injectors, genuine Ford remans.
That didn’t fix the misfire.
The customer was more understanding than most people would be, and when he brought it back, we actually did do a compression test and found out that cylinder 2 didn’t have the compressions it needed. Y’all can look back through the blogs for exact numbers, but I think it was 100psi and should have been 300psi.
So the customer decided to buy an engine . . . that’s a major financial investment on this truck, but he won’t be able to find one as nice for that price used, and it’s sure as heck cheaper than a new one.
As hard as it is for some of you to believe that automakers actually consider maintainability when they design stuff, they do. (Sometimes they ignore it, but they do consider it.) The previous version of this truck would have had the 6.0L diesel, and that was plagued with problems, including cylinder head problems. Ford had all sorts of specialty tools to get the heads unbolted and off the engine, but techs figured out pretty quickly that it was faster and easier to just take the cab and front fenders off as a unit and then you could get to everything. Eventually, Ford made that an authorized method of repair, which meant that the dealers could do it without having to pretend they weren’t, and Ford actually kept this in mind with the new design of truck.
Since the cab isn’t something you’d normally remove, on the older Fords all the bolts that held it down went in from the inside (I assume it was easier to build that way). The new design has them going in from the bottom, which is nice.
Except that they go in cage nuts, which is less nice.
I may or may not have mentioned those when I blogged about the 6.4L that got the up-pipes, if the little cages that keep the nuts from turning don’t hold the nut well enough and it spins in the cage, you’ve got either an annoyance or a big problem that involves cutting access holes in the body. That one needed two access holes, and I think two or three extra hours of work to make them.
This truck was cleaner, this truck had already had a remanufactured engine put in it, so in theory those bolts would come out.
And to my surprise, they actually did. [Getting them back in was a different story, a couple of cages were damaged in that direction, but I was able to make it work with no access holes needed.]
Once the cab was off, it was fairly simple to replace the motor. All the fasteners I’d struggled with when I put the injectors in were right there in the open, easy to get to. I didn’t have to stand on a stepstool and lean over the radiator to work, I could stand right alongside the engine or behind it or wherever I needed to in order to get at things.
The engine hoist struggled to lift that beast of an engine up, but it managed.
A few blogs back is a series of pictures of the operation. I’ll link it if you want to look at pictures of the process and somehow missed that one.
Unless you’ve got lots of engine hoists around the shop, you need somewhere to put two motors to transfer parts and whatnot. We don’t even have an engine stand . . . and honestly if we did, it would have folded under the weight that 6.4L. Clever viewers who know how engine hoists work might notice that the adjustable arm is all the way in for maximum lifting strength (and minimum reach, which is another reason having the cab off was a worthwhile procedure).
When you buy engines from the junkyard, they come on a crate nailed together with whatever they could find out back. From the dealer, though, they come in nice plastic totes with a base molded to the engine which is pretty stout, and with a couple of steel beams I made a temporary engine platform on our inground hoist. You can see it (engine-less) in the picture captioned “New motor in the frame, bolted to the trans, ready for further assembly. That was Monday.”
I took a systematic approach to make sure I put everything back in the correct order, and got delayed once when I was putting together ‘cause the manager sometimes likes to wait until the engine is being reassembled to order the rest of the gaskets and stuff needed. Interestingly, there is supposedly a Ford install kit that contains all the gaskets and seals and other stuff you need, but you can’t actually order one. At least that’s the story I heard; he had to order all the parts individually.
One thing he didn’t order was new fuel lines. This diesel has a high-pressure fuel system; it runs up to about 20,000psi. If you’ve ever watched waterjet videos on YouTube, you have an idea what a high pressure liquid can do to things, so all the high-pressure lines are one-time use.
He also didn’t order low-pressure fuel system sealing washers, the truck takes about a hundred of them in all its various feed and return and transfer piping, and they’re also supposed to be one-time use.
But what could possibly go wrong?
As that previous blog post said (’cause I know most of y’all looked), the engine was installed and assembled on a Tuesday, but the video showing it running is from Thursday. Surely I didn’t just laze around for two days before starting it up, right?
