Spark plug confusion.

[carguy300]

My 68 440, had the middle plug, all 8 installed. I purchased plugs on the right, what is called for, and the one on the left, set of 8 is what came with the car. Which one should the correct plug? All stock with point, condenser ignition still. Any imput please.

 

[Big_John]

The plug on the left is not the correct plug for a 440.

You'll have to look up the application for it to see what it fits, but if you screw that one in, it will hit the piston top and cause all sorts of havoc and destruction.

 

[Snotty]

Use the ones the specs call for.

 

[bronze turbine]

The plug on the left is definitely not the right one, its threads are too long. I think that type is used in a slant six or small-block. The plugs are supposed to be resistor plugs so I would say the one on the right is correct. I don't think the difference between the 12 and 13 is very significant. That indicates the temperature range.

 

[carguy300]

Thats what I thought, Im just glad the previous owner didnt install the long reach and find out the hard way. The RJ12YC is what is called for so thats what I got. Thanks for the imput gentlemen, always appreciated!

 

[mobileparts]

The J13Y is half a heat range hotter —- and that is why you see that is black by the electrode —- it is too hot…

The J12Y —- replaced by R ( Resistor ) J ( short reach 3 /8 “ )
12 ( heat range ) Y ( extended tip ) C ( Copper Core technology) —- hence the part number : RJ12YC …. IS correct for the whole 383 & 440 cars….

The “ N “ plug is long reach ( 3/4 “ ) for the Small Block Cars —-
273 , 318 , 340 , and 360 —— and would strike your piston and create serious damage to the motor…
And , yes , the RN12YC serviced the Slant Six class from 1960 - 1974…..

 

[watchfatha]

I use Autolite 85 in my current 66(440) imperial and in all of the preceding 26 Imperials before it with 413's and 440's. I have found that the Autolites resist pinging on today's reduced octane fuels much better than any other plug

 

[CBODY67]

Not worrying about your specific vehicle or what the catalog you looked at had in it, but the way it was generally, was that 383 2bbls were J-14Y and 383 4bbls were J-10Y. Our '72 Newport 400 2bbl came with J-13Ys in it, one step colder. The plugs looked the same on the ceramic as to color.

When I got my '70 383 N Monaco, I believe it was spec'd for J-11Ys or J-10Ys, which I felt was too cold for normal driving, but might be just right for an extended pursuit by a police car. Which is what that engine was basically calibrated for. So I went more toward a J-12Y and they worked just fine, coloring the ceramic the light beige like the other heat ranges had done.

The plug in the middle obviously has failed or the plug wire going to it has failed. No spark is the reason for its sootiness.

The RN11YC plug on the left is for a LA motor. No workie in a B/RB engine with the stock heads on it.

Take away the "R" from the front (resistor) and the "C" at the end (copper core) and what remains is the original Champion Spark Plug number from old.

Usually, deviating up to two heat ranges colder than stock works fine as long as the cylinders are not using oil. But going hotter than "14" is not something I'd be doing. There were some 383HP engines in the '60 383 police cars which spec'd J9Y Champion plugs. They were not chasing people all day, but probably sat idling a lot, too.

Just my experiences and observations,
CBODY67

 

[Ripinator]

I use Autolite 85 in my current 66(440) imperial and in all of the preceding 26 Imperials before it with 413's and 440's. I have found that the Autolites resist pinging on today's reduced octane fuels much better than any other plug

I run Autolite P85s in both my 66 and 70 HP 440s. They are great.

 

[commando1]

Choosing the Right Spark Plug Heat Range

 

[70bigblockdodge]

First of all they are champions and belong in a lawnmower at best, have a second mower without champions just in case.
Big blocks with factory iron heads never used long reach plugs.
The ones on the left are for a small block.
I've used Autolite plugs lately in regular engines if I need it to fire for sure NGK.
Really just send those Champions to the museum so they can do a display of the downfall of manufacturing.

 

[Big_John]

Big blocks with factory iron heads never used long reach plugs.

Those industrial/RV/truck engines used a 3/4" long reach plug with a tapered seat.

Never used in a car engine.

 

[carguy300]

I have used autolites in mopars in the past. In fact I worked in a Texas state facility back in the late 80's in the motor pool with a fleet of dodge trucks and vans and we used autolites then. I may give them a try now again in my 440.

 

[CBODY67]

I never had any issues with Champion plugs, but that was when Champion was Champion. Yes, they DO work in Briggs & Stratton lawn mower engines, which is where I used my old Champions from past times after a few re-gaps and electrode filings. J-14Y, J-14Y, and J-12Y. Just that they are longer than normal (and more expensive!) lawn mower spark plugs.

Autolite is not the same company it was in the 1960s, in Ford's pre-Motorcraft days, either. Probably one of the earlier OEM and aftermarket suppliers of electrical items? Seems that many in several forums like them. I've never used them, figuring their popularity hinged more on inexpensive prices at WalMart (and similar).

When I got my '80 Newport 360 2bbl, it has some Autolites in it. They worked well and burned clean, with light beige ceramics. But when I put the NGK V-Power plugs in it, I could tell an immediate difference upon first fire-up. At that time, Toyota was using them OEM and had one which was a direct cross to a Chrysler LA motor, which is the one I used. Later, NGK came out with the "V-Power" plugs per se.

At one time, I tried Bosch spark plugs, back in the middle 1970s. Durability was nothing near as good as the Champions back then. After Champion seemed to "get flaky" with all of their "Copper Core" orientations, I gravitated to Motorcraft spark plugs. They lasted much better than ACs in our GM cars by a long shot. Even OEM-Production ACs.

I used to advocate using the OEM brand of plugs the engines came with from the factory. THEN branch out for others, if desired. Which is how I got to using Motorcrafts and then NGKs.

The one time I used a set of SplitFires in my '80 Newport 360, I found them to be over-priced and over-hyped and under-durabilitied. 10K miles and they were gone! Physics indicates that the spark will jump only once, no matter the available electrodes AND to the point of easiest firing. The V-Power plugs expose more of the spark kernel to the air/fuel mixture, which is that that gap design is all about.

Whatever works! Enjoy!
CBODY67

 

[Snotty]

Nothing but Champions in my American engines. Never have had a problem. I've used Bosch and NGK is some foreign engines I've owned.