Klinh

I've changed spark plugs on all the Mercedes I owned in the past but never really compared the old to the new before install the new. I will now........after reading these thread.



https://mbworld.org/forums/c32-amg-c...ml#post5712089

mis3

I emailed FCPEURO for the updated version of Bosch 7422 spark plugs for CLK320 and CL500.

They replied to say that 7742 has been replaced by 4418: Bosch Spark Plug - Bosch 4418 FGR8DQP (Platinum +4). I saw the picture and each plug has 4 tips on top.

In both Autohausaz and FCPEureo, 4418 is cheaper than 7742 for about $1.

I am leaning for the 7742 because this is what my local MB dealerships are using. Anyone has experience on this 4-tip platinum plugs?

Glyn M Ruck

That ring fire plug is an adaption of the old plug that Bosch made for Alfa Romeo in the sixties. The only benefit of, so called "ring fire" plugs is they are more likely to fire in the presence of oil. Italian engines used quite a lot of oil as they had no valve guide seals and plugs could oil up.

It's your car & you can fit whatever you wish. I would stick to the plugs that Benz fit in production. They cost more but they are designed to last 100K miles.

mis3

By "fire ring" plugs, you are talking to about 4418, right?

I plan to stick to 7422. It is a bit tricky, stock plug is FR8DPP33 but it has been replaced by FR8DPP33+.

As for Alfa Romeo, I recall I had a friend who owned one of these 20-25 years ago. He had to add engine oil every time he fueled up at the gas station. He said the car had a high compression engine and it was normal to burn oil.

Glyn M Ruck

Yes, the 4418 is ring fire.

If it was my car I would fit Bosch F 8 DPER if I could get them or Bosch FR-8-DPP-33+ (7422)

mis3

Yes, I am getting FR8DPP33+ for my car. Also, I am getting the same plugs for my friend's 2003 CL500 as well.

I have no idea where to get FR8-DPER.

Rudeney

FYI, the M272/M273 engines fire the plug multiple times during the combustion phase. Multi-point plugs are probably not really necessary in these engines.

Glyn M Ruck

+1^ ~ the plug companies keep trying to reinvent the wheel. After lead errosion ceased to be an issue with unleaded fuels & really long life became feasible there is not much more they can do. It's materials vs cost now. The original Alfa plug was a work of art but not gappable. The latest effort is clumsy by comparison.

Alfa plug made by Bosch & Lodge.

mis3

As I mentioned in my other post, I usually change my spark plugs every 100K KM (60K miles) for all my cars.

For my current w209, I changed my plugs on Mar, 2011, some 70K KM before (42 miles).

I know the frequency depends on many factors. Since I did not use my car for long trips for the past year, I am thinking to change my plugs earlier but is 42K miles too early?

Yidney

Just did mine at 43,000 and glad I did. Very obvious pitting and/or little tiny blobs of melted metal deposits on the electrodes as they traded body fluids. Not terrible, but more than just dirty.

mis3

Before I posted the quesiton, I did research on the service interval of spark plugs. It varies from 30K miles to 100k miles!

I read that it's better to change the plugs before the stated lifespan. Spark plugs deteriorate over time. On the other hand, I read that I should not touch the spark plugs and the wires unless it throws a code.

Does anyone know the OE of the spark plug cables?

Fatz

Rodney, changed my plugs last week (Monday) and wanted to be able to say "my old plugs were better than your old plugs"........ but I can't. I started witth the passenger side and things were looking great. On the drivers side, my bragging hopes were dashed....

Any thoughts (from anyone) based on the attached 4 pics?
1 pass side plugs on left (random order) - drv side plugs (rear to front)
2 close up of pass side plugs
3 close up of drv side plugs
4 close up of drv side plugs

The dark stuff is sorta "carmelized". Had not noticed any issues in driving. But I have noticed more "punch" when I accelerated "briskly" from any speed since changing the plugs.

Just wondering if I should hold my "self insurance" money for another year before blowing it.

I plan to pull the drv side rear and front plugs after 2K miles and visually checking them.


thx

Fatz

Forgot to upload........

Fatz

One more (&^*#()) time.... Can't upload the 4th pic - probably redundant anyway....

Glyn M Ruck

All those plugs look absolutely fine. It's only the tips that matter.

The goo on the threads is due to burnt on lubricant of some sort when they were fitted & possibly they were not torqued correctly against the crush washer.

There is a lot of controversy about applying anti seize or whatever compounds to plug threads in aluminium heads.

Many plug manuafacturers believe that the zinc plating on the threads is sufficient anti seize & that applying any form of lubricant causes over torquing of the plugs affecting heat transfer.

Anyway ~ your plugs are fine. Nothing to worry about.

Fatz

Thanks Glyn.... I'll start planning the party..