Over the past couple of weeks I asked a few questions about my powerhead that had rusted up with water in the crankcase. I stopped by the machine shop this afternoon and the machinist said he got the stuck piston out. Before proceeding any further I would like to post everything I know about this crankcase and see if I can get any ideas how the water got into the crankcase that caused the rust. Hope DHadley, Rodbolt or some of the other experts can give me some ideas.
As posted in earlier threads the compression before the engine sat for 9 months was excelent. The last couple of times I used the boat before letting it sit I had noticed rust on the lower left spark plug tip. When I tried to turn it over after sitting 9 months it was froze up. I removed the heads and the top 2 pistons were in the all the way out position, the lower 2 were in at the exhaust ports. I soaked it in various types of penetrating oils for a couple of weeks and still could not break it loose.
I removed the powerhead and opened the crankcase. The piston I expected the most trouble out of came out easy. Once I removed the rodbolts a tap with a mallet and she fell right out. The bore I thought was a little rough with rust around the exhaust ports. The top two pistons were a little harder to get out. I tapped on them a while with a mallet and a block of wood and they both came out slowly. The bores had only a little surface rust that cleaned up nice with a oily rag. The lower right piston was a bear, I could not get it to budge at all. The rod bolts were in a position where I couldn't get to them so I took it to the machine shop and let the guy there get the piston out. He had to press it out but it came out fine. That bore is pretty rough and the piston had white chalky corrosion all over it.
All 4 cylinders were already .0020 over from a previous rebuild. According to the machinist he thought the other 3 are fine as is but the lower right needs to be bored to .0030 or possibly .0040 over.
The rods and crankshaft had only a few spots of surface rust on them that wiped right off and the smooth areas are still shinny with no rust at all. Once the rusty oil was wiped off none of the bearings (which I won't be reusing anyway) showed any sign of rust. None of the piston rings were broken although a couple of them were rusted in place. One of the rings on the crankshaft was broken, I don't know if it was broken before the engine rusted up or if we broke it. Also the rust in the cylinders seemed to be mostly in the bottom 2 and mostly from the exhaust ports back.
So does anything I have posted give us any clues as to where the water got into the crankcase?
As posted in earlier threads the compression before the engine sat for 9 months was excelent. The last couple of times I used the boat before letting it sit I had noticed rust on the lower left spark plug tip. When I tried to turn it over after sitting 9 months it was froze up. I removed the heads and the top 2 pistons were in the all the way out position, the lower 2 were in at the exhaust ports. I soaked it in various types of penetrating oils for a couple of weeks and still could not break it loose.
I removed the powerhead and opened the crankcase. The piston I expected the most trouble out of came out easy. Once I removed the rodbolts a tap with a mallet and she fell right out. The bore I thought was a little rough with rust around the exhaust ports. The top two pistons were a little harder to get out. I tapped on them a while with a mallet and a block of wood and they both came out slowly. The bores had only a little surface rust that cleaned up nice with a oily rag. The lower right piston was a bear, I could not get it to budge at all. The rod bolts were in a position where I couldn't get to them so I took it to the machine shop and let the guy there get the piston out. He had to press it out but it came out fine. That bore is pretty rough and the piston had white chalky corrosion all over it.
All 4 cylinders were already .0020 over from a previous rebuild. According to the machinist he thought the other 3 are fine as is but the lower right needs to be bored to .0030 or possibly .0040 over.
The rods and crankshaft had only a few spots of surface rust on them that wiped right off and the smooth areas are still shinny with no rust at all. Once the rusty oil was wiped off none of the bearings (which I won't be reusing anyway) showed any sign of rust. None of the piston rings were broken although a couple of them were rusted in place. One of the rings on the crankshaft was broken, I don't know if it was broken before the engine rusted up or if we broke it. Also the rust in the cylinders seemed to be mostly in the bottom 2 and mostly from the exhaust ports back.
So does anything I have posted give us any clues as to where the water got into the crankcase?
