grey spark plugs

[cdwood37]

i did a plug check and the electrode and top of plug was grey? is this to rich to lean or what, the plugs are br8eg. I am running 155 mains 42 pilots and cgl needle in the middle clip.

[RATBIKE0130]

Lean or detonating

[KlotzBanshee]

The "gray" is aluminum, probably off of your pistons :baseball_pinch:

 

not good

[dajogejr]

You're at a pretty good elevation, last I remember wood.

 

What octane you running? What elevation? What about your compression and timing...where they at?

[cdwood37]

i am at 6000 feet and i am running 110 octane race gas and am at plus 7 timing. compression is at 175. I was at a 152 main and then the plugs looked lean so i went to a 155 and then it turned gray so how can that be?

Edited July 27, 2006 by cdwood37

[dajogejr]

You should be rich at that elevation...

 

Are you doing a plug chop properly?

Hate to say it...but, you might want to pull the head off. A lot of Cubs are having an issue with the nikasil starting to flake off...

 

You really need to do a plug chop for your jetting...but, gray on the plug is not a good thing...trust me.

[bansheeseat$$]

Another thing you might check is what your mixture ratio is.When I put my cub together I had so much oil in the fuel for break-in and the first time I ran the engine up for full throttle run my plugs were gray also.I drained the tank and put the proper ratio in it and had proper color in the plugs.

[cdwood37]

i am running 40:1 mixture

[dajogejr]

That's what I run. With lead in the race gas and 40:1...I know I'm good to go.

[cdwood37]

That's what I run. With lead in the race gas and 40:1...I know I'm good to go.

well what the hell then the motor only has like 5 hours on it i barely got it dialed in.

[dajogejr]

Head over to PlanetSand (I've seen you on there) and search for cubs, plating, issues, etc.

 

There are quite a few of them on there, including the post you had with it leaking coolant into the cylinders, if I remember correctly.

 

I'm not bashing the cubs. I finally got mine running this past weekend. Cost me a bit more than I anticipated...but I'm very happy with it.

 

But...the more I've read, there are problems popping up here and there. The problems are not with the cylinders themselves...rather the nikasil plating and sandblast finishing from Millenium.

 

badassbanshee479 has been having issues with his lately, he put it on alky...and the nikasil is starting to flake off he said....

 

I hate to be a downer, and it could be nothing...but, for the cost of a head gasket or Orings and some coolant, I'd be checking...that's for sure...