spark plug color
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=42515
Printed Date: April-20-2024 at 2:51am
Topic: spark plug color
Posted By: shierh
Subject: spark plug color
Date Posted: March-20-2018 at 10:51pm
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Carbureted 351w how even are your insulator color over the 8 plugs Mine vary, fact is I have one that's way too clean. very puzzled on that. |
Replies:
Posted By: KENO
Date Posted: March-21-2018 at 8:37am
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How clean is way too clean? Perfect time for pictures would be right about now. Is the plug firing at all or is it looking like new? It could be that you have water leaking into that cylinder and you're steam cleaning that plug while the engine is running. Some variation is normal but this sounds like one is a whole lot different. |
Posted By: SNobsessed
Date Posted: March-21-2018 at 9:50am
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I had valve stem seals that were cracked & leaking, causing some plug fouling. Wasn't using enough oil to notice otherwise. Replaced seals with heads on. Now all plugs stay off-white. ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: shierh
Date Posted: March-21-2018 at 10:21am
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75 hours on this engine rebuild. Everything was new. I will verify if plug is firing and also stick a camera in the cyl and look at piston and see if its being steam cleaned. Wire set came from Skidim. Plugs are NGK BPR6FS. I checked gap and they were smaller than 035 so I re gapped all of them. Engine does seem a little rough at slow speeds lately, Seems to run up properly though. This could be sign of water I would guess. |
Posted By: GottaSki
Date Posted: March-21-2018 at 11:14am
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To answer your question, all mine are even, and clean. How is your PVC Plumbed? To just one runner, or to the carb, or spacer plate? ------------- "There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole |
Posted By: shierh
Date Posted: March-21-2018 at 11:58am
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PVC goes to base plate. I didn't replace the PVC when I rebuilt engine, only cleaned it out with brake parts cleaner. |
Posted By: JoeinNY
Date Posted: March-21-2018 at 12:04pm
Does everything include the exhaust manifolds? Super clean and rough at idle could certainly be a slow drip down a manifold runner... ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1477 - 1983 Ski Nautique 2001 1967 Mustang 302 "Decoy" http://www.youtube.com/watch?v=cO5MkcBXBBs - Holeshot Video |
shierh wrote:Posted By: shierh
Date Posted: March-21-2018 at 12:55pm
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New manifolds and risers. Heads were replaced with used ones and magnafluxed. New head bolts, arp. Marine head gaskets. Fact the only remaining original component is the distributor. Engine was built properly however failure can happen. Think riser gasket could be an issue. Have seen some signs of external leaking on both sides. Will get new riser gasktets and bolts just to rule this out. |
Posted By: shierh
Date Posted: March-21-2018 at 3:09pm
| its cyl #6 which is at the forward edge of the center riser. |
Posted By: shierh
Date Posted: March-21-2018 at 11:15pm
| Bore Scoped all 4 on left side. all have rust speckles on upper cylinder walls. pulled riser and did find some evidence of a water leak. I believe this is the culprit. Honed surfaces and getting gaskets tomorrow after work. |
Posted By: shierh
Date Posted: March-22-2018 at 3:45pm
 Im on a fence post with this |
Posted By: KENO
Date Posted: March-22-2018 at 8:34pm
| I think the logical thing to do is spend about 20 or so on new plugs after you're done with the gasket replacement and check them pretty frequently.to see what's happening. |
Posted By: Duane in Indy
Date Posted: March-22-2018 at 8:38pm
It's a shame that it is so difficult to check EGT (exhaust gas temp) as it would tell a lot at all RPM's. I watch mine in my airplane continually  ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: MrMcD
Date Posted: March-23-2018 at 2:32pm
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Use a hand held temp gun. I have a fluke that does a great job. I bought it after watching a friend use his while running a dyno test. They give you instant temp reads, as fast as taking a picture. ------------- |
Posted By: shierh
Date Posted: March-26-2018 at 2:37pm
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I ordered plugs last week. I do have an ir gun, Will try that next time. Right now my number 1 plug is too clean and my number 6 is way too clean, at least compared to other plugs. |