ysb8, its drives me crazy!!

[Wotname]

Also check the lip clearance - especially for consistency all the way around.

While this is not a wear item i.e. it should remain constant since manufacture, I have seen one that was never bored / milled correctly when manufactured. It was a couple of thou greater on one side than the other. This makes it difficult for the head gasket to work properly.

The YSE manual calls for ~0.2mm while the YSM manual (same block and liner) calls for 0.06mm to 0.14mm. Any number close to these will be OK providing it is consistent all the way around.

[AKA-None]

Hopefully with all this cranking you have the water intake turned off

[Halifax Sailor]

unfortunately, not in the water yet!! All this trouble started last year when I hauked for the winter. I knew I had issues when I started to get ready for this season but crossed my fingers it would be easy. Silly sailor, its a sailboat!! If the rngine doesnt start immediately, I always shut the valve so I wont water lock, not for long, dont want to burn out my impeller. So all this has been operating out of a bucket in the cockpit with a garden hose feeding it.

[Halifax Sailor]

I will check the lip clearance, dont want to seal this up and then discover other stuff. Was lucky enough to fid parts once and in stock. Dont want to chance waiting for a couple of weeks if I screw up.

[Wotname]

Originally Posted by grantmc

Wotname nailed the 3 models. They are all almost identical and I found parts interchanged. If left original all have gravity fed fuel tanks sitting on top of the motor. Another great advantage that meant that if (when) you ran out of diesel no need to bleed.

Nor do you need a fuel pump.

For anyone who is interested - grantmc is on the money in that most parts between the YSE, YSB & YSM are the same. The notable differences are the injector pump. The YSM has a much newer Bosh style of injector pump while the YSE & YSB has a much simpler design of IP although it is more friendly to DIY IP maintenance. The older style IP does require some DIY adjustment as the regulator needle / seat wears.

The YSE has a heavy cast iron housing for the gearbox while the YSB & YSM use an alloy housing.

The service manual for the YSM has much more detail than the YSE manual and most of the information is backwards compatible.

[Compass790]

My best tip is to use Permatex 51813 or Loctite 515 or 518 when installing new head gasket. That alleviates leaking issues & our liner lip does not protrude above the block evenly but it still seals using 518. Without 518 using a new head gasket it leaked after about 50 hrs The head looks a lot better than ours. If your engineer mate has a dial bore gauge you could check liner diameter too. I would throw new rings in it anyway if you can remove piston in situ. Its easy to get to conrod bolts thru the oil breather plate on the side of the block if you have room. Any pitting on exhaust v/v seat?
Did you have any salt crystals around the head gasket joint?
Good Luck with getting it apart, your engine no room looks problematic. Ours is similar in terms of access.

[Compass790]

Originally Posted by grantmc

YS8s don't have glow plugs and they're single banger with horizontally mounted cylinder. Quite difficult to test the compression as they have a pre-combustion chamber, and a control lever to decompress.

Really old motors. There were 3 different models produced E, M and another I can't remember. All were available in either 8 or 12 hp variants.
They all had the option of a hand crank (a sort of chain arrangement, and not a bad thing either), and so it wasn't unusual to find there wasn't a starter motor.

The cylinder head gaskets corrode on the down side because the motors are raw water cooled. And it's the corrosion that causes the reduction in compression. Replacing the gasket is just standard maintenance every 500 or so hours. It's a very simple job, and the only special tool needed is a torque wrench, shouldn't take more than an hour or so.

OP and others with these motors, you can take the head off without removing the injector. And I would encourage not removing the injector as it is quite tricky to get them to sit right and seal once removed. There's a special copper washer that must be replaced if taking the injector out, and the two little injector mount bolts bend really easily (but not so easy to spot).

There is one alternative to sealing injector, I use a thin smear of loctite 518 or permatex 51813 on injector face, never need to replace copper washer then but what you say about them better left in is true.
I dont find it difficult to test compression on the ys engine but you do have to remove injector.

[Halifax Sailor]

I was going to ask today how to ensure a tight proper seal with the injector and the head gasket. Your post answered my questions. I did buy two (in caseI screwed up) of the seats that are replaceable, the ysb does not use a copper crush washer, it is a composite (fiber and something. Definately not copper.

Originally Posted by Compass790

There is one alternative to sealing injector, I use a thin smear of loctite 518 or permatex 51813 on injector face, never need to replace copper washer then but what you say about them better left in is true.
I dont find it difficult to test compression on the ys engine but you do have to remove injector.

