A lot of the boats I'm looking at have this engine and most are in need of attention. Been wondering what would be involved, so I'm so glad you did this video. Thank you!
The rust in the water passages after you acid washed the engine is just from the lack of antifreeze, nothing more. An "empty" engine will deteriorates incredibly fast compared to one that at least has antifreeze in it. I've searched for engines in a junkyard where the oil pan had rusted through because there wasn't any oil left in the crankcase. If you can see crosshatch on the cylinder wall, the last thing you need to do is overbore the engine. Rings are a wear item on any engine... that's why they come off. There is just enough rust-able metal in old hard piping to make them rust, that's why the new ones are some kind of alloy. No more rusting, it's called progress and it's usually a reaction to stuff that has happened.😊 The piston will always have scoring on it, just because of the way it moves in the cylinder. A brand new one will have scoring on it in six months ( depending on how much you use the engine).
Sounds like you should carry a spare lift pump too. Debris in the pan and the scoring of the rod bearing are concerning. On auto motors, you can "roll" new main bearings in without removing the crank. I would be inclined to do this. A bearing set will not be too expensive. Now is the time... Don't forget to look at the valves and seats to make sure they are in good shape. There should be a clean sealing surface, not pitting, etc... Keep the old steel oil tubes and banjo fittings on the boat just in case... You will "know" this engine very well after this project.
Fascinating tear down really great job on getting the video. I have a Yanmar 3gm30F, same engine, 3 cylinders, and just like you I've never done such an extensive tear down. About 40 years ago I rebuilt a Triumph Spitfire engine, my only real experience. But I'm about to replace the exhaust system on mine. I envy you having the engine out, I have an Alberg 35 and space is tight.
Thanks for this comment, Ed. I find that some folks recommend replacing the head studs, but primarily when damage is found (replacement them all, not only the damaged stud). The Yanmar service manual doesn't call for their replacement, so I'll keep using the ones I have.
Have you fixed the rudder issue yet? I was thinking I would calculate how much correction is needed and grind one side of the shaft keyway enough to "center" it and grind the tiller keyway to match then use an oversized key in the enlarged keyway. Could probably be done with a Dremel and cut-off wheel or angle grinder with a cut-off wheel and a file, while checking with a micrometer.
For eliminating rust: Just make sure that you use the correct antifreeze/coolant in any engine you have. There is a difference between diesel engines and gasoline engines. I believe one is nitrite based, the other silica based (auto engines with aluminum radiators). Do diesel engines use different coolant? To counteract the effects of cavitation, diesel coolant contains special additives (primarily nitrite). Nitrite works by coating the metal components that are in contact with the coolant. The nitrite coating cushions and absorbs the impact the cavitation bubbles.What happens if you put regular coolant in a diesel engine? Diesel engine coolant needs to have SCA (special coolant additives)in it to keep tiny air bubbles from forming on the cylinder liners. The shock of combustion can cause cavities to form in the metal (cavitation) when these tiny air bubbles in the coolant explode. This cavitation will eat right through a cylinder liner.
Hey Owen, new subscriber to your channel. I just bought my first boat (83 Cape Dory 25D) hull #112, we have the same boat but mine came with the Yanmar 1GM10 and a three blade prop. Have any idea why they're different? Thanks...
Congrats on the new purchase. The 1GM was only manufactured 1980-1982. My 25D is #98 and put together in Oct 83. I suspect it was one of the last to get the 1GM before CD moved to use the updated and more powerful 1GM10. Thankfully, parts for both are still readily available. Enjoy!
So far I've only used a few wraps of parachute chord over the anchor's shank, which was good enough for the relatively short trips I've done so far. I'll be looking for a more elegant solution as I go.
@@randyborland9236 I never considered contacting Spartan about it. You might post the information to the message board on the Cape Dory Owner's Association site, capedory.org.
When you mentioned the thermostat had rust my first thought was complete tear down to check main bearings and timing chain for wear. There is also the rear main oil seal. Rust means bad coolant and bad coolant means bad oil and bad oil means excessive wear on lower end.
A lot of the boats I'm looking at have this engine and most are in need of attention. Been wondering what would be involved, so I'm so glad you did this video. Thank you!
I'm glad you found it useful.
