new head gasket on GS550 results in oil dripping from front 10mm screw

[DimitriT]

Well, after all that work it really is a disappointment to find it dripping from the front there.

I used an OEM head gasket and a new square o-ring around the timing chain well. I didn't apply sealant to the head gasket (never had to in the past).

I got it up to temp and will re-torque but it probably won't make a difference.

It only drips about once every 5 minutes and then only when its running. But can't have that as it will make a mess.

Darn thing runs beautiful but for that.

Any advice?

 

[tom203]

That?s a drag......did you by chance check the head for flatness ?
and what year 550?

 

[DimitriT]

That’s a drag......did you by chance check the head for flatness ?
and what year 550?

Nope. The same head and block were fine (no leaks) before I stripped it down.

I stripped it to replace the cylinder sleeves due to low compression. Now the compression is very good but I have the leak.

It's a 1982.

In the past I would apply some sealer around the rectangular o-ring and let it cure before dropping the head onto it. I think the problem is that this o-ring will squeeze out of place when compressed unless it has some sealer to hold it in place.

This time I only used sealer in a couple of spots. I was in a hurry.

 

[Brendan W]

Have a go at retorque. I got more than half a turn on mine after 500 miles.
That 10mm screw? Is it doing anything?
The threads on mine were effectively stripped and there is a longer screw in there now with a nut on.

 

[uk gs nut]

You changed the sleeves ??. If you mean the cylinder liners, are the replacements flush and all flat on the gasket face.

 

[2BRacing]

Well, after all that work it really is a disappointment to find it dripping from the front there.

I used an OEM head gasket and a new square o-ring around the timing chain well. I didn't apply sealant to the head gasket (never had to in the past)....

Sorry to read about this - a real frustration after all your hard work.

Two things come to mind here - did you use the latest version OEM multi-layer steel head gasket, or an earlier original version? I have not experienced it myself, but have seen on here that with the latest multi-layer steel head gaskets, that square O-ring around the timing chain tunnel is not required.

Secondly, what I have experienced is that an oil leak at the top rear of the valve cover gasket will cause oil to run down and into the open passages in the head, coming out at the front of the head above the area of that 10 mm bolt. So check if you can pinpoint the exact source of the leak - clean all the oil off, and spray with foot powder or similar, then start the engine and observe where the powder gets wet first.

Good luck!

 

[DimitriT]

It may well have been an older type:

I have a newer style head gasket from a kit. It's one of those with a composite core sandwiched between steel. Do you know if those are any good?

I will check the valve cover.

 

[GregT]

You changed the sleeves ??. If you mean the cylinder liners, are the replacements flush and all flat on the gasket face.

And again - you changed the sleeves ?

If this has been done it's imperative to have the top surface of the block skimmed flat.
Even if you think it is already flat.

 

[DimitriT]

You changed the sleeves ??. If you mean the cylinder liners, are the replacements flush and all flat on the gasket face.

Yes they appeared flush.

 

[DimitriT]

And again - you changed the sleeves ?

If this has been done it's imperative to have the top surface of the block skimmed flat.
Even if you think it is already flat.

Hmmm.. When the top surface is machined, do they do that with the liners in the block? I guess they must otherwise the liners would sit proud of the surface.

 

[GregT]

Hmmm.. When the top surface is machined, do they do that with the liners in the block? I guess they must otherwise the liners would sit proud of the surface.

Correct. It's the only way of ensuring everything is level.
Take it to a machine shop and ask for a very light levelling cut on the top surface. They'll probably only take about .005in off which won't change cam timing enough to bother with.
I'd pick that at least one of the inner cylinder liners is standing slghtly proud of the gasket surface.

 

[fastbysuzuki]

You need to make sure the head and cylinder mating surfaces are flat more so if you use the multisteel head gasket if so the cam chain oring/gasket is not required

 

[Nessism]

Those MLS gaskets require a very clean and flat sealing surface in order to seal. As mentioned, I don't think the square O-ring should be used with the MLS gasket.
Changing the liners requires the surface to be decked afterwards. I'm not sure what the deal is but the liners/cylinder have different colored dots on the bottom so I think they are a graded fit of some sort.

 

[DimitriT]

So do I need to have both the block and the head surfaces skimmed? Or is it enough to just do the block since I replaced the cylinder sleeves.

I re-torqued after running up to temp a few times and got 3/8 of a turn on a few studs. It actually fixed the leak at that front 10mm bolt but now I noticed another major leak between #1 and #2. So I will take it apart again and do it right this time.

 

[GregT]

Just the block should suffice.But if you've used an MLS head gasket, I wouldn't re-use it as you will almost certainly have stretched/indented areas of it already - and it may not seal again.

 

[DimitriT]

So what do folks think of this type of head gasket:

https://photos.app.goo.gl/TLq3csJxjiSCcg7h7

I had this left over from a gasket kit. It looks like two pieces of steel with a black composite material in between. It measures 1mm thick. The OEM measured 1.25mm.

That extra .25mm may be why it's leaking even though I used the o-ring.

 

[Nessism]

That's a MLS gasket.

 

[DimitriT]

That's a MLS gasket.

ok so the OEM gaskets don't have that composite core and they are stamped with "TOP"?

For MLS gaskets, which side goes up?

 

[DimitriT]

So I tore into it today and here's what I found:

1. the surfaces are clean, flat and smooth. I mean you cannot tell there's new sleeves in there.

2. since I was using a NOS OEM gasket (I measured it at 1.25mm thick, BTW) I added the four o-rings in the corners, plus the middle o-ring.

3. somehow I ended up with two sizes of corner o-rings: 1.15mm thick and 1.45mm thick.

4. one of the corners (cylinder #1, front) had a thinner o-ring - aha, there's your problem.

Now the MLS gasket I have is 1mm thick and maybe those thinner o-rings were meant for that type of gasket, I don't know. But using the OEM gasket with the thin o-rings is never going to seal.

 

[Nessism]

Am I understand correctly that you reused the original OEM gasket that came on your bike 40 years ago?