Ironhead iridium spark plugs

[tink409]

anybody run these in the iron heads? any feed back on them would be great..thanks

[alaska62sporty]

I have never run run in an Ironhead, but have pulled them out of several carburated boat engines. I would avoid them. Iridium and Platinum plugs are good for fuel injected engines with O2 sensors and the like, they can last alot longer than copper core plugs in ideal conditions. The problems I have seen with them is that once they get slightly fouled, they are done. Fuel injected boat engines, say a 350 vortec chevy, run alot richer than car engines. They do this to keep cylinder temps down. Running rich fouls plugs. With a copper core plug, you run it up in the RPMs, with a load on it, you will burn the crap off the plug and life is good. The precious element plugs seem to not clean up like the copper ones do. I am not a chemisist, dont ask me why, but I have fixed many misfires by changeing platinum and iridium plugs back to copper.

[ironhead red]

I have been running the same Denso 0.4 Iridium plugs for 3 years. But, They don't make these for our engines. I machined my heads to accept them.

Ironhead Red

[tink409]

ok thanks for the info. good to know

[ryder rick]

Don't bother.
Many times exotic plugs that were not OEM equipment will cause problems.
I have seen this plenty.

[Fe Head]

I found a set of the iridium fine wire ones that fit most GM 305 engines have the same overall reach.

I machined off the chamfered sealing part and placed a regular gasket over the threads - quite tight - and used them with no problems.

They have a much denser plasma arc and did not foul up nearly the same as the OEM ones.

In my case the irregular miss of the rear cylinder disappeared also.

I would, however, recommend swapping the front and rear ones every few thousand miles to nullify the the effect of our dual fire coils always having one plug's centre electrode negative.
This has been shown to wear down the fine centre elrectrode moreso than if its polarity was always positive.

Cheers;

[mycle1000]

for an ironhead i have discovered the harley plug "xl 10 s" which is like the split fire, when used with a se coil works quite well. it takes the cold-blooded out of starting and adds to the fuel mileage.

[forqueue]

Off the shelf NGK Iridium BR7HIX (7067) with a .065" index washer for depth correction.
Not a problem in 3 years. Running with a single fire electronic ignition.

[wlkilmer]

NGK iridium BPR6HIX or BPR6HIX will fit.

[IronMick]

Originally Posted by wlkilmer

NGK iridium BPR6HIX or BPR6HIX will fit.

Hmmm, nice to have a choice, eh.