Rusty Spark Plug Holes and Threads

[darrenc]

What would you do. About a year ago, I installed some Autolite platinum spark plugs in my Jeep. Within about 1 month, I noticed rust on all of the plug bolts. Seeing this, I immediately replaced the plugs with new NGK’s. But, the lame Autolite’s threads had developed rust too, leaving rust in the threads on the motor’s head. Since then, the engine hasn’t idled very smooth. I suspect that the rust has caused resistance in the plug to engine ground.

Here’s what I plan on doing. I’m going to take a stainless steel pipe brush and scrub out the plug holes. I know that some of the rust will get into the cylinder, but, I suspect the amount will be minor, and will be quickly combusted.

What do you guys think?

 

[Shannow]

On cast iron heads, I used to get one of those battery terminal cleaning brushes (with the cap over the cynindrical brush at one end, and a hollow "internal" brush at the other end).

Screw it in, screw it out, and hope that not too much crud went down the hole.

 

[7TFord]

I've never had this happen. Do you live in a particularly damp climate or store the vehicle in one? Assuming you have just superficial rust in the plug holes, I wouldn't bother with the wire brush and would just apply some anti-seize compound (Permatex makes this) to the new plugs and install them. If they are a gasket type spark plug make sure that you are tightening them with the right amount of torque? A rule of thumb for gasket plugs is to install the plug finger tight until seated against the head and then add 1/2 to 3/4 of a turn to finish. Maybe one or more of the plugs you are using now aren't seated properly.

 

[darrenc]

Shannow...The pipe brush is about the same as a battery terminal brush, so I think it should work fine.

7tford...I live in a very dry climate, but this happened after I cleaned the engine with something like Gunk Engine Cleaner (something I've done many times before without incident). All the plugs were properely seated (gasket crushed) and torqued when installed (25 lbs), so I'm not sure how the plug threads rusted (perhaps galvanic corrosion). On the NGKs I installed, I did use allumized anti-seize compound.

What was shocking to me was the extremely poor corrosion protection on the Autolite plug...never seen anything like it.

 

[7TFord]

Unusual indeed! Mind you water can get into a small space which is maybe how it worked its way into the plug holes, especially if you are frequently shampooing your motor. Maybe Autolite doesn't coat the bare metal on their plugs. If so, the caustic affect of the motor cleaner would soon corrode it. Do you use compressed air to blow away any excess water after cleaning the engine?

 

[cryptokid]

if its wet start it up and itll evap quick before it flash rusts.

 

[darrenc]

Okay. All’s better. I got everything cleaned out and replaced the NGKs with factory Champions. Engine runs much smoother now.

I think I’m slowing learning as I get older that the engineers may actually know something about the spark plugs and other components they spec. for a particular application. Many times it seems, when I replace an OEM part in the quest for more performance, I often find the OEM part superior. I have gone through this same exercise with my boat, my Volvo, and now my Jeep. Live and learn.

 

[Greaser]

quote:

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Originally posted by darrenc:
Okay. All’s better. I got everything cleaned out and replaced the NGKs with factory Champions. Engine runs much smoother now.

I think I’m slowing learning as I get older that the engineers may actually know something about the spark plugs and other components they spec. for a particular application. Many times it seems, when I replace an OEM part in the quest for more performance, I often find the OEM part superior. I have gone through this same exercise with my boat, my Volvo, and now my Jeep. Live and learn.

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I have two 4.0's to do...use Champ Gold truck plugs #4412 and a light coat of anti-sieze before install...change em' every 2 years..they run/start fantastic

 

[UncleS2]

FWIW:
For *many* years, lots of mechanics have recommended: FoMoCo products, Autolite/Motorcraft plugs. GM, use AC's. Chrysler products(& lawn mowers!

), Champion plugs.

 

[Greaser]

quote:

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Originally posted by Stuart Hughes:
FWIW:
For *many* years, lots of mechanics have recommended: FoMoCo products, Autolite/Motorcraft plugs. GM, use AC's. Chrysler products(& lawn mowers!

), Champion plugs.

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Lkie the quib about Chrysler &lawnmowers...it's true though..Japanese cars like NGK,G.M. like Delco etc....by the way my lawnmower was bought new in 83...starts first pull every spring with Champs...and if you are referring to D/C products as lawnmowers...My Jeep starts first pull every morning also..