I find myself coming to these forums a lot for this project. So far I've gotten so many useful answers to fix my issues. However this one seems like its dreadful.
Long story short... I bought my first boat, with my first outboard a 1971 105 HP. Motor had issues getting it started but I got it going and it was a blast. compression was slightly low on #2 so I pulled the head and found deep scoring. I contemplated for a bit then decided it was worth the work. At the time all I could see was damage in #2 towards the top. at the time I could see no other damage but the walls were dark and everything else covered in caked on grease. I cleaned surfaces lightly but I should have cleaned them better to get a more clear view.
I brought it to a local machine shop and he said it was repairable and estimated about 2 weeks time. I waited for 5 weeks and finally got the block back today. When I picked it up he said he found 2 cracks in the cylinder wall but told me not to worry to much as they are on the exhaust side and on the exhaust stroke of the cylinder and the engine should run fine. The crack has gone all the way through the sleeve and into the block.
I believe I can weld the aluminum to keep the crack from spreading while a piston and rings are in the cylinder to keep the iron sleeve from warping under the heat... I am also worried about over penetration in the weld and aluminum getting in between the crack in the iron sleeve, which might make the crack worse under heat from the engine running. I think this can be managed as the aluminum is quite thick. However the crack near the back is in the direction towards the water jacket but hast not reached it yet and I don't want the exhaust getting flooded with water and potentially getting in the cylinders when the engine gets shut off.... but this is just me wanting to follow through with this project that has already bled so much out of me. I am not one to give up on projects but i feel I've gone too far into this one.
The engine rebuild alone is costing me roughly $1700 CAD which seems astronomical. most of the cost was new oversize pistons and boring and honing all 4 cylinders. plus a gasket set and other misc parts that broke during disassembly. Regardless I am going to reassemble the motor and run it. These cracks were probably present while I was going out this year so it does run with them. I just want to know how much I should worry about this or if theres anything I could do to prevent it from getting worse.
Pictures attached....
Long story short... I bought my first boat, with my first outboard a 1971 105 HP. Motor had issues getting it started but I got it going and it was a blast. compression was slightly low on #2 so I pulled the head and found deep scoring. I contemplated for a bit then decided it was worth the work. At the time all I could see was damage in #2 towards the top. at the time I could see no other damage but the walls were dark and everything else covered in caked on grease. I cleaned surfaces lightly but I should have cleaned them better to get a more clear view.
I brought it to a local machine shop and he said it was repairable and estimated about 2 weeks time. I waited for 5 weeks and finally got the block back today. When I picked it up he said he found 2 cracks in the cylinder wall but told me not to worry to much as they are on the exhaust side and on the exhaust stroke of the cylinder and the engine should run fine. The crack has gone all the way through the sleeve and into the block.
I believe I can weld the aluminum to keep the crack from spreading while a piston and rings are in the cylinder to keep the iron sleeve from warping under the heat... I am also worried about over penetration in the weld and aluminum getting in between the crack in the iron sleeve, which might make the crack worse under heat from the engine running. I think this can be managed as the aluminum is quite thick. However the crack near the back is in the direction towards the water jacket but hast not reached it yet and I don't want the exhaust getting flooded with water and potentially getting in the cylinders when the engine gets shut off.... but this is just me wanting to follow through with this project that has already bled so much out of me. I am not one to give up on projects but i feel I've gone too far into this one.
The engine rebuild alone is costing me roughly $1700 CAD which seems astronomical. most of the cost was new oversize pistons and boring and honing all 4 cylinders. plus a gasket set and other misc parts that broke during disassembly. Regardless I am going to reassemble the motor and run it. These cracks were probably present while I was going out this year so it does run with them. I just want to know how much I should worry about this or if theres anything I could do to prevent it from getting worse.
Pictures attached....
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