The rust in the water passages after you acid washed the engine is just from the lack of antifreeze, nothing more. An "empty" engine will deteriorates incredibly fast compared to one that at least has antifreeze in it. I've searched for engines in a junkyard where the oil pan had rusted through because there wasn't any oil left in the crankcase. If you can see crosshatch on the cylinder wall, the last thing you need to do is overbore the engine. Rings are a wear item on any engine... that's why they come off. There is just enough rust-able metal in old hard piping to make them rust, that's why the new ones are some kind of alloy. No more rusting, it's called progress and it's usually a reaction to stuff that has happened.😊 The piston will always have scoring on it, just because of the way it moves in the cylinder. A brand new one will have scoring on it in six months ( depending on how much you use the engine).
I am amazed that you dont have training as a mechanic. You clearly have a talent for it. Absolutely fascinating. Thank you.
That's very kind of you. I've simply spent a lot of time watching videos of others doing these kinds of things.
Love your videos Owen. Thanks for sharing!
Glad you like them!
Sounds like you should carry a spare lift pump too. Debris in the pan and the scoring of the rod bearing are concerning. On auto motors, you can "roll" new main bearings in without removing the crank. I would be inclined to do this. A bearing set will not be too expensive. Now is the time... Don't forget to look at the valves and seats to make sure they are in good shape. There should be a clean sealing surface, not pitting, etc... Keep the old steel oil tubes and banjo fittings on the boat just in case... You will "know" this engine very well after this project.
Fascinating tear down really great job on getting the video. I have a Yanmar 3gm30F, same engine, 3 cylinders, and just like you I've never done such an extensive tear down. About 40 years ago I rebuilt a Triumph Spitfire engine, my only real experience. But I'm about to replace the exhaust system on mine. I envy you having the engine out, I have an Alberg 35 and space is tight.
"Do no harm".. and proceeds to belt engine with hammer! Onwards Owen!
Not sure but you may want to consider replacing the studs that hold the head on. Thanks for sharing
Thanks for this comment, Ed. I find that some folks recommend replacing the head studs, but primarily when damage is found (replacement them all, not only the damaged stud). The Yanmar service manual doesn't call for their replacement, so I'll keep using the ones I have.
Have you fixed the rudder issue yet? I was thinking I would calculate how much correction is needed and grind one side of the shaft keyway enough to "center" it and grind the tiller keyway to match then use an oversized key in the enlarged keyway. Could probably be done with a Dremel and cut-off wheel or angle grinder with a cut-off wheel and a file, while checking with a micrometer.
I no longer believe the rudder needs repair, but your idea for correcting the offset is interesting. I'll keep that in mind. Thank you.
For eliminating rust: Just make sure that you use the correct antifreeze/coolant in any engine you have. There is a difference between diesel engines and gasoline engines. I believe one is nitrite based, the other silica based (auto engines with aluminum radiators). Do diesel engines use different coolant?
To counteract the effects of cavitation, diesel coolant contains special additives (primarily nitrite). Nitrite works by coating the metal components that are in contact with the coolant. The nitrite coating cushions and absorbs the impact the cavitation bubbles.What happens if you put regular coolant in a diesel engine?
Diesel engine coolant needs to have SCA (special coolant additives)in it to keep tiny air bubbles from forming on the cylinder liners. The shock of combustion can cause cavities to form in the metal (cavitation) when these tiny air bubbles in the coolant explode. This cavitation will eat right through a cylinder liner.
Hey Owen, new subscriber to your channel. I just bought my first boat (83 Cape Dory 25D) hull #112, we have the same boat but mine came with the Yanmar 1GM10 and a three blade prop. Have any idea why they're different?
Thanks...
Congrats on the new purchase. The 1GM was only manufactured 1980-1982. My 25D is #98 and put together in Oct 83. I suspect it was one of the last to get the 1GM before CD moved to use the updated and more powerful 1GM10. Thankfully, parts for both are still readily available. Enjoy!
Owen, for your anchor roller on the bow, what do you use to secure the anchor?
So far I've only used a few wraps of parachute chord over the anchor's shank, which was good enough for the relatively short trips I've done so far. I'll be looking for a more elegant solution as I go.
@@VoyageDreams I sent an inquiry to Spartan Marine. They responded, but I’m not sure how, yet, I can share with you and the rest of us 25D owners.
@@randyborland9236 I never considered contacting Spartan about it. You might post the information to the message board on the Cape Dory Owner's Association site, capedory.org.
When you mentioned the thermostat had rust my first thought was complete tear down to check main bearings and timing chain for wear. There is also the rear main oil seal. Rust means bad coolant and bad coolant means bad oil and bad oil means excessive wear on lower end.
It's a raw water coolant engine my friend.