Reading Plugs? Calling all FE experts...
 

Hi all. Today I took ERA601 for its inaugural drive - which I will cover in general in another thread.

The main thing I would like to solve right now in this forum is a miss when under load - it starts and runs OK, but stutters and misses when the go pedal is pushed. The first thing I did was yank the plugs. Can anybody help in reading these? Are there any clues here?

http://www.clubcobra.com/photopost/d...ll8Plugs_2.jpg

The plugs are Autolite 45's, gapped to a loose .040". Are these right and gapped right?

The second thing I observed is a noticeable amount of of oil - along the base of the plug thread - see a closer up pic of the right bank plugs below.... Most plugs have it - some more than others. There is not a spec of oil anywhere else on the motor. Is this normal?

http://www.clubcobra.com/photopost/d...sRtSide_21.jpg

I go back to my old engine basics - 95% of all carb problems are electrical...am I in the right area?

I do not know the engine build story (it is new engine - based on the outside, a quick look under the vc's, and based on the rest of the car which has a total of 2k miles), I can't comment on much as to settings - the former owner is somewhere in the slammer, I can't call him for comments.

The car was run about 20 miles and on return to the shop I ran it up to 3k and quick-shut/killed it to shut it off - there was some run on. The plug color seems a bit white to me.

As for carburation...here is all I know....

http://www.clubcobra.com/photopost/d...ERA601Carb.jpg

Comments and any advice most appreciated...:confused:

Hi luke-44,
The plugs look good, to me white is good. What your describing to me sound like bad wires. I assume there new though. Check for a good accelerator pump shot,check distributor for good advance, mechanical and vaccum. What kind of ignition are you running? HEI or points? HEI plug gap .045, points .035. At what RMP do you experiance this problem and at what % of throttle. Sounds like maybe the jets are too small (lean missfire?).:confused:

Thanks for the reply. Ther problem seems to be at any rpm over 2500 or so - when you start to roll on the gas - either medium or hard. Here is the ignition setup....

http://www.clubcobra.com/photopost/d...16625MSD_2.jpg

What timing specs should I be looking for?

You say it stutters and misses when you hit the gas. Is that a temporary situation that then smoothes out or does it continue to miss and sputter under load? If it continues, I'd say it's more likely an ignition problem as opposed to a carb problem.

I'd start with the basics. Make sure you have all the plug wires in the correct firing order. Double check the timing (both initial and total). My FE likes lots of intial advance. I'm at about 25 initial and 40 total. Not sure what kind of distributor you're running but if you're using points, double check the point gap.

Chris

luke,
38 degrees of total advance. 10 base, where you set it at at idle. I'm not sure about that MSD system, but I think its all electronic after the base. Are there any springs or weights in the distributor? I have the MSD Pro BIllet Type. Whats your elevation/altitude? Do you know what jets you have? What model holley is that? You may need the rejetable plate between the secondary float and base of the carb.

What is all the black stuff on the plugs ?
Exhaust leak or leaking valve covers ?

I tend to think you have voltage from the plug wires going to ground down the outside of the plug.The voltage is taking the path of least resistance.

Here's a very good link to "reading sparkplugs".
http://members.uia.net/pkelley2/sparkplugreading.html

The black stuff, oil above the sparkplug seat is probably valve cover leaking. Try the spray bottle test, plug reinstalled, with the engine running spray water on the plugs and wires. In the dark/garage lights off you will see the sparks jumping off the plugs, or take a jumper wire ground one end and move the other around the spark plugs and look for arching. Looked at the plugs again and I dont see any carbon tracking.

ST,

Interesting site on plug reading, but it says that the tests are only valid under certain conditions:

"This is only valid if you shut-off the engine after the finish line then tow the car back to the pits where you remove the plugs for reading !!
Or if you are on the dyno
VALID ONLY for full load acceleration or steady state dyno tests"

Also, I've always been told that you can't really read plugs running today's unleaded fuel like we used to on leaded fuel. True or not?

Fred - thanks for the input, but I am ruling those possibilites out as the headers/valve covers are clean as a whistle. It is strange though - the oil seems to be more below the seating area and on the threads than above it. Again, these are the first ever miles, so I am feeling my way here.

