Hi gents...just looking for some thoughts on these plugs...brand new upon breakin ...rebuilt 455...has maybe an hour run time...was doing fine every start after break in...then just wouldn't idle once warm???compression test all around 145 150...noticed this on 6 of the plugs...is this steam cleaning(bad head gasket) or they haven't burned enogh...

 

Well...guess I know when to seek another site bye bye!!!!

 

Hang in there Crankit. I wanted to post a reply yesterday but honestly its a little hard to tell what's going on there.

Your symptoms and visual cues don't easily match the spark plug issue chart. That's why I held back hoping somebody more knowledgeable to your concerns would post. The right person may not have seen your post yet... Everyone doesn't open every post ...

 

I was thinking the same thing when I saw your post yesterday. What ignition do you have on your Oldsmobile?