Yanmar 2QM20 - Should I rebuild or replace it? Maybe convert to electric?

[NakedCity]

it looks like you had a blown cylinder head gasket. I would take the head to a local automotive machine shop for a valve job & head resurface .

[charliehows]

Originally Posted by leveche420

Hi all!

I am starting to refit a Southern Cross 31. It has a Yanmar 2QM10 engine that it doesn't seem to run. I dont have the history of the engine, the seller told me he thought the issue was low compression.

Is it a 2qm10 or a 2qm20?
having got the head off, you should clean all surfaces - I'm not sure from your photos whether the marking people are referring to as evidence of head gasket leakage are on the old gasket or the head or block surfaces - if there is pitting on the primary surfaces to the extent that it appears in the photos you have a problem which wont be solved by a new gasket. But if the pitting is in the gasket, a clean up and a new gasket should suffice. As a previous poster pointed out, these are very tough and reliable little engines, until you actually get the thing running, you dont really know what condition its in.

[leveche420]

Originally Posted by charliehows

Is it a 2qm10 or a 2qm20?
having got the head off, you should clean all surfaces - I'm not sure from your photos whether the marking people are referring to as evidence of head gasket leakage are on the old gasket or the head or block surfaces - if there is pitting on the primary surfaces to the extent that it appears in the photos you have a problem which wont be solved by a new gasket. But if the pitting is in the gasket, a clean up and a new gasket should suffice. As a previous poster pointed out, these are very tough and reliable little engines, until you actually get the thing running, you dont really know what condition its in.

Sorry for the typo, it is a 2qm20

[leveche420]

Good Evening!

I am certain I had a blown head gasket, see attached photos.

For more quality photos go here: https://drive.google.com/drive/folde...lC?usp=sharing

I am currently looking for local machine shops. I am planning to ask for a quote to few shops and see how much we are talking about...

Our next challenge is removing the liners to install new ones. The yanmar original tool is no longer available. I am not sure if I could use any other type of tool to remove the old liners. Once I remove the old ones... How do I put the new ones in place? I have been told to put the liners in the freezer and put an air heater to the engine block, let it run overnight and then tap the frozen liners in. Will that really work? Will I be able to install the new ones in my garage by myself or will I need to go to a mechanic shop?

[Wotname]

These are wet liners so they go in easily, normally by hand or occasionally with a very slight tap to get past the o ring sealers that seperate the water and the oil sections of the block.

Getting them out takes a bit more effort but almost always doable at home. It's not hard to make a suitable tool but I have seen it done with a hammer and a block of wood. If you have a press, it can be used.

Time doesn't permit a fuller explanation and perhaps others will post soon but rest assured, it can be done at home.

Dry liners take a bit more effort.

[Compass790]

Originally Posted by leveche420

Good Evening!

I am certain I had a blown head gasket, see attached photos.

For more quality photos go here: https://drive.google.com/drive/folde...lC?usp=sharing

I am currently looking for local machine shops. I am planning to ask for a quote to few shops and see how much we are talking about...

Our next challenge is removing the liners to install new ones. The yanmar original tool is no longer available. I am not sure if I could use any other type of tool to remove the old liners. Once I remove the old ones... How do I put the new ones in place? I have been told to put the liners in the freezer and put an air heater to the engine block, let it run overnight and then tap the frozen liners in. Will that really work? Will I be able to install the new ones in my garage by myself or will I need to go to a mechanic shop?

Yes i wuda bet A64s lunch you hada blown gasket too lookn at earlier pics. I made my own liner puller outa threaded rod & scrap steel. No time to find it now but will post pic later. Are you sure you need new liners? Yanmar will ream you for those ( & everything else ) have you measured them?Consult manual for all the tolerances. Often you can get away with just a hone & new rings.
I found the liner easy to install with freezing & heating as described. Getting them out can be a different story but a client of mine had good success with filling up block with crc rust eliminator & letting sit overnite before trying to pull. CLR mite work too but remove anodes & thermostat before doing this. Its the rust & salts that make liner hard to pull. I actually put block in oven for re-install but I don't have a wife & its a single cylinder.
I've found Loctite 518 master gasket works real good on cylinder head gaskets without machining but it depends on how bad it is. Look at tube for tolerance. Will post pic of puller when I can.Hope something helps

[Compass790]

WHOOPS CORRECTION, I'm getn forgetful. I had to put ice down the liner & heat the block to get it out NOT TO INSTALL. Lucky Wotname posted whilst i was typing. He's right they easy to install. I'm sorry, old age sucks.

[Compass790]

I hope attachment pic of puller is there. I'm not too guod on 'puter.
Looks like you had both cylinders leaking! I used 10mm ss for threaded rod but I would recommend at least 16mm if trying to pull dirty liner. Put top plate on head studs & square bar on btm cut to fit liner.
The bronze bit was my main bearing puller, just used as spacer.

