Finally Got Head off for rebuild found a hope crusher

[GSTurbo1]

First of all, sorry for posting this in 4g63... figured it wouldn't matter either way. Ok guys, so here is the story for you who don't know. Bought this boosted 420a about 3 months ago... found out it was drinking water and overheating. So I finally decided to do a head gasket replace (cometic mls), because I had all of the symptoms, white smoke out tail pipe, milk shake in coolant fill. After about a week and a half of dismantling everything I finally get the head off and I find this.

You can also see the beadlets of coolant on the piston head.

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Piston #1 and 4 are chipped, car was running before I parked for the rebuild. Should I just go ahead and pull the entire block and replace these too? I really don't have the money to buy an entire kit... I would rather just buy the two pistons since number 2 and 3 are still ok.

Could I just pull all of them and re-ring them? my compression was 150 psi with these chips.

Here is why I'm still getting 150 psi, all that happened was the top of piston head chipped away a little. If you look straight down you can see the rings contacting the cylinder wall, still making a good seal. I wonder how long it has been like this

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It just really makes me nervous having a piston look like that.... honestly as soon as I saw that I wanted to cry, then I wanted to put it back together, sell it and let someone else deal with it.... but i'm not that guy. Had to cool off a bit and get a clear head

 

[dsmcrzy]

Any scratches on the cylinder walls? Do you plan on getting you head check for straightness? Or just replacing the HG?

I wonder what did that to the pistons.

 

[WES_393]

Those don't look chipped, they look melted. Most likely from either running lean, detonating, or both. That would explain the headgasket damage as well.

I would pull the pistons and see how much damage was done to the ringlands/cylinders. I definitely wouldn't run those two pistons again, but your best bet would be new pistons and the cylinders at least honed. It wouldnt be a bad idea to replace the bearings while your at it.

 

[GSTurbo1]

I'm going to def take the head to someone I just am so worried about those pistons.... Has anyone ever driven on anything like this? I bet it happens more often then not and people don't know. I'm about to go turn the crank shaft a couple of times and look for scratches.

 

[dsmcrzy]

Those don't look chipped, they look melted. Most likely from either running lean, detonating, or both. That would explain the headgasket damage as well.

I would pull the pistons and see how much damage was done to the ringlands/cylinders. I definitely wouldn't run those two pistons again, but your best bet would be new pistons and the cylinders at least honed. It wouldnt be a bad idea to replace the bearings while your at it.

I was thinking this but have never seen results from that but I agree with it.

 

[WES_393]

There is a very good chance that the ringlands look like this. I'd just pull them.

 

[mattasi]

The pictue is scary looking . Anyways the chip on your piston looks bigger than that picture, that is amazing you have 150psi on the compression test.

 

[born2tune]

Any scratches on the cylinder walls? Do you plan on getting you head check for straightness? Or just replacing the HG?

I wonder what did that to the pistons.

Air in the chamber may compress, Liquid cannot(i.e. water or coolant), therefore when the piston reaches its compression cycle and non-combustible liquid remains present in the chamber, the weakest point will give under the strenuous force i.e. cast aluminum pistons.

 

[BoostedPhoenix]

Things got fairly warm here didn't they ? What do the bores look like when 1&4 are at the bottom ?

What brand pistons are these ?

 

[dsmcrzy]

Air in the chamber may compress, Liquid cannot(i.e. water or coolant), therefore when the piston reaches its compression cycle and non-combustible liquid remains present in the chamber, the weakest point will give under the strenuous force i.e. cast aluminum pistons.

JEs are forged aluminum and they will have different material properties than cast. But i see where you are comming from and OP was having coolant in the chambers and the area it cracked is the thinnest part on the dome.

 

[GSTurbo1]

Yea w/ no water running through the head/block... things got mighty hot.

 

[BoostedPhoenix]

I'm gonna go out on a limb here and say that when you pull those pistons, that you will see some fresh scuffing on the sides, and that you will probably want to measure all 4 of the bores for out of round at this point.

 

[Bud92gsx]

This thread is epic win...Tell your girl you need to replace the pistons.And get that bitching out of the way..And UPGRADE..

I told mine I blew 3 vale seals.I got to buy another head..That was epic win too.

 

[GSTurbo1]

This thread is epic win...Tell your girl you need to replace the pistons.And get that bitching out of the way..And UPGRADE..

I told mine I blew 3 vale seals.I got to buy another head..That was epic win too.

Ha ha ha!!!! You da man!

Here is why I'm still getting 150 psi, all that happened was the top of piston head chipped away a little. If you look straight down you can see the rings contacting the cylinder wall, still making a good seal. I wonder how long it has been like this

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[Josh97eclipse]

Most likely gonna need new pistons. Id buy some new je's new bearings, rings and gaskets and start fresh with a new motor. The rods you got are fine.

 

[bryanwheat]

Ha ha ha!!!! You da man!

Here is why I'm still getting 150 psi, all that happened was the top of piston head chipped away a little. If you look straight down you can see the rings contacting the cylinder wall, still making a good seal. I wonder how long it has been like this

They did a little more than chipped away. It is clear that you were running lean and the pistons are melted. Pull them out and inspect them.

 

[GSTurbo1]

They did a little more than chipped away. It is clear that you were running lean and the pistons are melted. Pull them out and inspect them.

I never ran lean... if anything it was someone before me, i'f anything I ran on the rich side.

I wonder if JE would just sell me two pisonst to match other two good ones

well I just searched JE and found 2 pistons for $300. If I replace these two pistons, i'm going to do new piston rings and bearings.

 

[Josh97eclipse]

i would spend the extra 200 and get all new 4. whose to say you get the other 2 in and then the next 2 melt.

 

[white92talontsi]

That engine was ran excessively lean and was detonating excessively. That's is also what killed your head gasket.

You might as well pull the engine and get ready to spend some money