Reading Spark Plugs (HELP)
Thread Starter
&amp;quot;Rodstoration &am p;quot; In Progres
Joined: Jun 2004
Posts: 1,397
Likes: 1
From: Frisco TX
Reading Spark Plugs (HELP)
Would appreciate some help with reading these spark plugs. I just removed them from my 1980 and the engine seems to have been running with less power than it had when it was last dyno-tuned this past July. Here are the specs on the engine:
* Original L48 now rebuilt and Stroked to 383 - 11.1 :1 compression
* Forged SRP flat-top pistons - Moly rings
* Comp XR276 Cam (extreme energy hydo roller)
* Edelbrock RPM Heads (Ported and Polished)
* Edelbrock RPM Air-Gap Intake
* Demon 750 w/manual secondaries
* Hooker Comp Headers
* MSD Digital 6 - MSD Blaster 2 Coil - MSD Billet Distributor - MSD Super 8 wires
* Dewitt Radiator w/ dual SPAL fans
Plugs are ordered (Drivers or Passenger side and from front to back)
Driver #1
Driver #2
Driver #3
Driver #4
Pass #1
Pass #2
Pass #3
Pass #4
Thanks in advance Everyone! Ed
* Original L48 now rebuilt and Stroked to 383 - 11.1 :1 compression
* Forged SRP flat-top pistons - Moly rings
* Comp XR276 Cam (extreme energy hydo roller)
* Edelbrock RPM Heads (Ported and Polished)
* Edelbrock RPM Air-Gap Intake
* Demon 750 w/manual secondaries
* Hooker Comp Headers
* MSD Digital 6 - MSD Blaster 2 Coil - MSD Billet Distributor - MSD Super 8 wires
* Dewitt Radiator w/ dual SPAL fans
Plugs are ordered (Drivers or Passenger side and from front to back)
Driver #1
Driver #2
Driver #3
Driver #4
Pass #1
Pass #2
Pass #3
Pass #4
Thanks in advance Everyone! Ed
Last edited by 80TexasC3; Jan 1, 2007 at 09:58 PM.
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
that some plugs indicate excessive oil. There is a possibility that you're getting some oil in from a bad intake gasket. Before you get too radial best to do a leak down test on the suspect cylinders to rule out rings.
Safety Car
Joined: Aug 2001
Posts: 3,892
Likes: 13
From: Pettis Performance 565 with two stages of Nitrous Supply nitrous 1.082, 4.61 at 155, 7.17 at 192
Boy, those look like he!!....the blown away electrode porcelain is a primary symptom of detonation. 11 to 1 compression and a relatively small cam could be the cause of that. How much timing is in the motor??
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Thread Starter
&amp;quot;Rodstoration &am p;quot; In Progres
Joined: Jun 2004
Posts: 1,397
Likes: 1
From: Frisco TX
Great input so far... Thanks everyone... here is some additional info based on the questions and input.
First... they are AC Delco Rapid Fire part #5 plugs.
- We participated in two Christmas parades this past month...lots of idling!
- Does blow blue smoke only on cold startup... no sign of smoke while running
- The picture can be misleading...there is no electrode damage...what appears to be damage due to detonation is actually deposits on the insulator.
I had a situation back in Oct or so where a few of the intake manifold bolts were forming oil around the head...so I torq'ed each down and the problem stopped. Believe I have changed spark plugs since then, so these plugs were installed since re-torqing the intake.
Any additional thoughts based on this additional input????
Thanks in advance...
Ed
...here is a pictre of the exterrior - just need the engine to run as good as the paint looks. Dyno'ed at about 387hp at the flywheel last July.
First... they are AC Delco Rapid Fire part #5 plugs.
- We participated in two Christmas parades this past month...lots of idling!
- Does blow blue smoke only on cold startup... no sign of smoke while running
- The picture can be misleading...there is no electrode damage...what appears to be damage due to detonation is actually deposits on the insulator.
I had a situation back in Oct or so where a few of the intake manifold bolts were forming oil around the head...so I torq'ed each down and the problem stopped. Believe I have changed spark plugs since then, so these plugs were installed since re-torqing the intake.
Any additional thoughts based on this additional input????
Thanks in advance...
Ed
...here is a pictre of the exterrior - just need the engine to run as good as the paint looks. Dyno'ed at about 387hp at the flywheel last July.
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Race Director
Joined: Nov 2002
Posts: 12,142
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From: Taylor Michigan
If I think what a 5 relates too, the heat range will probably be correct. I suspect you have a mild problem with the valve seals and they are going farther south than you are. 
My conclusion is also possibly confirmed by your statement of the hint of blue smoke on start up. Therefore the logical answer is that oil is being sucked through the valve guides and burning in the cylinders.
My conclusion is also possibly confirmed by your statement of the hint of blue smoke on start up. Therefore the logical answer is that oil is being sucked through the valve guides and burning in the cylinders.
Thread Starter
&amp;quot;Rodstoration &am p;quot; In Progres
Joined: Jun 2004
Posts: 1,397
Likes: 1
From: Frisco TX
If I think what a 5 relates too, the heat range will probably be correct. I suspect you have a mild problem with the valve seals and they are going farther south than you are. My conclusion is also possibly confirmed by your statement of the hint of blue smoke on start up. Therefore the logical answer is that oil is being sucked through the valve guides and burning in the cylinders.
My conclusion is also possibly confirmed by your statement of the hint of blue smoke on start up. Therefore the logical answer is that oil is being sucked through the valve guides and burning in the cylinders.It has always had very high oil pressure after the rebuild... usually peaks out the guage at 80+ then will be around 40 at idle and peak out under acceleration. Could this also be forcing oil into places due to the pressure?
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Actually no, oil pump pressure is not related to internal engine pressure. Something to consider may be the 80 lbs. is scavaging the oil pan and putting too much oil in the overhead covers thereby leaking past the guides and seals. This is a doubtfull analisys however as my engines hold similar pressures without any problem.
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
Yeah, I would say the plugs look really bad for just 1300 miles and that oil is coming into the cylinders. Even some of the threads are coated. What fuel are you using?
Thread Starter
&amp;quot;Rodstoration &am p;quot; In Progres
Joined: Jun 2004
Posts: 1,397
Likes: 1
From: Frisco TX
I did notice that several of the plugs were not difficult to remove (not loose but definitely not tight).
Tech Contributor
Joined: Aug 1999
Posts: 14,385
Likes: 6,413
From: At my Bar drinking and wrenching in Lafayette Colorado
You have detonation. It may have caused you some engine damage. Do a cylinder leak-down test. If the engine is okay, you need to run less timing or higher octane fuel.
Drifting
Joined: Sep 2004
Posts: 1,959
Likes: 1
From: North Bend Ohio
Is the PCV system operational? If you had oil foaming around the intake manifold the PCV system may not be operating properly. This could be blowing oil past the rings. Check for crankcase vacuum.
BigBlockk
Later.....
BigBlockk
Later.....