Is my engine about to pop? Got a trip in 12 days, should I pull it???

[Classicfordguy]

Well the mystery knocking that my truck has been making for the last 1000 miles has gotten progressively worse in the past few weeks. The knock is loud, too loud I think to be a valve or lifter. It will go away for a few seconds every so often then come right back.

For a while when I would start it from cold it would miss on one cylinder till I revved it a bit. Now its so bad every time it comes back to idle it starts missing again on one cylinder. Every time it misses a puff of blue smoke comes out. When under moderate acceleration I can see puffs of black and blue smoke in time with one cylinder in my side mirror. I have a good bit of blowby that also seems to puff in time with one cylinder, truck only has 126k on it but was not taken care of for the first 113k before I got it.

I'm hoping to head to the 12 hours of sebring race on march 12 with some of my college friends pulling our crappy camper. Its about 110 miles each way and I think something terrible will happen if I try to make the trip.

Any thoughts on what it could be or where I should start? I think its in the driver side bank, should I start pulling the head? Or should I just pull the whole engine? If I have to I have a E350 Van/truck think in my backyard with a 6.9 in it, I can pull that engine and stick it in to make the trip.

Lemme know what you guys think, this problem is getting bad at just the wrong time making me freek out just a bit. Don't want to dissapoint my friends and tell them my ford won't make it so whatever I do I need to do it fast.

Thanks for all the help,

-Robo

 

[Diesel JD]

You need to pull it and see what's up. Its probably in the process of swallowing a valve. I say that because a bad valve problem can make a pretty bad knock and 7.3s and even some 6.9s dump valves but rarely spin bearings or throw rods. You could pull the valve covers and remove all doubt. A bad valve problem is pretty easy to see, or so the more experienced members say, I haven't yet had to diagnose one. You can get the driuvers valve cover off in a few minutes and the passenger side is a lot more work but you still need to figure out what it is. I suggest you either fix the motor, swap in the 6.9(wityh some fresh head gaskets mind you) drive something else or pull out of the event. It would not be fun to be stuck on the side of the road with a hole in the block :O

 

[suv7734]

Sounds like there is an exhaust guide that is pretty much gone. If you remove the valve cover you can check for any side to side motion by pushing the valve sideways at the tip (with the rockers loosened off).
Here's a thread with a couple of good pics. His symptoms sound about the same as yours.

 

[Classicfordguy]

I can pull the valve cover in the morning but the noise seems so heavy and loud I just would't think its a valve. I noise is louder laying under the truck near the flywheel. If the noise went away when I let out the clutch I would say it was the flywheel but it doesn't.

-Rob

 

[Shadetreemechanic]

My guess is its up top. a loose rod wouldn't cause a miss at idle as far as I know. Anyway a valve cover is eaiser to pull than an oil pan.

 

[Classicfordguy]

Well I just pulled the driver side valve cover and removed all the rockers. What should I look for? I pushed and pulled on all the valve stem/spring assemblies and could not get any of the stems to move. Should I do something else?

-Rob

 

[Diesel JD]

might mean you have to pull the passenger side one, apparently the problem is not on the drivers side

 

[icanfixall]

My thoughts are an injector is bad. If one injector stays open it causes a really bad fuel knock. Sounds like a rod knock too. Loosen each injector nut on the hard lines and see if it goes away.

 

[towcat]

What kind of trans is hooked up to the motor?
If it's an auto, a cracked flexplate would make the sounds of a rod knock. Problem is, you can't easily see the flexplate since the flywheel is blocking the view.

 

[Classicfordguy]

Trans is a 5 speed. Cracked injectors before I replaced them as well as last night, didn't do a thing. Took it to a guy who's been a ford diesel mechanic for 27 years this morning and the moment he heard it he said it was a cracked piston. So now the hoist is in front of the truck and its about to come out. We'll see what went wrong pretty soon.

-Rob

 

[icanfixall]

These pistons are over 1/2 inch thick on the tops... Actually they are .560 to .580 thick. Yes, they could crack but that means something caused it to crack like maybe hydrolocking with coolant or fuel... Maybe even rain water leaking past the hood seal at the firewall and running down on top of the air cleaner ...... It has happened before.... With a turbo it may be impossible for it to happen though. Just some thoughts. Good luck and keep us posted as to what you find. Lots of interest here.

 

[Diesel JD]

Gary's right they don't crack for no reason. Usually its glow plug tips dropping in or excessive egts...or as in Travis' case, overzealous water/methanol injection..eh. Also a dropped valve could cause it... just make sure you fix whatever caused it before a new engine or repaired current engine goes in.

 

[troy_caleb]

So what was the result?

 

[alienturtle]

 

[troy_caleb]

"" says the guy with the 6bt