Glazed Plugs

[MSRacing89]

I have done some research/reading on this but I thought I would throw it out there.  I know my way around a carb and engine but rarely do I get an issue plugs glazing.  I have a 440 with pocket ported 452's, near 10:1, RPM manifold, mallory/MSD ignition,  #60303 Voodoo cam (270ish duration), 20 initial - 35 total, and a Stage 5 BIGS 750 (75p-83s).  Currently running NGK XR-5's #3332 with .042 gap.   Now the car runs good, idles fine, has good power, no stumbles, runs cool, ect.  I can't really complain. 

The deal is everytime a pull the plugs, 6 of the 8 plugs are glazed over,  and wet with NO soot.  Does not matter if they are new or have a couple hundred miles on them.  Seem to have a decent color under the glaze, maybe a touch dark. I also noticed the past few times that several of the plugs actually started flaking off some the glass on the porcelain near the tip.   Now is the simple case of too hot of a plug or too much carb/fuel washing them?  The two that are not glazed have a nice tan color.

If anyone has some suggestions on this that would be great.

[firefighter3931]

Marty, you might try jetting down to see if that helps....maybe one size to start off with. I would also look at the plugwires and see how much resistance you have....check it with an ohm meter and compasre the good cylinders against the bad to see if there is any variation.

How much vacuum is your engine pulling ? It's possible the signal is so strong that it's pulling too much fuel and washing the plugs down. 



Ron

[MSRacing89]

Marty, you might try jetting down to see if that helps....maybe one size to start off with. I would also look at the plugwires and see how much resistance you have....check it with an ohm meter and compasre the good cylinders against the bad to see if there is any variation.

How much vacuum is your engine pulling ? It's possible the signal is so strong that it's pulling too much fuel and washing the plugs down. 



Ron

Thanks Ron for replying.  I believe I am good as far as the ignition and wires go.  Like I said I have not felt a miss yet, but I just don't know if one or even  two jets down will cure the problem.  HP carbs start at 74p and 84s, so I trying to keep it in that ballpark.  Like you said in the PM, I may just have too much carb with that stage 5 HP 750.  I am literally washing the plugs, but I believe it is only happening mainly when all for barrels are open.  Driving around on the primary's it is very responsive.  But took everything you said to heart and I will maybe change the carb to the more mild 750 and see if it cures the wet plugs.

[firefighter3931]

Sounds good Marty....keep us up to speed on your progress. 


Ron

[Rob R]

There's a quick and simple cure for that but first what ign box and wires do you have specifically?

[MSRacing89]

I run a Mallory unilite, MSD 6A and MSD 8mm wires with NGK XR5's.  Colder plugs??

[Rob R]

The plugs are fine but those std impedance wires from MSD and that unilite are more than likely attributing to the sooty plugs...You should have a set of those MSD 8.5's on your car...You have 15-18000 ohms per wire with the std 8mm wire from MSD and with the 8.5's you'll have .175-.200 ohms per lenght...that alone will increase the voltage to your plugs by 10000%...that will clean off the soot off your plugs and you'll pick up some tq in the midrange as a bonus...or you can just give it more high speed air bleed...both will get you where you want to be..."I'd put the wires if it were me"

[MSRacing89]

That is good stuff, I will see what I can do about the wires.  The thing is the plugs are not sooty, just wet.  But either way, won't hurt to get the best wires on there.  Firecore50's instead for MSD 8.5??  What do you guys think?

[Rob R]

  The thing is the plugs are not sooty, just wet.

Then it's your ign...that old unilite only has about 18 degrees of dwell at best and that's not at every pluse... plus you add some wire resistance and you end up with wet plugs 

Fire core or MSD both are the same...I like MSD because of the non terminated option (I hate plug wires that are Too long)
you put wires on it (Firecore/MSD 50 ohm) and it'll lean it out a bit with all that new voltage to the plugs and cure your plug problem...

[MSRacing89]

http://store.summitracing.com/partdetail.asp?autofilter=1&part=MAA%2D4757801&N=700+400249+4294908110+4294840062+4294881256+115&autoview=sku

So you are saying this Mallory distributor is a problem?  I have used these things for years, did not know they were inferior.  By the way I did check, I am running #31313 MSD 8.5MM wires.  So maybe it just comes down to jetting....75p-83s is just too much in combonation with that HP mainbody, like Ron said in an earlier post.