[Halifax Sailor]

so I figured out what that pipe was that was jammed between the starter and the clutch plate? Its a clutch breather. So I am assuming that as long as it can breathe, if its 2" shorter it doesn't matter?

[Wotname]

Originally Posted by Halifax Sailor

so I figured out what that pipe was that was jammed between the starter and the clutch plate? Its a clutch breather. So I am assuming that as long as it can breathe, if its 2" shorter it doesn't matter?

Correct!

[Wotname]

Originally Posted by Halifax Sailor

I was going to ask today how to ensure a tight proper seal with the injector and the head gasket. Your post answered my questions. I did buy two (in caseI screwed up) of the seats that are replaceable, the ysb does not use a copper crush washer, it is a composite (fiber and something. Definately not copper.

There are 2 copper washers and 1 fibre washer.

In the diagram, the copper washers are called 'packing' and the fibre one is called 'heat insulator'.

You will only need the 2 copper washers if the pre-combustion chamber has been removed by the machine shop doing the work on the head.

[Halifax Sailor]

wont know about pitting on exhaust valve until I get it back, but gave them two new valves so they should make it good as new. There was some saly crystals aroumd the gasket, it all appeared to be in the cooling chambers, when I winterize, i flush for about 20 minutes with fresh water before antifreeze. Saw a youtube video where the guy used vinegar then flushed with baking soda I think and it cleaned out much stuff. He hooked a hose to the cooling water exhaust and recirced the water with the flush while running the engine. Might be an option depending on the report when I get it back. I know the passage for the drain/petcock was completely blocked, cant turn the petcock so before I reinstall I will be working on that and make sure its clean and working. Never worked since I bought the boat and I was afriad to break it off. Now that its apart, much courage.

When I pulled the head, I also removed the injector to have enough room to work without breaking anything. The bottom half of the injector was quite oilly so am wondering if it may have been leaking a little? I had a new gasket/insulator, didnt disturbanything else. Torqued to 15.5 ft.lbs (specs said between 14.5-16.5). Went from side to side, little at a time so thought it was straight. When I removed the injector, the insulator looked pressed evenly but not crushed. I like your idea of perma gasket to ensure a tight seal. The gaskets for exhaust, intake and starter are two weeks out of USA so going to use hihg heat gasket maker for all those. I have a gasket for the valve cover but also used gasket maker to get a good seal last time.

As far as room, yes little tight. Edged the head out by moving the battery just a bit. Had about 1/2 inch so lots of room!! Great thing is with removing all this stuff, going to take the opportunity to clean up misc wires and rerun or organize a lot better. Going to look at the exhaust elbow as well although it was new last spring with about 10 hours on it maybe, just in case there is some blockage. Cant see there would be any but............

I have been lookking thru all my info and cant find the torque specs for the head and a pattern to tighten. Would anyone have that at their fingertips. I know I have it somewhere but just cant find it.

Ric

Originally Posted by Compass790

My best tip is to use Permatex 51813 or Loctite 515 or 518 when installing new head gasket. That alleviates leaking issues & our liner lip does not protrude above the block evenly but it still seals using 518. Without 518 using a new head gasket it leaked after about 50 hrs The head looks a lot better than ours. If your engineer mate has a dial bore gauge you could check liner diameter too. I would throw new rings in it anyway if you can remove piston in situ. Its easy to get to conrod bolts thru the oil breather plate on the side of the block if you have room. Any pitting on exhaust v/v seat?
Did you have any salt crystals around the head gasket joint?
Good Luck with getting it apart, your engine no room looks problematic. Ours is similar in terms of access.

[Halifax Sailor]

picked up the head, no issues. no cracks, no blemishes, no problems. Now to reinstall. They didn't remove the insulator or the copper washer (under the injector) so I am good to go. they still look good. Precombustion chamber looks like new, all the holes are now open.

[Wotname]

Originally Posted by Halifax Sailor

...............

I have been lookking thru all my info and cant find the torque specs for the head and a pattern to tighten. Would anyone have that at their fingertips. I know I have it somewhere but just cant find it.

Ric

From the YSM manual (it's the same block and head as the YSB)

[Wotname]

A good hint for single horizontal cylinder engines.

When planing to shut down the engine for more than a few days - before leaving boat, hand rotate the engine through to TDC of the compression stroke (use decompression lever to make it easy). This ensures the valves are closed with minimum air in the cylinder. Helps greatly in keeping liner / head / valve corrosion at bay.

It is the little things that make the engine happy.