Forum

[Marko]

Yesterday on a test run my Connie blew a head gasket. I asked some advice on other forums/groups I belong to and have also been in touch with Mark M who has given me a fair bit of advice. Anyway I've ordered new copper gaskets, I've opted for the thicker ones. Right, other than annealing & re-torqueing etc do any of you use any sealant on them? I ask because if I was working on a Triumph twin I wouldn't hesitate to use a sealant with copper gaskets.. however.. as i'm totally new to Royal Enfields and Connies in particular any tips/advice from owners is always appreciated at this end.. best regards Mark

[Dennis C]

Hi Mark, I normally Just use a smear of grease on head gaskets, but on problem ones I have found that Threebond TB1215 usually works fine. It's a type of silicone so withstands the heat but unlike normal silicone it is unaffected by petrol.

[Tim NZ]

Which head blew, L or R?


Any sign of 'tracking' across the face of the head? If there is it will keep blowing...


With the thicker Meteor head gasket you will need to reset the ignition timing to 3/8"


Do you have the correct hardened washers under the head nuts? Watch out for the old ones, they often get trapped and stuck to the head...


Dont use grease on the head-gasket. Kopper-Kote or similar

[Dennis C]

Why not grease Tim?, I have been using it for close on 60 years and never had a problem.

[Tim NZ]

'grease' is a generic description for all sorts of Soap based carriers, loaded with lubricants and fillers. Not all are equal, and most are not suitable to act as a media membrane other than for low temp applications. (Steering heads, swing arm-bushes, wheel brgs etc)


Oil or grease on absorbent paper/card based gasket materials is ok for low clamping pressure applications, but not on solid copper head-gaskets. Least of all a head known for high-pressure sealing issues, marginal claiming strength, and a disposition for running hot.

[Marko]

Tim hi, l/h side blew, I do have the hardened washers. Hopefully i'll be doing the job today; I have some silicone sealant in the garage that is supposed to be ok up to 750f (i'll double check later, its raining cats & dogs here) so I might use that when it comes to assembly time. I was not aware that a change in gasket thickness necessitated a change in ignition timing; reading the workshop manual timing figures of 3/8" to 7/16" I, as a triumph owner, assumed it was another Royal Enfield "quirk" that i'd just encountered

[Dennis C]

Thanks for that information Tim, interesting, I realize that grease and sealants must have changed in the past 58 years since I fitted my first head gasket, at the time I was advised by my motor mechanic neighbour to only ever use grease on a head gasket, since that time I have always done so and used it without problem on hundreds of head gaskets, I am probably to old to change now. 😁

[calv]

On my 3rd torque down...is this normal?? Using composite gaskets and hitchcocks new material base gaskets...

[Tim NZ]

LH side is more likely to blow; that cylinder frequently runs hottest being furthest from oil pump. It is also most likely to have been skimmed previously to remedy gas erosion tracking across the head??? If you have both heads off, attempt to compare/measure combustion chamber depths; it is not unexpected to have to fit additional base gasket under one cylinder to accommodate a skimmed head.


The variable in quoted ign timing figure reflects on which compression ratio piston is in service... (Same with the Bullet)


Hi Temp 'exhaust' silicone can be used on the head gasket, but be sparing with it. You dont want globs of it breaking free and blocking the camshaft tunnel oil drains.


Especially with the composite head gaskets, 3 stages of torque setting is advised and then again after the top end has been through a full heat-cycle.

[calv]

Got engine up to temp as done an 80 mile ride. Then was blowing. Retorque to 22 ft llbs. So hoping now it's all good.. if not I ain't got the foggiest?,,