burnt pistons
 

What causes burnt pistons, and are there any major problems of having them? The reason I'm asking is...I pulled my motor apart to change the rings, and noticed that the pistons were burnt. They are JE 9:1 pistons and there's no way Im buying another set.

Re: burnt pistons (bQQsted hybrid)
 

Are you sure it's not just carbon on top of the pistons? Is it on all the pistons?

Re: burnt pistons (bQQsted hybrid)
 

the carbon raises the cr a bit and doesnt really hurt untill it stars blocking valves, use some HD degreaser and they will look new again

Re: burnt pistons (bQQsted hybrid)
 

Check out the SafeGuard knock controller: http://www.safeguard.20m.com

If you have time, here are some threads about burned pistons from an MR2 forum.
http://www.board.mr2faq.com/showthre...ighlight=J%26S http://www.board.mr2faq.com/showthre...ighlight=J%26S

Re: burnt pistons (John at J&S)
 

Describe what you mean. Is it black carbon deposits or does the piston top look slightly brown and burnt like?

Re: burnt pistons (DirtyLude)
 

The machine shop cleaned the pistons to the best of their abilities. I know the difference between carbon buildup and burnt pistons http://images.zeroforum.com/smile/emhammer.gif. I was worried because I know that the carbon deposits could just be cleaned off, but when a piston is burnt, there's nothing you can do (as far as I know).

Re: burnt pistons (bQQsted hybrid)
 

What causes pistons to burn is generally running too lean, possibly detonation, possibly excessively retarded ignition.

Re: burnt pistons (dbman96)
 

As long as the pistons have not warped or changed dimensions you are ok but find out why the pistons are discoloring (too lean or detonation) and FIX the problem.

Re: burnt pistons (earl)
 

if the piston is not in perfect form... i wouldnt use it... just scrap them... u can get new ones for 500

Re: burnt pistons (ek9t)
 

THIS is a burnt piston.


http://home.midsouth.rr.com/jdmcivic...ts/Melted1.jpg
http://home.midsouth.rr.com/jdmcivic...ts/Melted5.jpg


[Modified by SiR Kid, 3:19 PM 11/20/2001]

Re: burnt pistons (SiR Kid)
 

good kill!

Re: burnt pistons (SiR Kid)
 

U were running lean. U melted a part of the piston, just to make sure check Ur Injectors and make sure the fuel and air is mixing properly. Send them to RC for a good cleaning.

Re: burnt pistons (VaporTrail)
 

D A N G . http://images.zeroforum.com/smile/emsmileo.gif

Re: burnt pistons (Rob92SC)
 

That's stock LS pistons in a B16a, with stock injectors trying desperately to run 11 psi with only a 6:1 Vortech Fuel Pressurizer http://images.zeroforum.com/smile/emwink.gif

Didn't work too well.

LS pistons for the record in a B16a net a compression ratio of about 8.3:1, and they have valve clearance issues to boot. Notice the nice shiny crecent moons on the outer edge of the valve reliefs. NEVER make this mistake, PLEASE! http://images.zeroforum.com/smile/emsmile.gif


[Modified by SiR Kid, 3:44 PM 11/20/2001]