Packard Forum Index » V-8 (1955-56)

OK this may be the world's dumbest question, but automobile electrics/ignition is not my strong point - so I assume it is OK to use resistor plugs NGK BPR4ES in my 352? The parts dealer didn't have either the non-resistor BP4ES, or BPR5ES plugs mentioned in another thread...??

I don't know. The real questions ARE:
How did u (OR ANYONE) come up that number????

Did the parts store give u any reason WHY the NONresistor plug can not be ordered?????

What does "B" and the "P" and "E" and the "4" and the "S" indicate about the plug????

So far what we have is alot of owners throwing alot of numbers around with no specific source reference for the plug numbers nor any characteristics aboout the plug that the numbers mite define.

So far all we have is some number that some parts jockey verbalized for the application. The same parts jockey was probably flipping hamburgers last week at McDonalds or the parts store just has alot those plugs on the shelf they need to move.

I'm not trying to be critical or sacastic. I'm trying to make a point that unless the CHARACTERISTICS of the plug can be determined then there is no way to know.

See post #6:
https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=5102&forum=3

It defines the characteristics for the AC plug (45XLS now difficult to find).

To determine the NGK compatability one must be able to deciper the NGK number just like the AC number is decipered in post #6 above.

If I correctly decoded that chart you found but not able to download, BPR4ES decodes as
B 14mm
P Projected insulator
R Resistor
4 Heat range 4 from 2=hot to 11=cold
E Thread reach 19mm
S Standard 2.5mm center electrode

SO then. If we compare that tot he 45XLS:

"4" = 14 mm.
"5" is middle Heat range (3 thru 8(3 is cold 8 is hot )).

"XL" = extra long reach (3/4 for 14mm).

"S" = Extended Tip (except 7/8 threaded plugs).

NGK:

B 14mm
P Projected insulator
R Resistor
4 Heat range 4 from 2=hot to 11=cold
E Thread reach 19mm
S Standard 2.5mm center electrode


We can see that the NGK is very close EXCEPT for the heat range. THE NGK "4" is rather hot compared to the AC "5" within it's range. Probably ok for weak engine and colder operations. (actualy the AC range is "2" thru "8" and Not "3" thru 8). Probably better off with an NGK heat range of 6 or 7 for general use.

Quote: The NGK 7 is a relatively cold turbocharger plug. I would use 5 for normal driving and maybe 6 for high performance use.

thnx jack vines

One should have all the facts before stating an opinion. That said, I came up with the NGK number based on an NGK site that spelled out what each code was. I wanted a non-resistor plug and did not want a Champion The AC plugs were getting hard to find. That was several years ago.
As far as flipping burgers, just make sure you spell it with a "U".

"That said, I came up with the NGK number based on an NGK site that spelled out what each code was"

Yes. That's fine. But how did u know what characteristics to look up the NGK codes for to begin with???? Characteristics of the plug for the 56 V8 is not specified in the service manual nor anywhere else that i could ever find. ONLY in the 1976 AC manual.

It wasn't rocket science. The site I looked at also gave crossover info. I didn't save it - wish I had.
For those who like Champions, try to find an N18 or Champion equivalent. If you don't like my choice, that is your prerogative. However, don't slander others or assume you know how their choices were made when you don't have all the facts. I have been running the NGK plugs for several years with exemplary service. I don't recommend anything. I do say what has worked for me.

G'day All, I too prefer to run NGK plugs in my cars and have never had a problem with them. I note that Randy runs a hotter plug (BP4ES) than mine (BPR5ES), although mine are resistor type which I understand are better at minimising radio interfernce and potential eletronic damage to the Petronix electronic kit I fitted to the distributor. I also note that Jack V suggests a heat range of 5 is about right so I think I will stick with this type for now. At around $4.50, they are a bit dearer over here in good old OZ, but similar to other brands and readily available. Also, I found the NGK part numbering system on the AUS NGK website. Go to ngk.co.au, then to Product Information, then to Part Numbering System. By the way, I might have inferred on the ignition advance curve thread that I was having pinging problems but this is not the case when using mid-range premium unleaded (ie, 95 RON). I was more concerned about reconditioning the distributor to maximise power and mileage, while continuing to avoid pinging. Cheers, John