I was Bored so Pulled the Head on my Yanmar

[sailorchic34]

Originally Posted by nimblemotors

Sometimes they have reverse threads, I know my midget axle does on one side, and boy that one will get you! Nothing will get it off when you are tightening it until it breaks off. And using a chisel to remove these big nuts can work, a risky method though.

I'm wondering about that, the reverse thread thingy. The yanmar shop manual hardly mentioned it except for torque value. I'm pondering taking the whole block to the bay and having a yanmar shop remove the %%^& nut.

The other two pistons look fine. Ring to side clearance/ land is still within new tolerance. But yes I'm thinking that there might have been a bad batch of pistons there for a while.

Worried about sleeving as there is not a lot of cylinder material on the cam side of the block. The center looks to be only 1/8" thick. Of course there is no water jacket on that side of the cylinder either.

AND... I found one of the engine mounts has one side loose to the steel support. Lordy every time I look at the engine something else turns up. Maybe a little 5200....

I'm starting to think I should fit oar locks and press gang some rowers... er that be crew...

[Therapy]

Originally Posted by sailorchic34

I'm wondering about that, the reverse thread thingy. The yanmar shop manual hardly mentioned it except for torque value.
.

Since you can look at the nut straight on you may be able to see where the last thread meets the nut. You can then figure out the rotation.

[nimblemotors]

Well probably normal thread if engine rotation would tighten it, but never hurts to confirm...did you know many Honda engines rotate counter clockwise, the opposite of other engines.

Do you have to remove it to take it apart? Can the crank come out with it left on? I assume you must tear it all down and have it cleaned before they will bore it.









Just a whisper..electric propulsion..

[sailorchic34]

Originally Posted by nimblemotors

Well probably normal thread if engine rotation would tighten it, but never hurts to confirm...did you know many Honda engines rotate counter clockwise, the opposite of other engines.

Do you have to remove it to take it apart? Can the crank come out with it left on? I assume you must tear it all down and have it cleaned before they will bore it.

Just a whisper..electric propulsion..

I think its a regular rotation on the nut. Yes the nut HAS to come off to pull the crank out the rear. Interesting design on the crank. Big flange on the back and the whole thing including intermediate bearing holders come out. Then just remove the oil pump and the block will be bare.

Most likely off to the bay with block in hand ( well not really in hand as its still pretty heavy) to have the crank nut pulled.

I would love electric propulsion. But that's pricey too.

[sailorchic34]

So pondering the design of the yanmar 3gm series. The cylinders have a full water jacket on the intake side. But the exhaust side the cylinder block has only a partial jacket above the camshaft and not anything much below it.

I'm not sure how the water circulates on that side. But there are areas where there is no or very little water jacket. Like right at 3 oclock. Just wondering how there can be much circulation on that side. Maybe the oil flowing back to the sump cools the cylinders there. probably some thermal convection too. It just looks odd to me.

Just wondering how many other 3gm owners had ring / land failures on the exhaust side at roughly 3 o-clock. To my engineering mind and no I'm not an automotive engineer, but I do have a fair understanding of stresses involved.

Anyway, the unbalanced cooling design and unbalanced mass, I think would cause extra stress and distortion on the cam side of the cylinder. Which oddly enough is where my piston broke..

[bobconnie]

Sailer Chic, Theres a LARGE warehouse parts outfit in Sac. They have everything ya need and are a bunch cheaper then Yanmar! I don't remember the name but Im sure you can find it tho ! I did a yanmar when I was on the coast for a buddy of mine, got everthing from this place from pistons rings gaskets, bearings, ect Darn Im getting old LOL have that CRS trouble!! But as smart as I know ya are, you will find it ! hope this helps ya !

[nimblemotors]

Originally Posted by sailorchic34

I would love electric propulsion. But that's pricey too.

It can be for sure. Some DIY and used parts can make it a lot less.
Just for kicks, did a little research on the 3GM3F and shows it is 24hp at 3400rpm with 2.6:1 gearing down to 1400 at the prop, 40 lb/ft of torque. Comes in at 300lbs.