Right. I started it. The truck wasn’t even fully-assembled when I did, it’s always best to start an engine when it’s put together enough to verify it works, but not so put together that it’s extra effort if it doesn’t and you have to get back in and do more work.
It fired up, eventually. When I put the injectors in it, I didn’t bleed it properly and it took forever to get it running. This time, I did, but this time I was also fighting weak batteries, and a more completely empty fuel system. Doing just the injectors left the injectors, injector feed pipes, and fuel logs empty, but the low-pressure and high-pressure system were theoretically full of fuel. This time the high-pressure pump had come off, the fuel filter housing had come off . . . .
I can’t remember exact numbers, but desired fuel pressure was five thousand PSI, and I had eighty, then a hundred, then I let the starter rest and the pressure dropped. Finally, though, it started, ran kinda rough, and I figured it would smooth out once it idled for a bit, the engine voltage stabilized, and the last of the air went out of it.
But it didn’t.
In fact, it showed that both cylinder 4 and cylinder 8 were not contributing. Came in for an engine because of a miss on cylinder two, and now it’s got a misfire on cylinder 4 and cylinder 8.
And that side of the engine is the harder side to access.
Nothing for it but to do the injector tests again. There’s a harness that goes under the valve covers that runs the injectors which I said should be replaced because they’re high-failure items, and we didn’t replace that either.
Accessing that harness is a huge pain on the left side (it’s easy on the right!), but I did after a few hours of disassembly, and tested the resistance of each new injector on that side.
Injector failed hard. The ohm reading wasn’t close to what it should be, even though all that’s happened to that injector in the last few months was coming out of the engine, being put in a box, and then put back in the remanufactured engine.
The good news is that Ford will warranty it, it’s only a month old. They send out a new one, I also move injector 8 to a different, easier-to-access position (and that way if the misfire on 8 moves to the cylinder where I put the injector, I know that injector is bad, even if it ohmed good). Manager also orders a wiring harness, because why not? That could be bad, although I tested it and it didn’t seem bad. But I can’t test it with the engine actually running, and we’re there and it would be stupid not to.
The torque-to-yield high pressure fuel lines weren’t happy about being torqued a second time, and they’re really not happy about a third. I’m sure it will be fine, nothing could go wrong.
I’m getting good at taking this thing apart. Had it running poorly on Tuesday, diagnosed Wednesday morning (mostly, no idea why 8 was misfiring), got parts Thursday and put it together, started it up, and it actually ran fine.
Like, it ran fine.
Drove it around on Thursday and again Friday, put some miles on it, watched data with the scan tool, no codes, cylinder contribution graph was a flat line (that’s what you want), this thing is finally fixed and I’m not sad to see it go. In fact, I’d love to not do any engine work on it for the next year or more.
Alas.
You’ll never guess what was parked on the sidewalk in front of the office, unmissable, Monday morning.
That very same truck.
(I’m sure none of y’all were actually surprised.)
It still runs great, the customer informs us, but it knocks on startup and smokes. Sure enough, after the engine’s warm, you shut it down, let it sit, and when you start it there’s a couple hard knocks, then it runs fine but it’s smoky and smells of raw diesel. Things which a brand new engine should not do.
Most likely cause is one of the injectors is sticking open. Did I mention seven of them are month-old Ford remans and the eighth is several day old Ford reman? They shouldn’t be bad.
Luckily, there’s a test for that. All you have to do is remove both valve covers and all eight glow plugs and then crank the engine over. If there’s a leaky injector, it’ll spray diesel out the glow plug hole.
So back I go into that engine for the third time in as many weeks. Four or five hours of disassembly later, crank it over and you’ll never guess which cylinder it sprays fuel out of.
Seven.
(You were going to guess 2, 4, or 8, or maybe 6 to complete the pattern.)
The good news is that seven is on the easy side, the bad news is it’s the hardest injector to get to on the easy side.
Ford’s probably not happy about warrantying another injector but they grudgingly send a new one out, and I get it installed and have the truck running in relatively short order and once again everything is perfect, and the customer picks it up and is happy.
