Visit The Dirt Forum for More Information

Author Topic:   blowing off plug wires
Dirt Freak

Total posts: 417
posted September 01, 2002 08:43 PM UIN: 13209501
What would cause this? We lost one plug wire last week, and two this week in the feature. They were still on the plug, but not connected. They all seem to fit tight, and are hard to pull off, but they still come off during the race. Anyone have any ideas?


Dirt Freak

Total posts: 499
posted September 01, 2002 08:53 PM UIN: 23443678
Are they on the same side of the motor? You say the boot is still on the plug and the wire comes out of the boot?

Dirt Freak

Total posts: 417
posted September 01, 2002 09:01 PM UIN: 13209501
No, they were on both sides. The wire was still in the boot. What I meant was that the boot was still on the ceramic of the spark plug, but it had moved off some so that there was no longer a positive contact between the wire and the plug. I know that it wasn't in contact any more because when I would push the plug back on, the engine quite missing. This one really has me baffled. I am getting new plugs and wires this week and see if that solves it. I would still like to know what's going on though.


Dirt Full Roller

Total posts: 73
posted September 02, 2002 01:11 AM
I put zip ties on the plug wires and the coil wire. even on the cap also, we have never had a plug wire come off yet, and dont really intend on starting now.

Dirt Maniac

Total posts: 135
posted September 02, 2002 04:35 PM
Sometimes it's very hard to tell if the contact has actually 'snapped' onto the plug. If it hasn't, and the boot is not fully pulled down the porcelain, it can enventually push the contact off and away from the plug. Inexpensive wires not made for racing conditions are best for this, although they are sold as 'Racing' wires. You can help the situation by lubing the inside of the boot and the porcelain of the plug with MSD's Spark Guard dialectric grease. Sparingly. The boots will be much easier to get on, and you will be able to feel the connection 'click' much better. Then make sure the boots are fully pushed down around the porcelain. I view the boot as an insulator first, and a connection reinforcement second. The primary strength of the connection is the fit of the plug wire termination onto the spark plug.

Dirt Forum Champ
Total posts: 1565
posted September 05, 2002 05:07 PM UIN: 54865418
i would get some new wires myself it is more than likley that they are a little loose and a mud clod hit them off

Dirt Full Roller

Total posts: 70
posted September 06, 2002 01:16 PM
Had same problem on an ashphalt car, plug wires and boots were new and sealed well to the plugs. The fix was to fill the boots with dielectric(non conducting)grease. This solved the problem. We beleived the cause was due to heat and the plug boot sealing too well. The air in the pocket inside the boot would get hot and expand and pop the wire off. Filling it with the grease took the air pocket out

Dirt Newbie

Total posts: 2
posted September 18, 2002 09:56 AM
i've had problems with autolite plugs leaking compression between the electrode and the ceramic. changed to ngk's and haven't had a problem since.

Back to the Archives