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| spark plug forensics https://slantsix.org/forum/viewtopic.php?t=59366 |
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| Author: | rich006 [ Mon Mar 28, 2016 2:19 pm ] |
| Post subject: | spark plug forensics |
Any thoughts on the appearance of this spark plug? I've had the car for about 20 months and driven about 1500 miles mostly in town. There's a chance the plugs were brand new when I bought it but they might be many years old. I checked the gaps when I got the car and they were at spec. Today I've pulled them because the tube seals are leaking oil. They all look like this. They are covered with oil but I'm not sure if that's because the tubes were full of oil, or if it's completely normal. 
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| Author: | SlantSixDan [ Mon Mar 28, 2016 2:50 pm ] |
| Post subject: | |
Nothing alarming here — that reddish-orange colour is a result of certain gasoline ingredients. I wouldn't put Autolite 66s back in it, though; I'd get NGK ZFR5N (3459), minus the metal ring washers. Oil all over 'em is pretty normal just from removal. |
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| Author: | rich006 [ Mon Mar 28, 2016 6:31 pm ] |
| Post subject: | NGK ZFR5N not listed for this engine |
I've read several threads recommending the NGK ZFR5N (3459) plugs, but if you search by vehicle, those aren't listed. There is a range of NGK plugs that turn up for a 1974 Dart, but not the 3459. I don't doubt they will work, but what is the difference? Is it just that washer? I assume if you remove the washer, the plug extends deeper in. Is that the reason for choosing this plug? |
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| Author: | Nicademas [ Mon Mar 28, 2016 7:48 pm ] |
| Post subject: | |
Also what if you have the latter head without the oil tubes? Do you use the same plugs? |
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| Author: | SlantSixDan [ Tue Mar 29, 2016 9:01 am ] |
| Post subject: | Re: NGK ZFR5N not listed for this engine |
Quote: I've read several threads recommending the NGK ZFR5N (3459) plugs, but if you search by vehicle, those aren't listed.
That's right. These were originally designed for AMC and Chrysler in the late '70s when they were trying to make engines run reliably with extremely lean and stratified charges. Their use in 1960-'74 Slant-6 heads is an "off label" application -- they have the correct heat range and physical dimensions. The difference is they have an extra-long projected set of electrodes that moves the spark deeper into the combustion chamber, away from the quenchout zone, for more reliable ignition under borderline mixture conditions, which in turn results in more complete combustion, which gives an improvement in starting, idling, driveability, and economy. The mixture is much less variable in the middle of the chamber than at the edges, and these long-electrode plugs give more consistent light-off of the cylinder under borderline-combustibility conditions. A similar electrode set is used in many late-model Chrysler engines.resulting in better driveability and economy. Here's the business end of an NGK ZFR5N:  And here's the ordinary NGK GR5 "official" spark plug for the pre-'74 Slant-6:  Quote: I assume if you remove the washer, the plug extends deeper in. Is that the reason for choosing this plug?
No, you remove the ring washer no matter what brand or number of plug you buy for use in a '63-'74 Slant-6 cylinder head.
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| Author: | rich006 [ Tue Mar 29, 2016 5:31 pm ] |
| Post subject: | no anti-seize |
In case anyone is wondering about using anti-seize on your plugs, the NGK web site has this to say about anti-seize: Quote: NGK spark plugs feature what is known as trivalent plating. This silver-or-chrome colored finish on the threads is designed to provide corrosion resistance against moisture and chemicals. The coating also acts as a release agent during spark plug removal. NGK spark plugs are installed at the factory dry, without the use of anti-seize. NGK tech support has received a number of tech calls from installers who have over-tightened spark plugs because of the use of anti-seize. Anti-seize compound can act as a lubricant altering torque values up to 20 percent, increasing the risk of spark plug thread breakage.
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| Author: | Nicademas [ Tue Mar 29, 2016 10:24 pm ] |
| Post subject: | |
Thats funny because when I worked at a Honda dealership we used antiseize on NGK plugs all the time. We also were told to properly torque them as well (12Flbs). Now I know you cant properly torque a head bolt if there is any liquid in the hole so........ |
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| Author: | emsvitil [ Wed Mar 30, 2016 12:07 am ] |
| Post subject: | |
Aluminum head is 12 ftlbs, 14.4 is 20% Iron head 35 ftlbs, 42 is 20% (35 if I remember correctly) I don't see a problem with aluminum heads, maybe with iron heads (with the spark plug, not the head) |
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| Author: | Charrlie_S [ Wed Mar 30, 2016 3:30 am ] |
| Post subject: | |
I would think the problem would be with aluminum heads. It is fairly easy to strip or "pull" the threads in the head. Remember most engines made today have aluminum heads |
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| Author: | rich006 [ Wed Mar 30, 2016 4:34 am ] |
| Post subject: | |
On the AutoZone site under how to change spark plugs, it specifically says to use antiseize IF you have an aluminum head to prevent the dissimilar metals from bonding together. Sounds like NGK thinks their coating takes care of that regardless of head material. |
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| Author: | DadTruck [ Wed Mar 30, 2016 6:29 am ] |
| Post subject: | |
Dan,, are the NGK UR-5 and UR-6 still the recommended plugs for the peanut head? thanks |
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| Author: | clode85ca [ Fri May 27, 2016 6:32 pm ] |
| Post subject: | |
 Sorry to ask an another time but i'm changing plugs in my 1964 belevedere because the oring are leaking. According to this thread I have ordered the Zfr5n but there are a lot longer than the trl79 (motomaster) that was in place. Also the plugs still has the washer. And the was running great. A need someone to confirm me than i'm doing it right. Thank you |
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| Author: | DusterIdiot [ Fri May 27, 2016 7:02 pm ] |
| Post subject: | Yes... |
Quote: NGK UR-5 and UR-6 still the recommended plugs for the peanut head?
UR-5 is a good mid range start, it puts you in the middle with the options for UR-4 and UR-6.... for hotter and colder...
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| Author: | SlantSixDan [ Fri May 27, 2016 8:58 pm ] |
| Post subject: | |
Quote: i'm changing plugs in my 1964 belevedere because the oring are leaking. According to this thread I have ordered the Zfr5n but there are a lot longer than the trl79 (motomaster) that was in place.
Go ahead and use the ZFR5N plugs.Quote: Also the plugs still has the washer. And the was running great.
Remove the metal ring washers from the new spark plugs.
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| Author: | Wesola78 [ Sat May 28, 2016 8:04 am ] |
| Post subject: | |
Quote: On the AutoZone site under how to change spark plugs, it specifically says to use antiseize IF you have an aluminum head to prevent the dissimilar metals from bonding together. Sounds like NGK thinks their coating takes care of that regardless of head material.
Keep in mind that Auto Zone, like a lot of retailers, wants to sell you more stuff.My part-time job is at an Auto Zone store. Auto Zone stores are graded (and then berated) on how well the employees sold customers extra stuff. FYI... |
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