1GM10 Head Gasket - Which Way Up?

[Ubergeekian]

I have a brand new Yanmar head gasket for my 1GM10. Unfortunately the instructions about fitting it in the manual are ambiguous. The diagram show "Flywheel side" on what isn't the flywheel side and claims that the gasket says "Top" on one side, which it doesn't - though it does say "A".

Does anyone have definitive knowledge about which way up it goes? For the moment I have fitted it with "A" - on the smooth metal side - up, but I can invert it if necessary ...

 

[steve28]

the gasket should have two additional holes on the side which would be the gear side, if the pushrods are furthest away from you the holes would be on the right.


steve

 

[Ubergeekian]

the gasket should have two additional holes on the side which would be the gear side, if the pushrods are furthest away from you the holes would be on the right.

That's one of the ambiguities. With the pushrods furthest away, the diagram in the manual has "gear side" on the right and "flywheel side" on the left ... but in that orientation my flywheel is on the right and it's not clear whether "gear side" means the gearbox or the (valve) gear case.

They also helpfully note that there are only holes in the block to match these extra holes in the gasket on one side ... not on my engine! It has a full set of block and head holes on both sides.

Still, I think I put the extra holes on the right as you say!

 

[NorthUp]

I had the same problem a couple of weeks ago, even posted on a Yanmar help forum-didn't do much good though!
I eventually placed the gasket with the A uppermost... so far so good.

 

[Bilgediver]

That's one of the ambiguities. With the pushrods furthest away, the diagram in the manual has "gear side" on the right and "flywheel side" on the left ... but in that orientation my flywheel is on the right and it's not clear whether "gear side" means the gearbox or the (valve) gear case.

They also helpfully note that there are only holes in the block to match these extra holes in the gasket on one side ... not on my engine! It has a full set of block and head holes on both sides.

Still, I think I put the extra holes on the right as you say!

Did the gasket that came of have a full set of holes both sides???

 

[NorthUp]

Did the gasket that came of have a full set of holes both sides???

On mine, the holes were restricted to about 3mm diameter on one side, the other side was the full size of the holes in the block casting.

 

[Ubergeekian]

Did the gasket that came of have a full set of holes both sides???

Sort of. The thick gasket material is completely symmetrical but the thin metal sheet on one side only blanks off two (as I recall) holes and restricts another. just to add to the annoyance, the top of the block isn't symmetrical in shape on the pushrod side, so if they just made the gasket to the same shape none of this would arise.

 

[Ubergeekian]

I had the same problem a couple of weeks ago, even posted on a Yanmar help forum-didn't do much good though!
I eventually placed the gasket with the A uppermost... so far so good.

Ta. It's good to know that I am not alone in the problem or my solution!

 

[Bilgediver]

Ta. It's good to know that I am not alone in the problem or my solution!

The manual doesn t help either

 

[steve28]

the gear side they refer to is the pulley side. They assume the engine has no gearbox attached at this stage.

steve

 

[Ubergeekian]

the gear side they refer to is the pulley side. They assume the engine has no gearbox attached at this stage.

That's what I thought. The problem with the picture in the printed manual is that it shows "gear side" on right hand side as you look across at the pushrods and "flywheel side" on the right, which is the opposite way round from reality!

I have just had a look at the pdf manual which floats around. It's not the same as the printed manual and has no diagram, but the rather blurry photo on p76 (pdf page 82) seems to show the unblocked holes on the gearbox/flywheel/airfilter side of the engine. Which is how I fitted mine.

I think.

 

[Topcat47]

I've just done mine. For some reason, Yanmar have put out a load of replacement gaskets stamped "A" instead of "Top". Marine Power confirmed that they go "A" side uppermost.

 

[Ubergeekian]

I've just done mine. For some reason, Yanmar have put out a load of replacement gaskets stamped "A" instead of "Top". Marine Power confirmed that they go "A" side uppermost.

Murky buckets. I didn't like to ask them, since I imported my gasket from the US ...

 

[Lakesailor]

Is this any help, or is it just what you have already?

I found a guide which states (and it lines up with many years of head gasket replacing) that the flat side of the gasket goes against the head. The curled-over ring against the block.

Which would make this the block face side

 

[Ubergeekian]

Is this any help, or is it just what you have already?

Thanks very much - that's the picture in the printed manual. If you align the engine as shown then the flywheel and intake are on the right, with the gearbox, while the gears are on the left. Oh yes, and the hole on the cylinder side is drilled on mine.

I've fitted it as the text you posted suggests: smooth face up.

 

[Mel]

I recently posted a thread about a problem I have been having with water temperature alarm on my 1GM10 after fitting new cylinder head over winter. After much delving I found that I had fitted the head gasket the wrong way round.
Today I replaced the gasket correctly and the temperature problem has gone !

Attached picture shows correct position for this gasket for anybody still in doubt

 

[steve28]

well done for solving it and the picture will help future searchers.

steve

 

[Ubergeekian]

well done for solving it and the picture will help future searchers.

Seconded. Many thanks.