What plugs for my 2.7 MFI?

[Ho Hum 74]

Hi folks,

Starting the assembly of my 2.7 rebuild. I'm looking for recommendations for a set of plugs for the engine.

Currently it has Bosch WR7DS. Any good?

Engine is 2.7 with custom JEs and MFI.

Thanks
Tristan

[Early_S_Man]

Tristan,

Are you talking about later in spring or summer?

What cams and compression ratio will the engine have?

NGK BP-8ES would probably be a good starting point later in spring/summer weather ... those Bosch definitely sound too hot.

[Yellowbird RS]

try DENSO IW24 http://www.densoiridium.com/findmypart.php

[Ho Hum 74]

Warren,

Fogive the ignorance. What do you mean by "too hot"? I didn't know I had to have different plugs for different times of the year.

I have 9.5:1 pistons, MFI and some custom cams (I think - PO was vague!). I'll be running it at Road America on the 17th April (cold!).

Tristan

[Early_S_Man]

Tristan,

Here are some NGK info pages you may want to read ...

http://www.ngksparkplugs.com/techinfo/spark_plugs/techtips.asp?nav=31000&country=

http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp2.asp?nav=31000&country=US

http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp3.asp?nav=31000&country=US

http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp4.asp?nav=31000&country=US

http://www.ngksparkplugs.com/techinfo/spark_plugs/overviewp5.asp?nav=31000&country=US

Bosch and Champion heat range numbers go from lows [2 - 3] that represent cold plugs to highs that represent hotter plugs. NGK uses an opposite numbering scheme, with lower numbers being the 'hot' plugs, and higher numbers being 'colder' plugs for high performance ... higher compression, hotter cams, etc.

Bosch WR7xx plugs are 'hot' plugs ... detonation or pinging would be a certainty on the track with those plugs!

Bosch W4DC and W3DP0 plugs are 'cold' plugs more suitable for your engine, as are the NGK BP-8ES, B-8EV, BR-8EIX, or B-9ES.

[Ho Hum 74]

Warren,

That's VERY interesting. I'm trying to find the reason for my #3 big end bearing failure at the track in Sept. Wonder if I was getting any detonation??? Thanks for the great info.

Tristan