Cylinder liner waterproof paint or grease?

[pmagistro]

Hey folks,

I'm about to dive into my Yanmar SB12 rebuild project. I'm installing a new cylinder liner and piston rings. In the instructions (which I've tried to link to below) it says to "coat the outside of the cylinder liner with waterproof paint or grease". Any suggestions as to what product I should be using?

Thanks!
Phil

https://books.google.com/books?id=n4...diesel&f=false

[shakey doug]

Assuming you mean to locate the new liner, a smear of grease block of hard Wood and a big hammer job done.

[a64pilot]

Only liners I have ever pulled and replaced were John Deere, and there was no hammering or other force required.
However what was important was to ensure that the Orings were well lubricated and didn’t roll over when you inserted the cylinders. The O rings of course are what separate the oil and coolant, so of course you don’t want them even seeping, I assume that is what they are talking about.
Wet liners of anybody’s motors are subject to cavitation damage of the coolant from high frequency vibrations, and you need to be sure to use a good coolant specifically formulated to prevent this damage. Maybe that is why they wanted the liners painted? Although that is just a wild guess.
http://blendtech.biz/antifreeze-info...y-engines.html

[a64pilot]

Actually looking at the pages of the manual, I’d bet lunch that what they are saying is paint on a layer of waterproof grease and something went just a little off in translation.

[seabreez]

Originally Posted by pmagistro

Hey folks,

I'm about to dive into my Yanmar SB12 rebuild project. I'm installing a new cylinder liner and piston rings. In the instructions (which I've tried to link to below) it says to "coat the outside of the cylinder liner with waterproof paint or grease".Thanks!
Phil

Definitely grease, stay away of water, paint! no! lube your seals and cleanliness is very important. Do not hammer your sleeves. If the block is very clean just a small tap of the handle of a hammer to make sure the sleeve is bottomed out. Then install a bolt and washer to hold the sleeve down until all other cylinders are installed and you are ready to install the head.

[Wotname]

Phil, this thread may be of some interest http://www.cruisersforum.com/forums/...nt-190165.html

[Capt Gill]

Originally Posted by a64pilot

Actually looking at the pages of the manual, I’d bet lunch that what they are saying is paint on a layer of waterproof grease and something went just a little off in translation.

I agree with that, paint makes no sense, if they meant to say paint seems they'ed mention what type out of the v.many available.

[Wotname]

Originally Posted by Capt Gill

I agree with that, paint makes no sense, if they meant to say paint seems they'ed mention what type out of the v.many available.

A couple of points to consider.
The service manual was written in the 1970s. The original engine was designed in the 1930s (in the UK AFAIK).
The slightly later version of the OP's engine is the YSM and it uses the same block and liner. The YSM manual is quite clear; use white oil paint and apply to the inserted lip section and to the area between the two o rings.

This makes sense (IMO) as these are two areas that need protection. The rest of the exterior surface of the liner is already protected. The exposed section in the sump is protected by oil and the exposed section in the water jacket is protected by the zinc anode.

I will be refitting the liner in the next couple of weeks in a YSE (earlier version of the YSB) and as per the advice given in the thread noted above, I will use Duralac as I believe it will be better than "white oil paint".

[Wotname]

Originally Posted by seabreez

Definitely grease, stay away of water, paint! no! lube your seals and cleanliness is very important. Do not hammer your sleeves. If the block is very clean just a small tap of the handle of a hammer to make sure the sleeve is bottomed out. Then install a bolt and washer to hold the sleeve down until all other cylinders are installed and you are ready to install the head.

The OP shouldn't have an issue here - the YSB is a single cylinder engine

[Compass790]

Originally Posted by pmagistro

Hey folks,

I'm about to dive into my Yanmar SB12 rebuild project. I'm installing a new cylinder liner and piston rings. In the instructions (which I've tried to link to below) it says to "coat the outside of the cylinder liner with waterproof paint or grease". Any suggestions as to what product I should be using?

Thanks!
Phil

https://books.google.com/books?id=n4...diesel&f=false

Yes i think they mean it's for corrosion protection. The liner is smaller diameter where they want the paint to go. I just painted mine with epoxy when i did the liner on my YSM8. Dunno if you really need to as original liner wasnt too badly corroded on outside but I did it to make it easier to remove in future. But agree with all the other post about greasing o-rings as you don't want salt water going anywhere but back in the sea

[Perna]

Originally Posted by a64pilot

Wet liners of anybody’s motors are subject to cavitation damage of the coolant from high frequency vibrations, and you need to be sure to use a good coolant specifically formulated to prevent this damage.
Cavitation Corrosion of Wet-Sleeve Liners in Heavy Duty Diesel Engines

+1 for using a good quality antifreeze. They come with corrosion inhibitors which prevent cavitation damage not only on the liner but in water pumps, cylinder head and so on.

Very important for engine long life.

[Wotname]

Originally Posted by a64pilot

........
Wet liners of anybody’s motors are subject to cavitation damage of the coolant from high frequency vibrations, and you need to be sure to use a good coolant specifically formulated to prevent this damage. Maybe that is why they wanted the liners painted? Although that is just a wild guess.
Cavitation Corrosion of Wet-Sleeve Liners in Heavy Duty Diesel Engines

Originally Posted by Perna

+1 for using a good quality antifreeze. They come with corrosion inhibitors which prevent cavitation damage not only on the liner but in water pumps, cylinder head and so on.

Very important for engine long life.

FWIW.

I'm sure this is correct for coolant (freshwater) cooled engines however the OP's engine is raw water cooled and is probably somewhere between 30 and 40 years old. It's only protection is zinc anodes...

[pmagistro]

Originally Posted by Wotname

FWIW.

I'm sure this is correct for coolant (freshwater) cooled engines however the OP's engine is raw water cooled and is probably somewhere between 30 and 40 years old. It's only protection is zinc anodes...

That is correct. Sounds like duralac or similar would be my best bet. Thanks everyone for all the input!!!

[Compass790]

[QUOTE=pmagistro;2541895]Hey folks,

I'm about to dive into my Yanmar SB12 rebuild project. I'm installing a new cylinder liner and piston rings. In the instructions (which I've tried to link to below) it says to "coat the outside of the cylinder liner with waterproof paint or grease". Any suggestions as to what product I should be using?

Thanks!
Phil

Woops! I didn't read the manual properly. Go with what Wotname says. It says paint or grease the parts that come in contact with the block. I did that with grease, but i painted the part of the liner that is in contact with the water with epoxy but that was my experiment. People may say that painting the liner with epoxy may cause it to run too hot but after about 40 hrs I see no evidence of that. Motor is running fine & cooler than before the rebuild.

[a64pilot]

A cylinder doesn’t get very hot. Combustion and that heat is in the head. I don’t think the paint will hurt at all