Spark Plugs Keep Burning Out The Electrode????

[Dans66Stevens]

I had this happen once before. I pulled my plugs today.I found that one plug is missing the metal center to the electrode. Anyone have a clue what could cause this? The motor is a 402 BBC with a unilite dist. The plugs are R44XLS A/C
Im thinking they are to hot? Anyone have any clue? Thanks Dan

[gnarley]

OUCH!
What Cylinders? DO A COMP TEST! What carb, fuel pressure, jet size, octane, total timing & RPM? You have a blower on there don’t you? How much boost?
Sounds like its way lean & plugs ??? I don’t know the numbering sequence anymore but I run on the cold side of what’s recommended.

[Dans66Stevens]

No Blower, It only ever has happened to one plug at a time. Its not the same cylinder. The compression is like 150 psi in all cylinders. I run like 38% total advance. If I try to run less the motor runs terrible.

[Havasu Hangin']

Hey Dan...I had spark plug problems (separated ceramic, burned electrode) right before the motor let go...
...turns out the spark plugs did not like pinging...they just gave in faster than the piston...
http://www.planetsmilies.com/smilies/happy/happy25.gif

[Infomaniac]

DETONATION!!!!!!!!!

[Boater Bill]

All these guys are right. Drop down to a 43 or 42 plug, these are cooler and coolest. With 38 degrees of advance you better be running some good fuel, todays pump gas ain't gonna cut it at that setting IMO. Cooler plugs, rejet carb as necessary, back timing down, better fuel, and you shouldn't have a problem. If you don't fix it now, your gonna fix a lot soon!

[stressedout]

And try a autolite #23.Is the porcelin cracked too, or is the electrode melted? If it's melted then theres too much timing and or too lean.

[Blown509Liberator]

DETONATION,DETONATION,DETONATION
I work for Robert Bosch, here in Broadview IL we do all the Spark plug testing and we see this all the time.
MikeW

[GEOO]

DETONATION..
Run better fuel.
Cooler engine Temp.
Less timing.
Cooler Air intake. (If you idle a long time the engine compartment may get hot. Air it out or run easy until it cool's down).
Richen fuel mixture a little. GEOO

[Dans66Stevens]

Well the porcelin is ok. Just the tip of the electrode is gone. The other 7 plugs look great. I will drop a heat range or two and back off the timing a little.

[Thunderbutt]

Dan, Havasu is right get that motor down to 36 or lower. Originally posted by Dans66Stevens:
No Blower, It only ever has happened to one plug at a time. Its not the same cylinder. The compression is like 150 psi in all cylinders. I run like 38% total advance. If I try to run less the motor runs terrible.

[HammerDown]

Dan if I recall when I checked it your timing was off the chart...ya gotta bring it down!

[triple x tx]

arent you running a pair of 450s on a edelbrock tr2x tunnel ram????sounds to me like you better fatten up the carbs......what jets are you running???

[Mrs. 66 Stevens]

Well this is Dans66Stevens
Yes Im running a tunnel ram with 2 450 Holleys.The plugs are black.
If I set the total advance at like 34% the boat runs terrible. No power and just acts like its running on half the cylinders. If I take the distributer and just advance it to about 15% initial advance it runs great. Im probaly at like 38% or 40% total.
The cam is timed straight up. I had a good friend look at it once. He set it at the 6-8%. We took it out and I was like shit this thing won't run.

[kojac]

Dan,does your engine run bad at idle with the timing turned back to 34 degrees and ok at cruising and top end? My brother had this trouble with his unilite and we had to take some of the advance out of the distributor.
Start with 34 degrees and go up one degree at a time until the motor runs good without detonation. Go up one jet size at a time. check your float levels at idle when the boat is in the water at the angle the boat idles in the water. Gas tends to go away from secondaries when under start and full throttle When you make plug changes to colder plugs go one temp range at a time. Do all this with good gas so you don"t detonate while you are testing.
Check your timing to make sure it does not continue to advance past the 3000 rpm mark. We have have seen this happen. Especially with the unilite. Let us know what you find?
good luck
Kojac.

[kojac]

Dan, I forgot, check your plugs after a wide open run and shut off the motor Do not let the boat idle before checking plugs or you will get a false reading.
kojac.

[Dans66Stevens]

Yes Kojac I know how to do plug readings.
If I retard the spark so that I have like 8% or maybe 10%. The boat will start and sound great on the trailer. As soon as its in the water in runs terribble. It has this huge flat spot. Almost like the cam is degreed wrong. I put lots of motors together and I know its right. It ran the same way before I rebuilt the motor.
I bought plugs that are two colder. By the way what plugs should I be using? I had A/C R44XLS in it before.

[gnarley]

Dan maybe you should bump your initial up a few degrees and reduce your advance so the total is less than or equal to 36 degrees. Something like 15 degrees initial as you say it runs good there then limit your advance to 21 degrees so you will have the total of 36 degrees this should keep 'em from burning and still make it run good.

[Dans66Stevens]

ok how do you limit total on a unilite dist? Can I adjust the total somehow?

[AMBUSHER]

DETONATION I AGREE ,SPARK KNOCK TO THE HILT !!!A/C 42 PLUGS AND 36 TIMING OR LESS AND FOR SURE BETTER GAS IT WILL FOR SURE MELT THE MOTOR , FOR SURE ,PLUS WERE DO YOU THINK THE TIP IS GOING ??IT WILL KILL VALVE SEAT OR PISTON TOP ,ECT

[gnarley]

Dan mallory makes a kit that has a chart with springs and keys. Buy the kit at Summit I did and works great, you adjust the allens that limit the weights & its easy!

[DansBlown73Nordic]

Well up-date on the timing troubles. I talked to Mallory twice this week. He told me that I could send my dist. back to them to have less advance put into it or I could bend the little tab that stops the advance. I took it apart and called him back to make sure I was bending the correct thing.
Today I bent it as far as I could. I now have 15% initial with 34% total. :D
When I started I had about 40% 0r maybe even 42% total..... eek!

[HammerDown]

SOOOOOOO...how's it run????

[DansBlown73Nordic]

Well I will run it tomorrow. It seams to run great in the driveway. :confused:

[gnarley]

Dan who'd you talk to at Mallory?

[Froggystyle]

Another thought is to lock out the timing and run a starter button. I have had great success with jets bringing in the advance early, and the most success with a blower motor. This would run 36 degrees at all RPM's, and avoid the BS.
With an MSD, it has a function for locking it out, I think you have to wire the Mallory out using safety wire.
Squirts up!