I Found My Problem!

[Doug Meldrum]

I have had this sporadic problem for months and I took the car to the car wash to get the bugs off after the Idaho trip last week and had a little extra time on the wash so I took the wand to the engine. I was very careful not to hit the critical places but upon leaving the car wash, the problem came back, with a vengence. I replaced all my plugs and found the problem. Can water from a rainstorm (a real wet one) cause the ceramic on a plug to crack like this?
Plugs replaced, problem gone!

[ROADRACER83]

Doug:

Water on hot plugs should not make them break. I'm not sure which plugs you've got there, but if you have several broken plugs, my guess is they broke when you installed them. The cracks wouldn't show up until they got wet and then the plug would short out through the crack in the insulator.

Make sure you use an actual plug socket to install the plugs. A plug socket has a rubber insert to center the plug and cushion the insulator from being pushed from the side by the socket. It is easy to break an insulator.

Ron

[Wade Chamberlain]

Doug - is that an actual picture of your plug, or a representative cracked one? If it's yours, and you're still running the Performer heads mentioned in your graduation thread, they're the wrong plugs. You need a long reach, gasket seat plug. That's a short taper seat. Should run better too...getting the spark down in the chamber!

I'd recommend Autolite 3925 (stock heat range), or 3924 (one step colder) if you're beating on it.

[Doug Meldrum]

Originally Posted by Wade Chamberlain

Doug - is that an actual picture of your plug, or a representative cracked one? If it's yours, and you're still running the Performer heads mentioned in your graduation thread, they're the wrong plugs. You need a long reach, gasket seat plug. That's a short taper seat. Should run better too...getting the spark down in the chamber!

I'd recommend Autolite 3925 (stock heat range), or 3924 (one step colder) if you're beating on it.

Holy Crap, your right! Yes it is an actual picture... I didn't even catch the fact that it was the wrong plug... I'm putting in the right plugs right now. Thanks for the catch Wade.

Ron, I used the plug socket and installed the plugs before the body was on so chances of breaking the ceramic when I installed the plug is low but I guess i must have... What matters is, I guess, I found the problem.

Edit: I just took it for a ride... I'm such an idiot! I have been driving the car for a year like this. I can't believe the difference it made. It used to pop (backfire) as I went downhill or decelerated. That is gone. It used to load up and hesitate at three quarter throttle while accelerating. That is gone as well. It runs perfectly now. I'm learning new things every day. Again, Thanks for the input.
D

[Dan Babb]

I had a problem with my hemi where a plug socket (with the rubber boot) was cracking the ceramic on the plugs. I pulled the rubber boot out and no more problems. Not sure why it was happening, but it was.