spark plug heat

[Barry Donovan]

I am curious to fails and success.



I am finding a boxer is backwards in the plug heat judging category..the more I feed it, the tighter I made the compression.... it made an ngk bpr6 a loser. (6 is the heat number). I shredded the right bank tips right off..coloring normal. normal to someone else is the brown color.

a bosch wr8dpx is one heat number hotter than the ngk..and...it is better

I am wondering what a wr9dpx (9 is the bosch heat number) would do with aluminum alloy.

heads are sleeved at the plug holes. brass copper radiator (that is a big deal for this one)

anybody go that number on a 10 point something compression aluminum head v8? it is very similar...except for the boxer trait.

[Scott Liggett]

I'm running hotter plugs than are recommended for my cars. Generally, two steps hotter. Cars don't like the colder plugs at all. Could be because the higher levels of methanol in the gasoline here. Don't know for sure. I've never asked a professional.

[Barry Donovan]

I'm running hotter plugs than are recommended for my cars. Generally, two steps hotter. Cars don't like the colder plugs at all. Could be because the higher levels of methanol in the gasoline here. Don't know for sure. I've never asked a professional.

I guess I can bump it up one more.

I found another writing showing softer engine is need hotter, harder is cooler.
that seems backwards at first...
but is the way my own went.
a hard thump is a hot one..irons/solids etc.

the aluminums, I am guessing, heatsink even more the harder you feed them..hence the backwards thoughts of it.

I did find the number 8 bosch seats the header.. but warm up time is still plain silly. This engine, like alof of japs, needs to burn the oxides. no hide, no games..the sumbitch needs to burn them.

EDIT:
I just went to bosch and found the wr8dpx is obsolete.
without fail, 3 engines..100k, I don'e even know how may years that is. I then let them sit in a bucket to try iridiums.
this same set went on my 25 hours of east coast ride in a 165k mile loyale in 2006..then survived a wreck (I totalled it)

not to be spamming, true life.

I guess I stay #8 but get the "plus"
wr8dpx+
?
says cooler electrode temp. maybe go for the 9 now that it is a "plus"?

blah. these experiments blow it all away sometimes.

[Scott Liggett]

I'm running cheapy Autolite 26's in the Caprice. And, Autolite 3924's in the Impala.

[Barry Donovan]

I'm running cheapy Autolite 26's in the Caprice. And, Autolite 3924's in the Impala.

I do miss that about the big 8.

I decided on wr9dpx+
4 of them is 15 bucks, and found my coupon of "ebay dollars", gets it down to 8 bucks four of them.

all the old stuff out there has a lot of new stuff to try.
even the 87 boxer has the old 8cyl plain rustable steel copper core as oem, cold in the chamber and wanting to melt the head...and no iron head to go with them safely.
Maine kept them from stripping out on my own engines..but it has not been a good time for others.

the past 20 years has been great. to think two plug sizes hotter, and a flush mount electrode.. I would have laughed at it once upon a time.

digging at this found some other backwards things. the #9 was listed for toyota corollas and little iron four cylinders..that is backwards according to ngk today.
bosch still lists the oem matching parts.

the boxer needed hot, the iron fours needed a cool. I ponder a flip flop, as the boxer not only walks away in every way, the power runting is ridiculous. they got some little marketing evil "brotherhood" going on overseas, and it is as repulsive as 5 mains in a boxer today.

anyway..onto where not many have gone before.

[Beagle]

the NGK's 6 is pretty hot - but we used them in a lot of air cooled stuff. Mostly old honda's. The Briggs we put
CJ8 and sometimes CJ6's, the Tecumseh's all pretty much J8's. I had a rm125 that would eat a 7 in about 5 minutes, an 8 in about 4 hours, and a 9 in about 5 minutes.

Two strokes seemed fussier about the heat range, but as I remember it, almost all of my bikes ran an NGK 8 whatever, and so did the ex's Accord... not sure what to tell you there.

[Barry Donovan]

the NGK's 6 is pretty hot - but we used them in a lot of air cooled stuff. Mostly old honda's. The Briggs we put
CJ8 and sometimes CJ6's, the Tecumseh's all pretty much J8's. I had a rm125 that would eat a 7 in about 5 minutes, an 8 in about 4 hours, and a 9 in about 5 minutes.

Two strokes seemed fussier about the heat range, but as I remember it, almost all of my bikes ran an NGK 8 whatever, and so did the ex's Accord... not sure what to tell you there.

I guess I had to put the unique things into some think.

