[quote=Kwikkordead;5997573]Is this truck modified in any way with a tuner or is it still all stock? Burned pistons are the direct result of too high EGT.quote]

It does have a chip of some sort in it. I bought the truck used not quite a year ago so not sure just how it is chipped. I also really don't know the history of the use on the truck, but I do know it has been used hard. The guy I bought it from hauled 13 ton loads of hay with it from Montana to Wyoming, he said he bought it from a rancher who hauled cattle with it. I have hauled some 9 ton loads but usually stick around 7 ton, all on Gooseneck trailers of course. The Exhaust temp have never been above 1200 since I have owned it but who knows what happened earlier, 223k miles on it.

I bought it right knowing it was tired so I'm not real suprised that this has happened. I have another PSD 7.3 engine to canablize.

Farmdad;
Thanks for the tip on pulling the engine, raise the cab, that sounds like a lot of work. This is the first time I have been this far into a Ford. I was thinking I could get by with just removing the radator core support, coolers, grill etc. Guess I better get a book and look at the instructions.
Thanks a lot, anymore tips would be appreicated
Ken Gardner

 

Sounds like a cooling jet fell off that cyl. I know you just changed the oil, but if you drain the oil and stick a bent wire in the pan you might be able to detect the jet sitting there.

 

Ken, I agree that it sounds like a lot of work but after I got over the shock of seeing the cab in the air and the tech working easily on the engine, I started asking questions and was told "this is a lot easier". 'Course, they had all the nice tools and lifts to do the work. I never did see what all they had to disconnect to do the job but they said that the trucks are designed to be done this way.

I agree that it should be able to be done the "old fashioned" way like you said, but I don't know for sure. Sometimes even "real men" have to read the instructions.

 

Any good online "Parts Houses" for these engines?
Ken Gardner

 

Powerstrokeshop.com - PSD and Ford Superduty Parts

 

Here's a "triple whammy effect" theory as to why cylinder #8 might be the most vulnerable to burnout.

1) Cylinder #'s 1, 2, 7, & 8 receive less air flow during their intake strokes than do cylinder #'s 3, 4, 5, & 6 due to the taper in the intake plenums. I've drawn this conclusion from my engine model, and from several reports on "dusted engines" which clearly showed that most of the dusting damage occurred in the center 4 cylinders. BTW, your #2 which shows some damage is also one of the outer 4 that receives less air flow!

2) Cylinder #'s 8 & 6 are in the process of filling at the same time, i.e., during the same 1/2 crankshaft revolution, and they both fill from the same intake plenum, and that means that #8 gets even less air flow than do the other outside cylinders.

3) Cylinder #8 has the injector with the fuel cackle issue, and it seems to me that this "water hammer" effect that causes the knocking noise from the #8 injector might mean that the ICP and therefore the fuel rate is a little higher for #8.

Combining the least amount of air flow with perhaps the most fuel would certainly make #8 the most problem prone! I'd sure like someone to start a pole (which I don't know how to do) and see if #8 has caused significantly more issues than a random sampling of 1/8 would suggest if all cylinders failed equally.

 

Not to disagree with your technical logic ernest, however it's probably just a cooling jet that fell out, piston ran hot from the bottom up, only cooling of the piston was just the relatively cool intake charge, and over time that piston became red hot and eventually like a cutting torch, the compressed oxygen poked a hole in the thinnest spot of the piston, right at the edge of the bowl.

 

Pull'n her out to work on it isn't to bad of a job unless you've got a shop with all the fancy tools to lift the cab thats about the only way to do it. Get couple of buddies to help makes it much easier . You will need a pretty stout hoist and as you pull it out you will have to rotate it .

 

The driver side is notoriously the hottest across the board on the 7.3. I have proven this out with my IR thermometer as have others, so this is pretty much fact as far as I am concerned.

It is also compounded by the fact that the rear most cylinder manifold tubes are the hottest. So the #8 starts out as a potential problem, and only gets worse with the firing order and what Gene spoke of with how the intake plenum lends itself to poor air flow to the outer cylinders. The front cylinders are only saved by the fact the exhaust goes back on the manifolds and carries that heat there.

 

Regarding whammy #2, cylinder #'s 7 & 3 are also in the process of filling at the same time, i.e., during the same 1/2 crankshaft revolution, from the same plenum, BUT, they fill from OPPOSITE ends of the same intake plenum (passenger side), whereas cylinder #'s 8 & 6 fill at the same time from the SAME end of the intake plenum (drivers side), and that means that #8 gets less air flow than do any of the other 8 cylinders!

 

I swaped engines on my 99.5 F350 cc last year. Part of the front end clip comes apart from the bumper up giving you clearance to remove the engine. Remove everything from the top of the engnie (Y pipe, Turbo, ect.) I used a picker I bought from checker auto. This engine weighs around 1100 lbs. so be careful with the houst and dont extend the houst arm out to the end or it will topel over. Over all it wasnt to bad to remove and install. Good luck

 

I spent 6 hrs hanging around the CAT shop in Vegas as they repeatedly flushed my cooling system so I could switch to the CAT ELC which isn't compatible with the standard cheap crap that Freightliner installs at the factory. Point is that I got to watch 2 engine tear downs that turned out to have cooling jet issues. Both engines had been rebuilt by a general diesel mech, not by CAT, and both had a single cooling jet that had apparently been "dinged" during the assembly process, one was cocked sideways and the other was partially closed. In both engines, the related piston was sized in the bore and had to be removed with a mallet. I left with the impression that cooling jet issues typically cause the piston to heat up and seize in the bore, whereas over fueling and lack of air causes burn through from the top side.

 

I saw quite a few of the cummins and detroits that lost piston cooling just seize as you describe
the older cummins didn't have piston squirters and if turned up too high would sieze

 

Thanks for all the good info. Should have the engine out of the truck today.
Ken Gardner

 

Ken, let us know how it goes. Got pictures? Do a write-up for future reference.