SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Rogers Hopeful on July 14, 2012, 05:33:47 PM
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2 plugs looked like this. One had some h2o on it. One hit by piston. 2 black with oil. And 2 were snow white (no fuel?). Time for rebuild. Hopefully no cracked block or head.
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didnt you just buy this boat?
time for a big block, prolly cost about the same
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It's going to be kind of important to figure out what caused the problem, to make sure you don't repeat that!
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Yep just bought it. Ran it about 10-15 times. Last time out it got a little warm (water 140*)(maybe fuel starved bc I would lose pressure at WOT). So new fuel pump will be in order. Could that have fried the electrode?
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what hit the piston? too much heat, lean or timing,hmmmm
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Piston hit spark plug. I am thinking it was running lean
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Did the spark plugs look like they had oil on them or did they actually have oil on them? Ive seen spark plugs that looked "wet" but actually werent. The plugs got too hot and melted whatever residue/deposits that built up on them giving it that glazed look. Ive only seen this happen once so i dont know how common it actually is. If there was actually oil on them, you were getting blow by in those cylinders from bad rings, scored walls or both. Snow white plugs means you were running really really lean.
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Piston hit spark plug. I am thinking it was running lean
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did the piston come apart? because if not i dont see how it could hit the piston :screwy:
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did the piston come apart? because if not i dont see how it could hit the piston :screwy:
How does the piston hit the spark plug if it is running lean???? I thought it would never touch lean or not, unless you are useing the wrong plug
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How does the piston hit the spark plug if it is running lean???? I thought it would never touch lean or not, unless you are useing the wrong plug
we think alike ;)
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That spark plug never got anywhere near a piston, it detonated itself apart....JMHO ;)
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BTW...If still going SBC I have a machined four bolt block, steel crank (standard), good rods, forged pistons (LT1 11.0:1) good heads and so on..
Was saving it for something special, but it seems a shame to let it just sit there...
All that needs to happen is a good balance (didn't know if I was going manual or automatic so never balanced it) and assembly, all the machine work is done.
Let me know, we can work something out...Also have the 454 in the little boat, can make you a screaming deal either way...I need a Jeep CJ or a Willys pick up to go play in the rocks... :sly:
Pull the heads, do some forensics and report back...Inquiring minds are nosy... ;D
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That sounds like a stout little motor. I will think about it. Pm me a price. If everything looks ok on my motor I will compare it to a rebuild. Don't car motors have different clearances then boat motors tho.
Got the boat home gonna tare down soon
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That spark plug never got anywhere near a piston, it detonated itself apart....JMHO ;)
. The pic is not of the plug that looked like it got hit. One of the plugs had the ground smashed up against the electrode. Spun bearing?
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Yep just bought it. Ran it about 10-15 times. Last time out it got a little warm (water 140*)(maybe fuel starved bc I would lose pressure at WOT). So new fuel pump will be in order. Could that have fried the electrode?
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If you knew you were losing fuel pressure, but still continued to run WOT, then you probably have the answer to the problem. I guess there is no real way to check timing at this point, but it's possible there was too much ignition timing as well. As I said above, you are going to want to know what cause the problem and make sure you don't do it again with a fresh engine. Where are you located, I can look at some of the parts for you if you want some help figuring it out.
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If you knew you were losing fuel pressure, but still continued to run WOT, then you probably have the answer to the problem. I guess there is no real way to check timing at this point, but it's possible there was too much ignition timing as well. As I said above, you are going to want to know what cause the problem and make sure you don't do it again with a fresh engine. Where are you located, I can look at some of the parts for you if you want some help figuring it out.
I would not make passes very long (10 secs max) because original tach was broke, tried to replace with new Stewart Warner but the Sun transmitter only works with original sun tachs. i thought it was a mag signal converter till someone corrected me. I am in lakewood near 605 & 91.
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First pic is 1-3-5-7
second is 8-6-4-2
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Old school plugs? What heads ya runnin? secondaries too lean?
Curious to see heads & piston tops
Daniel
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Gonna say it again...Not seeing a contact with piston plug..
Seeing some severe detonation, nothing lean, a little carbon buildup, are you sure you didn't suck an intake gasket....
C'mon, tear that fugger apart..... :banghead:
;D
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Gonna say it again...Not seeing a contact with piston plug..
Seeing some severe detonation, nothing lean, a little carbon buildup, are you sure you didn't suck an intake gasket....
C'mon, tear that fugger apart..... :banghead:
;D
Yea. No plugs touching going on there thats for sure. You are going to have to dig deeper into that one....
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so the #5 was maybe just hit by a dropped valve?
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C'mon, tear that fugger apart..... :banghead:
;D
Take 15 minutes and pull the heads off >:D
then we'll know
Daniel
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Gonna get the heads off on friday. Will post pics
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so the #5 was maybe just hit by a dropped valve?
nothing was "hit" by anything. you have 0 damage to the ground electrode. at WOT those eletrodes would be GONE had anything touched but they're perfectly fine.
you sure you dont have a vacuum leak?
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Had a little water in the oil in the valley. Aren't the springs supposed to be level
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someone really likes red RTV. heh.
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Oops
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Is the water from pulling the head without draining water first?
On your previous question about springs, they should be even only if the rockers were all loose so no valves were open. I guess that broken piston probably bent at least one valve?
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Is the water from pulling the head without draining water first?
On your previous question about springs, they should be even only if the rockers were all loose so no valves were open. I guess that broken piston probably bent at least one valve?
yes the water came from when we pulled the heads. i drained the block from the drains. the head gasket on the other side blew as well
The intake valve was pitted but none were bent.
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Gonna say it again...Not seeing a contact with piston plug..
Seeing some severe detonation, nothing lean, a little carbon buildup, are you sure you didn't suck an intake gasket....
C'mon, tear that fugger apart..... :banghead:
;D
X2 on the detenation, been down that road a couple of times with my 406 sbc. I just got done replacing pistons again this week. watch your timing and don't be cheap with the fuel
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Detonation.
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New refreshed motor!
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