B
Copper Head Gasket
- Thread starter Kiwi Laverda
- Start date
Reggie3cl said:My persistantly leaking 180 head was within tolerance for flatness (yes, I had it checked properly) but the Exxon Valdez-alike leak was only cured when I had the head and barrels skimmed dead flat and the liners set exactly to tolerance with the flanges 0.1mm (or whatever it was) below the surface of the barrels. Them buggers got to be dead flat whatever gasket you're using...
In a nutshell, that's it!
If everything is set up correctly, the stock gasket, including the o-rings, works as well as any other, on a stock sort-of engine. Once the compression or combustion pressure goes through the ceiling by means of forced induction, etc, something stronger may well be required.
If I were in a position to have gaskets made, they would be of the composite type with the "o-ring" holes the same size as the others, and have a sealing compound applied directly to the gasket as is common practice these days.
But, with a warped head/barrel or liners standing proud, even such a modern gasket is sure to leak!
piet
- Location
- Calgary, Alberta, Canada
nick7 said:
Hi Nick
gasket cement? Hell no, I used a skim of wheel bearing grease on both sides of the copper gasket to let it squirm around as needed while the head was torqued carefully in stages and in the correct pattern.The 80.4 mm J & E pistons I am using on Carillo rods in the RGS engine are I think about 10:1 or 10.5:1, whatever they are when they come from Wolfgang, I have the earlier type that he originally had made to accept standard Laverda type rings.
With the head and barrels properly skimmed flat, the copper gasket properly annealed according to Clem's instructions, a light skim of grease on both sides of the copper gasket, and a careful proper torquing of the head (and subsquent retorquing after a couple of hundred KMS), the copper head gasket is giving great service, no leaks, very comforting to know that the solid copper gasket is in there in that very carefully built and bloody expensive RGS engine and unlikely to allow compression leaks!
Paul LeClair
CLEMTOG
Hero member
now some of you are starting to "get it"
Pip higham was "trying to contain considerable cylinder pressure"
Piet states that "combustion pressure goes through the ceiling by means of forced induction etc something stronger may well be required"
Both of the above imply that the standard gasket can be unsatisfactory,or inferior and a stronger type is sometimes vital, so why not make a better one, and then everyone can enjoy it? even those with naturally aspirated engines on 7:1 compression,well I did, and there are many hapy users.
CLEM
Pip higham was "trying to contain considerable cylinder pressure"
Piet states that "combustion pressure goes through the ceiling by means of forced induction etc something stronger may well be required"
Both of the above imply that the standard gasket can be unsatisfactory,or inferior and a stronger type is sometimes vital, so why not make a better one, and then everyone can enjoy it? even those with naturally aspirated engines on 7:1 compression,well I did, and there are many hapy users.
CLEM
Hi Paul,
Glad it works for you, of course. But on the subject of the grease you mention, Clem's instructions to me were to not even leave a finger-print of grease, and on the subject of annealing, a torch is apparently very second best to an appropriate oven...something to do with the need to heat evenly. I must say, I would think it unlikely that if its going to fail, any grease would make a difference.But the various articles i have read about copper gaskets vary as to what if any sealants to use. I have never had a problem with a conventional gasket, only with a copper one. As noted above, it seems that the sheer work (and cost) involved in using the copper gasket is not justified ,or necessary, except in high performance applications. Clems gaskets are art...Keith has swiped mine for future use on barrels that are properly machined , per Clem's advices.Personaaly, I would not have been willing to subject my new barrels and head to the milling process...they are flat enough (witness the no leak at present with a conventional gasket) ..it was the slight standard recess of the barrels that caught the gasket out. Hopefully I wont be taking the thing apart for a while yet and the subject of gaskets can RIP for a few years!
Nick7
Glad it works for you, of course. But on the subject of the grease you mention, Clem's instructions to me were to not even leave a finger-print of grease, and on the subject of annealing, a torch is apparently very second best to an appropriate oven...something to do with the need to heat evenly. I must say, I would think it unlikely that if its going to fail, any grease would make a difference.But the various articles i have read about copper gaskets vary as to what if any sealants to use. I have never had a problem with a conventional gasket, only with a copper one. As noted above, it seems that the sheer work (and cost) involved in using the copper gasket is not justified ,or necessary, except in high performance applications. Clems gaskets are art...Keith has swiped mine for future use on barrels that are properly machined , per Clem's advices.Personaaly, I would not have been willing to subject my new barrels and head to the milling process...they are flat enough (witness the no leak at present with a conventional gasket) ..it was the slight standard recess of the barrels that caught the gasket out. Hopefully I wont be taking the thing apart for a while yet and the subject of gaskets can RIP for a few years!