Hopefully that’s actually the end of the engine replacement saga for this truck, because I spent three weeks of May mostly working on it.
And this blog’s already running long but it wouldn’t be fair to leave you without knowing what major job I did for the rest of May, because in many ways it ties neatly into this one.
We had a pile-up of engines (in fact one of our service bays has been unusable for the past month because it was full of engines). The next engine to replace was in a Chevy Tahoe, 2011 or thereabouts (I legit don’t remember, even though I was working on it today for reasons you’ll soon find out). Unlike the Ford, this one comes out pretty easy. Take off the hood, intake manifold, all the belt drive accessories, and it just squeaks out of the engine compartment. Just being the operative word, there’s maybe an inch of clearance.
Like the previous customer, this guy had a high-mileage vehicle and when it became apparent it needed an engine, he did some price shopping and figured out that replacing the engine was a better value than buying a new Tahoe. He got a genuine GM remanufactured Displacement on Demand 5.3L.
As usual, the manager was on me to complete the job quicker, complained when I left work at the end of the day only an hour after closing time, etc. Also just like on the Ford, it wasn’t until the engine was actually out that he ordered all the parts I’d need to finish assembly and installation of the new one, and I also had to wait to pull it out until Ford came and picked up the old engine for that 6.4 (that engine was occupying the engine hoist). It should have been on the ground Tuesday by noon, but instead didn’t actually get pulled until an hour before close.
Wednesday, I put the new one in, had a few setbacks with installation, but assured him it would be running by the end of the day, and it was.
Alternator wasn’t charging, though.
We tested it, and could find no reason why it wouldn’t be—all the wiring was good, the fuses were good, so just like the injectors on the Ford, the alternator apparently decided that being unbolted from the engine and then bolted back on was a good excuse to fail.
Ran it anyway, since we couldn’t get one until the morning. There was a ticking noise from the freshly remanufactured GM engine that we didn’t like, but my manager figured maybe it was a lifter that hadn’t pumped up all the way yet.
All this time, the battery voltage was dropping, and after maybe 20 minutes of running, the engine quit abruptly. We figured that probably the voltage had gotten low enough, the coils wouldn’t fire any more, or else the PCM cut out (they’re pretty tolerant to fluctuating voltage, but of course like any computer, they’ve got a minimum voltage they need to work).
Thursday morning, I put a new alternator on it, hooked the charger to the battery, and after a sufficient time, started the engine, wondering why the fates were conspiring to kick me with random electrical failures after two engine replacements in a row.
If only just the alternator had been the problem.
It started up, but it had a dead miss. It was showing misfires on both five and seven (on the driver’s side; someday we’ll get into how/why cylinders are numbered, for now just trust me that it’s not weird that the even cylinders on the Ford were on the driver’s side but the odd cylinders on the Chery are the ones on the driver’s side). We had spark, and the next easiest thing to check was compression.
Cylinder 5 had zero.
Zero is not a good number. It should be more than zero.
Did a leakdown test, which is where you introduce pressurized air into the affected cylinder and see where it goes. Through the intake, it’s an intake valve, through the exhaust it’s an exhaust valve, through the crankcase, it’s a piston or ring, and through the cooling system it’s a catastrophe. If it goes into the transmission, call a priest.
It went through the intake, which is easy to pull (especially since it was just off), and come to discover that the valve is held open by a head bolt that the rebuilder left in the engine.
Oops.
It also turns out that the bolt comes out easily, which means the valve is already bent, and in case you’re curious the pushrod was, too. While the 5.3L isn’t normally an interference engine, it turns out when a bolt jams a valve open, it might be.
Guess which pushrod is the bad one?
And that’s where the valve hit.
GM warrantied the cylinder head, both parts and labor. I would have been happier getting a whole new engine, but they don’t actually have any available right now. This one had to be shipped from Texas, and it was apparently the last one.
So once again, I got to tear into a brand new engine—this one with about 20 minutes of run-time and 0 miles—and replace something that never should have gone bad. Remember earlier how I said to run it before the vehicle’s completely assembled? You have to take the hood off in order to remove the engine, and I hadn’t put it back on, which made the head replacement at least somewhat easier.
