Author Topic: Gasket cement?  (Read 12704 times)

Offline JohnH

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Gasket cement?
« on: 14.07. 2010 23:23 »
As a newbie on this list - and as it's been 30 years since I did any serious engine refurb, can anyone advise which gasket cement is considered to be the "bees knees" these days. I used to use Hermetite Red .... not even sure if it's still available. I have two jobs to do on my GF - the first is to remove and refurbish the head (I really like the looks of the Chaterlea head steady) and the second is to stop a proimary chaincase oil leak (definitely a dicky gasket I think). I also need to strip the Monobloc - but won't be using gasket cement there!! All thoughts very gratefully received ...
John
Triumph Bonneville - long gone (sadly)
AJS 16MS - keeps coming back (thank goodness)
BSA B31 - also long gone
Greeves 250 twin (good fun)
Francis Barnett 197 (first bike)

Offline mike667

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Re: Gasket cement?
« Reply #1 on: 15.07. 2010 00:20 »
i really ;like the yamabond #4 gasket goop  - works great  - and is easy to remove - not sure about the other yamabonds but they come in different #'s

Online bsa-bill

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Re: Gasket cement?
« Reply #2 on: 15.07. 2010 09:01 »
Red Hermatite was a pain 50 years ago and still would be if you could get it (I think you can), blue hylomer or any of the others available are good but go sparingly, it squishes out and if it breaks off can get into oil ways, so just a slight smear, if the mating faces of whatever your joining are good then the proper gasket should be enough, but none of like to lose oil I know I know I know.
I used to use a liquid type that would only set in the absence of air, but any that escaped just dissolved harmlessly in oil, cant seem to find it now though, if anybody knows where it is available I would appreciate a nod
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline muskrat

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Re: Gasket cement?
« Reply #3 on: 15.07. 2010 09:17 »
G'day John,
                  I like to use permatex #3 doesn't go hard, can even reuse the gasket ( must be the Scott in me ). But nothing will seal my B****y rocker box.
Cheers.
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
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Online groily

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Re: Gasket cement?
« Reply #4 on: 15.07. 2010 10:52 »
Wellseal is meant to be up there but not always easy to find (also doesn't go hard), blue Hylamar is great, but for every day I just use a Loctite grey silicon product for things like primary sides. Seems to work quite well, and any small excess is hard to see against an alloy casing, unlike red, orange or primeval puce-coloured goop. But 'sparing' is right, nothing worse than loads of extruded gunge round every joint (and probably on the oily side as well).
The best other aid to a relatively leak-free life that I've found is a few rolls of decent gasket paper in various thicknesses, a modelling knife, a few of those sharpened, hard, tubular hole cutters - and not too many beers before doing cutting. A modest stock means you're never stuck and don't have to play with cornflake packets or brown wrapping paper. It really only leaves head gaskets having to be bought . . . which appeals to the mean streak in me too.
Bill

Offline brackenfel

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Re: Gasket cement?
« Reply #5 on: 15.07. 2010 17:26 »
Hi John,
As Groily says Wellseal has a good reputation so I bought some. I found it reasonably priced on Ebay a few months back - can also be found at shows & jumbles..
Am using it now but as the rebuild is still under way I can't tell how effective it is... It is certainly better to use than red Hermatite..
Hope this helps..

Adrian
1961 A10 650 Golden Flash - Blue
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Offline Rusty nuts

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Re: Gasket cement?
« Reply #6 on: 15.07. 2010 17:52 »
G'day John,
                  I like to use permatex #3 doesn't go hard, can even reuse the gasket ( must be the Scott in me ). But nothing will seal my B****y rocker box.
Cheers.

Bog standard household noname clear silicone (cheap as chips) has worked on my primary & more importantly on my rockerboxes where blue Hylomar et al failed.
Wouldn't put it on my head though!
No wonder I haven't seen Scott since I left Oz  *smile*

Rusty Robertson
1949 A7 Plunger
1947 A7 Rigid Star Twin
1969 Triumph T120R
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Offline zitman

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Re: Gasket cement?
« Reply #7 on: 15.07. 2010 19:43 »
I second the silicon.  Although I use black.  2.50 for a mastic gun sized tube from the local hardware store.

Z

Offline JohnH

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Re: Gasket cement?
« Reply #8 on: 16.07. 2010 09:11 »
     What a brilliant set of responses! Thanks to all who took the trouble to respond - I knew that joining this list was a good idea). I'll certainly give Wellseal and blue Hylomar a whirl - and Yamabond and Permatex - if I can get it in the UK. I'm really interested in the use of (presumably household - ie bathroom) silicone sealant. To those who use it (Zitman and Muskrat) - do you also use a gasket or do you just rely on the gap-filling properties of the sealant? I'm thinking primary chaincase, rocker box and rocker box covers here. Do you get a good seal when you have to remake the joint? - silicone sealant is a b*****d to seal over - so how do you get all the old stuff off .... or desn't it matter?
    Groily brings back major memories - I can recall using gasket paper (or brown paper if I had no gasket paper)and a small ball pein hammer to tap out a gasket on one of the gasket surfaces .... those holes were always a problem to cut out cleanly!
    Now, who uses gasket cement on their head gasket? I'm intending to use a solid copper gasket which I shall anneal (heat to red heat and quench in water) before fitting and I would not expect to use any gasket cement. Any thoughts from those much more experienced than me?

