Spark plugs

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dartlove

dartlove

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Ok friends I need a little help with spark plugs. I have a new 383 stroked to 496 and am questioning my plugs. I am currently using NGK CR8E. I am wondering if they are the correct heat. Engine has 14: 1 comp msd distributor & 7al3 ignition box. Is this the correct heat range for my application? Any help is appreciated?
 
Cudafever said:
Any pic's of your plugs?
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I don't. Car is at the shop. I can say they were blackish, but not all sooty . But at the same time not black oily. I can say that the headers started to glow red. So I was thinking it was lean, but plugs say different. I am a little baffled
 
when you say the pipe were red.........was that at a high idle or like during a dyno pull??
 
dartlove said:
High idle break in process
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Not nearly enough timing. You should have had 40-45 degrees of timing at the least at whatever RPM you used for break in.

Hopefully you didn't stick some exhaust valves.

An 8 sounds pretty cold unless you are up around 13:1 and with that ignition, you shouldn't see any fuel residue on the porcelain except for the fuel ring at the bottom where the porcelain meets the shell.
 
yellow rose said:
Not nearly enough timing. You should have had 40-45 degrees of timing at the least at whatever RPM you used for break in.

Hopefully you didn't stick some exhaust valves.

An 8 sounds pretty cold unless you are up around 13:1 and with that ignition, you shouldn't see any fuel residue on the porcelain except for the fuel ring at the bottom where the porcelain meets the shell.
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Checked valves during leak down test. 37 at 2300
 
dartlove said:
Checked valves during leak down test. 37 at 2300
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37 isn't bad. That should not have turned the exhaust red though.

Usually, when you see the EGT high enough to turn the headers red without a load on it, you either have the timing too far retarded or it is dead rich, or both.

It may have been that you are pretty rich and 37 wasn't enough total to get everything burned (while not under load) so combustion was still happening when the exhaust valve opens. That makes the headers turn red.

I've seen guys who data log EGT get sideways because the EGT is high so they pull timing and fatten it up and the EGT goes even higher. That happens so often on alcohol it's not funny. The correction follows a curve where the EGT starts dropping, will flatten out and the start heading back up as you ADD timing and REMOVE fuel. Once you get the EGT heading back up then you are getting the tune close.

EGT response is relatively slow, so you need a large sample across a fairly long time. I generally only looked at the point from high gear on durning the run.

I mention all this because I'm bored. Worthless information, but I typed it out anyway. That proves I'm bored. I hope you get something out of it.
 
I've always thought that there was heat spikes at break in. The glowing could have just been a break anything. It sounds like you haven't been doing much driving in the car? Like a little time to get things sorted out?..
 
Ok, out of curiosity I looked up that plug. I'm pretty sure (99% sure) that there was never a cylinder head made for any V8 Chrylser that used a 10mm 3/4 reach plug.

So I'm doubting that plug number. The heat range I don't doubt, but the C plug in an NGK is a 10mm 3/4 reach. If that is the plug used I'm not sure how it stays in the plug hole.

Now I am curious.

BTW, IMO that plug is a range, maybe two too cold. But I'd rather see some pictures of the plugs before I owned that.
 
yellow rose said:
Ok, out of curiosity I looked up that plug. I'm pretty sure (99% sure) that there was never a cylinder head made for any V8 Chrylser that used a 10mm 3/4 reach plug.

So I'm doubting that plug number. The heat range I don't doubt, but the C plug in an NGK is a 10mm 3/4 reach. If that is the plug used I'm not sure how it stays in the plug hole.

Now I am curious.

BTW, IMO that plug is a range, maybe two too cold. But I'd rather see some pictures of the plugs before I owned that.
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This is the plug. You helped set the gear dri
15836045243511224538082126509584.jpg
ve over the phone
15836044258475379556287047087042.jpg
15836044838148802187184207881571.jpg
 
dartlove said:
So maybe I have the wrong plug all together?
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What's the number on the shell? That's not a 10mm thread. Looks like 14mm to me.

I may be wrong. There may be cylinder heads for Chrysler's that use that 10mm plug. I've never seen any. But doesn't mean they haven't been made.

With the number on the shell we can know more. Is there any numbers on the porcelain where the boot slips on?
 
I'm just going to add some detail to this, and YR, feel free to correct me.
Ground strap says more timing
base ring says (Maybe) jetting is ok on top. but vary rich everywhere else.
Plug is to cold because there is no sign of heat on the threads. (top 3 threads should have some discolor to them).

Now that i have said all of this, you can't go by any of this without a new clean plug that has had a couple of 1/4 mile runs and then shut down clean at the end of the run.
 
Cudafever said:
I'm just going to add some detail to this, and YR, feel free to correct me.
Ground strap says more timing
base ring says (Maybe) jetting is ok on top. but vary rich everywhere else.
Plug is to cold because there is no sign of heat on the threads. (top 3 threads should have some discolor to them).

Now that i have said all of this, you can't go by any of this without a new clean plug that has had a couple of 1/4 mile runs and then shut down clean at the end of the run.
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He has enough ignition that he should be able to keep the porcelain clean without making a full pass and clean cut.

All the rest is very correct. He needs some heat in the plug. And then once the plug has some heat in it, start looking at timing.
 
go hotter on plug. I like ngk in my suzuki, autolite n9yc or autolite 53 in the old 11.5 355
 
yellow rose said:
He has enough ignition that he should be able to keep the porcelain clean without making a full pass and clean cut.

All the rest is very correct. He needs some heat in the plug. And then once the plug has some heat in it, start looking at timing.
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Good point! The plug may be too cold to burn of the porcelain.(keep the plug clean) it may not be as rich as it looks.

didn't he say he was running 14:1 compression?
 
Cudafever said:
Good point! The plug may be too cold to burn of the porcelain.(keep the plug clean) it may not be as rich as it looks.

didn't he say he was running 14:1 compression?
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Yeah he did say 14:1 but even at that, the plug says it wants more heat, even though it isn't seeing much load.
 
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