So yeah, that was how May went.
Fun in the sump again. That vlave was sooo close to embedding in the piston crown. I wonder what wouldve happened to the rest of the engine.
Hopefully. That sounded like a beast of a job. Good work!
I'm looking forward to this, and I have no idea why.
Damn...just damn it!
Sounds like fun.
Why didn’t you swap two fuel injectors and see if the problem followed the widget? Seems quicker.
"...and come to discover that the valve is held open by a head bolt that the rebuilder left in the engine."
Time to call the rebuilder and work off some of that stress with primal scream therapy.
I've always wondered why firing orders don't always start on 1. It's a repeating sequence so it seems you could start anywhere in the sequence when listing it. I had a 1970 MG Midget with the firing order 2-3-4-1. Always bugged me that it could have just been 1-2-3-4.
And I do not envy you in the least! I used to do a lot of shade tree mechanic stuff and then some. But I've gotten to the point I don't even want to look at an engine anymore. Living vicariously thru you is plenty!
A random question just popped into my head: What's the oldest car you've ever worked on for a customer? There have been a few times when I brought my truck in for maintenance and saw some classics also being worked on. '67 Mustangs, '57 Bel Airs, that sort of thing.
I'm not a car person - I understand that diesels compress the fuel to make it burn, but what can cause a lack of compression that badly but doesn't affect the other cylinders?
oh no, I see where this is going.
With this engine I would actually have guessed something like 9, or 23.
Does that mean you get a free new engine and your client gets to wait an extra week?
*reads further*. hmm, guess not
That doesn't look right at all.
I couldn't work out what you meant, so I enlargened the image. Oh, yes. Then I set the image back to normal and can still definitely see that doesn't look right. At all.
Future maintenance issues on Tahoes are things that I dread hearing about - mine's a 2013 and is just starting to have stuff pop up - at this point it's electrical and sensor gremlins:
I'm hoping it keeps everything together for a few more years until car prices settle down - my wallet would prefer that it suffers as minimally as possible.
I hope your June gets better.
"Interestingly, there is supposedly a Ford install kit that contains all the gaskets and seals and other stuff you need, but you can’t actually order one."
Then... why does the kit exist?
Wow. Well, good luck with not having to do anything with that engine for a while! :D
"but my manager figured maybe it was a lifter that hadn’t pumped up all the way yet"
What, in this context, is a lifter?
"If it goes into the transmission, call a priest."
Wouldn't it have to go through the crankcase first to get there? Or is an impossible direct route why a priest would be needed?
What's an interference engine?
...Yeah, so, sorry that didn't go better? At least it led to some interesting blog posts.
Good luck in June!
I once had a Nissan Altima(?) stuck in my bay for 3 weeks with exhaust leak issues. Some of them were obvious. Wimpy, undersized, backed out/missing manifold hardware. Some were less obvious. The Y pipe was rusted to Swiss cheese. Underneath its heat shield. No more Nissans for me. For ANY Reason.
Just
NO
.
5529378
Interference engine means the valves when open extend past the piston's maximum vertical travel limit (called Top Dead Center, TDC), so if the valve is still fully open at the wrong time (generally because something else broke first), the piston rams into it. best case is in his pictures -bent valve and scratched piston. worst case, the valve head snaps off and bounces around scratching and gouging everything it hits and/or gets embedded in the piston.
5529467
Ah, thanks!
5529241
Yeah, lucky it didn’t TBH.
I’ve seen it before. It ain’t pretty. Somewhere I might have pictures of a car that came apart at high RPMs, pistons looked like porcupines with all the valve stems stuck in them.
5529242
Yeah, it’s not one I want to do again, and that’s a fact.
It’s less exciting than you think, but hey. It is a thing that exists.
5529244
My next engine job is likely to be a four-cyl in a Chrysler, and we sourced the engine from a junkyard. What do you want to bet that’ll be the one that goes smooth and runs perfect?
5529245
Hours of entertainment. Hours and hours and hours and hours and hours of entertainment.
