So the tuner says he was about to do ethanol map
He just finished setting the gsc s2 cams and findanza gears. He set cams at -1/+1.

He says the car kept burning the number 4 cylinder plug.. when they tested compression number 4 shows no compression. .

What do you guys suspect

 

I would guess maybe timing is wrong and/or they bent the valves.

 

This is only on the number 4 cylinder. . Rest are all fine

 

A piece of burnt plug probably bent or broke a valve.

 

How does it happen on 1 cylinder after tuning

 

burnt ring land

 

This isn't a Subaru

 

so what you are saying is that evo pistons don't have ring lands?

 

I still fail to understand how does it happen on 1 cylinder

 

Check the valve springs

 

Ok well tha head is off and seems 1 exhaust valve is burnt.. all other cylinders are fine.

Any idea what caused this?

 

I had a bad valve seal that kept leaking into the cylinder causing higher exhaust temperatures and melted the ring "land" in piston #2 seizing the ring. I ran like that for months not knowing as the car ran great....figure that one out!!!

 

Well it seems the spark plug that broke mades scratches in cylinder wall