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What’s on my spark plugs?

rightytighty

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B510AE7C-F973-4EA3-B8AE-04F7E91B8DBC.jpeg

Something is weird on some of the plugs. There’s a bunch of “reddish fuzz” around the insulator on some of the plugs but not all. Not the best pic but you can see it. There’s hardly any insulator visible on this plug. I can clean it out with a tooth pick and no clue what I’m looking at...just a reddish fuzz. Insulator looks fine when I removed the gunk. Looks like I’m getting some water in on some cylinders as well, with rusty funk on bottom of a a few plugs.
Gonna test the exhaust tomorrow to check if water jacket leaking. Just edelbrock turbo logs. . Oil is NOT milk shaked.
Engine is a 565” BBC with single Dominator. Mild .600 ish“ lift roller cam. Less than 10 to 1 compression. I’ve been running it on AV gas for past 3 years (solely because I hate ethanol gas stability.this boat sits a lot, and it’s been easy starting after it sits since I switched it over. Boat runs good still, but I know something isn’t right. Thanks in advance
 

spectra3279

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View attachment 928637
Something is weird on some of the plugs. There’s a bunch of “reddish fuzz” around the insulator on some of the plugs but not all. Not the best pic but you can see it. There’s hardly any insulator visible on this plug. I can clean it out with a tooth pick and no clue what I’m looking at...just a reddish fuzz. Insulator looks fine when I removed the gunk. Looks like I’m getting some water in on some cylinders as well, with rusty funk on bottom of a a few plugs.
Gonna test the exhaust tomorrow to check if water jacket leaking. Just edelbrock turbo logs. . Oil is NOT milk shaked.
Engine is a 565” BBC with single Dominator. Mild .600 ish“ lift roller cam. Less than 10 to 1 compression. I’ve been running it on AV gas for past 3 years (solely because I hate ethanol gas stability.this boat sits a lot, and it’s been easy starting after it sits since I switched it over. Boat runs good still, but I know something isn’t right. Thanks in advance
Covid. Your vehicle has covid

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LazyLavey

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I think we called that fire crotch syndrome
 

rightytighty

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E969B405-EC18-4528-8A74-28460C2D9661.jpeg

Here’s 3 (first one was 5- with the “fuzz”. 3 has a some rust at base but no fuzz around insulator...1 and 7 look fine. All tested similar on compression(165) and no leaks on the log(stuffed ports full of tp and ran water through for 15 minutes. Dry as a bone.
Gonna pull even side next
 

rightytighty

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626B8A3B-0199-44DB-AED9-55945EC5C65F.jpeg

6 is showing moisture as well. Compression is good (165#). So water showing on both sides... damm...

Oil not milked so I assume head gaskets ok. Wondering about intake leak?? any way to test this?
 

alohajeff

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It might be worthing purchasing a cheapo lighted Bore Scope. They are small enough that can stick it inside the Cylinder and take a peek around. Same goes for the intake manifold. I picked mine up on Amazon for $20-ish bucks. It connects right to the USB port on my phone. The LED brightness is controllable. I was able to find I had water in a a few cylinders caused by a leak in the boat cover that allowed rain water to make its way down through the carb, through the intake manifold and past the cylinders with open intake valves.

Aloha
 

Hydroman55

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Stock or modified cam? Sure looks like reversion to me
 

Racer56

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The first picture you posted is probably lead deposits from running AV gas.
 

obnoxious001

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View attachment 928944
6 is showing moisture as well. Compression is good (165#). So water showing on both sides... damm...

Oil not milked so I assume head gaskets ok. Wondering about intake leak?? any way to test this?

Yes, you have some rust, I couldn't see it in the first photo you posted the other day, been busy out here this weekend so didn't look again. Put a wrench on intake bolts and gently see how much give they have, working from the center outwards. Gently, no need to get crazy, they get about 30 ft lbs or so. If any of the eight on the ends are loose it could allow the gasket to leak. I used Aviation Permatex on the water ports on your (and every other engine I build) engine.
 

rightytighty

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Yes, you have some rust, I couldn't see it in the first photo you posted the other day, been busy out here this weekend so didn't look again. Put a wrench on intake bolts and gently see how much give they have, working from the center outwards. Gently, no need to get crazy, they get about 30 ft lbs or so. If any of the eight on the ends are loose it could allow the gasket to leak. I used Aviation Permatex on the water ports on your (and every other engine I build) engine.
EED02C51-F1D4-4CBD-8D75-2D7FBD2DBCEA.jpeg

There was between 1/8 and 1/4 turn on most of the intake bolts before snugged. I guess I’m changing plugs and testing again?

Fingers are crossed!

Barry- looks like your 12 year old engine might live another day or two.

Thanks for checking in!
 

rightytighty

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Oh- does it make sense that the issues are all on the center 2 cylinders on each side?
 

obnoxious001

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Oh- does it make sense that the issues are all on the center 2 cylinders on each side?
That would be more indicative of something with the exhaust, if you had center rise manifolds instead of logs.

I don't expect that the intake bolts had anything to do with that, I normally always tell people to put a wrench on intake and exhaust bolts after the engine has run as the gaskets will take a set. If the intake were leaking, it would put water in the oil more than directly into a cylinder.
 

HAP

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I bet you will not get that with race and premium mix. I had some weird deposits like that when I ran avgas to break-in my 466 w10.9 compression. Boat engines just don't run the way aircraft engines do...

R,
HAP
 

Mikes56

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Could it be from condensation in the cylinders?
 
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