5529252
On some cars, it is. On this Ford, replacing injectors is a 9 hour job, so that’s not the fastest way to do things. Also if you’re doing injectors on the left side, you lose about $80 of Ford Specialty Gold coolant unless you’ve got a nice, pure vacuum sucker you can keep it in.
Heh, that’s my manager’s job. My therapy is blog posts and fluffy pony pics, and y’all get to benefit from those. Nobody benefits from some dude screaming in the phone.
5529259
On every car that I know of in the US produced in the last 40 years, the firing order does start with 1. That’s traditional. Also AFAIK if you’ve got an inline four numbered normally, you can’t have a firing order of 1-2-3-4 unless you like vibrations or want to do fun stuff with countershafts (but I’m not an engineer, so don’t take that as gospel . . . IIRC, firing order of most inline 4s is 1-3-4-2).
One of the reasons I don’t do shadetree stuff is the last thing I want to do on my time off is fixing more cars. Heck, that’s why all of mine are falling apart. I don’t blame you in the least for not wanting to do it at all, and I’m more than happy to provide the tales of horror for you instead of you having to live them.
5529269
Pretty sure it was a 1949 Chrysler Town and Country. Not 100% sure, but nothing else comes to mind.
I’d personally rather stick to newer stuff, ‘cause that’s where I have the tools and expertise. I know some people do love that older stuff, though, and they’re welcome to it.
5529270
Either valve problem or rod problem. Possibly a head gasket or cracked piston/bad rings.
I’ll be honest, a lot of times when we know it’s a serious problem that warrants engine replacement, we won’t go further, since there’s nothing to be gained by further diagnostics. So we don’t know what went wrong on this one, but we do know that replacing heads (if it was a problem with them) is not much less expensive than just doing the whole engine, which comes with heads and a longer warranty, so we stopped diagnosis knowing it was low compression without ever doing further tests to figure out why.
In general, engines are air pumps, and anything that affects airflow affects compression. On a single cylinder, valves not opening or closing properly, leakage around the piston for whatever reason, bent rod (unlikely on a normal gas engine, but possible), failed head gasket, cracked cylinder bore. Multiple cylinders, usually engine timing is to blame or restricted exhaust (if it’s on one side but not the other). There are probably some other weird edge cases I’m not thinking of . . . we did have an old Chrysler with a 3.3L once that had compression on the first three cylinders but not the last three due to a broken camshaft.
Surprisingly, it hasn’t yet.
I mean, that’s not unreasonable
If we were living in the normal timeline and there were engines to be had, we’d’ve gotten a new one for free and he would have waited another week.
Yeah, that curve might be aerodynamic, but it’s not ideal for valve lift.
It’s kind of subtle, especially if you don’t know what you’re looking for, but when you see it you can’t unsee it.
5529301
Without knowing the mileage, yours is in prime time for little annoyances to pop up.
Huh, that’s odd. Wiring is the only other likely problem I can think of on that. We haven’t run into that one yet.
I think there’s a connector under the seat that has problems. I know some GM vehicles have issues with it, but I don’t know what years/models off the top of my head.
That’s one where your best bet is to look around on Craigslist or whatever and see if one that’s a match for yours is offered at a reasonable price. I have rebuilt seats and it sucks and I’d rather not do it again.
I question the normalness of that, I wonder if maybe it’s got a worn or broken motor mount?
I hope so, too! Car repairs aren’t fun, nor are they cheap.
5529306
So do I. It’s not off to a great start, but we’ll see.
5529378
I assume some times it is in stock and you can order it. Or else they’re just taunting you.
That’s what I’m hoping for!
What, in this context, is a lifter?
