E: Engine Best Choice Comet Assembly Sealant
- Thread starter craig
- Start date
I suggest you stay well away from ANY type of silicon sealant because if there any any traces inside of the motor joints that pat of the silicon will NOT cure, instead it is just waiting for the engine oil to 'move' it around inside the motor where it will, not can, restrict oil flow with potential disaster consequences.
The solution that I have used on EVERY Vincent rebuild I have undertaken is Loctite 510 , It is an aerobic cure but better still, any uncured material will dissolve in oil so there is no chance of it causing any problems. I recommend an oil change after the first couple of hours of motor operation.
510 has added benefit of being able to seal gaps of up to 0.25mm and being low strength it makes any future disassembly easy.
Martyn
The solution that I have used on EVERY Vincent rebuild I have undertaken is Loctite 510 , It is an aerobic cure but better still, any uncured material will dissolve in oil so there is no chance of it causing any problems. I recommend an oil change after the first couple of hours of motor operation.
510 has added benefit of being able to seal gaps of up to 0.25mm and being low strength it makes any future disassembly easy.
Martyn
Thumbs up for Loctite or other anaerobic seals for this place. I don´t know the Threebond type above, maybe anaerobic as well, no silicone type ? Had a Threebond seal decades ago which was plastic like after cure so allright for cases. There are soft rubberlike Loctite anaerobic seals as well, number not available in my head at this time. But for sealing the engine case here I´d better have the little bit higher strength anaerobic "plastic" type seal for more shear strength against fretting, the 518 or 574 types I think.
Vic
Vic
Threebond 1184 is NOT a Silicon based sealant but is the same sealant used by ALL the Japanese motorcycle manufacturers when assembling their motors. It is solvent based, semi-setting and will seal scratched and damaged metal to metal engine faces without problem. I use it on my Velocette for ALL metal to metal faces and also use it in place of ALL thin paper gaskets where the gasket thickness is not important for clearances or end floats. On those joints I use the correct thicker gaskets with a smear of 1184 on either side to ensure sealing and in the majority of cases have been able to reuse these gaskets several times after cleaning off the old sealant using cellulose thinners.
There is a contrarian view:
https://www.vincentownersclub.co.uk/threads/1951-black-shadow-restoration.14564/page-37#post-137421
https://www.vincentownersclub.co.uk/threads/1951-black-shadow-restoration.14564/page-37#post-137421
A big worry for any sealant used in an engine is that "lumps" of it will be floating about in the oiling system. If Loctite 510 is soluble in oil that would be a big plus.
I have looked at the two documents and haven't found where it says it is oil soluble.
If you do this sort of thing often, then you generally find out the hard way if you use the wrong sealant somewhere on these bikes........Personally I would never use an anaerobic sealant on a case joint for the simple fact that you cannot guarantee that you can bolt the case halves together fast enough before the sealant goes off.........the only sealant i use on case and many other joint surfaces is either Threebond 1215 grey on alloy cases and 1207B on black cases........The trick is to use a nice small bead of it padded down with your finger tip........the excess once the cases are assembled is minimal........I've never had any issues with strands of the sealant coming adrift and causing damage to an engine........As has been mentioned the Japanese have been using this stuff generally with no gasket for decades........Anyone who thinks they can better that .........Good luck.
Sorry, I didn't check the link, the relevant contrarian view is in post #24 of https://www.vincentownersclub.co.uk/threads/1951-black-shadow-restoration.14564/page-37#post-137421