I made a mistake in my posts, being a bit pissed was making me not think too well, it was number 7 and now that I looked at it more, it was also number 4 or 6(can't remember). Got the head off the one side, I know what the other side is going to look like...

Oh yeah, the piston has a crack on the top(hard to see in the picture) that is at 12 oclock and goes all the way from the bowl to the end of the piston. There seems to be no damage to the cylinder wall, Ill have a picture later. Might not be as bad of failure as I thought.

 

Yeah, if you just need a new set of pistons, should be fairly simple to get er up and running again, minus reinstalling the engine...

 

John,

I had to PotoShop it to see what I think is the crack. Is this it?

 

Sorry John, doesnt look as bad as initially thought though From the start i thought it was pretty loud to be a rod. Good luck with the repair im sure it will run twice as good and strong when you get it put back together

 

Shoots the skirt clearance explanation all to hell, doesn't it?

I still "worry" about my slapping, however, and hope it doesn't turn out like this someday.

If you get out of this with just broken aluminum, you've got to be the luckiest man in North America today!

Are you going at least .010-over, or putting back stockers?

I can offer absolutely no explanation for THIS kind of break-up. Doesn't look like they got hot, even.

Since you've got the pan off, how many pistons can you see broken up in there?

Pop

 

Yes, stock pistons, and even Mahle's are cast. You want to use a cast piston for anything except hardcore racing. Arias and a few other companies make forged pistons, however they are very expensive, wear quick, and shouldnt be daily driven as i think the rings are different, designed for racing.

 

Correct. They're not a keystone type of ring. No good for DD work.

 

You mean nobody makes a not-for-racing FORGED piston for these things?

Ewwww......

Pop

 

No, but a couple of guys are trying to get Mahle to make steel pistons

 

Steel? What the heck FOR???

I shudder to think.... but I suspect I know...

Pop

 

The ability to withstand tremendous heat and pressures, less risk of cracking. Probably would be alot harder on rods and rod bearings though, having to throw around all that extra weight.

 

You need lightweight and strong? How about titanium?

Now THOSE are gonna cost ya'!

Pop

 

I thought titanium burns easily?

IMHO the pistons should be white metal, pressed into a stainless steel sleeve.

White metal for superb heat transfer capability, and SS for longer wear time...

The white metal expands faster than SS, so once she'd warm up, any chances of cracking or losing the wrist pin are gone. The SS sleeve would also attach somehow to the wrist pins, adding strength.

 

Alot of OTR truck engines (one's ive had experience with are the 3406's), that use a two piece piston. The skirt is lightweight aluminum since it doesnt need to be heavy and strong, and the piston crown and the center that connects to the wristpin is steel, to withstand the heat and combustion forces. The rings are in the steel section, its a great idea.

 

You are thinking of magnesium.

Doesn't need to be strong? Isn't that what this thread started out as? Broken, weak, skirts?

Just razzin' ya', Kris.

Pop