Manta Spark Plug Weirdness

ephillippe · 06-17-2006

Here's a good one for theories...

Like on other cars, I believe that the sparkplugs on my Manta should screw in until they crush the metal washer and lay flush in the engine. Mine, however go in very easy (hand tighening) about half way down and then come to a complete stop.
I've actually been driving it ok this way, but my working theory is that a PO had not screwed previous plugs all the way in and that carbon has built up in the plug hole on the last couple of threads keeping a new plug from being screwed down all of the way.

What say the fellow opelers?

Just wanted to check around before I break out a socket and really, really, really put some pressure on them to tighten down all of the way...

opelnut10 · 06-17-2006

First of all are you using the correct reach plug for the head you have?? Secondly you can go to an auto parts store and buy a spark plug thread chaser and scrow it in the spark plug holes to clear the threads. Try that before you rip the threads out and have to put coils in so you car run spark plugs in your engine.

ephillippe · 06-17-2006

I know I've got the right plugs. Im going to use NGK's that I've double checked the #'s a couple of times to make sure.
Is a sparkplug chaser just a sharp threading tool you run though the threads to clean then out? I'll go grap one today if there common.

timemachine · 06-17-2006

Good point on the right plugs. It's also possible your head is already crossthreaded and you can carefully use a tap to correct that.

The threads on a spark plug are much harder than the material of the engine and will cut through carbon pretty easily. They should pull down flush, but whatever you do, don't get carried away with tightening them or you'll be sorry. The washer on the plug is not so much a seal as a mechanism to keep the plug from loosening.

I learned in a shop a long time ago to hold the ratchet by the head (and not the handle) when installing spark plugs so as not to accidentally apply too much torque and cut the thread.

namba209 · 06-17-2006

To really be on the safe side, use a torque wrench on the spark splugs and slowly tighten them to 30 Ft.Lbs. If the plugs do not seat, then get the thread chaser and run it through the threads, slowly, with the piston at top-dead-center. Then, adapt a hose to go through the plug hole and attach it to a vacuum cleaner, minute pieces of the threads don't do the cylinder walls any good. HTH.

ddoyle · 06-17-2006

also a coating of grease on your tap will catch a bit of the junk.

dan

ephillippe · 06-18-2006

Thanks for the input everybody, I bought a 14mm chaser today and will give it a shot (carefully) tomorrow.

Again, opeling wouldn't be anywhere near as fun without a site like this one, thanks all!

06-17-2006	#1 (permalink)
ephillippe Manta Ray Join Date: Sep 2005 Location: Alameda, CA Posts: 68 Classified Rating: 0% (0)	Manta Spark Plug Weirdness Here's a good one for theories... Like on other cars, I believe that the sparkplugs on my Manta should screw in until they crush the metal washer and lay flush in the engine. Mine, however go in very easy (hand tighening) about half way down and then come to a complete stop. I've actually been driving it ok this way, but my working theory is that a PO had not screwed previous plugs all the way in and that carbon has built up in the plug hole on the last couple of threads keeping a new plug from being screwed down all of the way. What say the fellow opelers? Just wanted to check around before I break out a socket and really, really, really put some pressure on them to tighten down all of the way...

06-17-2006	#2 (permalink)
opelnut10 Living in the past Join Date: Oct 2005 Location: Virginia Posts: 1,197 Classified Rating: 0% (0)	Manta spark plugs First of all are you using the correct reach plug for the head you have?? Secondly you can go to an auto parts store and buy a spark plug thread chaser and scrow it in the spark plug holes to clear the threads. Try that before you rip the threads out and have to put coils in so you car run spark plugs in your engine.

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06-17-2006	#3 (permalink)
ephillippe Manta Ray Join Date: Sep 2005 Location: Alameda, CA Posts: 68 Classified Rating: 0% (0)	I know I've got the right plugs. Im going to use NGK's that I've double checked the #'s a couple of times to make sure. Is a sparkplug chaser just a sharp threading tool you run though the threads to clean then out? I'll go grap one today if there common.

06-17-2006	#4 (permalink)
timemachine Member Join Date: Jan 2006 Location: Swarthmore, PA Posts: 638 Classified Rating: 0% (0)	Good point on the right plugs. It's also possible your head is already crossthreaded and you can carefully use a tap to correct that. The threads on a spark plug are much harder than the material of the engine and will cut through carbon pretty easily. They should pull down flush, but whatever you do, don't get carried away with tightening them or you'll be sorry. The washer on the plug is not so much a seal as a mechanism to keep the plug from loosening. I learned in a shop a long time ago to hold the ratchet by the head (and not the handle) when installing spark plugs so as not to accidentally apply too much torque and cut the thread.

06-17-2006	#5 (permalink)
namba209 6,000 Post Club Join Date: Aug 2002 Location: Imperial Beach, CA South of San Diego Posts: 6,033 Classified Rating: 0% (0)	To really be on the safe side, use a torque wrench on the spark splugs and slowly tighten them to 30 Ft.Lbs. If the plugs do not seat, then get the thread chaser and run it through the threads, slowly, with the piston at top-dead-center. Then, adapt a hose to go through the plug hole and attach it to a vacuum cleaner, minute pieces of the threads don't do the cylinder walls any good. HTH.

06-17-2006	#6 (permalink)
ddoyle Member Join Date: May 2003 Location: oakland,or Posts: 231 Classified Rating: 0% (0)	also a coating of grease on your tap will catch a bit of the junk. dan

06-18-2006	#7 (permalink)
ephillippe Manta Ray Join Date: Sep 2005 Location: Alameda, CA Posts: 68 Classified Rating: 0% (0)	Thanks for the input everybody, I bought a 14mm chaser today and will give it a shot (carefully) tomorrow. Again, opeling wouldn't be anywhere near as fun without a site like this one, thanks all!

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