Spark Plugs on P-Mags

Bob Brown · #1 06-14-2007, 03:49 PM

I'm beginning my first condition inspection and wonder what experiences those who are using P-Mags/E-Mags are having with spark plugs? Any preferences or bad experiences? The plugs shipped with my system are NGK BR8ES. I've got 80 hrs on them, they all look OK but I was just wondering what anyone else is running??

jbDC9 · #2 06-14-2007, 04:28 PM

Not much different to report here; I'm using the same NGKs with my P-mags and all is well with 'em at 140 hours. I might change to a new set around the 180-200 hr mark, we'll see...

MCA · #3 06-14-2007, 05:40 PM

205 hours and look fine.

tommylewis · #4 06-14-2007, 09:59 PM

yes they may look fine but I bought 8 plugs today for $12.50. So why not change them out at each annual?

Tom Lewis
RV7a - two PMAGs

RV7Guy · #5 06-14-2007, 10:01 PM

I use the same plugs. I replaced them at the Condition Inspection with 180 hours on them. At a $1.78 each why not. At 100 hours I removed the plugs and cleaned them. All of them looked great with no bad signs at all.

I'll probably pull my plugs and clean them before saddling up for Oshkosh. I'll have around 100 on the new ones by then.

Bob Brown · #6 06-14-2007, 11:21 PM

One of my neighbors, an early adopter of electronic ignitions on his -4 and now his -8 uses a spark plug he buys at tractor supply houses...it's the same thread size as the aviation plugs but is an auto style plug. He swears by em...I'll post the specific info when I get it on Saturday and will probably try a set if for nothing else to eliminate the brass thread adapters...which I really don't like using.

MCA · #7 06-15-2007, 06:07 PM

To clarify, I'm using the BR8EIX Iridium plugs, which have a fine tip and are supposed to have a better spark. I have no idea if that's true or not, but since they cost a bit more than standard, thought I'd leave em in for a while. Will probably go with the BR8ES next annual and see if any change is noticed.

dan · #8 06-15-2007, 07:09 PM

Quote:

Originally Posted by Bob Brown

One of my neighbors, an early adopter of electronic ignitions on his -4 and now his -8 uses a spark plug he buys at tractor supply houses...it's the same thread size as the aviation plugs but is an auto style plug. He swears by em...I'll post the specific info when I get it on Saturday and will probably try a set if for nothing else to eliminate the brass thread adapters...which I really don't like using.

I'd guess he uses the Autolite 386. It would be sorta nice to get rid of the adapters, but I gotta be honest...if it ain't broke, don't fix it. That's why I'm stickin with adapters + NGK BR8ES. Cheap & reliable.

I swap my plugs out every 100 hours since they're so dirt cheap. I do see a fair amount of electrode wear. My Lightspeed Plasma II is sparkin' the heck out of those puppies. For $7 every 100 hours, I can rationalize replacing 'em rather than gapping.

My next engine will have 14mm spark plug holes in the cylinder heads, assuming I can get angle valve heads made that way.

Bob Brown · #9 06-18-2007, 12:14 PM

You had it right Dan, the Autolite 386's are what were recommended to me. I just don't like the adapters and if I can ditch 'em I'll probably save almost 1/2 pound (I put that in there just for you since you inspired me to save weight where I could). The Autolite 386's were 2.04ea at NAPA.

osxuser · #10 06-18-2007, 01:55 PM

Quote:

Originally Posted by Bob Brown

You had it right Dan, the Autolite 386's are what were recommended to me. I just don't like the adapters and if I can ditch 'em I'll probably save almost 1/2 pound (I put that in there just for you since you inspired me to save weight where I could). The Autolite 386's were 2.04ea at NAPA.

I'm not sure the difference is weight is real since the 18mm plugs would be heavier. Also Dan, is it possible to have a cylinder head made to your spec? I've never heard of a 14mm Parallel valve head, much less the more rare, angle valve.