Chris - good question - to be honest with you, I need to drive the car again - I was kinda overwhelmed by a bunch of senses with my first ever drive and all, and I was wondering the same thing upon reflection - this might be a clue to gas starvation/settings. I will try again tomorrow - bringing the revs up slow and seeing how it goes - being a new motor, I don't want to rev it too high - I was thinking up to 4500 or so - I guess this is safe for a new motor....as well, you end up well over the speed limit real quick in these cars (another "first" observation)

I can only assume the firing order is right, based on how it starts and idles - (do you have the firing order handy?). Thanks for the timing specs - I'll check it in the AM.

Ted - I'll dig into the distributor in the AM. I thought MSD replaced points, but my experience is from the old coil/points/rotor days. I am also a newby when it comes to holleys - I don't know what size or type, or how to play with jets. My 1st thought was to eliminate electrical, and if that doesn't get it I would dig into the carb.

Hey luke-44, just curious about something else...

Its hard to tell from the pics, but the passenger side plugs look to be coated with a bit more oil. So the question I have is how is the oil getting there in the first place and is this a symptom that also might be related to the motor missing under load?

If all else checks out okay, you might consider looking at the intake manifold to be sure its sealing properly. If not, its also a possibility that you have an intake/vacuum leak going on causing a lean/miss condition under load, and at the same time having oil from the lifter galley sloshing up and getting sucked down into the cylinder head intake ports down into your cylinders on the passenger side. Some Intakes on FEs don't always seal really well if the slightest part of the gasket gets buggered up on the install (which is easy to do).

Do you ever see any type of extra or blue smoke from your sidepipes/exhaust, at any point?

Does the miss/break-down condition change between when the motor is hot/cold?

You might check/retorque your intake or look down the intake by removing your carb and using a small mirror to see if the intake is all black inside from oil on any of the intake runners on the passenger side.... Sometimes the intake needs to come completely off and regasketed to fix this type of problem; if this is the problem. Good Luck. :)

Bruce,

Your problem might be from electrical interference within the MSD circuitry.

We create two bundles of wires from the MSD unit:

* The harness to the distributor is run down behind the engine and to the left side of the carburetor.
* A second bundle to connect with ERA harness #40 runs down the right side of the engine and across to the left wheel house.

http://www.erareplicas.com/427man/wi...sd/wirelay.jpg

ERA MSD installation page

Bruce,

First off white on the plugs in not a good thing. Sounds like it may be a bit on the lean side. The normal color for plugs when everything is right is light tan. Have you tried pulling on the choke as you drive the car? If the car is lean as you pull the choke on the engine will start to feel and sound stronger and the miss will go away. If it is to rich, no way in your case, the engine will start to load up and black smoke will come out of the pipes.
Before you dig into any other "problems" try this. It is quick and easy to to do.
Remeber when it comes to working on and repair or even building cars K.I.S.S. Keep it simple stupid. Words to live by!
Look for the easy stuff first! It could save you a lot of time and work.

Bruce:
Simple question, The MSD 6AL has a rev limiting (ceiling) chip, this is a white chip with two prongs on it AND the ceiling RPM of the chip written on the outside of the chip. This chip plugs into the MSD unit.

Is your seated well?
What is the limit on the chip? ie: what is printed on the chip face?

You probably should have a chip in the MSD6AL that reads 6000 or so. Is this what you have in the box?

Check and report back.

luke-44,
Also... see the wires that strictlyperson posted... I had a similar condition to yours (under load a higher rpms) when the #40 wire was right next to the wires going to the coil. Installed an isolator jacket on the two coil wires, and the miss at higher rpms under load went away immediately. My wiring is routed exactly as strictlpersonl has shown.

- still curious as to why you are getting oil on/into the spark plugs though...?

One other thought, after looking at your plug pictures....

It appears to me that IF your car is new and has not been run too long or often (is this true?) that you have what appears to be alot of carbon discoloration caused perhaps by blow-by on your plug ceramics?? I notice my plugs do not have this feature after about 1000 miles on them...

As for the oil, it may be that your plugs are showing oil if your mechanic did a compression leak-down test and was less than tidy with spraying oil into the cylinders?? You may want to clean that area up.

