Carbon on Pistions

[Rugby]

I have been looking trying to find out what is to much carbon on top of the piston to cause detionation knock?
I have looked at mine with a bore scope and noticed that there is carbon on top of the pistons the is rough looking. I have proud seafoam in the spark plug holes and let if sit and try to remove it.

I just wanted to see if any body has any pics of what would be considered to much build up.

Brandon

 

[earlbrown]

My experience with a borescope is that stuff in the combustion chamber looks much worse than it does in real life.


As far as what is 'too much', that's impossible to say. Back in the old days if you had a high compression carbe'd V8 with carbon.... and fuels got de-nutted, you might have ping that was blamed on the carbon.


Depending on your setup, you might have to lower the boost level to work around some carbon contamination. I can't imagine there's enough in there to raise your static compression to 10.5:1, so if carbon is causing an issue it'd be due to having little glow plugs all over the place.



Sounds like a good time to get one of Razor's alky kits and steam clean the internals

 

[Rugby]

The scope I used will take pics. I will pull them off and post them tonight. I have been reading about carbon causing issues but have not seen any pics where somebody pulled the heads off and found excessive build up.

 

[earlbrown]

I've never heard about a TR being crudded up like a junkyard engine. It would have to burn oil for a long time for that to happen, and with catalytic converters, and 02 codes, and smoking and whatnot... I just can't imagine it's possible to drive one enough to make it happen.


When my machine shop first got a borescope, we used to scope engines before we'd tear them down. The idea was to try and 'calibrate' ourselves to what we seen .vs what was actually there. Turns out, we really couldn't so the borescope rarely comes out of the box. It's just not accurate enough for us. Turning on the light made things even worse... that goofy little mirror threw accuracy right out the window too! lol

 

[Rugby]

This just came to about my pos. I pulled the intake shortly after I bought my car and the egr passage was completely block. I did this about a year ago.

Brandon

 

[earlbrown]

Yeah, that's pretty common. The tower in the intake can fill all the way to the top with carbon.


..and if you pull the upper plenum and chip it out with a screwdriver, it'll blow carbon flakes all over your buddies yard and driveway.



Now if you have a clogged EGR and a chip that still calls for EGR, that can cause part throttle knock. (and you need to toss that chip for a new one)

 

[Rugby]

Awsome. I am not going to worrie about it.

I have a turbo tweak chip with the egr turned off.

Brandon