Nick7
P
paul-haggis
Guest
The o-rings certainly are a pain in the arse, the thing I dislike most is that you are never quite sure how they will move when the head is torqued down. They dont excatly have a lot of land to sit on.
nick7 said:Hi Paul,
Glad it works for you, of course. But on the subject of the grease you mention, Clem's instructions to me were to not even leave a finger-print of grease, and on the subject of annealing, a torch is apparently very second best to an appropriate oven...something to do with the need to heat evenly. I must say, I would think it unlikely that if its going to fail, any grease would make a difference.But the various articles i have read about copper gaskets vary as to what if any sealants to use. I have never had a problem with a conventional gasket, only with a copper one. As noted above, it seems that the sheer work (and cost) involved in using the copper gasket is not justified ,or necessary, except in high performance applications. Clems gaskets are art...Keith has swiped mine for future use on barrels that are properly machined , per Clem's advices.Personaaly, I would not have been willing to subject my new barrels and head to the milling process...they are flat enough (witness the no leak at present with a conventional gasket) ..it was the slight standard recess of the barrels that caught the gasket out. Hopefully I wont be taking the thing apart for a while yet and the subject of gaskets can RIP for a few years!
Nick7
It's quite likely that the liners do settle, even after having the whole lot skimmed flat. I had that done, and on using a new Composite gasket, the fire ring simply settled the liners a further few thou into the barrels. (it's a lot of pressure, pushing the liner into a ledge of relatively soft alloy)
I did use the Copper Gasket that Clem kindly supplied me, it was very useful for me at the time as I had to tear down the motor several times for various problems and
I stopped using it and have kept it for future potential use. I stopped using it because I didn't like the way the the combustion gases appeared to be creeping outward further than they should. Ie instead of having a fire ring under more compression than the remainder of a std gasket, you have an even pressure over the whole area = a much reduced pressure where you need it, to contain the combustion gases.
With a liner that has a pre disposition to sink rather than stand proud, it's something I wasn't comfortable with. I'm sure with the recess and wire that tuners combine it with (Bob mentions earlier in this thread), you have a watertight solution but me I've gone back to a composite gasket and a bead of Silicone sealant on both sides around the periphery. All surfaces are skimmed and it remains oil tight.
I'm not sure what the hardness of work hardened copper is vs Annealed LM25 of a Laverda Head, block but it also concerns me. As I say, I'm grateful for Clems work and in no way intend to do him down, I'm just a reporter and present the facts as seen to me. I probably used the gasket 4 times with no reduction in quality or misshape.
I've had the head off with new composite gaskets about 5 or 6 times since and so I get to see whether sealant works, where the oil or gases creep to on the same motor.
I hope this is accepted in the right way and not as criticism or lack of appreciation. My feeling is this forum is for all to learn and make decisions based on fact as well as experience, some good and some bad.
Nothing wrong with the gasket I used, both the head and barrel were skimmed by Osselli and the head is still in use, though the barrels were destroyed.
The engine came apart several times for what turned out to be a poorly fitted inlet valve guide that allowed a passage of oil into the inlet port between guide and head casting. It took several attempts before I found it.
Here are a couple of pic of the gasket, whether my fault or not, I wasn't happy with the way the gas seal was being made. Hope it will allow a bit of extra thinking.
This is a powerful motor and therefore presumably makes considerably more combustion pressure than a standard motor, which will have some impact right ?
The original photo's are larger and therefore a little clearer.
Nothing wrong with the gasket I used, both the head and barrel were skimmed by Osselli and the head is still in use, though the barrels were destroyed.
The engine came apart several times for what turned out to be a poorly fitted inlet valve guide that allowed a passage of oil into the inlet port between guide and head casting. It took several attempts before I found it.
Here are a couple of pic of the gasket, whether my fault or not, I wasn't happy with the way the gas seal was being made. Hope it will allow a bit of extra thinking.
This is a powerful motor and therefore presumably makes considerably more combustion pressure than a standard motor, which will have some impact right ?
The original photo's are larger and therefore a little clearer.
B
bob
Guest
Rob, The conclusion I draw from these photographs is that you're not one of the better spanner men on this forum, much like myself...
Romeo.D
Hero member
- Location
- Zadar - Croatia
Paul H said:The o-rings certainly are a pain in the arse, the thing I dislike most is that you are never quite sure how they will move when the head is torqued down. They dont excatly have a lot of land to sit on.
