Originally posted by Jonathan
Another question... I have a RB C5 .21 engine w/ a little more than a gallon thru it. It ran flawlessly until I switch glow plugs I was using a RB #6 but switched to Nova 6 (C6Tf) after I ran out of the RB's. After one tank... the nova plug popped... I richened the top slightly and subsquently popped 2 more plugs... Last nite I took it apart to check for wear... the rod pin on the crank's counter weight is out of round by .01mm and there is .02mm of play between the rod bushing and the crank pin. I am planning changing out the rod.... but I don't wont to change the crank unless I have to ... are these measurements within tolerances??Furthermore... the piston and the button looks slightly sandblasted... what effect would this have on the engine and should these be polished out.? Lesson for everyone else... not all # 6 plugs are the same...
Thanks in advance...
When you say the plugs popped,do you mean the filament has distorted?
If you were using a standard 6 and then went to a 6tf then they definitely aren't the same the 6tf is a colder plug assuming RB and nova plugs are the same which i think they are.Although colder wouldn't cause it,check the nova site which has a plug list and also what conditions they say to use them under.
As for the crank this is the measurements Rody gives;
The big-end new measures 5.02mm and if you go under 5.00 we suggest you change the crankshaft.
If you have signs of sandbalsting also then you could be having pre detonation maybe you need to add an extra head shim but it depends on what % nitro you are running and your plug etc.