Oil leak at the head?

N0rt0nelectr@ · Jan 16, 2017

Got my new to me 74 Mk2A started today. Second kick and she was running. Then I noticed that it was leaking oil again. I just replaced the head gasket due to an oil leak and pretty much the same spot. It is not as bad but any leak is not a good thing.
I installed a new copper head gasket having annealed it and used copper coat. It looks like it is leaking from the 3rd fin up from the bottom of the head which is where the 2 studs coming up from the cylinder are. I have re-torqued the head.
I seem to remember reading a long time ago about an issue with oil migrating up those studs?
Ideas, solutions?

John in Texas

texasSlick · Jan 16, 2017

Is the leak on right cylinder, rear of the spark Plug? If so, likely to be from oil drain hole located near there, with oil crossing over to the stud.

Refer to Jim Schmidt's technique to prevent leaks using 0.005" copper wire circumscribed around drain hole and pushrod tunnels as well. Search on jseng1 on this site.

Slick

Fast Eddie · Jan 16, 2017

Have you followed the re-torqueing procedure?

People have different ones, mine was to re-torque a day after starting it (without riding it) then at 50, 100 and 500 miles. I was amazed at how loose some fixings were the first two checks I did!

And... If its a normal bore size, and for road use, why not use a composite head gasket (only a 'proper' one from AN)?

If the head an barrel is flat, and everything is clean, and its torqued up properly they just work!

Towner · Jan 17, 2017

N0rt0nelectr@ said:
... It looks like it is leaking from the 3rd fin up from the bottom of the head which is where the 2 studs coming up from the cylinder are. I have re-torqued the head.
I seem to remember reading a long time ago about an issue with oil migrating up those studs?

The third fin leak is a known issue. After several attempts with new head gaskets (compound type) and sealant around the studs I ended up in a XS650 reed valve which stopped the leak.

Ralf

N0rt0nelectr@ · Jan 17, 2017

I woke up early today and as I was thinking about the leak it occurred to me that when I pulled the head the bolts were coated with carbon. I wire wheeled the carbon off but didn't chase the holes out with my tap. So I'm thinking that maybe, just maybe, I was getting a false torque reading because of that?
The leak is in the front between the cylinders as best as I can tell. As for my choice of head gaskets, it's what I had new on the shelf and I have never had an issue with either the copper or flame ring gaskets.
Going to start it up again to see IF the re-torque solved the problem and go from there.

John in Texas

freefly103 · Jan 17, 2017

What thickness flame ring gasket did you remove from your head? 0.75mm or 1.00mm?

I have the same problem, pulled the cylinder head off and removed a 0.75 mm flame ring gasket. I then sought advice from my go to Norton guy. Here's his reply:

Regarding head gaskets - I prefer composite gaskets because they do generally seal, well. I use them on all builds, unless the customer specifies or a custom thickness is necessary. And for as long as I've known the Norton composite (flame ring) head gasket thickness has been .75mm (.030"). We've built many motors around these dimensions. Then, just last month, we were doing up a customer's motor with very close tolerances and realized the composite head gasket we were using direct from Andover suddenly was 1mm (.040"). So I called Andover and their explanation was that they were having troubles with the .75mm gaskets sealing, and are now permanently supplying 1mm gaskets which, according to them, seem to seal much better.

Now... Having said all this, I have had troubles with .75mm composite head gaskets sealing before, but usually after a couple of heat cycles and torques this will tighten up. Often the head surface is irregular, or the barrel surface. And I have never used any sealer on the composite head gaskets.

As for copper - I have used them with good success simply by annealing properly, then coating with CopperKote and letting it dry for a few hours. I have always felt the copper gaskets weep and mist just a bit - a small annoyance - and while this is fine on a race bike with a fairing, I don't like it on street bikes as they get dirty quick.

So - I suggest you try the 1.0mm gasket from Andover, and see how you do. I wouldn't coat it, but only because I've never been so deep in the need to coat them. Not saying it's wrong (I would never contradict my mentor Mick Hemmings!), but just haven't had to go down that road.