I've had an 8" ADC motor for a long time collecting dust for my 3-wheeler EV project. A look at its torque output shows it can do 40 lb/ft of torque no problem with 75 volts and 210 amps. Motor is about 100lbs. This is just loafing, no stress at all at these levels. New these are like ~$1500, but can be found used for ~$500. The smaller 7" motor would do.
Then you need the motor controller, at that HP, not hard to find, new about $1000 or so, used $500, I've made my own.
Then some batteries, the golf cart flooded ones will do, as many as you can find room for, let's say $1000 worth. So we are up to $2000ish.

Might want to add an external generator to charge the batts just in case for the long haul, these vary all over from $200 to $5000.

I'm thinking you can sell that Yanmar and it would more than pay for the electric drive.

[sailorchic34]

Well did lots O driving today. No one had a 36 mm really deep socket, Even the yanmar repair folks and john deere (who uses yanmar) did not have one. As Yanmar wanted $187 for the "special tool", which was alas too dear for me. So having a socket fabricated for $60. Then I can take the block to the machinist to bore and sleeve the bad cylinder and hone the other two. I took the block by the machinist today, just to make sure he could sleeve it. He quoted $200-$250 to bore and sleeve the cylinder and hone the other two.

Then get the parts in and have lots O fun putting the engine back together. But have a buddy "car" guy who will help.

If this engine blows up again, I may go electric, or maybe just go sailing and hang an outboard off the stern, or dinghy which I don't have yet, for the times I need to motor.

One engine mounts are quite dear too. About $150 each and I need the two front ones replaced. One was delaminated.

[sailorchic34]

Originally Posted by nimblemotors

It can be for sure. Some DIY and used parts can make it a lot less.
Just for kicks, did a little research on the 3GM3F and shows it is 24hp at 3400rpm with 2.6:1 gearing down to 1400 at the prop, 40 lb/ft of torque. Comes in at 300lbs.

I've had an 8" ADC motor for a long time collecting dust for my 3-wheeler EV project. A look at its torque output shows it can do 40 lb/ft of torque no problem with 75 volts and 210 amps. Motor is about 100lbs. This is just loafing, no stress at all at these levels. New these are like ~$1500, but can be found used for ~$500. The smaller 7" motor would do.

Well most of the time, actually all of the time, I motor at 2100-2200 rpm which is 14-15 hp. What size electric motor would that take to push that. I think whoever had the boat when it was repowered had too large an engine installed. They went be boat length (34') and not water line length which is 25'. I probably could use a 2gm just fine. Gee 14 hp on a 2 gm would be 2870 RPM. So right at the sweet spot. Too late now..

[nimblemotors]

Sorry to hear the shops couldn't help you, seems strange.
I did offer to make a socket for ya :confused

15hp electric motor is not too big, and the motor controllers are not expensive at all,
we are talking golf carts, they are very common. Someone on CF recently bought a 30ft-ish boat with a 15hp electric motor, I have a couple of them in fact, they are only 22lbs, 15hp continuous is pushing them without extra cooling. There is no harm in too big a motor for your sailboat, but can use a smaller motor controller.
I think I have a 10hp golf cart controller around here.
You don't need as much battery also, could probably put together something pretty inexpensive.

I'd say if you sell the rebuilt yanmar to one of those with a diesel fetish and get top dollar, say someone with an Atomic-4 looking to go diesel, you'll end up with cash in your pocket on the e-swap, and motor about in peace and quiet.

[olaf hart]

Originally Posted by sailorchic34

Well did lots O driving today. No one had a 36 mm really deep socket, Even the yanmar repair folks and john deere (who uses yanmar) did not have one. As Yanmar wanted $187 for the "special tool", which was alas too dear for me. So having a socket fabricated for $60. Then I can take the block to the machinist to bore and sleeve the bad cylinder and hone the other two. I took the block by the machinist today, just to make sure he could sleeve it. He quoted $200-$250 to bore and sleeve the cylinder and hone the other two.

Then get the parts in and have lots O fun putting the engine back together. But have a buddy "car" guy who will help.

If this engine blows up again, I may go electric, or maybe just go sailing and hang an outboard off the stern, or dinghy which I don't have yet, for the times I need to motor.

One engine mounts are quite dear too. About $150 each and I need the two front ones replaced. One was delaminated.