• compression unknown, 25foot pounds more torque on 9 bolts per head.. you could see the squish by pathetic human eyeball.
• plug is above the valves, not below..this means it will blow it out as power increses.
• I found a bizarre feedback related to the ohms of speaker and carb choke..took it away, added diode.
• 250cfm with one barrell leaves this coughing like an 1980s ferrari f40.(not an error at best)
• the spec stage 1 is a super clamp (I love it) no wallowing energies..it kicks static like a hammer.
• steel sleeved heads for plug holes (longest I could find - 17mm) this also takes up some more chamber..more compression mystery
• the NGK 6 was so slow an overwhelmed, I lost timing, no adjustment.
• bosch 8 equals a ngk 5, and I gained timing..seated header after full warm, and it still took a very long time to get to full warm.
• the rochester acts like a peltier at the throttle base (rejects engine heat by oem design)
• speaking of possible peltier..a full brass copper side tanked radiator, the cooling is astounding just by being hooked up.
• the heater for cabin tells me cold intake or hot..still takes forever to gain heat (should work without thermostat open)
• 2 inch stanless header, <900cc a bank..equal merge, (more than 18 inches back before merge)
• the fattest injection cams this has ever had (1993), on the oldest solid lifters. cam casings squashed to the engine very carefully, no slob anywhere..machine surface to machine surface. (This one move was the huge for the tiny engine)

if above is not a list of reason for #9 bosch or even ten (the hottest plug they make...)

the hot plug goes somewhere, I would be the one to have the weirdo that runs normal with it.

[JeffMcKC]

Post some pictures of them.

[dieselgeek]

x2 on the pictures.

Perhaps heat range isn't your problem at all, instead tuning? this is the same engine with the Rube Goldberg carburetor that replaced the EFI yes?

[Barry Donovan]

x2 on the pictures.

Perhaps heat range isn't your problem at all, instead tuning? this is the same engine with the Rube Goldberg carburetor that replaced the EFI yes?

some day fuel injection will catch up to a needle and seat...
oops.

add some italian math like piezo to humor it.


the plugs..
iridiums survived a hg fail, photos useless. I did throw in some new ones, chewed the electrode off, right bank, and darker than the brown claiming good. hg fail never cleaned out, even after physically cleaning. bosch 8 is finishing that problem now.

the bosch 8 was on healthy engine, and crazy lean. white clean and lean.I means 40s to 50s to "omg I am dizzy and don't know why" LEAN.

less than 500miles on the current setup, plugs swapped around. can only judge by heat.
mileage is at 30-35, stomping on it or level. (needle magic)



to check the rochester is main jet big or small with no clue, just take needle out. there. now there is a rich reference to refer to.(this one keeps going without needle, needle is simply perfection.)

I love those air bleeds on throttle let down..the return line works as well.

at 4 bucks a gallon. don't even get me going on my rocket science of "tune".

I go for #9 plug..maybe ten.

although the carb can do blow thru..maybe add 700 pounds of boost to get over the giant intake and over resistored individual glow plugs..I mean injectors.. oops. wrong car thoughts.

the carb is at 20inches with the big monojet..34 years later.

[dieselgeek]

I would recommend not attempting to poke fun at EFI until your carburetor isn't burning the electrodes off your plugs.

Meanwhile, people are trying to help you out, can you post up some pics? What makes you think heat range is the problem? if you are burning off parts of your plugs, heat range is pretty far down the "what can be wrong" list.

[Barry Donovan]

I would recommend not attempting to poke fun at EFI until your carburetor isn't burning the electrodes off your plugs.

Meanwhile, people are trying to help you out, can you post up some pics? What makes you think heat range is the problem? if you are burning off parts of your plugs, heat range is pretty far down the "what can be wrong" list.

it is the heat range.

plug is on top of valves, not like a v8 on the bottom... or even a hemi with a dome.
straight up and down in and out is the a/f with a twist of sideways for the valves.


the burning electrodes is oxide that could not leave. the hitachi starved it to pig. monojet brought the truth out, and now finding the plug is not enough. it makes sense..
on normal burn this welds heads like old volvos.

that is not an error, that has to happen.

hot plugs needed.
I exceeded in every direction with no instruction..was curious about aluminum heads and number 9 bosch on the chart.
this will do that forever is my best guess.

just going to self educate again.
(that is always fun)

I don't make fun at injection when it is not invading rudely in my thread.
the one engine I play with has had all versions..single, multi, double carb, blo through carb..the 34 yr carb just happens to be the forgotten champion.

I could vomit on the world.


edit:
some simple info in an autolite vid:

at 70-120F gain for each heat range..

yes. #9 is the answer I am quite certain now.
a bigger charge on n/a engine does not need a plug sending it into the head..it needs a hot plug to keep it in the chamber.

and what weight is getting hauled determines it as well.
I guess I proved to myself the 1.8 is a 3000 pounder in a tin can. if that same engine was in a decade newer chassis (add 500-1000 pounds), it would use subarus down the middle number.