Spark Plug Colors????

When I replaced plugs I noted that #1 looked normal light tan, #2 lighter tan, #3 almost white, #4 like new white.

I thought I read that running lean made the plugs look lighter. Could the above plugs indicate a manifold leak?

One more thought. Do you have the plug wires in the proper order. The N will run with the plugs wires in the wrong order but not very well (low on power) and it is usually #3 and #4 that are reversed.

hth

Mountainman...CA

It could well be that you are running lean in the #3 and #4 cyclinders. And you could have a manifold leak. Use WD -40 and squirt it around the intake for those cylinders to see if the engine speed changes or you get smoke at the exhaust.

But I still think you should do a compression check as that will determine the condition of the valves and rings as well as tell you if you have a blown head gasket which could also look like a lean mixture on the spark plugs.

The smaller dia nuts are the correct ones on the manifold and they should be brass. They are made to strip out when removed so use new ones if you take it apart.

hth

Mountainman...CA

Thanks for the reply. The engine has fewer than 200 (probably 100) hours on it. However, I be foolish to say that the compression is fine without checking it, so will do so tomorrow and report back. I also have to do a compression test on my 5.7 liter GM block in my boat... now that's a job from hel. Makes me realize how easy the 8N is to work on.

I helped a friend put a big block where a small block had been in a boat so I can relate to that job. Not much fun.

"The engine has fewer than 200 (probably 100) hours on it."

Did you retorque the head after the initial warm up? If not that could be the source of your troubles.

hth

N - joy.

Mountainman...CA

Negative on the retorque. I'll look in FO4 and get to it! Thanks.