I'm going with a new 1.00mm gasket from AN.

regards,

Joe

Towner · Jan 18, 2017

N0rt0nelectr@ said:
So I'm thinking that maybe, just maybe, I was getting a false torque reading because of that?

My experience is that a retorque rarely stop a leak (especially this). Consider that the 2 studs in front need lower reading than the other. Usually you can see a small runnel coming from the nuts. If it is more than a runnel you will probably end up in renewing the gasket. I always used the composite type and apply a thin layer of sealant (hylomar) around the studs and the pushrod tubes. In the beginning it was dry but after some hundred miles the leak recurred even after several retorques. Before renewing the gasket you could try to mount the nuts with sealant.
My recommandation is to mount a new composite gasket from AN with sealant (as mentioned). After mounting let it sit over night and do a first retorque the next morning. Then ride a little tour (20 miles) and do a retorque after cooling down. This is very Important. Maybe it is dry then. If the leak still occurs I would try the reed valve.

Ralf

jeffmack · Jan 18, 2017

Towner said:
N0rt0nelectr@ said:

... It looks like it is leaking from the 3rd fin up from the bottom of the head which is where the 2 studs coming up from the cylinder are. I have re-torqued the head.
I seem to remember reading a long time ago about an issue with oil migrating up those studs?

Click to expand...

The third fin leak is a known issue. After several attempts with new head gaskets (compound type) and sealant around the studs I ended up in a XS650 reed valve which stopped the leak.

Ralf

this worked for me as well

N0rt0nelectr@ · Jan 18, 2017

freefly103 said:
What thickness flame ring gasket did you remove from your head? 0.75mm or 1.00mm?

I have the same problem, pulled the cylinder head off and removed a 0.75 mm flame ring gasket. I then sought advice from my go to Norton guy. Here's his reply:

Regarding head gaskets - I prefer composite gaskets because they do generally seal, well. I use them on all builds, unless the customer specifies or a custom thickness is necessary. And for as long as I've known the Norton composite (flame ring) head gasket thickness has been .75mm (.030"). We've built many motors around these dimensions. Then, just last month, we were doing up a customer's motor with very close tolerances and realized the composite head gasket we were using direct from Andover suddenly was 1mm (.040"). So I called Andover and their explanation was that they were having troubles with the .75mm gaskets sealing, and are now permanently supplying 1mm gaskets which, according to them, seem to seal much better.

Now... Having said all this, I have had troubles with .75mm composite head gaskets sealing before, but usually after a couple of heat cycles and torques this will tighten up. Often the head surface is irregular, or the barrel surface. And I have never used any sealer on the composite head gaskets.

As for copper - I have used them with good success simply by annealing properly, then coating with CopperKote and letting it dry for a few hours. I have always felt the copper gaskets weep and mist just a bit - a small annoyance - and while this is fine on a race bike with a fairing, I don't like it on street bikes as they get dirty quick.

So - I suggest you try the 1.0mm gasket from Andover, and see how you do. I wouldn't coat it, but only because I've never been so deep in the need to coat them. Not saying it's wrong (I would never contradict my mentor Mick Hemmings!), but just haven't had to go down that road.

I'm going with a new 1.00mm gasket from AN.

regards,

Joe

Thanks for the information. I have never seen but 1 flame ring gasket listed. Are the thicker ones a new item? What is the part number?
I just ordered a couple of flame ring / composite from RGM. Should be here next week.
Again, thanks
John in Texas

Deets55 · Jan 18, 2017

FWIW
I ordered a complete gasket kit and a spare Composite head gasket from AN last August. The one in the complete kit was .75 the loose one was 1.00. So the change over is at least that old.

Pete

Towner · Jan 19, 2017

N0rt0nelectr@ said:
Are the thicker ones a new item? What is the part number?

I didn't need a new gasket last year, but I think that they treat it like an improvement not as a new part.
https://andover-norton.co.uk/en/shop-de ... 50-eyelet-

Fast Eddie · Jan 19, 2017

Does anyone know what these 'new' gaskets are like when installed?

Are they still 0.010" thicker than the old ones when 'crushed down' or do they crush down more than the old ones and end up closer to the old 'crushed down' thickness ??

