Holy missing piston batman

[moosetang408w]

So I finally decided to see what the hell mess was in my engine. Pulled everything out and pulled off the heads. Found a couple problems. Cylinder six blew a head gasket and cylinder four had a broken piston. The cylinder with that had the broken piston has markings but the head is salvageable; however it appears part of the piston made it up the intake and over to cylinder one. Everything looks salvage able though besides the pistons. So I am relieved right now.

Anyway here a a couple pics of the tear down.

The car was wonderfully simple to remove the engine

Pulled the engine out

The majority looked like they where very happy.

Except this one

Also the flywheel had some marking that look like cracks. I have to talk to someone about this. I don't know if this is not good or bad.

 

[COBRA90GT]

Someone lightened up that one piston without telling you.

 

[Bullitt95]

The broken ring land with pitting of piston crowns/combustion chamber and blown head gasket are sure signs that the engine was detonating. You might want to look into why this happened as you rebuild the engine and correct it so that you don't get a recurrence.

 

[moosetang408w]

I thought detonation but all the pistons look great with no detonation pitting. I will have some investigating to do for sure about why this happened. I was only at 6000 km on this engine.

 

[BlackVert]

you are naturally aspirated, right? what is your compression ratio? and who made the pistons?

 

[moosetang408w]

My compression ratio was 10.9:1, I was running 94 octane fuel, and the pistons are probe.

 

[BlackVert]

Probe ... Mark O'Neal ... he's often over on the forums at hardcore50.com if you want to contact him. From the looks of it, and lurking over there over the years, my bet is he would say that looks like a result of a tuning issue.

 

[moosetang408w]

I am starting to think it was from two weeks before I stopped driving the car. I used a bit more fuel than I had thought and ran out of gas pulling into a gas station. I heard it dying so I killed it but it didn't sound good. Once I filled it ran fine. I have a feeling what I felt was detonation from barely any fuel going in. I paid 800 dollars for my tune I would be very pissed off if it was my tune that killed it. I hope it was just my stupidity of running out of gas.

 

[1slow95]

Same thing happened to one of my Probe pistons. I'm pretty sure mine was caused by my tune because I had it way lean due to a faulty wideband. I got that fixed, then it broke a few weeks later when I missed a shift and held it on the 6800 rpm rev limiter for a second or two. That was on my 8 or 9th pass of the day at the drag strip.

 

[moosetang408w]

Same thing happened to one of my Probe pistons. I'm pretty sure mine was caused by my tune because I had it way lean due to a faulty wideband. I got that fixed, then it broke a few weeks later when I missed a shift and held it on the 6800 rpm rev limiter for a second or two. That was on my 8 or 9th pass of the day at the drag strip.

Why would 6800 rpm cause that? Are you running a hydraulic roller in your 418?

 

[Rick 91GT]

Typically when I see pistons burn out or break there it is due to severe heat or detonation. That area with the relief so close to the edge is where they burn out/melt first.

Once you get it apart, look on the underside of the piston above the wristpin, you may see some signs of detontation there, heat/blueing, at times the pitting is not on the top.

I know down here in PA they have swapped over to the "winterized" gas which has a lot more oxygen content in it, it greatly effects the tune on pump gas. We torched a head gasket once year fresh off the dyno with a real safe tune, stopped at the gas station on the way to to track and filled it up...first pass, lean and pop. Pulled the crown up on the pistons, Id pull all the pistons (which I assume you are going to do anyway) and inspect the lands, you may find further damage.

I use a lot of Probes, and that is typically where they break once you get greedy. Mark is a great guy, stand up and honest. He would look a the pistons for you if you have questions. I have some of the Probe 408 pistons burning a hole on my shelf I can make you a good deal on if I have the correct PT#.

If I can help anymore let me know


BTW, severe heat in the flywheel, if the crack is not that deep you can turn/surface them out.

 

[revhead347]

That seriously sucks dude. I hate it when a huge investment like that goes sour so quickly. It's like taking the hottest girl at the party home, and then having a premature moment it in your pants.

Kurt

 

[moosetang408w]

Typically when I see pistons burn out or break there it is due to severe heat or detonation. That area with the relief so close to the edge is where they burn out/melt first.

Once you get it apart, look on the underside of the piston above the wristpin, you may see some signs of detontation there, heat/blueing, at times the pitting is not on the top.

I know down here in PA they have swapped over to the "winterized" gas which has a lot more oxygen content in it, it greatly effects the tune on pump gas. We torched a head gasket once year fresh off the dyno with a real safe tune, stopped at the gas station on the way to to track and filled it up...first pass, lean and pop. Pulled the crown up on the pistons, Id pull all the pistons (which I assume you are going to do anyway) and inspect the lands, you may find further damage.

I use a lot of Probes, and that is typically where they break once you get greedy. Mark is a great guy, stand up and honest. He would look a the pistons for you if you have questions. I have some of the Probe 408 pistons burning a hole on my shelf I can make you a good deal on if I have the correct PT#.

If I can help anymore let me know


BTW, severe heat in the flywheel, if the crack is not that deep you can turn/surface them out.

I travel for work so I haven't been home to tear the engine down. I will be going through this engine throughly. I also need to replace at least two pistons. The one in the pic and then cylinder 1 had a part of the ring land jump over and put three good pops into that pistons. Thanks for the info. I will update this thread once I have it torn down completely next week. Cheers