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Discussion Starter #1
Here are some pictures of #2 and #6 spark plugs.


Do they look lean?


The motor started running hotter than normal today. I have a 180deg thermostat and it was running about 203deg today.


I started feeling a hesitation or misfire when pulling away from stop lights. No misfires at speed or under heavy acceleration.

The plugs are Autolite Platinum's.



Thanks
Gary
 

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Hard to tell anything by the pics.
Have you changed anything on the carb?
How old are the plugs?
How big is the gap?
What kind of ignition system do you have?
6sally6
 

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Tips of platinum plugs also run hotter than copper ones. I dont rely recomend platinum on old school engines.
Have had problems with many friends old school engines when they switched to them corrected by going back to copper
 

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I've never had anything but trouble out of older motors with new "fancy" plugs. I would throw some normal copper plugs in there and take another look in a few hundred miles or so.

Those deposits certainly aren't helping anything. Hard to say where they came from, could honestly even be the age of the plugs. How long have they been in service? If you wanted to you could also take a wire brush to them to get a better look at the tips to look for melting or pitting.
 

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For having run them that long, they do look very lean to me and even to the point of pre-detonation.

I agree on the plugs too. My Kawasaki loves NGK's but my 65 mustang appears to love the old tried and true Autolite copper plugs best. I'm hitting it with an MSD box too. I also wind up changing the plugs in the mustang about every 6 months on average so the platinums are just a waste of money.
 

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Yup, all of my bikes have always loved NGK's. From 4-cyl sportbikes to my usual parallel twin british stuff. But for ford v8's autolite 3924's are what I run. In fact when I first got the motor running in my fastback I decided to be all fancy and put in some platinum ones. Didn't like the idle, so pulled them back out and put in some good ole copper ones and it cleared right up. I was actually a bit shocked I could tell a difference in idle quality. Both were gapped the same, same EFI settings, and same MSD box BTW.

GTONavy, have you put a timing light on it lately? Retarded timing could certainly cause it to run warmer than usual. Whether or not it would cause deposits like that I honestly don't know. But if it was me anyways, I would try some copper plugs, check your timing and go from there.
 

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For having run them that long, they do look very lean to me and even to the point of pre-detonation.

I agree on the plugs too. My Kawasaki loves NGK's but my 65 mustang appears to love the old tried and true Autolite copper plugs best. I'm hitting it with an MSD box too. I also wind up changing the plugs in the mustang about every 6 months on average so the platinums are just a waste of money.
Why so often ?
 

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Agree that platinum plugs are not really beneficial here. But the deposits on the plugs appears to possibly be oil ash. Do you get any oil smoke in the exhaust under any condition? Are you running a functional PCV system or just crankcase vent filters? Also, how about putting a timing light on her and seeing what it looks like (and let us know). Finally, when was the last time you got compression and leakdown numbers on the engine? I am thinking there may be a few things going on......
 

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Discussion Starter #13
Correction, the plugs are about 2 years old.

Earlier this year when I installed the Fitech, the accel pump was way to rich. The plugs were black with soot. Got that sorted out, long story. Drove the car 1200 miles to the KC leg of the Hot Rod Pour tour. No issues. Looks like I burned off the soot. Perhaps it is some fuel additive residue.

My initial timing is about 10 deg. I will check it tomorrow when I install some new copper plugs.

Gary
 

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Which Autolite are you using? It looks to me that its too hot of a plug. See where the color change of the ground strap is, its down close to where its welded to the base. Ideally it changes at about halfway of the strap.
If its too cold of a plug the change is out towards the end of the strap.
Too hot of a plug can cause preignition.

gtonavy, what did you use to take those pictures?
 

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Discussion Starter #15
Which Autolite are you using? It looks to me that its too hot of a plug. See where the color change of the ground strap is, its down close to where its welded to the base. Ideally it changes at about halfway of the strap.
If its too cold of a plug the change is out towards the end of the strap.
Too hot of a plug can cause preignition.

gtonavy, what did you use to take those pictures?

I have a microscope in my home electronics lab. Just hold the digital camera over one of the eye pieces. Little tricky but it works.

The plug is a autlote platimum, I believe the part number is AP45

Autolite Platinum Spark Plug AP45: Advance Auto Parts

Gary
 

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Platinum plugs are more prone to foul on an engine that doesn't have a high power ignition system
copper conducts better platinum/iridium last longer

Looks like you could have some pre igntion going on as well

Although I suppose it could be ash deposits ,hard to tell



Car spark plugs: Find out which are the best spark plugs for your vehicle.
^^^^^^

Put plain ole Autolite 45 plugs in. Cheaper and work better with ANY ignition system. In fact even MSD recommends using plain copper plugs with their ignitions.

Z
 

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Discussion Starter #17
Well I changed out the plugs yesterday.

I guess the plugs had become fouled, probably due to he over rich issue I had when setting up the EFI.

Put in some Motocraft copper plugs. I seem to idle much better and now hesitation.

Set the gap to about 0.42. Initial timing is at 14deg.

I also found why it was over heating. Had a small coolant leak and was down about 2 quarts.

Here is the picture of the old plugs.

Thanks
Gary
 

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Well I changed out the plugs yesterday.

I guess the plugs had become fouled, probably due to he over rich issue I had when setting up the EFI.

Put in some Motocraft copper plugs. I seem to idle much better and now hesitation.

Set the gap to about 0.42. Initial timing is at 14deg.

I also found why it was over heating. Had a small coolant leak and was down about 2 quarts.

Here is the picture of the old plugs.

Thanks
Gary
Again, why the large gap? Wider gap means more voltage is needed to maintain the spark. Although your P-III coil will CHARGE faster than a stock coil it doesn't produce a lot more voltage. Cylinder pressure also plays a big part in the equation. Higher cylinder pressures need smaller gaps. Lower pressures need wider gaps. That's why most engines of the smog era had HEI with .060" gaps... they had low compression and lean mixtures.
 

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Just a thought: You might want to open up the self-learning function on your EFI to allow for any improvements that might be left on the table now that she's in better health.
 
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