Deets55 · Jan 19, 2017

Fast Eddie said:
Does anyone know what these 'new' gaskets are like when installed?

Are they still 0.010" thicker than the old ones when 'crushed down' or do they crush down more than the old ones and end up closer to the old 'crushed down' thickness ??

Nigel,
I can't confirm what they crush down to, but they are clearly stamped with the thickness. I would venture to guess that the .100 would be thicker than the .75 when crushed. IMHO.
Pete

N0rt0nelectr@ · Jan 19, 2017

Deets55 said:
Fast Eddie said:

Does anyone know what these 'new' gaskets are like when installed?

Are they still 0.010" thicker than the old ones when 'crushed down' or do they crush down more than the old ones and end up closer to the old 'crushed down' thickness ??

Click to expand...

Nigel,
I can't confirm what they crush down to, but they are clearly stamped with the thickness. I would venture to guess that the .100 would be thicker than the .75 when crushed. IMHO.
Pete

I went onto AN web site and only saw 1 composite gasket listed. Wonder if they are using the existing number but with a thicker gasket?

John in Texas

Danno · Jan 19, 2017

Just checked the AN head gasket I recently received from Old Britts and it's printed .100 on one side. It actually measured .108-.112, so there's some crush margin.

It's been a while since I used anything but copper. Am I correct in assuming these are applied dry-dry-dry?

Fast Eddie · Jan 19, 2017

Danno said:
Just checked the AN head gasket I recently received from Old Britts and it's printed .100 on one side. It actually measured .108-.112, so there's some crush margin.

It's been a while since I used anything but copper. Am I correct in assuming these are applied dry-dry-dry?

Scrupulously dry and scrupulously clean is how I've fitted composite gaskets and they've sealed perfectly each time.

This thickness change and unknown crushability is a pain for guys who like to set the squish though! At least on my new motor I have to use copper cos of the 81mm bore, and copper is a much more stable material in this sense. I'll just have to accept some oil mist I guess!

N0rt0nelectr@ · Jan 19, 2017

Got the head off today (I'm getting way to good at this). Looks like the leak is between the left push rod tunnel and the left stud hole. I measured the distance on the left .130, and on the right .160 at the narrowest between the push rod tunnel and the stud hole. I am going to paint the gasket surface with Prussian Blue and lap it on a piece of glass. See if there might be a low spot.
Thank you all for your insight and suggestions.

John in Texas

texasSlick · Jan 19, 2017

N0rt0nelectr@ said:
Got the head off today (I'm getting way to good at this). Looks like the leak is between the left push rod tunnel and the left stud hole. I measured the distance on the left .130, and on the right .160 at the narrowest between the push rod tunnel and the stud hole. I am going to paint the gasket surface with Prussian Blue and lap it on a piece of glass. See if there might be a low spot.
Thank you all for your insight and suggestions.

John in Texas

Review Jim Schmidt's leak fix:

sealer-for-copper-head-gaskets-t26022.html?hilit=Oil%20leak%20wire#p344282

Slick

gortnipper · Jan 19, 2017

oil-leak-the-head-gasket-t25033.html

jseng1 · Jan 20, 2017

texasSlick said:
Review Jim Schmidt's leak fix:

sealer-for-copper-head-gaskets-t26022.html?hilit=Oil%20leak%20wire#p344282

Slick

I haven't found a better high temp HG sealer than Pliobond. The trick is to coat each surface - the head, the cylinders, and both sides of the copper gasket (with the .005" copper wire around the pushrod tunnels and oil return hole). When you let it semi dry it becomes bonded to each metal surface so oil can't weep through. You can't half-ass it and skip coating a surface or it might leak. You don't have to worry about evenness of the sealer. Any extra sealer squishes out and flattens to nothing.

I'm having no leaks at all and it doesn't seem to matter if I use waisted (triangulated) bolt shanks or not - I'm not seeing leaks either way. It may be that the waisted head bolts are more important on larger displacement motors that want to blow the head off - I haven't determined that one way or the other.

Oil leak at the head?

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