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| Weird plug coloring https://www.slantsix.org/forum/viewtopic.php?t=61691 |
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| Author: | dirtyd100 [ Fri Dec 08, 2017 1:00 pm ] |
| Post subject: | Weird plug coloring |
Pulled the plugs today and had some interesting coloring on 2-5 plugs, 1&6 were a nice caramel color. The middle plugs were black sooty on one side of the plug and the other side was the caramel color except for #4 which was black all around. I know that black means that it is either oil leaking into the cylinder somehow (rings or valves) or a rich condition. Could this also be caused by mis-adjusted valves? Why are there different colored sides (or top and bottom) on the spark plug electrodes? None of the plugs had any moisture on them, just a sooty condition. Thanks |
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| Author: | Dart270 [ Fri Dec 08, 2017 1:48 pm ] |
| Post subject: | Re: Weird plug coloring |
Yes, if you have valves with different lash, that can cause mixture variations. Lou |
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| Author: | dirtyd100 [ Fri Dec 08, 2017 7:21 pm ] |
| Post subject: | Re: Weird plug coloring |
Also noticed tonight that I leave a nice black spot on the ground where the exhaust dumps. Have not had time to really check it out to see if there is any oil smell to it or if it is something else yet. Usually happens when I let it warm up in the morning before going to work and I park in the same spot. I let it idle tonight for about 5-10 minutes while waiting for a buddy and there it was again. Not sure what that means yet either. |
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| Author: | wjajr [ Sat Dec 09, 2017 5:09 am ] |
| Post subject: | Re: Weird plug coloring |
First perform a hot valve lash with engine running. Black spot on ground after cold start and extended idling is caused by rich mixture. Suspect slow or less than full choke pull off. Make sure air cleaner is not restricted. Idle air mixture may also be on rich side. Once engine is fully warmed up, any vacuum leaks found and corrected, and choke fully open, adjust idle mix screw with vacuum gauge reading intake manifold (not #6 runner) vacuum until highest reading is reached. You may need to readjust idle rpm while adjusting idle mix. This assuming base timing is correct. Keep in mind advancing base timing will increase idle rpm, retarding the opposite. |
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| Author: | dirtyd100 [ Sun Dec 10, 2017 11:14 am ] |
| Post subject: | Re: Weird plug coloring |
Where do I hook up a vacuum gauge if not #6 runner? The only other option is the vacuum advance line which is ported from what I have been told. Will the PVC port give me full vacuum? I have no other holes on the intake or the carb. |
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| Author: | SpaceFrank [ Wed Dec 13, 2017 7:02 pm ] |
| Post subject: | Re: Weird plug coloring |
Yeah, you should be able to use the PCV port. |
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| Author: | Charrlie_S [ Thu Dec 14, 2017 4:10 am ] |
| Post subject: | Re: Weird plug coloring |
Quote: Where do I hook up a vacuum gauge if not #6 runner? The only other option is the vacuum advance line which is ported from what I have been told. Will the PVC port give me full vacuum? I have no other holes on the intake or the carb.
You could use the port on the carb, for the choke pull off. That is full time vacuum.
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| Author: | dirtyd100 [ Thu Dec 14, 2017 7:21 am ] |
| Post subject: | Re: Weird plug coloring |
I am not using a factory carb, it is a Weber style 32/36 and the only vacuum port is for the dizzy advance which is ported so it shows no vacuum at idle. I have a port on the adapter plate that the PVC gets its vacuum from. This should be full vacuum I believe, but would it be detrimental to a vacuum gauge to have it tee'd off of the pcv? I am thinking of putting in a permant in or under dash gauge to monitor vacuum and economy like they did back in the 70s. |
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