Burned Piston

[DarthBuick]

I got around to checking all my pistons. keep in mind this engine didn't smoke. I disassembled it to fix oil leaks and paint and detail engine compartment. I haven''t driven it too much since I purchased it. This is the number three piston. You can see the factory steel insert at top piston ring. That insert saved the piston from blowing apart. Was this caused by detonation?

 

[earlbrown]

Holy crap. That is one melted stocker!

I used to detonate the everyloving shit out of my engine for almost a year over a stupid wastegate hose at around 200,000 miles....

50,000 miles later after I got it back from the car thieves blown up from lack of water and oil pressure...

My pistons still looked fine up top! Somehow you were laying some serious heat into the crown.

 

[turbofrank]

Did u remove the ridge ĺots of scratches on sides ?

 

[delcowizzid]

thats gone past detonation and preignited by the looks

 

[DarthBuick]

I can';t believe it was running as good as it was. Would a forged piston have held together better. The steel insert saved this one from exploding. It had solid copper head gaskets and o-rings so if it could have blown a head gasket it might have saved it I think the nitrous switch in the car was used before.

 

[DarthBuick]

Did u remove the ridge ĺots of scratches on sides ?

I have not done anything but pull off the rings

 

[dynoman]

Do the other 5 pistons look OK ? If so I would check for a partially clogged or poor connection on injector #3 causing it to go lean .

 

[turbo89]

I can';t believe it was running as good as it was. Would a forged piston have held together better. The steel insert saved this one from exploding. It had solid copper head gaskets and o-rings so if it could have blown a head gasket it might have saved it I think the nitrous switch in the car was used before.

And that's why the piston looks like it does ... you can detonate a stocker @ 13psi and will live until it pops a headgasket .... try that on a motor with all the power adders running more power ... and the room for error diminishes quickly.. seal up the headgaskets tight as a drum and the results are easy to see

 

[DarthBuick]

Do the other 5 pistons look OK ? If so I would check for a partially clogged or poor connection on injector #3 causing it to go lean .

Whhere is a good place to test injectors and flow match them? The other pistons look fine. I guess I am going to have to buy a new set of pistons for sure now. The block is at machine shop to see if he could hone out a rust stain on #6 cylinder. I can see where it melted and the top has a ripple in it. I bet this thing was glowing like hot lava.

 

[earlbrown]

Now that makes more sense..... Throwing a shot of NAAAWWWWWSSS on there that's not running perfect can cause bad bad thing to pistons.

Forged alum might have fared out better, but it till would have taken as ass whipping.


You mentioned seeing if your shop can hone out a stain? Do you know what your current bore is?

 

[DarthBuick]

Now that makes more sense..... Throwing a shot of NAAAWWWWWSSS on there that's not running perfect can cause bad bad thing to pistons.

Forged alum might have fared out better, but it till would have taken as ass whipping.


You mentioned seeing if your shop can hone out a stain? Do you know what your current bore is?

The bore is still standard. it looks like the previous owner had moisture in cylinder and it had surface rust. You can see the place where it was but can't feel it. The machinist told me if it was his he would run it like that because he has seen many rust stains that were worse than that run fine and not burn oil. Since I cant buy a stock piston I may have to bore it and get new pistons.

 

[dynoman]

Post your car info in your signature , it will help us help you . Stock injectors ? Do you have a Scan Master or Power Logger ? If injectors are stock , maybe now is a good time to upgrade rather than cleaning .

 

[turbo89]

The bore is still standard. it looks like the previous owner had moisture in cylinder and it had surface rust. You can see the place where it was but can't feel it. The machinist told me if it was his he would run it like that because he has seen many rust stains that were worse than that run fine and not burn oil. Since I cant buy a stock piston I may have to bore it and get new pistons.

you can get stock pistons .. if you need one let me know.. if they do a light hone you maybe able to get by .. also if you coat the stock piston you can make it work ...

I cant tell from the pic how bad it is .. but I wouldn't be quick to bore it out

 

[DarthBuick]

you can get stock pistons .. if you need one let me know.. if they do a light hone you maybe able to get by .. also if you coat the stock piston you can make it work ...

I cant tell from the pic how bad it is .. but I wouldn't be quick to bore it out

If you have a stocker that would be great. Who coats the pistons? Thanks

 

[turbo89]

If you have a stocker that would be great. Who coats the pistons? Thanks

lots of places coat pistons .. Swain coats them and they do a good job ... if you need one let me know I have some nice low mile pistons 17K mile GN

 

[earlbrown]

I can make you a set of forged pistons in one or two over (or any more from 2.500 to 5.500 for that matter) if you want to upgrade while you've got it apart.

 

[DarthBuick]

I can make you a set of forged pistons in one or two over (or any more from 2.500 to 5.500 for that matter) if you want to upgrade while you've got it apart.

I appreciate that but custom pistons are probably out of my price range for now. This engine was supposed to be good with only problem was supposed to be a oil leak. He was supposed to have block checked and finished last week but he caught the flu.

 

[earlbrown]

Right now they're $450 a set for pistons, pins, and locks. Since I can make them any OD you need, you won't have to pay for a bore job to do it right.

 

[DarthBuick]

Right now they're $450 a set for pistons, pins, and locks. Since I can make them any OD you need, you won't have to pay for a bore job to do it right.

That is not a bad price for custom pistons. I wish I had more options for machine shops around here. he does good work but he doesn't have the Buick V6 hone torque plate. What type of pistons are they. I am guessing floating pins since you mentioned locks.

 

[earlbrown]

Yeah, they're floating if you want. They can also be pressed fit if you want to use stock rods and don't want to float them. They're forged 4000 series with either a 1/16" or 1.5mm ring pack. 22cc inverted dome that's deigned to get the job done with around 2* less timing. I'm kinda proud of them.

The torque plate helps. Based on my experience the Buick V6 block does squirm when you put a plate on it. I've been thinking about trying to tool up and do a production run on the if I can get the price down enough for the average guy.