The camshaft is what indirectly opens and closes the valves. Lifters ride on the cam lobes, and engage with the pushrods. The other end of the pushrod pushes the rocker arms, which are what engage with the valve. Most modern lifters are hydraulically adjusted, which means that you don’t have to adjust valve lash (looseness) to make up for wear, and they would likely be at their most relaxed (loosest) setting new from the factory.
researchgate.net/profile/Dequan-Zou/publication/258177738/figure/fig2/AS:667833784602624@1536235390036/Schematic-of-a-pushrod-valve-train-system.png
(In this illustration, the lifter is labeled ‘tappet,’ which is another name for them)
Yes, it would have to go through the crankcase first, and then the front cover of the transmission . . . while I can think in my head of some very unlikely cases where that could actually happen, it would involve multiple catastrophic failures. Sorta like a train leaking diesel fuel out of the FRED, it’s maybe possible, but the number of things that would have to break to make it happen is a lot.
5529467 ninjaed me on that one, but basically what he said. In the field, the term isn’t always used correctly, but he has the correct technical definition.
At least y’all got some good blog posts and at least one fluffy pony story out of it all, so I’d say that’s a win.
Thanks! It got off to a rocky start, but still plenty of the month left for improvements!
5529419
I’ve worked on a car like that. It had every sketchy exhaust repair you could imagine, including soup cans. (Might have even been a Nissan, I can’t remember.) We were only willing to touch the exhaust if we replaced everything, and the customer didn’t like the price.
Also speaking of exhaust, I’ve done five exhaust manifolds in the last week, all on Chrysler products. Eight or nine broken studs between them, only one of which required heroic effort to remove, the others all came out with my stud getter-outer.
5529529
The last guy who serviced my truck has a '41 Plymouth Custom Deluxe that he's apparently trying to restore. His many cats love sleeping on it. I took one look in the back seat and immediately became jealous of 1940s riders. You never see a car these days with that much leg room.
5529528
OK, that was a huge brain fart! I went and double checked and I don't know WHY I thought 2-3-4-1 was the order. On the Midget it actually IS 1-3-4-2 as you said. Haven't had that car for years, but I don't know where I got that in my head. Tho I did come across a mention that some British engines apparently DID use 1-2-3-4. I think was confused me is that sometimes for that engine it gets written as 2-1-3-4, usually when discussing trying to fuel inject it. The 1-2 and 3-4 cylinders share intake ports, so you get two intake strokes in quick succession on each intake runner. Normally it had a carb feeding each intake runner. But you could get an intake for a single Weber, and some people have used a TBI like that. I've also seen aftermarket crossflow heads for it with one port per cylinder, and even custom cams to change the firing order to something like 1-3-2-4 or whatever would alternate the intake strokes between the banks. Crazy rare and expensive upgrades. Kinda wild what folks will do with a dinky little engine like that!
5529534
2013 - approaching 125,000 Miles. I got it when I went off to college when it had 14,000 and I have not been gentle.
I often question the normalness of that too but have been informed that there's nothing that can really be done about it.
The repairs I can stomach, but I got the Takata airbag recall dealt with at the dealer and took a look around - they were selling a 2017 Tahoe with 82,000 miles for $45,000. Unless this thing explodes I'm waiting until the chip shortage ends before I even think about looking for a replacement.
Meanwhile, I'm just here, waiting patiently for more people to get their hands on LiquidPiston rotary devkits so they can write reviews or their unbiased analysis.
So far only Warped Perception (youtuber, does slow mo engine videos) has got their hands on one. Theirs are the only videos with positive comments. The marketing videos from the official engine vendor just have comment sections filled with random trolls or haters declaring that "it'll never work, I don't care if you fundamentally redesigned the engine, the Wankel was bad therefore this is bad too".
5529533
Re: *all broken somewhere, time to stop looking*
Yeah, that makes sense
5529543
Oh. :D
Well, thanks. :)
re lifters:
Ah, thanks!
So, to check my understanding, rather than the cams directly contacting the pushrods, they contact the lifters which contact the pushrods, with the intermediate step provided by the lifters allowing stroke length adjustment (to make up for wear, possibly among other uses)? With hydraulically adjusted lifters handling the process automatically instead of a mechanic having to get in their and take a screwdriver to each one individually, or whatever it'd be?
re the leak to the transmission:
Ah, thanks. That's about what I thought. :D
re interference engines:
And thanks!
"At least y’all got some good blog posts and at least one fluffy pony story out of it all, so I’d say that’s a win.