[charliehows]

bear with me - I'm not trying to labour a point, I'm just curious. Given you have not had the engine running and are accepting the PO's assertion that the compression seemed to be down - well it would be with both cyls leaking through the side of the gasket - Why are you jumping straight to replacing liners? Is it not possible to hone the existing ones and fit new rings? I'm asking because I dont have much experience of this sort of thing with diesel engines, I've mostly done this with petrol engines and I've always gotten away with honing - i do realise the compression is higher on a diesel. Second question; To me, your photos of the block appear to still have the gasket in place - what is the condition of the block surface once the gasket has been removed and the block cleaned?

[charliehows]

BTW - replacing valve guides on harley heads was pretty straight forward - guide goes in the freezer, head goes in the oven, bit of hylomar on the guide, light tap to push it in, job done. Not sure about stuffing a 2qm20 block in the oven, sitting it over night in front of a heater does sound more feasible.

[Wotname]

Originally Posted by leveche420

Good Evening!

I am certain I had a blown head gasket, see attached photos.

For more quality photos go here: https://drive.google.com/drive/folde...lC?usp=sharing

I am currently looking for local machine shops. I am planning to ask for a quote to few shops and see how much we are talking about...

Our next challenge is removing the liners to install new ones. ..........

Unless you have already purchased the liners, I agree with the other posters who suggest measuring your existing ones first. They don't have to be removed for measuring. Genuine Yanmar liners aren't cheap!

However if you are removing them, then this is my approach. BTW, Compass790 is correct, it is the corrosion and scale on the water side of the liner that makes removable difficult.

1. Remove and plug any anodes in block
2. With block vertical measure how much volume is required to fill the water jacket to the very top of the block (use water for this).
3. Drain out the water
4. Now fill water jacket with same volume of hydrochloric acid (muriatic acid in USA), use 20% or 30%, eye protection and acid resistant gloves etc.
5. Do this slowly, it will fizz and carry on as it reacts with the salts and calcium build up etc.
6. The reason for the acid is to remove as much as possible, the scale etc on the external walls of the liner (as well as on the block).
7. Leave about 30 minutes and then drain and flush with water.
8. Then neutralise any remaining acid by filling with a solution of bicarb of soda and water. Maybe a couple of tablespoons in the same volume of water is enough.
9. Leave 30 minutes and then drain and again flush with water.
10. Now refill the water jacket with a 50/50 mixture of ATF and acetone and leave for a day or two.
11. This mixture is to penetrate any scale / rust etc that is sticking the liner to the block , mainly around the top lip of the liner / block interface.
12. Drain and remove the liner either with press, puller or hammer and wood.

The good news is that refitting the new liner is way way easier. With everything clean , lubricated correctly and new o rings fitted etc, the liner is a hand fit.

If it helps, here are a couple of photos of a YSE block (liner removed) and liner (unfitted), your 2QM will be very similar.

[RaymondR]

I'm inclined to side with those expressing the opinion that the liners may not need replacement. Since you have the engine out I would probably pull the pistons and rods to check the rings and bearings, hone the cylinders and rebuild the engine an run it. From the images posted there does not appear to be any scoring to indicate ring breakage or lip in the top of the bores to indicate wear.

[brad torrence]

[QUOTE=leveche420;2665418]Hi all!

The question now is.... Should I rebuild or replace it? If I replace it, should I go for another diesel or should I convert to electric? Help! I dont know what to do!!

I just saw a boat that had $25,000 in engine work done, by a supposedly reputable place (Raven Marine, Sidney, BC). The owner had said go over the engine (1985 Westerbeke 21), and fix what needs fixing. They replaced the water pumps, exhaust elbow, manifold, thermostat, filter, and pages of minor inexpensive parts that are mostly clamps, bolts and hoses. $23,000 plus tax (Canadian). The cost of a new Westerbeke replacement engine in Canada is $8400, plus installation.

So now they have a 35 year old engine nearing the end of its useful life, instead of a brand new engine for far less money.

I shudder to think of the bill if they'd actually replaced anything major.
My vote is go with new.

[a64pilot]

A wet liner motor is a no brainer. Overhaul, you can easily return it to a better than new motor, for a lot less money.

[Cheechako]

Stay diesel.
Nothing wrong with rebuilding it if you can find someone to trust. Can you do the removal work etc? Is it frozen up or does it turn over? We need more status of it's current problem.
Get a quote to overhaul it from a reputable source . Then decide if new or rebuild makes sense. If you remove the engine, and it's not frozen up, then a basic rebuild shouldn't be too much for a 2 cyl Yanmar. But there are a lot of "if's"!
I think anything over 40% of a new engine is best to go for new. I have used machine shops that do a lot of classic car work etc for rebuilding things. Those places that the classic car guys like are usually used to doing a good job for knowledgeable owners. You would need one of course who doesn't shy from Diesels.