Can I re-use these Pistons??

[Talonman92]

Hello,

I bought a GSX with a broken timing belt. I want to re-build it back to stock for as little money as possible. I would like it to be reliable too. I have expirience re-using pistons with valve damage on my 1g N/T, and the thing runs like a champ. Here are some pictures of the pistons that came out of the GSX.

Piston #1

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Piston #2

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Piston #3

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Piston #4

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I cleaned them off as best I could and I put a mic on them to make sure they were standard size. As you can see in the pics, its mainly the exhaust valves that hit the hardest. I took a pnumatic (sp?) die grinder with a soft sand paper \ SoS pad combo thing on it to try and smooth off the sharp edges created at the impact sites.

I want to know if I CAN re-use them. I know its easy to just "buy new ones". I'm on a tight budget like everyone else, but my only 2 concerns are because this engine will see boost if the minor damage to these pistons will make a big difference. Also would these pistons be to far out of balance to be used. Lemme know what you guys think.

thanks,

-Curtis

 

[fourreGsixty3]

In the bottom pic, on the rim of the piston Im guessing thats where the exhaust valve hit, I wouldnt use them, since those to indented marks got to the outter rim of the pistons, if it were just the marks from the intake sure, but those gouges from the exhaust valves are a little scetchy.

Dustin

 

[i1nk83]

fourreGsixty3 if you are talking about the marks on the bottom of the piston, those are factory indentations. They are supposed to be there. I have reused my stock pistons and id say they were about the same as yours. Take a razorblade/pocketknife/small file to the damaged area. remove all the sharp edges. Dont dig into it, just trim up the bulging part. They are fine to reuse w/ minor damage and many have done it w/ no ill effects. I personally wouldnt go at it with a die grinder or something of that sort, because the piston has a ceramic coating on the top.

 

[Talonman92]

Dustin,

Could you be a little more specific as to how the indents would effect the preformance of the piston? What would happen if I put those pistons back in? If the dents warp the outter diameter of the piston i can see how that wouldn't be good. The bottom pic isn't any different than the other 3 as far as the location of the dents.

thanks,

-Curtis

 

[dieseltech]

The pics don't work for me .

 

[Talonman92]

Thanks for the info, im going to go ahead and re-use them.

 

[95talon_in_ma]

Pistons don't look horrible, but you always are taking a chance....

I definitely wouldn't reuse the wrist pins though. They probably got marred too, or even slightly put out of whack.

good luck...

 

[99gst_racer]

I personally wouldnt go at it with a die grinder or something of that sort, because the piston has a ceramic coating on the top.

OE pistons do not come ceramic coated. It is something that you can have done, but they do not come from the factory like that. And a die grinder would probably be the best thing to use. You're going to want to smooth out the divot to make sure there are no sharp jagged edges that could create potential hot spots.

 

[shaunman1979]

I reused mine they seemed to work fine. I blew a head gasket and when I took the head off I had indeed burnt one exhaust valve. It was on the same cylinder that was washing out due to the gasket. Would this have anything to do with the valve or do you think hot spot? I never did shave the sharp edges that is somthing I am deffinetly going to correct. but where the valve burnt it didnt hit that hard.

 

[Big Woo]

I will second 99GST_racer's point about wanting to remove the burrs/sharp edges to eliminate any areas that could cause potential hot spots thereby leading to pre ignition. I also generally do this with a die grinder.


Be sure to check for cracks between the top of the piston and the top ring land, as I have seen valve hits on pistons cause cracks in this area before. Additionally check the big end connecting rod diameter to ensure proper bearing crush, and check wrist pin condition by measuring rod deflection with the piston secured through the wrinst pin itself.

 

[Talonman92]

I will second 99GST_racer's point about wanting to remove the burrs/sharp edges to eliminate any areas that could cause potential hot spots thereby leading to pre ignition. I also generally do this with a die grinder.


Be sure to check for cracks between the top of the piston and the top ring land, as I have seen valve hits on pistons cause cracks in this area before. Additionally check the big end connecting rod diameter to ensure proper bearing crush, and check wrist pin condition by measuring rod deflection with the piston secured through the wrinst pin itself.

Thanks for all the info, I will touch the pistons up as good as I can and post new pics later this afternoon. I will do those inspections as Big Woo has suggested too. I will look in my haynes manual for those specs do you think they will be in there? rod bearing crush specs and the wrist pin spec? I'll take a look, thanks again.

-Curtis

 

[Talonman92]

Well here they are.

Piston #1

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Piston #2

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Piston #3

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Piston #4

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They are smooth to the touch, and I tryed to take only the worst of it off. I think they look better now, im pretty confident they will work out. Lemme know if I completely ####ed them up or if I need to take some more off. Thanks

-Curtis