There seems to be a lot of controversy about which plugs to use to replace the H9DC Bosch plug. Does anyone have the definitive word on what is the best replacement plug? Apparently Beru makes a copper core non-resistor equivalent, but where can you buy them?

Thanks for any help.

This has been beat to death. Do a Search on , sparkplug copper core, or something similar. Much threads on the subject.

Steve

I'm not sure there is a best replacement plug, from what I've gathered there are two non-resistor options of choice, neither one of which is widely available:

Beru 14 F-7 DUO (K18) or 14 F-9 DUO (K80) - not sure which heat range is the right one, Beru's worldwide website lists the F-9. Available from www.kingsborne.com.

NGK BP5EFS. I've only been able to find these from an eBay retailer in the UK:

http://cgi.ebay.com/NGK-spark-plug-BP5EFS-plugs-BP5EF-S-check4-application_W0QQitemZ250086662247QQihZ015QQcategoryZ72205QQrdZ1QQssPageNameZWD2VQQcmdZViewItem

Shipping is fast, only took a couple days for me to get them in California. I haven't had the chance to install them yet though.

Anthony

Put NGKs in my chum's '87, runs fine.

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Try put NGK BP5EFS in my parts system, it supersedes to Bosch HR8DCX or NGK TR5.

One stupid question, can i use H8DC to replace H9DC or H9DCO in 300E (M103) engine?

I don't think NGK sells the BP5EFS in the US market, only the TR5. The closest I've been able to find is the BCP5ES, which is the wrong seat and reach for an M103.

You might be able to get away with the H8DC, it should fit but it will run cooler, which may require more frequent replacement intervals or possibly affect your emissions.