Yanmar 3gm 30 engine seized

Jun 12, 2013
213
Hunter 40 back creek
It is the position I had to put the connecting rod in to get the rod slid next to it as I was hammering the piston up the connecting rod got jammed on the lower lip of the liner but I figured I could just bang the piston back down a little bit and then try to guide the connecting rod into the center of the liner
 

Jim26m

.
Apr 3, 2019
579
Macgregor 26M Mobile AL
Yikes. You have to be careful not to do any damage to stuff you're going to re-use. Might only be the connecting rods, crank and block, but try to do as little damage as you can.

I know it isn't easy to be careful when you're trying to beat pistons out of an engine from the bottom end. Take it easy and monitor the progress as it goes to make sure nothing is binding. Take a break if you get frustrated. That's usually when I tear something up...

Bump it back down and get it free. It's got to come apart. If you bent or gouged the rod, you will probably be able to source a new one. Watch the bearing surfaces on the crank. You don't want to damage those.
 
Jun 12, 2013
213
Hunter 40 back creek
Pistons, rods and sleeves came out in one piece!! Pistons are welded tight and had to hammer the connecting rods to get the pistons out!! What next?
 
Nov 6, 2006
9,884
Hunter 34 Mandeville Louisiana
Rings are $63 per cylinder and the liners are $155 each.. You can probably save the pistons by carefully, patiently, slowly.. tap them down then up with lube oil in the space between them and the liner.. The ring lands in the pistons may have been damaged by the removal effort, which would make them toast and require new ones. A new piston with rings is $113.. It may be possible to reclaim the liners by honing after the pistons are out, but your description of how bad the rings are stuck probably says that they are toast as well.. These are part prices from Toad Marine Supply and if you can cross-match the 3GM30 to the Yanmar tractor motor, you can probably get these parts at a significant discount. From where you are now, a valve job and new seals and bearings would be in order..
Quite a job.. Good luck
 

Jim26m

.
Apr 3, 2019
579
Macgregor 26M Mobile AL
The hard part is done. Decide how much of the rest you want to take on. I agree with @kloudie1 - do the valves, seals, and bearings while you're here - especially if you're keeping the boat. You should be able to get a rebuild kit that has most of the stuff you need. Then, you'll have to add things like pistons, rods, and sleeves that don't typically come in the kit. You'll have to shop around and see what's available.

If you get queasy, check with a few machine shops and see what they want to put it back together for you including the cylinder head work.

I know it's a bit of cash, but I don't think I would mess with the old sleeves and pistons. Also, replace any rods that you damaged.

You're doing great!

I assume that the crank turns now?
 
Jun 12, 2013
213
Hunter 40 back creek
its been some time since i wrote my questions but I finally got around to taking the head off, i found the rings rusted to the piston liners, so i brought the head to a rebuilder who has a good reputation here in Annapolis. I was able to pop the liners with the pistons intact. I was able to salvage the connecting rods. Im replacing the liners, new pistons, rings and rod bearings. Im wondering since I have the engine block access to the injection pump I would replace the copper washers on the metal fuel lines going to the ink pump. everything that is connected to the block that has a gasket or crush washer will be inspected and at minimum re sealed. Any other suggestions before I put her together? Im not taking the crankshaft out journals on the rods look good, thinking about the front oil seal? I should replace it? Thank you for any ideas or suggestions, Hunter Healer
 
Jun 12, 2013
213
Hunter 40 back creek
The hard part is done. Decide how much of the rest you want to take on. I agree with @kloudie1 - do the valves, seals, and bearings while you're here - especially if you're keeping the boat. You should be able to get a rebuild kit that has most of the stuff you need. Then, you'll have to add things like pistons, rods, and sleeves that don't typically come in the kit. You'll have to shop around and see what's available.

If you get queasy, check with a few machine shops and see what they want to put it back together for you including the cylinder head work.

I know it's a bit of cash, but I don't think I would mess with the old sleeves and pistons. Also, replace any rods that you damaged.

You're doing great!

I assume that the crank turns now?
yes the crank turns easy
 
May 29, 2018
457
Canel 25 foot Shiogama, japan
As a bit of a guide.
Here is a guy with limited tools and knowledge pulling off a complete rebuild of a 2 cylinder Yanmar.
Inspirational.
There are follow up videos of the process and the final start up and dealing with the last bugs.
gary
 

Jim26m

.
Apr 3, 2019
579
Macgregor 26M Mobile AL
Any other suggestions before I put her together? Im not taking the crankshaft out journals on the rods look good, thinking about the front oil seal? I should replace it? Thank you for any ideas or suggestions, Hunter Healer
If you can get the oil seals without damage, yes. Especially if they are weeping. If the crank pulley won't budge easily, make a judgement call. Use the correct puller for the job, typically NOT a three jaw hook on the pulley rim. But, if you can get the seals it would be a good idea.

Sounds like you're making good progress!
 
Nov 26, 2012
1,653
Hunter 34 Berkeley
Best case scenario is to take it apart and rebuild it if possible. I don't see much chance it will run otherwise.
 
Jun 21, 2004
2,532
Beneteau 343 Slidell, LA
As a bit of a guide.
Here is a guy with limited tools and knowledge pulling off a complete rebuild of a 2 cylinder Yanmar.
Inspirational.
gary
Watched all three videos, awesome. Inspirational!
Think that you should rebuild the entire engine while you're at it. If you decide that you dont want to do the head job, bring it to a machine shop. Suggest that you allow a shop rebuild the injector pump also and rebuild or replace the injectors. Good luck, looks like a fun project.
Please keep up posted on the progress.
 
Apr 5, 2009
2,774
Catalina '88 C30 tr/bs Oak Harbor, WA
I agree. Given how deep you are into it, it make sense to pull the block out of the boat and do the bottom end as well. There will be some increase in cost but the results will be a new engine. Once the block is out of the boat, an engine machine shop can boil the block and head to remove all paint, rust and deposited and leave it ready for paint. I also would not do the head at home. that is best handled by the machine shop.
 
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Jim26m

.
Apr 3, 2019
579
Macgregor 26M Mobile AL
its been some time since i wrote my questions but I finally got around to taking the head off, i found the rings rusted to the piston liners, so i brought the head to a rebuilder who has a good reputation here in Annapolis.
He did take the head to a shop...
 
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