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I posted earlier about the motor in my boat being full of water.
------------------------------------------------------------------- Well, my friend and I just pulled our 1970 slickcraft out of storage (my uncle's driveway). We had the old boat cover on it, and a tarp over that we didnt have the original bows, so we mad some by ripping down a 2x4. Needless to say, these didnt last the winter, and a bunch of water was pooled up on the tarp, and resting on the engine cover. We get it back to his garage and open the motor cover, and it was covered with water, every little divit or vally on top of the motor had water in it, and it get's better. We try to turn it over, we get about a 1/4 revolution using the starter, and it doesnt move. We put a breaker bar on the crank and try to turn it by hand, it wont budge. So we figure the cylinders are rusted alittle. so we pull the spark plugs, every cylinder was full of water with alittle oil mixed in. (one cylinder had more oil than water in it. we then drain the "oil", which turned out to be about 7 quarts of water and 3 quarts of oil. We figure the water came in through the carb. (the stud that holds the flame arrestor on is alittle too high, so the previous owner just drilled a hole in the cover.) There's a few things i dont really understand: 1. How did all 8 cylinders get water in them?, did it just leak past the valves? 2. How did the water get into the oil pan? We're thinking maybe a freeze plug in the bottom of the intake manifold, which would open a hole to the lifter valley. We've had some varying temperatures, (enough to melt the snow and then cold enough to refreeze it) We just redid the headgaskets last summer because we had a few cracks in the water jacket in the lifter valley. So we are hoping it's just a couple of freeze plugs, but I'm expecting the worst. We're going to do a compression test on all the cylnders to see if there's anything unusual there. Are there any other tests we can do to determine how much damage there is without tearing it apart? Any insight on this would be greatly appreciated. Oh BTW the motor is a Chevy 307. ---------------------------------------------------------------------- My friend and I finally got around to doing a compression test. The results: 1 120 2 120 3 10 4 95 5 90 6 60 7 85 8 90 We definitly know there is a problem with cylinder 3. we are thinking it's a cracked piston. we are thinking about either repairing it or getting a new motor. (either way, it's gotta come out). for the new motor, we were thinking about getting a 350 out of a van or something. would there be a problem with doing this? would there be a problem with the water cooled exhaust. (engine sucking water in because the valve timing is wrong). a new or marine cam would fix this problem, but we dont want to fork over a ton of money for it. Any suggestions would be greatly appreaciated. |
#2
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![]() "Jeff Zimmerman" wrote in message om... My friend and I finally got around to doing a compression test. The results: 1 120 2 120 3 10 4 95 5 90 6 60 7 85 8 90 Cylinders 1 & 2 are up where I expect. 120 PSI is indicating a little over a 9:1 compression ratio which is typical of an engine that runs on 87 octane gas. Cylinder 3 has a major problem. Cylinders 4,5, 7 & 8 are weak, very weak. If all the cylinders were that way and the engine basically ran I might continue to use it, but I wouldn't be surprised if it burned a lot of oil. Cylinder 6, at 60 PSI, is also toast. We definitly know there is a problem with cylinder 3. we are thinking it's a cracked piston. we are thinking about either repairing it or getting a new motor. (either way, it's gotta come out). I had a similar situation once, once cylinder with almost no compression. I thought I had a bad cylinder head gasket so I pulled the cylinder head. Didn't look bad, and there was no signs of scoring on the cylinder walls and the valves didn't look bad. I put the head back on and tried again, no difference. I pondered this situation for a while and then I happend to be watching the rocker arms while the engine rotated and I noticed that one rocker (on the dead cylinder) just looked different than all the others. It turns out that the hydraulic lifter had expanded all the way out and stuck there, which didn't allow the valve to close. I replaced the lifter and PRESTO, the engine ran fine again. I would start by checking the rocker arms (just because I was bit that way once) and then pull the heads off. If you have room to work with the engine in the boat then it isn't too difficult to get the heads off and that might be where the problem is. for the new motor, we were thinking about getting a 350 out of a van or something. would there be a problem with doing this? Okay, I am sure that this is going to renew the debate on if you should use an automotive block in a boat. Supposedly, a marine block uses stainless steel freeze plugs and cylinder head gaskets that are more corrosion resistant. If you operated in salt water I would worry about it, or if this was a newer boat that you expected to have around for a long time. If you are just trying to get a few more seasons out of this old boat then using the automotive block could save you a lot of money. Using a block intended for a heavy truck might get you a camshaft that is more suitable for your needs. This is the BLOCK that I am talking about here. All the electrical and fuel system components need to be marine versions. Starter, distributer, alternator, fuel pump, carburetor, etc. would there be a problem with the water cooled exhaust. (engine sucking water in because the valve timing is wrong). a new or marine cam would fix this problem, but we dont want to fork over a ton of money for it. There is no camshaft timing adjustments related to water cooled exhaust. It is the design of the exhaust manifolds that prevent the water from flowing back, not the camshaft. It is typical for a boat engine to favor the low end rather than the top end since that is where you generally need the power. Rod |
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