Well, look on the bright side.
At least you are not bored anymore

[appick]

+1 on taking a good long look at finances and thinking about replacing all the pistions. Although its up to you. Just make sure when you replace the rings, to clean up the ring gooves very good and yous a magnifiying glass to inspect all the lands. Normally I do a quick check on pistons but with what went on with yours I'd be very thorough. Also when reassembling I'm sure you know but things need to be absolutely clean no grime grit dirt sludge ect. This includes all of your tools as well. I've seen too many people using the tools they pulled the engine apart with put it back together without cleaning them. It's never good to be tightening down a main bearing and hear the crunch of grime and sand as you slip it over the nut...

It looks like you're well on your way to getting this all back together and running. Good luck and keep up the good work and postings. I've always enjoyed and respected your posts .

For what its worth if you need to buy ring compressors or ring pliers Harbour Frieght has them for pretty cheap. I've used them on a couple of jobs, although cheap they get the job done. However, borrowing is always cheaper!

I'd hate to see you get it back together only to have it loose another ring land, but you've got to do what works for you and your budget. I'm pulling for your and another +1 on the paypal.

[zeehag]

chic--i have encountered 2 electric propulsion boats her einbarra de navidad....same ones also in zihuatenejo..... the formosa has a huge invvestment in lithium ion batteries--3 times price i paid for hti boat. he is happy.
the other uses an outboard system--is n0t an islander 36 but similar in hull shape and form---somehow they place this electric motor into an engine well and use it that way.

both said they are happy. i traded my cruising spinnaker to the formosa--he said that uphill he only gets 1.8 kts--kinda like i was before runaway--but that downhillhe gets to 7 kts boat speed.....that would be an improvement for me...lol

is a heavy investment but it would propel your islander hull nicely. remember we are deeper and heavier than you are...just a tad....if you have the bux, it would work for you. and you i believe are in the right locale for it--i think the guy in the formosa repowered in sf area.....

sad to hear you have propulsion issues---i have been dealing with my own same thing so i didnt see yours....i hope is not difficult to fix yours.

[sailorchic34]

Originally Posted by nimblemotors

Sorry to hear the shops couldn't help you, seems strange.
I did offer to make a socket for ya :confused

Sorry, I've been more then a little mental these last two weeks and forgot about the offer, which was sweet.

I thought it was strange too. but the yanmar mechanic said he could not remember the last time they took a yanmar crankshaft out. Of course comparing their labor rates and amount of time needed. Its probably cheaper buying a new engine. If you have the money. That's how its done now a days I guess

Same thing with the John Deere guy. Any special tools they need, they fabricate.

Really like the electric motor idea. Though will most likely stick with the diesel for a bit.

[sailorchic34]

Originally Posted by appick

+1 on taking a good long look at finances and thinking about replacing all the pistions. Although its up to you. Just make sure when you replace the rings, to clean up the ring gooves very good and yous a magnifiying glass to inspect all the lands. Normally I do a quick check on pistons but with what went on with yours I'd be very thorough. Also when reassembling I'm sure you know but things need to be absolutely clean no grime grit dirt sludge ect. This includes all of your tools as well. I've seen too many people using the tools they pulled the engine apart with put it back together without cleaning them. It's never good to be tightening down a main bearing and hear the crunch of grime and sand as you slip it over the nut...

It looks like you're well on your way to getting this all back together and running. Good luck and keep up the good work and postings. I've always enjoyed and respected your posts .

For what its worth if you need to buy ring compressors or ring pliers Harbour Frieght has them for pretty cheap. I've used them on a couple of jobs, although cheap they get the job done. However, borrowing is always cheaper!

I'd hate to see you get it back together only to have it loose another ring land, but you've got to do what works for you and your budget. I'm pulling for your and another +1 on the paypal.

Once the engine is off to machining on monday, I'm going to spend a few days cleaning all the parts and tools too. Then painting all the rusty bits too. Yes It all has to be spotless going together. It sure was a mess pulling apart though. Hate messy too.

I know this old car guy who seems to have every tool ever made. So hoping to get the ring compressor and ring pliers from him.

I sort of can see the light at the end of the tunnel, even if it's just a fast moving train heading towards me. Its a little daunting thinking of all the parts that go back on and getting the engine back into position. Plus bleeding the fuel side and pre-filling oil galley's before first cranking. If it all goes well it will be a month of work.