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**Wotname** · 19-08-2020, 19:04

Quote:

Originally Posted by jimbunyard

Head and valves turned out nice...

Since you've got a good flat head, I'm wondering if you know about getting a good flat block. The head engine rebuilder at a Detroit Diesel distributor 40 years ago showed me how.

What happens is when you torque the head, the 'crush space' in the gasket that seals the combustion chamber allows the area immediately around the head bolts/studs to be permanently 'pulled up', not much, but enough to possibly interfere with the sealing of the head gasket later down the road.

The fix is to pull the studs, take a good big (14" is about right) sharp flat file and dress the surface to remove these high areas around the bolt holes. You're not trying to mill the surface, so don't get carried away; just take long slow strokes with even pressure all the way across the entire sealing surface.

You'll see the 'halos' of bright metal appear around the bolts holes as you go; these will also tell you when you're done.

It's not absolutely necessary, but it will make the head/block joint last longer.

I've made this suggestion before on other threads here, so if I'm repeating myself, or if you already are aware of this, never mind...

Good tip - Thanks JB.

I had planned to "dress" the block surface ever so slightly using a straight edge and 120 (or finer) grit paper but I will now pay special attention to the areas around the bolts holes and work accordingly.

IIRC, the sleeves project from the block around 3 thou so that is the first thing to measure and ensure is correct before touching anything else on the deck.

Chayal · 20-08-2020, 19:17

Good call on decking the block. Your there already..

I use a mirror with sandpaper.

Do you have any plans for this engine when it’s finished and running?

I read through the posts again but didn’t see any mention.

**Wotname** · 21-08-2020, 21:18

Quote:

Originally Posted by Chayal

..........

Do you have any plans for this engine when it’s finished and running?

I read through the posts again but didn’t see any mention.

Yes and no....

I don't have a pressing use for the engine at the moment which is why I am OK with doing a slow rebuild.

Maybe (and hopefully) a suitable hull will turn up when the engine is finished.

I do have a 18' hull that I'm slowly refitting as a "river launch/gentleman's launch/putt putt/day boat". I had planned to use a single cylinder Yanmar YSE8 engine as it currently has the engine beds, shaft and prop that suits the YSE8. Part of me wants to fit the 2QM20 in lieu of the YSE8 but part of me doesn't!!!!!

I did rebuild the YSE8 to better than original Yanmar specs while the 2QM20 certainly won't be a 'zero time' engine. Decisions, decisions...

I started the 2QM20 project because I always wanted a 2QM20 and this one became available for $50 and was clearly going to be a challenge!

**Wotname** · 06-09-2020, 18:00

Does anyone have a pro-tips for:

1. Removing honing residue from inside the sleeves after having them professionally honed.

2. Should the bulk of external surface of the liner be prepared in any way.

The rings, bearing and other parts will be at least a month or so away so in the meantime I can prepare other parts of the engine so they are ready for fitting when the parts arrive.

Regarding #1 above, I would normally try various things like warm soapy water or kero or acetone or pressure cleaner etc to clean the residue from the sleeves but I am thinking someone here might know what is best and thus save me some time discovering what doesn't work.

Regarding #2 above, the manual suggests a waterproof paint or grease to be applied where the O rings are fitted and where the top of the sleeves contacts the block lip. It doesn't say anything about surface between these points. In the past I have left this area uncoated but maybe there is a better way.

All ideas welcome!

Compass790 · 06-09-2020, 18:11

I coated my liner exterior with epoxy but dont know if thats a better way or even if it should be done.
No doubt some will say it would interfere with heat transfer & they are right. Question is, is that harmful on a raw water cooled engine with it's low engine temps?
I did it to hopefully make removal easier as i'll do it in situ if I ever do it again ( unlikely)

So Wottie I'll be interested in your replies as well

**Wotname** · 10-09-2020, 00:05

In the absence of any pro-tips for cleaning the honing residue from the sleeves I have decided to soak them for a day or so in diesel / ATF mixture (3:1) and pressure clean (water) and finish up with brakeclean and paper towels. The diesel / ATF mix can then be filtered and used as fuel in the tractor!!!!