"
Glad those help. :D
And aye. :)
>> 5529543
I don’t know what a FRED is, but this reminded me of that time my bus started pumping diesel out of the coolant overflow. They never did get it back on the road after that, it was already 14 years old with something like 240k miles on it, and it had a chronic overheating problem, so it wasn’t worth fixing.
Apparently, this is a relatively straightforward failure on the Caterpillar diesel that it was equipped with. Injector seals fail, I’m guessing on the return side (since it was running fine, just making a huge mess)
5529552
Ahh, that’s cool! I have less interest in older cars than I used to, since I spend so much time working on cars it’s not really a hobby I want on the side, too. I did have a couple older project trucks I wound up selling after realizing that I was never going to do anything with them: a 1969 Chevy C10 and a 1957 Chevy pickup (not an Apache, I think it was a 3100).
5529590
I’ll be honest, as far as I knew the 1-3-4-2 was the only way to do an inline 4 with reasonable engine dynamics, but I’ll admit that I am not on the engineering side. Heck, for that matter I don’t know if the Brits used to number their engines the same way we do, it is kind of arbitrary.
There are a lot of cars or engines that have a dedicated following where you can get all sorts of speed parts for them if you’ve got the budget. Pretty sure a lot of Flathead Ford stuff is still available, despite that engine being out of production for more than 60 years (I think) and not being that great a design, either . . . good for the time, but it’s got some flow limitations that can’t be overcome AFAIK. If I ever do get back into doing stuff with older cars, I’ve got a Chevy truck with an old 250 inline six and there’s aftermarket parts to improve the terrible intake and exhaust and single-barrel carb it came with. I think you can easily double the horsepower and torque on that thing with a few grand in bolt-ons.
5529619
Keep the oil changed with good Dexos and that’ll go a long way. Those engines are decently robust. Brakes and wheel bearings, not so great.
I’m skeptical, but without seeing it or hearing it it’s hard to say. Maybe any fix would be cost-prohibitive, I’ve run into that before.
Yeah, used car prices are off the chain right now, it’s crazy. And truck prices are stupidly high anyway at the moment, although if fuel costs keep creeping up they’ll probably go down.
I’ve got a 2007 Dodge Caravan as my daily, and it’s nice, roomy, and reliable. Plus they’re cheap and parts are readily available, which is one of the reasons I bought it.
5529659
Huh, I hadn’t heard about that one. Just checked the video out, curious to see what applications it might have.
From a professional standpoint, there often is a bunch of pushback. Like can they meet fuel economy and emissions standards with it? (just because it’s more efficient doesn’t mean they will). How scalable is it? The one in that video was sized for a push-lawnmower, can that tech be expanded up to a car-sized engine? Will it be reliable and repairable? Is there a reason why this tech was considered a dead end years ago? (I’m thinking of the opposed-piston engine that was proposed for light-duty trucks (and some military applications); as far as I know, Ford considered it but didn’t use it but I don’t know why.
To be fair, I never thought hybrid cars would work, I thought that there was too much technology and too much weight that would have to be crammed into such a tiny package. I figured it would work for delivery trucks and busses but not cars, and I was obviously wrong.
5530229
Yes, that’s correct. In the old days, you would have to adjust valve clearance manually every now and then to make up for wear, but now it’s done automatically.
Mind you, this is only for traditional cam-in-block designs; overhead valves use a slightly different system—they don’t have pushrods, and many of them don’t really have any hydraulic adjustment either, now that I think of it. Possibly with the reduced length from the cam to the rocker arm, you don’t need it. I know you can put shims in some engines to make up for wear, but it’s not something I’ve ever done.
5534043
That’s the Flashing Rear End Device, the little blinking light you see on the end of modern trains. It’s powered by air from the air brakes system, and there is no reasonable way a locomotive is going to be putting diesel in that system, barring some interesting and catastrophic failure.
I bet the chronic overheating and the diesel in the coolant were related, weren’t they? Probably an ungodly expensive repair.