Thanks for the input!
John
Triumph Bonneville - long gone (sadly)
AJS 16MS - keeps coming back (thank goodness)
BSA B31 - also long gone
Greeves 250 twin (good fun)
Francis Barnett 197 (first bike)

Online A10Boy

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Re: Gasket cement?
« Reply #9 on: 16.07. 2010 09:41 »
There is absolutely no need to put a gasket cement on the copper head gasket - or if there is, something is wrong with the flatness of the faces.

I always find blue hylomar to be the best aid to gasket sealing. remember, thats all gasket cement should be, just an aid to help the proper gasket. It seems that most BSA's will leak from the chaincase and the rockerbox, but if the correct gasket is used with a dab of your favourite gasket cement, they shouldn't leak and if they do, there's most likely a proplem with mating surfaces.

Some chaincases will leak around the bolts and hylomar helps here too.

John, are you in the UK, if so where abouts?
Regards

Andy

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Online Brian

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Re: Gasket cement?
« Reply #10 on: 16.07. 2010 10:10 »
Hope I dont tread on any toes here but...........never, never use silicon in the engine. If you must then it can be used on the primary cover and maybe the gearbox but not the engine. I use loctite master gasket on the crankcase halfs and thats all, just a very light smear of grease on the other gaskets, no sealant. I accept if you have damaged surfaces it can be necessary but if the surfaces are half reasonable then no gasket cement is needed.

With the head gasket the same, I only use solid copper ones with a very light smear of grease and have never had one leak yet. The gasket must be annealed of course but you should not need any sealant of any kind.

Offline Rusty nuts

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Re: Gasket cement?
« Reply #11 on: 16.07. 2010 10:11 »
John,

Silicone can be removed with silicone remover but I just use nail varnish remover (the wife & daughters' I hasten to add), acetone is pretty much the same stuff.
Get as much off with an old feeler guage or similar then apply.
Screwdrivers are not recommended unless you fancy seeing if Pink Gripfill will act as a hole/scratch filler sealant *grins*

I use blue Hylomar very sparingly on composite head gaskets, back in the day grease was recommended by BSA service sheets.

Cheers

Rusty
1949 A7 Plunger
1947 A7 Rigid Star Twin
1969 Triumph T120R
1972 Triumph T120V

Offline BSA_54A10

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Re: Gasket cement?
« Reply #12 on: 16.07. 2010 11:44 »
Another Blue Hylomar devotee here.
I first used it on one of the Rollers because the RR manual said to.
Never used any  thing else since.
Magic stuff and even better you can simply rub it off with a damp thinners rag.
Soluable in thinners and spirits but not in petrol or oil.
Now that I have some money to spare I even use the spray can which applies it very thin indeed.
Bike Beesa
Trevor

Offline a101960

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Re: Gasket cement?
« Reply #13 on: 16.07. 2010 13:34 »
Quote
back in the day grease was recommended by BSA service sheets.

I find it hard to imagine that grease on a head gasket would would act as a sealant. What grease might do is to help hold the gasket in place, and maybe help the gasket to spread as it is compressed during the torque down. In other applications grease does work well. I always use grease on the timing cover gasket and on the primary cover gasket. In both instances it gives a leak free seal (well it does for me). Interestingly I assembled the rocker covers dry and so far there has been no detectable leakage. Before I rebuilt my engine this area was a problem. I can only speculate as to why. If anyone has watched the Triumph factory film (Meridan in the fifties) then you will have noticed that when the crank cases were assembled in the factory they painted on a shellac sealant with a brush. On my bike the only persistent leak that I have is from the sump to crank case joint. I have an SRM sump plate with the drain plug fitted. The reason for the leak here is that I do not use a sealant because the stiction effect renders the removal of the plate almost impossible, and each time I change the oil I like to clean and wash the gauze filters. The leakage is more nuisance value than a big problem because it is only slight anyway. Where ever I have unions I use Dowty washers and they work very well. Fibre washers do not seem to do the job properly in my experience. Oil incontinence is I think due to a multiplicity of causes. Internal pressure due to wear, poor mating surfaces, and inappropriate gasket material. Returning briefly to the rocker cover gaskets, the gaskets I used were soft and quite thick they are  green on one side and pink on the other. And as I said earlier in this post I have no detectable leakage from this area. So maybe it is the gasket material that determines how well the joint seals. Having said that before I rebuilt my engine it leaked almost everywhere. Which leads me to believe maybe wrongly that internal pressure is most likely to be the cause of oil leakage. But that is only an educated guess, and of course if you have a newly rebuilt engine that leaks then that theory goes out of the window.

John

Online bsa-bill

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Re: Gasket cement?
« Reply #14 on: 16.07. 2010 15:39 »
I think you got it on the third try John as I was told a few decades ago by trained mechanic that the grease was to allow the copper gasket to move freely as it was tightened down, this was on four cylinder diesel engines, probably has little benefit on our twins but also won't do any harm.
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco