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Piston issue...

DieselSlug

DieselSlug

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Hello, while cleaning the tops of the pistons off i noticed that in cylinders 5 and 8 there is a little of the piston missing. It looks as if it was burned off a little, i will try and get pics as quick as i can. Is this ok?? The worst is #8, but it only has a small piece missing....
 
Here are some pics... The cylinder wall is in excellent shape...
 

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Won't hurt a thing in a street motor, long as there are no cracks radiating from those areas - looks more like where the engine sat for long periods with a little moisture in the cylinder(s) - coulda been where a swelled glow plug flaked off - if you're gonna race this motor, you know the drill.................
 
DieselSlug said:
Im not going to race it, but i am going to use a gl4 and boost wot around 14 i hoped....
Click to expand...

Nah, a GL4 and 14psi won't hurt it. Just out of curiosity, you never changed injectors in that engine before? I'm sort of with JD - about the only things I know that make non-anodized or coated pistons flake are glowplug chunks, rust, and peeing injectors.

That being said, yeah, if the walls are clean, you should be fine unless you're planning on running big EGTs.
 
That is most likely from high EGT's, the PO or you probably didn't run a gauge and melted it. My turbo pistons in my Turbo Mini have looked like that when I've ran it too lean.
 
Thanks for the insigh guys. I was really worried i would have to break into the bottom end. I really didnt want to do that, i dont have the time or the money. The truck never gets towed with, al it does it plow, and an occasional coal rolling):h. I guess i will continue with the build, the engine only has 90k miles on it, so that is why this is puzzleing to me.... So nothing in the engine should be over the 100k mile marker. Unless somehting was failing or they were boosting the snot out of it. Im not quite sure. I have a recieot for it from a junkyard and the po saw it run and it ran well before pulled. The engine DID sit of around 2 years in a damp place tho. If that has naything to do with it. Thanks guys!!!
 
Contrary to other posters, i would be leary of using these pistons again.the first pic looks realy bad.
I seen a couple like that,with burn spots on both sides of the square cutout .They are actually melted there.1 was burned right up to the steel top ring insert.
IMO ,bad cracks in the precups might act like a torch in these spots,as they are right overhead.High EGT's and/or bad injectors prob agravate the situation.
 
Personally I would rip the pin off and swap in a couple clean good used pistons.

Just to be on the safe side.

If its a stock bore I have a few extras laying around that are available cheap.

Too much work to redo it later.

As long as there are no cracks in the piston tops of the others I would just replace the two (2) with issue.

These pistons are very durable and other than that you should be good to go.

Just keep the bearings and stuff all in order when you remove the two Rod/piston aseemblies and your set.

If the rear main is not leaing just install a new pan gasket or GOOOOP in the tube (Whichever you like) and you will not need to worry.


The issues in those two pistons may very well have come from having a bad injector in those holes.

An injector thats Peeeing a stream rather than a fine cone of mist can do severe damage to the piston crowns, especially if the thing is being pushed hard.


Now is a great time to fix it, while its out and on the stand.


MGW
 
Oh jeez... never looked at anything except the piston the first time through...

The darn thing is on a STAND - out of the truck! Heck yeah, change 'em out while you have the chance. I was thinking it was still in the truck, and I HATE changing pistons when I gotta pull the pan by jacking up the motor.

Robyn and Bison get my vote for good idea... you get my apology for not paying more attention earlier.

I still think it would be OK, but this is as good a chance as you'll get to do the job properly...
 
Missy, i may be interested in the good used piston heads. Yeah i would just need two of them, all the other six are fine. So what you are saying is replace the two bad pistons and rings? But keep all my bearings in the correct order to just put them back in? I would really like to save some money down there, this is getting bigger than i thought from the beginning. I need to finish this truck by winter or be forced in buying a winter rat. Should i hone the cylinders when re-ringing?? Im a newb when it comes to the bottom half of an engine, i have never done anything like this before....
 
Those pics are blurry as hell on my monitor, but if that first pic is showing upper ring land, then the offending pistons should be replaced - as mentioned, keep the original rod-serts with the rod for each cylinder
 
Sorry, my camera has an auto focus feature and it likes to focus on things in the backround of what im actually trying to take the picture of.....
 
DieselSlug said:
Sweet! Thnx. So are any of the bolts down there something funky? Like TTY bolt or anything?
Click to expand...

Nope, all just regular torque. You need to find a rod and piston assembly or you'll need a machine shop to swap over the pistons. If you want rods with pistons, I might have a couple stock bores to save the machine shop trip.
 
Everything is torque wrench stuff in the bottom,no TTY.
I would have a good look at the top ring on these pistons you pull out.If the ring face starts flaking,Pull them all and re ring + hone the bores.

Same goes for the brgs,if the babbit start flaking,replace them

If the rings look good,note where the gaps are and reinstall in the same spot on the replacement piston,and dont hone the bore.

Saving money is nice, but having to do it all twice is costing more in the long run.
 
Nope
The bottom end is all standard type torqed bolts.

50 lbs on the rod nuts.

Easy job to do, just pry out the snap ring, tap the wristpin out and swap the piston.

Mark the split line on the rods before removing them. mark on the side facing the outside. These are not stamped at the factory. Just mark it for the cyl it goes in. 7 or 8 or ????

The piston goes on with the Ricardo bowl facing the outside of the block.

No need to hone, just use some 400 emery paper and scuff the surface a bit and wipe out any grit. Cover the crank throw to keep crap off the crank.

Wipe the cyl out well with some solvent on a rag, dry well and oil before stuffing the piston back in.
MGW
 
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Ok sounds great, i will definately need help throughout the ordeal, i really dont know any of the "vocabulary" for the parts down there... So missy do your pistons come with rods?
 
Missy Good Wench said:
Nope
The bottom end is all standard type torqed bolts.

50 lbs on the rod nuts.

Easy job to do, just pry out the snap ring, tap the wristpin out and swap the piston.

Mark the split line on the rods before removing them. mark on the side facing the outside. These are not stamped at the factory. Just mark it for the cyl it goes in. 7 or 8 or ????


No need to hone, just use some 400 emery paper and scuff the surface a bit and wipe out any grit. Cover the crank throw to keep crap off the crank.
Click to expand...


I thought the wrist pin was a press fit, if not, good info, I'll store that away for future use.

Good catch on marking the rods, I tend to assume too much, lol.

I would NOT touch the bores with any sandpaper if reusing the rings. Just wipe down, light coating of oil and call it a day.
 
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