Best spark plug for the 355?

Here’s the Ferrari part #167098


https://www.ferrariparts.co.uk/part/ferrari/167098?id=12897

 

Price is 3x higher if it comes in a Ferrari Box.


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We spec 2.7 cars 1994-1995 to the PMR8B (192637) and 5.2 cars 1996-1999 to the PMR7A.

 

That invoice is 20 years old.

 

$58 for a Champion spark plug. Thats just hilarious.

 

Ferrari nearly went broke paying warranty to throw Champion plugs in the garbage where they belong and had us installing NGK. They got smart and started installing NGK at the factory. You can continue using Victorian era plugs if you insist but they are trash.

By the way, scraping carbon from pistons is another Victorian era no no. It ends up in the ring lands and that is exactly where you dont want it. Leave it where it is and when the motor runs correctly again it will burn off.

 

No, its been 30,000 miles for a long time.

 

Why does Ferrari embarrass themself.

Just pointing out what is in the 95 manual. But the PRMxA's aren't exactly new technology.

 

Read a few of the other threads around here right now. The world is full of people who follow in lock step behind the goons from Maranello. They are Gods don't you know? Anything they say, anything they charge, its all a tribute to the God Enzo.

They are light years ahead of the Champions. Its not just about technology. NGK has actual QA. We had so many running complaints Ferrari quit even bothering to ask us to diagnose the issue. They just told us to replace the plugs. When they switched to NGK just like flipping a switch the problems were gone. The PMR8B is a similar issue. Ferrari in response to problems had NGK produce a special spark plug. It has since been adopted by a number of others but it was made for Ferrari. You can blow them off if you want to but for a really cheap company like Ferrari to go to the expense of producing a special part for them alone is all anyone with any sense should need to know. .

 

Easy to find out when you google.
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This chart indicates a Champion 4 is equivalent to an NGK 9. Champion 7 equates to an NGK 7. Seems off

 

The table is from NGK website and a few other sources show the same heat range cross-reference between Champ and NGK. The current recommendation by NGK to use their heat range 7 or 8 does not tell that these heat ranges are equivalent to Champion 4. Perhaps Champion 4 was found to be too cold (which may cause plug fouling) so the current recommendation is to go a bit "warmer" to help burn-off the soot.

 

Which would be.......?

 

PMR8B. There was a widely used PMR8A and Ferrari began using them until it was discovered that misfire CELs would often happen prior to the 30,000 life span so had NGK change electrode composition to cure it. When they became available many of the other users adopted them as well.

 

Which would go back to my initial impression.. RG4PHp is not an equivalent to NGK’s PMR7 /PmR8

 

I'm not trying to be curt, trying to learn. But where does it say and any 355 literature that plug should last 30k miles? Certainly in the owner's manuals I have for 95, 97 and 99 model years they all indicate "change and replace if necessary every 20,oo0 KM". My PRM7A plugs were shot at 13k miles. I can't imagine a cooler plug (8a or b) would last longer.

 

Colder heat range should not reduce life. Double platinum would increase life.

 

1995 USA 355 Owners manual page N7 line 8. Replace spark plugs 30,000 miles
1996 USA 355 Owners manual Page N7 line 9 Replace spark plugs 30,000 miles.
1997 USA 355 Owners manual Page N7 line 9 Replace spark plugs 30,000 miles.

Should I continue?

 

I have 3 different versions of the 95 manual, 2 are PDF files, also a 97 and a 99 PDF. All the PDF files say check and replace if necessary at 20,000KM.

The hard copy in the car does indeed say change every 30,000 miles.Either way, no way the PMR7A will last 30k miles in my car.

PMR8B are still cooler.

Anyone else gone 13k miles on a set of plugs in a 95 or otherwise? What do they look like? All 8 of mine are the same.

 

Then you should fix the car. I have never heard of replacement of the NGKs in less than 30,000. My data base is just a bit larger. All during 355 and 360 production I was shop foreman of the largest Ferrari dealer service department in the world.

 

According to the descriptions on NGK’s site, PMR7A, PMR8A, and PMR8B are all dual platinum.

 

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*F355spider had a 5.2.

 

I believe the B was developed for Ferrari, but anyway, I tried both 7 and 8 (both B iirc) and noticed no difference in my 2.7. Iirc it had the colder 8 plugs in it when I got it and I bought a set of the 7's when I was troubleshooting a bank cutout issue which was cat temp sensor related figuring hotter plugs might help. Zero noticeable difference. I have a new set that came in the Ricambi major kit but I haven't swapped them in as the old ones are sub 10k miles. No juice there to be squeezed imo, not unless you're going to add fuel and might need a hotter plug for it to be happy. We have easy access to 93 octane here, so the 7's might be worth a tiny bit in terms of more complete burn. If in CA with lower 91, maybe the 8's will make it happier. My butt dyno isn't good enough to tell.

 

Which ones came with the Ricambi kit for 2.7?