This is what hepend with my foto in avatar , bike was runing normaly but on each end of straits judgegs was weaving with blak flag , havy smoke each time when i go down from full throtle . Go out and bike works normaly , we wonderd what might that be .
Come home from race wekeend , hed down and the gasket was burnd beteewn this O-ring (oil chanel) and combustion chambre . Then i buy few gaskets from OCT instaled new one and newer have same problem again . In my oppinion problem comes for 2 rasons 1. pistons 80,4 insted 75mm and 2. those gakets are not all the same they always vary litlle bit on left or right so i tried to find one who have bit more matirial on critic spots and never seen blak flag since than .
- Location
- Calgary, Alberta, Canada
bob said:Rob, The conclusion I draw from these photographs is that you're not one of the better spanner men on this forum, much like myself...
laughing out loud, Bob, you are such a shit disturber
laverdakeith
Hero member
I recon he is quite good at it Paul.
Keith.
Keith.
GregT
Hero member
- Location
- Christchurch NZ
Looking at those pics of the used copper gasket, i have to ask, how tight were you running the squish clearances ?
If I found one which looked like that, I'd suspect the pistons had been touching....
The bore O ringing which has been mentioned works very well if you've got suspect sealing or very high cylinder pressures.
A groove cut into the liner flange to suit 20Gauge (.9mm ?) stainless wire such that it protrudes about .004 in works very well.
On modern watercooled bike motors with alloy shim gaskets this is often the only way to improve the seal.The only problem here is that the gaskets are one time only use as they stretch over the wire.
If I found one which looked like that, I'd suspect the pistons had been touching....
The bore O ringing which has been mentioned works very well if you've got suspect sealing or very high cylinder pressures.
A groove cut into the liner flange to suit 20Gauge (.9mm ?) stainless wire such that it protrudes about .004 in works very well.
On modern watercooled bike motors with alloy shim gaskets this is often the only way to improve the seal.The only problem here is that the gaskets are one time only use as they stretch over the wire.
GregT said:
Hi Greg
I need more information, I can only assume you think the pistons are touching....the gasket ????
The Bore is 81mm, the gasket bore is 81mm, I relieve the crown of the piston (that is reduce the diameter not the height) to get the pistons to fit inside the head bore. There are other ways to do it possibly, like open up the chambers but that is my chosen way.
B
bob
Guest
Just having a tickle chaps , that's all.... One should never miss an opportunity for a bit of mirth when it presents itself.
One should never miss an opportunity for a bit of mirth when it presents itself.
GregT
Hero member
- Location
- Christchurch NZ
I'm talking piston to head clearance Rob....minimum of .040in I would have thought.
Were there any witness marks on the piston crowns ?
Were there any witness marks on the piston crowns ?
78jotadave
Hero member
This Forum really is working for me. Tonight I learned about copper head gaskets versus the original composite type. I now feel comfortable with the knowledge that the original gasket is all I really need. Before tonight I had no idea the amount of prep/machining needed to use a copper gasket. Thanks guys for sharing, Cheers Dave.
GregT said:
Hi Greg, I run a tight squish band, I remember researching the allowable amount when I built the engine, using data from the internet.
I undestand logic but I dont understand where you're coming from. No the pistons are not touching the head, I've had that, it's quite obvious.
I acccept I may be wrong (always happy to learn), but you're gonna have to explain me in simple terms what a small but non intrusive squish band has to do with gas creepage based on my Logical understanding?
Are you suggesting the piston is striking the head and and pushing it off its studs to release tension ?? or something else. I'm very interested but not getting you.
Thanks Rob
P
paul-haggis
Guest
Greg/Rob.
To help your discussion.....
To help your discussion.....
Kiwi Laverda
Hero member
- Location
- The wobbly bit of New Zealand
PaulH
Drawing looks like a great schematic for a barbecue, either that or the TV aerial is broken as there is no picture.........
Humour, she is good no?
Also think this forum is great, learn a lot and the greater knowledge of the group is a great help.
Also I get the answers while I sleep...............
I've decided to stay with the standard gasket, on its way from Red.
Still thinking of sending a sample off to the local gasket maker to see what could be done locally in NZ
Thanks for all the input.
Steven
Drawing looks like a great schematic for a barbecue, either that or the TV aerial is broken as there is no picture.........
Humour, she is good no?
Also think this forum is great, learn a lot and the greater knowledge of the group is a great help.
Also I get the answers while I sleep...............
I've decided to stay with the standard gasket, on its way from Red.
Still thinking of sending a sample off to the local gasket maker to see what could be done locally in NZ
Thanks for all the input.
Steven