Copper Head Gaskets

motoddrob

motoddrob

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S/W Australia
Thought I'd start a thread about the pros and cons of CU gaskets.

Should I fit it or not, and do I use a sealant or not, and what sort of sealant should it be.

Anyone with experience using them, comments, thoughts.

Cheers
Rob
 
Well, for what it's worth I'll get in first.

Rob - yes I used the copper head gasket I got from you (this is on my Motodd. 80.5 bore from memory).
I got a base gasket made because for some reason pistons were hitting the head with the stock base gasket (DPO skimming head each time it got removed...??). Base gasket could have been composite. In fact the mechanic (Dave Cole) who reasembled barrels and head had a copper and a composite base gasket made. He elected to use the copper base.

Dave Cole has considerable experience with D*****i's and some classic stuff (G50's??). He used 3 bond on the copper head and base gaskets. For some reason there is minor weeping, but I'd put that down to the condition of the surfaces, not the copper/3bond mix.

Dont seem to need to re-torque as much. I asked Dave if further re-torque check might cure weeping. He thought unlikely. It's a minor, which I'll live with for now. If it gets any worth I'll consider pulling barrels off, installing new pistons ex Red. I'd probably use copper again. If I did, would definitely apply 3 bond.

Apart from 3 bond there are other specific copper gasket sealing compounds. They must make the compounds for a reason.

HTH
Andre
 
Researching copper gaskets sealants, came across some petrol head forums and the general concensus is to use a sealant.
Hylomar Universal Blue seem to be a popular choice. Also doesn't set, kind of like that.
Just need to find some now.
 
I won't use a copper head gasket, they do not seal the combustion chamber or the oilways effectively without some flddly and pointless machining, what are you trying to fix? Stock composite gasket is the way to go for oiltight reliability unless you intend to run on methanol, supercharge, N2o ! whatever. Comparing with a Ducati is not relevent due to entirely different engine architecture.


  Keith.
 
Copper gaskets can work well in certain applications, which is why you'll see automotive tuning companies like Milodon extolling their virtues, especially for turbo applications. As Keith has pointed out, their effectiveness depends on the engine architecture.
Looking at the previous anecodotal evidence on this and other forums it's clear that they can cause problems on Laverdas. There was a quantity of them [for the 500s] in a spares cache I bought, I binned the lot of 'em. In my opinion they were oil leaks waiting to happen...
 
Don't bother. I tried one, very kindly supplied but this is about being honest. Used 3 times  in all and had both engine faces machined prior. I reused it too after annealing as I had several engine tear downs in a short space. I had no oil leaks but I would have had a combustion  leak soon enough as I could see the gases creeping. Without a fire ring or recessed wire, I personally think the concept is wrong in a relatively high performance motor.

ie, the compression of gasket is spread over the whole area rather unlike a composite with a fire ring.

I have photo,s somewhere which show what was happening, prefer a composite gasket and I personally use a Loctite silicon gasket sealer around the peripherary to prevent the oil smears that you get on  a properly leathered motor on a race track. Kind of like any modern gasket with a thin path of silicon bead already applied both sides.  
 
Don't know wether I should use it now!! Have a composite one here as well. The guy that did my rebores skimmed the top face so now I don't have that recess on the liners. Does that make a difference using composite with the copper flame ring? Probably a stupid question!!
 
motoddrob said:
Don't know wether I should use it now!! Have a composite one here as well. The guy that did my rebores skimmed the top face so now I don't have that recess on the liners. Does that make a difference using composite with the copper flame ring? Probably a stupid question!!
Click to expand...

Not at all, Rob,

The composite gaskets work best with a slight recess, but an absolutely flush surface is also OK.  The liners just should not stand proud of the sealing surface as is the case with hard-worked barrels.

If both surfaces are nice and flat and you don't intend to thrash the balls off the engine like (Jota)Rob does, the solid gasket should work OK imho.  A very thin layer of sealant around the outer edge will no doubt help keeping things oil-tight. 

piet
 
Good reply Piet :D  I'll give it a try, no big deal to change out if it doesn't work out I guess. It'll get a good workout but nothing like Rob's or Crispen's.
 
Hi All - As I'm not the biggest fan of the CU gaskets - I 've had another batch made of the composite gaskets that i used to use a while back - these have the oilway holes moved 1mm radially out from the centre to increase the amount of metal left round the flame ring in that area. I have never had a failure with this set up and now the material is even better. These gaskets are 1.3mm thick (0.3mm thicker than std) as so many heads have been skimmed now or need attention to make sure no problems will arise. The flame ring is annealed copper - not the cheaper steel item that tends to not seal as well  - and I've seen them with rust scars on them too. With the std 1000cc models this gasket is probably overkill - but with a tuned 1200cc it becomes a better option. if anyone is interested i can spare a few - price (with Viton O rings) is similar to prices being charged for ordinary gaskets. - Regards - Phil
 

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Phil,
What is the bore size of the flame ring ?
Our pistons protrude from the top of the barrel so need to pass through the gasket.
Need a flame ring bore size of 82.5mm ?
if larger even better

Red
 
Hi Red - These gaskets have a flame ring I.D. size of between 80.25mm and 80.75mm so are not suitable for a piston size larger than that which will protrude above top land of barrell -  I kept the smaller diameter to retain as much meat as possible in the "O" ring area. - Regards - Phil
 
on my RGS "1200" I am still using a copper head gasket from Clem. The head has been off twice for other reasons since first fitting the ccopper head gasket. Just use the oxy acetylene torch to re anneal the copper head gasket and use it again. The engine has been to the dyno a couple of times, but only once to the race track since the copper head gasket has been fitted, I have had good results fitting the copper head gasket with a light smear of grease and no gasket sealers.

Paul LeClair
 
phil37 said:
Hi Red - These gaskets have a flame ring I.D. size of between 80.25mm and 80.75mm so are not suitable for a piston size larger than that which will protrude above top land of barrell -  I kept the smaller diameter to retain as much meat as possible in the "O" ring area. - Regards - Phil
Click to expand...

thanks for reply Phil, bummer they are too small
will stay with current mob who are making our 83.0mm bore head gaskets
they have been running okay in the silver engine, no issues


 
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