So my trained machinist eye did catch that piston crack Yes a shop will know, but 99% of the time 7.3's are good to go on STD bore. Unless you have 300k or better. A shade tree way (not a tool by any means) but run your fingernail up the bore if you can feel a piston/ring ridge you have wear. If it catches your nail dead you have a hole you most likely have to bore. Guys like me can almost tell by the feel now. These blocks/engines shoot oil on the bore/piston not to mention your injecting oil on the topside. Makes for a long lasting engine. The heat generated on the crown is the real killer, as you can see on your pistons. That is why pyro gauges are THE real thing to have. And the other reason I have not went after more power. It is also my theory that as these engines get bored out you get coolant closer to the pistons. Sort of like the injector cup theory of cooling. Thus the piston temps will be cooler and allow for more power. So if you do end up going over bore It is my recommendation go for the .030 right away.


I could be wrong but I think those are factory pistons and also may be corrected they were made in Mexico. I know 100% the replacement parts for International are. My research has shown the Hyper pistons with the Silicone is supposed to work well in the vibration high stress Diesel environment. I know they would be Less weight. I know forged pistons would be strong but also heavier and need a touch more piston to wall as they expand more. And on those below zero nights want to to make some noise and would not take kindly to be driven off without proper warm up. IE they would side load and not hold the rings as well causing the most wear at those times. I think if I had to choose I would go with the hyper pistons. And I know I could go into a LONG LONG engine build recipe of what I would do but it is your engine. But I am here for any questions you may have for the asking.

 

I finally got the motor out the other day! I have began the tear down. That thing is one heavy sob! 6 of the 8 pistons have cracks around the lip

 

Like to see the cracks better if possible?

 

I'll take some pics of them this evening

 

Here's the driver side

 

That is not uncommon for 7.3's.

We often mill that lip off new pistons to mitigate that problem.

Some have said hard use on a cold engine can lead to this.

 

I'm having them mill off the lip when I order them. Now I gotta get some one to see if it needs to be bored. The cylinder walls feel smooth to me but I've never done this so what do I know lol what prep did you do when painting? Scuff it up with a scotch pad or sand paper?

 

What Jason said but still not good. Any way if you could go 10 over I personally would do that. But if you have no ridge you could hone it and re-ring it. Just check the ring gaps before install. I come mostly from the gas engine of the pass for rebuilding, so on diesels I'm a little new when it comes to that, had to say that. If you plan to keep this for a long time I would go over as close to stock size as possible. That's me.

 

I know people who would slap a set of (stock size) pistons in that engine and run it if there was no cylinder wall damage.

As far as prep for paint, the biggest enemy is oil contamination. I prefer to remove as much oil/grease as possible with p-washer before taking the engine apart. After disassembly, I use a little steam cleaner to get into the tight corners and places I couldn't get with zero-degree tip on p-washer. Brake cleaner and other solvents are the last thing I wipe it down with before paint. The 'white glove test' is appropriate here. I will use sandpaper to scuff up and feather out old paint.

Plain 'ole enamel is fine for blocks, oil pans, VC's, etc. I've been using the rustoleum 2x products lately. VHT 2000* 'header paint' works pretty good on exhaust manifolds, up-pipes and the exhaust side of the heads.

Good luck and keep us posted on your progress!!

(remember, we all like PICTURES! )

 

I found the knocking noise..

 

I'd tend to agree . . .

 

Only a 148K miles? Do you know the history of the truck? Was it running "toonz?"

 

HOLY ***** that skirt is gone. Man I am surprised that was not making more noise. Well as far as bore goes 2 thoughts. You can hone by hand with a hone or glaze breaker. And like I said above use that finger nail. See what ya have to start with. It is all about how long you want this to last as well. I think you went this far and your buying pistons anyway why not spend 200 and bore it the pistons are the same price. But thats me. Although I saw nothing in the pics so far that I could see any ridge at all or scoring in the walls. It all looked really good. Honestly these 7.3 's are seriously gentle on the walls for wear compared to a Gasser. I have seen 50k FE engines with more wear than a 200K 7.3 in the holes. If that tells you something. Most of the time damage is from exactly what you had. Piston breaks a skirt and wears the wall. Then it has to be bored but i think you cought yours in time.

Just looking at your pics #4 looked like the worst but Hard to see from those shots. Look for vertical grooves on the one with the broken skirt. Looked like #8 had a vertical line in it. That would make a bore mandatory.

 

Nadar- the guy before me had a ts chip on it. A month later all gp's went out found out he didn't even know where the heater cord was. I have also had to replace the Trans. I'm assuming he wasn't nice to the truck. My mistake buying it but I have learned so much from it although my wallet doesn't like it.

Hotrodfeguy- yeah I was in shock at how much of the piston is gone with hardly any damage. I am going to take it to a machine shop and get their opinion. I want this truck to last awhile because I have don't so much to it. What causes the skirt to break off like that? Running he **** outta it?

 

A blown skirt like that on a 7.3 with stock pistons I would guess was a chip/power mods. Lots of heat up top. gives for a thermal imbalance between a hotter than hell crown and a cold skirt thats getting a oil bath. Normally you see a ring or cracking down the side, maybe even a piston pin area. I have never seen a fail like that. New one by me bro. I have seen small fails on the skirt but nothing as major as that. That was a epic fail!

Like I said your buying pistons anyways may as well bore it. Pistons are going to cost the same.