Ok, here it goes. I discovered today while doing a compression test that my sparkplugs don't match the OEM part #. I have NGK # PZFR5. They should be ZFR5F-11. Obviously, the actual plugs work ok, since I have those for at least 120,000 miles, and they look not bad, except for being dirty. I've been told they are a different heat range plug.

My question is, is it the right heat range for my use, or does it not burn completely the fuel mixture? The engine internals are stock, I only have bolt-ons for now. I plan on adding an adjustable cam gear and FPR in about 2 months.

So there you have it. Any info would help, thanks in advance.

 

i think the 11 on the original code is the resistance of the spark plug, i think i heard that there are two types of spark plugs, the ones with resistance and the ones without it

remember, i'm not sure about any of that

 

The P is for Platinum

 

120,000 miles on one set of sparkplugs?

Dude, can you say "TUNE-UP".

 

I don't think I need to. The plugs don't look used, they just look dirty, dusty.

 

i thought the 11 refers to the factory gapping, 1.1mm?

 

you could be right, maybe the last F is the resistance? (ZFR5F-11)

 

5 is heat range, R is resistor

 

ok, so i went i check it up, here is what they really mean (at least for NGK)

ZFR5F-11
Z= Plug type (extended gap in this case)
F= Metal Shell Size (Ø14, 19mm (3/4") reach, 16mm (5/8") Hex in this case)
R= Construction (resistor in this case)
5= We all know this one which is Heat Range (2 Hot<--->11 Cold to the ones that don't know)
F= Firing End Construction ( it says in this case is a "special design")
11= Wide Gap (yes 1.1mm)


Most of you guys where right, i was wrong, i'm sorry.

As for your original question SAUCEMAN77 NGK apparently doesn't use codes that short, so my guess would be that the spark plugs are the ones just that didn't came with the right code on them. I think it would be a good idea to change them don't you think? and if you live on a hot climate or do a lot of high rev driving jump to the ZFR6F-11 which is a colder plug. I have to do this, cuz i leave in a hot climate (86 all year round) and do a lot of high rev driving

Hope this helps!

 

Thanks GZERO, good info. I will definately change the plugs back to OEM specs, at least until I start working on engine internals and timing. I should not need to go with hotter plugs, since the climate is cooler over here. Anyway, thanks.

Oh, by the way, the compression test gave 150-150-180-145. Is this supposed to be normal on a 137500 miles engine?

 

while the plugs may look good, I'd be willing to bet that the gap has worn down and is larger than 1.1

 

Taken from kentucky accord in this post: https://honda-tech.com/zerothread?id=370677


[Modified by GZERO, 12:26 PM 1/9/2003]

 

Right. So there is a problem with the 180-145 gap. Any idea on why only one cylinder would be much higher than the three others?

 

First: (not insulting or anything, just double checking) did you put the injectors fuse out? did you press the pedal all the way doing while doing it? was the engine warm?
if so, my guess would be that the 180 is cause by carbon deposists and that your engine is at 150 psi?
or a faulty head gasket perhaps, i think i read once that the #1 and #4 are the first ones to go, maybe someone with more experience on this help you out.

 

I wouldn't know, I was in the car while my mechanic worked in the engine bay. The engine was cold, it hadn't ran for several hours.