I can’t think of a reason off the top of my head why you’d have diesel and coolant running that close, but then I don’t know much about diesels in general and certainly not the bigger ones. You would have the diesel at a higher pressure than the coolant, so if the two could mix, that’s which way it would go.
Some modern light-duty truck diesels can mix the diesel and oil when the injector seals fail. I’d have to look back at engine drawings to see where the mixing happens. We did consider that as a failure mode on this truck; one of the recommended tests was to see if there was a lot of diesel in the engine oil and if there was, just replace the engine (IIRC, with the persistent misfire, that would indicate almost certain rod or piston damage)
5538295
afaik, Mazda picked it up for some of their racing cars for its high power-to-weight ratio, then had to stop selling them in said cars because of a fundamental flaw with running Wankel-type rotaries on gasoline; like any engine with seals on a moving part, lubrication is needed. In a normal reciprocating piston engine, the lubrication is provided by oil in the crankcase. But the Wankel design doesn't have a crankcase. So the only way to get lubrication in there was to inject the oil into the gasoline, which meant a lot of it would get burnt up, leading to lots of emissions. A smaller but still significant issue with long term use was that the Wankel design demanded seals on the edges of the spinning triangle, and those seals tended to wear out more often than they did on piston engines, though they were a lot easier to replace. Wankel rotaries also ran at very high RPMs, necessitating the use of a gearbox, but that isn't really that big of a deal.
LiquidPiston modified the Wankel design so the seals were now stationary instead of rotating, which helped with wear a lot, but it is unclear exactly how much. They claim that their modified design can maintain an oil film on the seals like a piston engine without the need to inject oil into fuel, and in the case of diesel no oil is needed at all, but MPG and emissions numbers are not revealed yet. As far as I can tell, although their marketing material sometimes references use in vehicles, their primary focus appears to be in use as portable flex-fuel generators and UAVs.
The modified design retains the Wankel advantages of only having two moving parts and high power to weight ratio, with the added benefit that external injection and exhaust timing isn't needed because the intakes and exhausts are on specific sides of the piston such that the geometry performs the timing. But that in itself also means that although only one piston is needed for three power strokes per cycle, that piston is also more fragile; how much or little more fragile is not known.
5538297
Ah, thanks!
And to check my understanding there, a cam-in-block design has the camshaft lower down in the engine (in the crankcase?) and uses pushrods while an overhead valve system has the camshaft mounted higher up, but both use rocker arms rather than having the cams act directly on the valves (for maintainability reasons, I'd guess?)?
5538702
My inner skeptic says that they’re going to have problems with that, but I legit don’t know. I’m not really up on the current standards, nor what tricks can be done in the engine or after to get the numbers you want . . . a lot of the older stuff I learned has changed over the years, like most cars don’t have EGR valves any more, ‘cause you can do that with variable valve timing.
That’s probably an easier market to go for, in terms of emissions and reliability overall.
Probably on a smaller design, the strength is a wash--like lawnmower-sized engines, for example. You’re hardly operating at extremes, generally, and for that market a small, powerful package might be a real selling point. The multiple power strokes per revolution is an advantage, too, although that would have some packaging concerns, depending on application (where the spark plugs go, how you get to them to change them).
I would be interested to see what uses that engine has. If it’s cost-effective to produce, reliable, and can hit appropriate emissions numbers, they’ve got a good shot at making a lot of money with it, even if it’s not in the automotive market.
5538836
Yes, a cam-in-block has the camshaft low in the engine, under the cylinder heads (in the engine valley in a V-motor, low-down and off to the side in an inline motor). OHV, the camshafts are above the valves, on the top of the cylinder heads.
The rocker arms aren’t only for maintainability, although that is a factor, but they’re to give increased lift--the camshaft puts a short throw on the short end of them, and the other end travels further to open the valve, usually. There’s probably a lot of thought that goes into the geometry of all that, and I have no idea about any of it, since I fix broken stuff rather than design it. . . .
5542983
Ah, thanks, and that makes sense. :)
(And simply making the cams bigger instead would add mass to the (usually) rotating-at-variable-speeds shaft, which is presumably undesirable.)