Detonation melted my piston..... but what caused the detonation?
05-21-2015, 01:47 PM
#21
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Wires laying over top of one another can arc between. I think it's msd if I'm not mistaking worns about this in their installation instructions when installing a coil. Plug wires should always be seperated and not touching one another. Never take a bundle of plug wires and zip tie them together.
05-21-2015, 01:54 PM
#22
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2 plug wires running in contact w/each other can cross-fire. Especially if wires are tired. In 5-7's case, it can fire 7 while it is halfway up on compression stroke. Causing big-time detonation on 7 cyl only.
05-21-2015, 02:05 PM
#24
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This was 5. Cross-firing would burn 7 up. It wouldnt really effect 5. It would fire after 5 fired and was halfway down in firing stroke. Would have no effect On 5.
05-21-2015, 02:16 PM
#25
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I saw your post here when you bought the boat. It is a cool looking old 28. With that being said, I hate to be the bearer of bad news, but after looking at your pics, I'm not at all surprised you are in the situation you are in now.
The general rigging of the engine looks horrible. First, what is up with the transom where the tailpipes go thru?? Second, nice throttle cable adapter modified by drilling a hole in the plastic throttle end. Cables and wires hanging on the exhaust pipes, screw holes all over the inner transom, Trailer too small for the boat, etc
Now, the engine is broken after a couple boat rides, had cheap hypercrackit pistons, is not a 496ci like you were told, car fuel filters, cheapy fuel pump, and who knows what kind of shape the other mechanicals of the boat are in.. my guess is poor.
Some friendly advice here. STOP and really think about what you wanna do at this point. Before sinking a bunch of money into the engine, I would thoroughly check the integrity of the transom, and stringers. The old scarabs were known to rot when treated like cream puff garage queens, and this one looks like it may have been violated a bit over the years.
If you really like the boat, and wanna pour money into it, like transom replacement, stringers, adding external steering, rebuilding a nice engine for it, possibly better trailer or modifying yours, etc, that is cool. But, be prepared to have 3 times as much into the boat, as its worth.
If the hull is rot free, a bilge makeover will go a long way. Filling in old holes, fresh repaint, redo all the wiring, cables, etc, and install a fresh engine in there. I was in your exact position at the age of 21 with my first boat. I bought a boat from some redneck who thought he was a real awesome engine builder/rigger. What did I know. Looking back, this guy had know business installing a license plate on a car, let alone building an engine and rigging it. After a complete summer of sweating my azz off in the bilge, blowing a bunch of money, working late nights on the boat, covered head to toe in mosquito bites, finally got the engine rebuilt and running good. Then, second time out with engine running good, the drive let go, and destroyed the upper housing. In the end, I was out over 10,000 dollars, and boatless. I got 4 boat rides out of it. That was alot of money for me at 21 years old. If I had only had someone to teach me, or a site like offshoreonly, I may have been saved a major headache and wallet draining. Good luck with the project.
The general rigging of the engine looks horrible. First, what is up with the transom where the tailpipes go thru?? Second, nice throttle cable adapter modified by drilling a hole in the plastic throttle end. Cables and wires hanging on the exhaust pipes, screw holes all over the inner transom, Trailer too small for the boat, etc
Now, the engine is broken after a couple boat rides, had cheap hypercrackit pistons, is not a 496ci like you were told, car fuel filters, cheapy fuel pump, and who knows what kind of shape the other mechanicals of the boat are in.. my guess is poor.
Some friendly advice here. STOP and really think about what you wanna do at this point. Before sinking a bunch of money into the engine, I would thoroughly check the integrity of the transom, and stringers. The old scarabs were known to rot when treated like cream puff garage queens, and this one looks like it may have been violated a bit over the years.
If you really like the boat, and wanna pour money into it, like transom replacement, stringers, adding external steering, rebuilding a nice engine for it, possibly better trailer or modifying yours, etc, that is cool. But, be prepared to have 3 times as much into the boat, as its worth.
If the hull is rot free, a bilge makeover will go a long way. Filling in old holes, fresh repaint, redo all the wiring, cables, etc, and install a fresh engine in there. I was in your exact position at the age of 21 with my first boat. I bought a boat from some redneck who thought he was a real awesome engine builder/rigger. What did I know. Looking back, this guy had know business installing a license plate on a car, let alone building an engine and rigging it. After a complete summer of sweating my azz off in the bilge, blowing a bunch of money, working late nights on the boat, covered head to toe in mosquito bites, finally got the engine rebuilt and running good. Then, second time out with engine running good, the drive let go, and destroyed the upper housing. In the end, I was out over 10,000 dollars, and boatless. I got 4 boat rides out of it. That was alot of money for me at 21 years old. If I had only had someone to teach me, or a site like offshoreonly, I may have been saved a major headache and wallet draining. Good luck with the project.
I have since adjusted the bow mount/winch on the trailer and it now sits well up onto the bunks without the transom hanging off the end but like you pretty much said, least of my worries at the moment.
The rigging is horrible in this thing and had all intentions of pulling engine next off season to redo all the wiring and clean everything up. Obviously doing that a lot sooner now lol. Went checking the boat out I knocked around the stringers and transom and all sounded solid. I will double check once I get the engine pulled and reevaluate everything if any rot is found. Aside from the mess under the hatch the rest of the boat is in great shape. Drive was checked out and in good shape. I appreciate all the advice and will definitely throughly check everything out now.
05-21-2015, 02:35 PM
#28
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Wires laying over top of one another can arc between. I think it's msd if I'm not mistaking worns about this in their installation instructions when installing a coil. Plug wires should always be seperated and not touching one another. Never take a bundle of plug wires and zip tie them together.
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