Yanmar YSE Liner Question

[Wotname]

Originally Posted by Compass790

Are they gunna skim the liner top in situ or mill the lip the liner sits on in the block?

Mill the lip and confirm deck is square and mill if necessary.

[Techtool]

Take it in. Ad while your there ask the guy about putting any sylicone in the seals.. Lets us know what He says..

[Wotname]

Originally Posted by Techtool

Take it in. Ad while your there ask the guy about putting any sylicone in the seals.. Lets us know what He says..

They were less than definitive with regards to what lube to use on the seals

One said silicone grease was OK, another wasn't sure about silicone products in general and suggest "normal" o ring lube (as in glycerine etc) is all that is required and the last suggested a petroleum based grease was more appropriate as one o ring is washed with the engine oil.

AFAIK, there is a huge variation of products in the "silicone grease" family just as there is the petroleum or lithium families and one shouldn't generalise too much.

They then debated if the grease / lube / etc provided any long term sealing properties or if the long term seal is achieved by the o rings only with the lube being used only to protect the o ring from damage during fitment. There was no consensus!

I remain in the camp that thinks the o rings provide the sealing and the lube provides protection to them during fitting - this is standard o ring engineering practice (AFAIK) and I still plan to use waterproof petroleum based grease - because I have it on hand but I sure a silicone grease should be suitable although I do wonder if a very low pressure grease like DC4 would be suitable.

Lastly the conversion moved on to what to use around the top lip of the liner and their consensus was nothing. I have to say I disagree with this position. I suspect they are more familiar with wet liners that have protected closed coolant cooling rather than raw (seawater) cooling. There is no way I would be happy without some waterproof grease or other anti seize product placed around the lip during fitting. Even the Yanmar manual makes a point of it!

[Techtool]

Yes thats industry standard Soap on wet liner seals and grease or copper coat on dry liners. What did you end up with for protrusion?

[Techtool]

Oh I forgot to mention do NOT use Luberplate between a steel sleeve (liner) and a cast block..

[Wotname]

^^ I have asked for 4 thou.

[Wotname]

Originally Posted by Techtool

Oh I forgot to mention do NOT use Luberplate between a steel sleeve (liner) and a cast block..

OK but what is the issue?

[Wotname]

Back to the grease around the o rings and the top lip, I also thinking of Thixo synthetic grease. ???

http://www.maryninternational.com/wp...hure-Press.pdf

[Techtool]

For some reason they are using more zinc in luberplate and over time it will seize the liner. I like light viscosity synthetic grease as long as it will stand the heat. I presume you know about staggering the rings opposite the thrust side on the piston???

[Wotname]

Originally Posted by Techtool

For some reason they are using more zinc in luberplate and over time it will seize the liner. I like light viscosity synthetic grease as long as it will stand the heat......

Hmm, interesting... Not sure I like the concept zinc around the any liner or block that is immersed in seawater - apart from the zinc anode of course

[Wotname]

Originally Posted by Techtool

....... I presume you know about staggering the rings opposite the thrust side on the piston???

Yes and no

Yanmar manual states the first ring gap should be at 1.30 (o'clock), the second at 7.30, the third at 4.30 and the fourth at 10.30. The gudgeon (wrist) pin aligns with 3 and 9 o'clock.

It isn't explicit as to 12 and 6 o'clock occurs but I understand that the thrust side corresponds to 6 o'clock on the piston crown. (when viewed from the flywheel with CCW rotating crankshaft).

No????

[Compass790]

Originally Posted by Techtool

For some reason they are using more zinc in luberplate and over time it will seize the liner. I like light viscosity synthetic grease as long as it will stand the heat. I presume you know about staggering the rings opposite the thrust side on the piston???

Reason I recommended silicone grease is thats what divers use on their o-rings. Molycote is a good example but I'm with Wotname in that it's main function is to save 0-ring from assembly damage but silicone helps in the longevity part too. I'd be happy with synthetic grease as well.

[Wotname]

Originally Posted by jimbunyard

........

If by '515' you mean a sealant, it's not really necessary on the head gasket, but won't hurt anything as long as it's used in sufficiently small quantities to avoid contaminating the metal ring that seals the compression. There doesn't appear to be an oil gallery, so there's no worries about restricting that...

I've reread that Yanmar manual and I note it states the head gasket should be coated both sides with Three Bond 50 prior to fitting.

I have always understood the head gaskets need nothing so it was a surprise to read this information.

Google tells me that Three Bond 50 is no longer available but apparently it was a high temperature RTV silicone. There are of course modern equivalents. Further googling shows that many of the older Yanmar manuals state the same.

Maybe the best thing is to stop reading the manual

[Techtool]

Yes thats perfect ring position.

[jimbunyard]

Originally Posted by Wotname

I've reread that Yanmar manual and I note it states the head gasket should be coated both sides with Three Bond 50 prior to fitting.

I have always understood the head gaskets need nothing so it was a surprise to read this information.

Google tells me that Three Bond 50 is no longer available but apparently it was a high temperature RTV silicone. There are of course modern equivalents. Further googling shows that many of the older Yanmar manuals state the same.

Maybe the best thing is to stop reading the manual

Gasketing technology has aaa --changed--in 40+ years, so maybe reading the manual with that caveat in mind might be the order of the day...