In other news, my mate turned a main bearing drift and spigot from some old steel pipe and I removed the flywheel end main bearing with a press (took ~2.5 tons to get it moving). The other main bearing will need a different approach as the block is a little awkward to fit in the press.

**Wotname** · 02-04-2021, 02:15

Six months have flown by and any reader could be excused if they have forgotten about this thread. Indeed, you could be excused if you thought I had forgotten about this engine - however I hadn't forgotten but the project did come to standstill when I discovered a crack in the block emanating from the oil feed gallery.

The back story - I had finally sourced all the new parts for the engine - rings, bearings, head gasket etc. The only thing left was to paint the major components before reassembly. So the block was degreased, lightly sand blasted as required, POR15 Metal Prep applied and pressure washed off. The block lightly heated to ensure there was no moisture in the cast iron and ready to paint - what could go wrong...

The pictures tell the story

This lead to the obvious question - what to do next. Four options -
1. Ignore it and reassemble the engine
2. Chuck the engine in the bin and forget about it
3. Fix the crack
4. Get another block.

I couldn't live with #1. As for #2, well I had spent too much money on the new parts, head and so forth to consider this option unless forced into it. I spent a lot of time exploring the options for #3 but at the end of the day, no repair method could be guaranteed to be a long lasting repair.

The hunt was on for another block.

**Wotname** · 02-04-2021, 02:32

And today, another block was picked up, ready for disassembly. I t will be interesting to see what it looks like inside and especially to see if there is a crack in a similar place. Note, the head shown in the photo is just there to cover up the cylinders etc - I'm told the pictured head is beyond repair.

The ancillary bits and bobs are just the icing on the cake as I already have the starter motor, alternator, water pump, injection pump etc. I will be able to compare the 'new' crankshaft, camshaft, pistons and liners etc with my existing ones and choose the best.

The serial number of the original block has rusted away so I'm quietly hoping the serial number on this block will be readable once the aftermarket blue paint is removed.

The only real question is which engine is getting rebuilt. I guess the identity follows the serial number. I recall in the aviation industry, any 'existing' airplane can be rebuilt if you still have the type certification / serial number plate.

GILow · 02-04-2021, 15:34

I wondered where my last engine went.

**Wotname** · 02-04-2021, 16:50

I suppose the blue paint was the clue.

dfelsent · 02-04-2021, 17:34

https://en.m.wikipedia.org/wiki/Ship_of_Theseus
With particular attention to Hobbes question.

“ Plutarch thus questions whether the ship would remain the same if it were entirely replaced, piece by piece. Centuries later, the philosopher Thomas Hobbes introduced a further puzzle, wondering what would happen if the original planks were gathered up after they were replaced, and then used to build a second ship.[3] Hobbes asked which ship, if either, would be the original ship of Theseus.”

**Wotname** · 02-04-2021, 18:14

Quote:

Originally Posted by dfelsent

https://en.m.wikipedia.org/wiki/Ship_of_Theseus
With particular attention to Hobbes question.

“ Plutarch thus questions whether the ship would remain the same if it were entirely replaced, piece by piece. Centuries later, the philosopher Thomas Hobbes introduced a further puzzle, wondering what would happen if the original planks were gathered up after they were replaced, and then used to build a second ship.[3] Hobbes asked which ship, if either, would be the original ship of Theseus.”

While I would never be considered a philosopher, the Certifiable Refitter in me would think if the original planks were gathered up after they were replaced, and then used to build a second ship, it would soon sink. I am though interested to know if I am wrong in thinking this way.

If the answer to Hobbes question is that using the gathered up original planks will indeed be the original ship then I'm going to gather up all those replaced Yanmar bit and bobs I have lying around and end with a boatyard of original engines -