https://www.ferrarichat.com/forum/threads/spark-plug-reading-101.121401/
You know, when I bought the car I had the major done with new guides. Look like this when the heads came off at 19k miles Image Unavailable, Please Login Looked like this before the heads went back on Image Unavailable, Please Login Put a borescope down the plug holes and took a look when I changed plugs and it looked pretty much like the 1st picture. As for the plugs, I probably should have changed the sooner.
The 360 motor has greater mean effective pressure in the cylinder than the F355 motor in the difficult 2,500-3,000 RPM range.
Not necessarily. Just that 13k seems too long in retrospect, at least for my car. Recommendation is 20KM, 12.5k miles.
LOL, I don't know what kind of roads many of you drive on but driving the country roads of New England, and staying at safe speeds, (notice I said safe, not legal), if I wanted to keep the RPM between 6k and red line I'd never get out of 2nd gear and would spend a lot of time in 1st.
Not sure if NGK’s recommendation has changed over the years, but their site currently only lists PMR7A’s for both 2.7 and 5.2 cars. Image Unavailable, Please Login Image Unavailable, Please Login
@johnk... Here’s something interesting you should try per James’ recommendation. Not sure if this applies to both 2.7 and 5.2, but pic shown is on a 2.7. Image Unavailable, Please Login Image Unavailable, Please Login
Bother checking the owners manual? The '95 plugs were Champion RG4PHP which cross reference to both PMR7a and PMR8a The '97 manual says PMR7A The '99 manual says PMR7A Seems the 7a is obvious choice.
I’m too lazy to check the manual . I just assume when others say they’ve checked the manual, they’ve checked it. RG4PHP has a heat range of 4. That’s pretty far off.
Those suggestions are waaay too generalized. Perhaps they “fit” on the car, but the specs are different enough. RG4 has a heat range of 4 (hotter plug). PMR7 has a heat range of 7.
Heat ranges aren't comparable across brands, unfortunately. So have to see what a Champion heat range of 4 lines up with in NGK. See the chart in the below link - Champion goes down for colder, NGK goes up. Champion 4 looks roughly the same as NGK 7, per the chart. https://www.imps4ever.info/tech/engine/sparking-plugs-spark-plugs/spark-plugs.html
Good point. Was unaware. That chart seems all over the place. I can’t tell if a Champion number goes hotter or colder with number going up or down, but Champion 4 does seem to correspond most with 7’s. I did see a 4 equate to a 6, but nothing close to an NGK 8.
The chart was just for support of my post #66,. The RG4PHP are still available (link). Maybe that's what we should run in '95 cars. https://www.oreillyauto.com/detail/c/copper-plus/ignition---tune-up/spark-plugs/b14eb31b13d7/champion-copper-plus-plug-number-rg4php-spark-plug/chp1/349
O Reilly has the specs listed in error. It should be a platinum plug with a .028” gap (.7mm) https://www.sparkplugs.co.uk/champion-spark-plug-rg4php-oe122-t10-2?utm_source=chatgpt.com