Also, your plugs may not have been snugged up enough in the heads? That could account for both blow by of carbon as well as some oil residue? Do not overdo the torque on them though. Does anyone have the actual torque for plugs??

Just a thought...

You may want to use a mirror and a good light and check your plug holes to make sure that there are no plug washers "stuck" to the plug seating area of the heads. Some plugs come with washers others do not. Oil can cause them to stick to the head when you remove the plugs (if yours have such washers).

Thanks everyone, for the input with my problem. Today we had poor weather here - cold, freezing rain etc, so further testing was not possible. I am rereading all comments and looking at all possibilities.

Ted - no weights/points in distributor - just a rotor.

Art in Ct - I checked for plug washers - negative. However, the more I look at these plugs, I thinkyour theory of the mechanic leak down test/excess oil may be a contributing factor. First of all, the oil is clearly above the plug seating face, which means it had to be from the outside - there is also a noticeable browning / darkening on the plug ceramic surface - something going on. I have cleaned the plug exterior up and will reinstall.

Bob and Duane - this could be the main issue. The MSD was moved by Doug/Ritchie when the car was at ERA end of Jan, but, the routing isn't as you describe. There are 2 wire sets that come from the firewall/MSD, running together, along the engine right side, and then going across the front, to the distributor. here is their routing, tied together, (I assume the 3rd line, which goes to the front of the intake is the water temp sensor line?):

http://www.clubcobra.com/photopost/d...RtSide_jpg.JPG

When they emerge on the left side of the engine, the lines connect as follows:

Pair #1 - orange and black - go to the coil.

pair #2 - red and white - go to a white connetor. Out of the other side of the connector are a black and red wire - which goes to the distributor, and the other side of the connector joins a 3rd white wire, coming in from a harness running down the cars left side - this white wire has the #40 label - visible in the pic, and clearly #40, but not readable in the photo. There are actually 2 wires inside the #40 bundle, one is cut off under the tape - only the white is attached to the connector. Is this 2nd wire redundant? Besides the miss under load, the car does start and idle ok. Comments?

http://www.clubcobra.com/photopost/d...ftSide_jpg.JPG


So....if the wires running together is a problem, then this may well be it, as they are tandem from the firewall to the distributor/coil. I will reroute for sure and see if this helps.

Luke:
Did you investigate the MSD chip in your MSD-6AL?
Each of these boxes has a plug in rev-limiting chip which is plugged into a slot on the box from the outside.
For your engine the chip should be labeled about 6000 RPM or so?
You must find this plug and make sure you have the correct rev limiting plug in the MSD. If you have a lower RPM plug, you symptom will be breakup of the ignition at the RPM of the plug.
Please check it and let us know what you have there ok?
Art

Update 4-9-04
 

Hi all. Thanks for all the previous comments and help.

During our week of lousy weather, I rerouted the MSD lines to splitting them as suggested by Bob P, and I cleaned up and resnugged the plugs.

BTW - Does anyone know the torque setting for the plugs?

I do think they were quite loose originally - as suggested by Art this could have been part of the cause for the deposits on the plugs. I also bought new wires from Southern Automotive, but, the ends don't fit my distributor, so I couldn't install them.:CRY:

Today I took ERA601 out again (finally in the sunshine!:D ). Bear in mind I have about 20 miles of Cobra experience under my belt.

The car is quite happy to burble around at low rpm's, but, I dunno - the car just doesn't have the snap I would expect when you punch it - - it works its way up to the redline alright, but, it just seems to come on kinda slow at first...and then really pins you back (almost feeling dangerously like a stuck accelerator when I let off :eek: - which I can't seem to find). Maybe my expectations are too high... maybe that's just the way they are...I have no real baseline...in conclusion, imho, it just doesn't feel....right.

My thoughts now are: it is definitely not the MSD chip - I ran it up to 5900 once, and it started to cut out and miss real bad - this is distinctly different to what I described earlier. I think the MSD cutoff is working real well.

This now leads me to conclude I am not dealing with a miss at lower rpm's, but rather a bog or stutter - I am now thinking timing or carb jetting. I will double check the timing specs and see where I am. I know I shoulda done this earlier, but I am working through 1 variable at a time. :confused: . Comments, as always, appreciated.

Oops! See below.....