circles on piston top's

anyone knows what cause's those circles in the center of intake valve relief of pistons?car is running really well,it's a bae 511 highhelix promod, msd 44 ignition.



http://iloapp.outlawracing.se/blog/blogg?ShowFile&image=1220133710.jpg

 

Looks pretty strange.

Are you running ground straps to the heads? Almost looks like the spark plug is arcing to the dome of the piston which can happen without proper grounding, but a perfect circle like that would be pretty amazing.

See the MSD website for grounding recommendations.

 

Did this happen , just on one cylinder?

 

no, its in 3-4 cylinders,randomly. the circle in pic is the biggest, the other one's is slightly smaller,like valve stem dia.

 

How do the plugs look from those cylinders versus the others? Are all the circles in roughly the same place (which looks to be quite far from the plug tip)? Kind of makes a person wonder if there is arcing going on between the chamber and the piston as the surfaces approach. Any indication of corresponding marks on the chamber roof, or edges of valves/seats? Anything weird about the rod bearing appearances for those cylinders? Very strange.....


PS: Please check your PM's. I see that you are in Sweden. I am about to send you a PM on an unrelated topic. Thanks.

 

Looks like something is stuck on the surface of valve, as the valve rotates so does the mark.
What sort of valve seat pressure and how close to coil bind are you fully open
P

 

they kinda look like crop circles.........aliens?

 

Man thats some weird s-it. I've been to three state fairs and five rodeo's and never seen anything like this. You are pulling our leg right! If not please post the results here and let us know what you find.

 

Ya know, this one sounds almost feasible. This damage (ring) is just too far away from the center of the plug location to cause this, yet it is circular in shape. If a faulty ground could possibly get through the valve and arc to the piston, this would make better sense. Somehow it appears to be arcing from the valve to the piston top. As the piston rotates it is making the circular pattern. I don't think that valve spring pressure of coil bind has anything to do with it. It looks exactly like an arc!
That's my story and I'm sticking to it!

 

Hey TA,
Remember your PM before the first reply

Richard Gavle

 

thats exactly what i thought but wouldnt say it ----------------( aliens was my guess ) are a very small GREMLIN

 

Do you stamp the head of the valve with the cylinder number?

This looks like the stamped number has transferred from the valve to the piston. The farther the stamp is from the center of the valve the bigger the circle is on the piston.

Chris

 

Now that you mention it...that does look like it could be most of a "6" or an "8" about a few thousand times...

 

the circles is on the exact same spot on every piston,the valves are not stamped.heads are grounded,but there has been some electrical problems so arching is possible. This car is on it's way to Santa pod right now.unarched/alienated/gremlined pistons in every hole.we'll see after this weekend if the gremlins are still there. Thank's for all replies and have a look at "eurodragster.com" this weekend to see if this spooked car wins the european pro mod championship.It's the Kendall oil sponsored black Camaro with mikael lindahl behind the wheel.

 

How well are the grounds to the cylinder heads? The picture looks about 14mm dia. rings, the plug could be going to ground and the being grounded thru the piston / cylinder bore to the block. What do the rings look like?

 

Good luck, but my support is behind the Lindberg Bros. They have a bad ass little Nova.

 

I really didn't want to go there, but, ................ Yep!!!!!!! It has to be aliens!
Nothing else even comes close to making sense!

 

Since there is a "6" written with a black marker to the left of the circle I am going to say the stamp is a "6".
Download the image and open it with your favorite image viewing software, then zoom in on the circle. It will become clear that the circle is made of a bunch of backward "6"s stamped over and over, with some carbon deposits highlighting the circle.
While the head of your valves may not currently be stamped with their cylinder number, at some point in it's life this piston was in a motor where the valves were stamped. The valves floated or the piston to valve clearance was set too tight. Not so tight that it left an imprint of the head of the valve on the piston, but just tight enough to transfer the stamp number to the piston. While the motor is running the valve is spinning around the axis of it's stem, creating a circular pattern to the stamps. You mentioned in an earlier post that some of the circles are larger than others. The farther the stamp is from the center of the valve head the larger the circle that will be stamped...
Each stamp creates small peaks and valleys on the surface of the piston. While the motor is running this area gets hotter than the surrounding surface of the piston. The extra heat causes carbon deposits to form in this area creating the dark ring.
I may be COMPLETELY wrong, but that's my theory and i'm sticking to it!
Chris

 

it sounds smart though i learn so much on ITA

 

Or maybe the antichrist(666) got in the cyl and was hiding from Frank Manzo. the god of TA/FC.