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Spark Plug problem in an old /6
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Author:  DusterMunster [ Mon Mar 07, 2005 12:36 pm ]
Post subject:  Spark Plug problem in an old /6

My engine idles erraticaly during warm up... it gets better, and then again later... specially with the brake pedal depressed on Drive in a stop light. I have to shift to Neutral and accelerate a little to avoid it to possibly stall.
I checked the problem and it has something to do with the spark plugs, mainly the #6. The engine is in a desperate need of new rings, the #6 sparks get wet with oil very fast. Some guy told me that it would ease the problem if I install hotter spark plugs in the #1 and #6 cylinders. Is it right?

Thanks,

Ed

Author:  SlantSixDan [ Mon Mar 07, 2005 12:48 pm ]
Post subject: 

Hotter plugs might help temporarily ease the problem. What year is your engine? Is it a '74 or earlier with the gasket-seat spark plugs, or a '75 or newer with the taper-seat spark plugs?

Author:  DusterMunster [ Mon Mar 07, 2005 1:13 pm ]
Post subject: 

Thanks Dan, it is a '74 with the aluminum spark plug tubes. I don't know if this is the answer to your question...

Ed

Author:  SlantSixDan [ Mon Mar 07, 2005 3:03 pm ]
Post subject: 

Claro que si, that's the answer.

See if you can get a set of Champion RN13LYC spark plugs. These have an extra-long set of electrodes that moves the spark point away from the metal walls of the combustion chamber. These tend to run a lot cleaner without pushing the heat range higher (which aggravates spark knock already caused by oil ingestion).

Author:  DusterMunster [ Mon Mar 07, 2005 3:29 pm ]
Post subject: 

Gracias, I will do... just another question. You mention to get a set... by that you mean to replace the six plugs with the RN13LYC?

Oh, and another doubt I got, is it good or bad to install "extension couplers" (don't know if it's the right term in English) to the plugs to prevent them to get wet?

Ed

Author:  SlantSixDan [ Mon Mar 07, 2005 3:36 pm ]
Post subject: 

Yes, install all six.

Spark plug extensions are a LAST resort to get the LAST few kilometres out of a really whipped engine. Do not use them unless you absolutely run out of other options.

Author:  Seis Inclinado [ Mon Mar 07, 2005 5:50 pm ]
Post subject:  Re: Spark Plug problem in an old /6

Quote:
My engine idles erraticaly during warm up... it gets better, and then again later... specially with the brake pedal depressed on Drive in a stop light.

Ed
I had a similar situation on my 79 \6 Volare. Tracked it down to a booster vacuum leak .
Check for leaks at the check valve on the booster itself, hose clamps between booster and vacuum tree on the sixth runner may not be tight enough and finally check the vacuum tree on the sixth runner. Mine was cracked.
Got one at the JY for a couple of pesos and problem solved.

Saludos

Author:  DusterMunster [ Mon Mar 07, 2005 6:55 pm ]
Post subject: 

Gracias Rafa, to be honest with you, the clamps on the brake booster are of the wire type and are not tight, they are actually loose, but I checked it using a fuel hose as an stethoscope looking for a hissing sound, but could not find one. I will follow your advice and replace the whole hose along with the clamps.

Saludos,

Eduardo

Author:  Rust collector [ Tue Mar 08, 2005 12:37 pm ]
Post subject: 

Try to block off the hose, and see if things change, Just remember you don´t have power anymore...

Author:  DusterMunster [ Tue Mar 08, 2005 12:47 pm ]
Post subject: 

Hey Rust...! thanks... I will try it. I think my brakes should be more powerful than they are now... Maybe they don't need adjustment and it has something to do with the vacuum line.

I will keep in mind the lack of power assistance while checking.

Ed.

Author:  cranky265 [ Tue Mar 08, 2005 1:28 pm ]
Post subject: 

Ive got to echo the sentiments about the brake booster. The booster will pull to much vacuum if it on its way out. This will cause inconsistencies with #6 plug. Another way around the problem is to run a carb with which has a booster connection (the problem would then be "dissolved" my all the cylinders).

Author:  DusterMunster [ Tue Mar 08, 2005 1:39 pm ]
Post subject: 

I'm sorry Cranky, I couldn't quite understand the carb explanation you give... Do you mean to connect the booster to some part of the carb instead of to the #6 runner?

Ed.

Author:  cranky265 [ Wed Mar 09, 2005 2:38 am ]
Post subject: 

Hey Duster,
I only mentioned that as there are aftermarket carbs available that have a connection for your brake booster (i.e Edelbrock AFB) Im not aware of what OEM carbs incorporate this feature. I know that none of the Carter BBD or BBS' that Ive worked on had this.

Clear as Mud?

Author:  DusterMunster [ Wed Mar 09, 2005 9:10 am ]
Post subject: 

Crystal my friend... :D

Ed

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