Well seal or blue hylomar

[DAVE BRADY]

Hi,

I use a similar method with the Hylomar on one side and high melting point grease on the other.  I have never had a mating surface bad enough to need a file but I would be more likely to get a large sheet of fine wet and dry on a piece of plate glass.  Lubricate the wet and dry with WD40 so the case slides easily.  This may sound like it will reduce the abrasiveness of the w and d but it allows the case to move with less effort so there is less likely hood of pressing down on one part more than another and making things worse. Use a circular movement and check progress regularly.
A way to check how well the surfaces a contacting is to assemble without a gasket but not fully tight. See if there are any gaps with a thin feeler gauge.  If any gaps are only a few thou then the gasket will seal it.
Wire wool is good at removing any traces of old sealant etc. from the mating face but make sure it is all cleaned away.   

Dave.

[Phil C]

My timing side outer cover has no gasket, so I was anticipating just putting Hylomar on both surfaces. But when I saw on the online description the figure 0.03mm, in other words just over .001", I thought there would be a good chance that there would be a bigger gap than that to fill. In any event, how do you smear the stuff that thin? Maybe you don't, maybe you put more than that on and it squeezes to that, and if the gap is bigger than that then the compound might not work so well. Is that right?   Phil

[mo goldie]

been using Wellseal since the mid seventies mainly on non seperating assemblies as it sets. where covers are likely to be needed to pull off then blue hylomar or equivalent. the Japanese use a product Michel which is grey and soft as they tend not to use gaskets. there is also a product which is oil and petrol proof best for fuel areas.
whichever I do like to clean off after use, so many restos of the late 80's still have red hylomar visible including fingerprints/

Wellseal, as it was a Vauxhall used workshop product when I  rebuilt my first engine , a Viva HB. if it was good for them.... and Ive been GM most of my driving life.

Hi Chaz. I too used to have HB ViVa took the 1159 out and put in a  Chevette 1256.......Oh I still have one of the inlet manifolds which is the Jack Brabham which take the twin strombuges must be worth a bit now LOL

[Bess]

Hi Phil,

          You're overthinking. There is no way you can get an exact uniform thickness kneeling down in your garage. A thin film applied as equally as you can is all that's needed, scrap off any excess when the compound has dried.

I only use Hylomar on main cases and faces with a gasket. I would be using silicone RTV in your particular face to face joint, the gearbox is not pressurised so a thin film of RTV will be fine.

Best wishes...

[Phil C]

I confess: maybe I do sometimes overthink things.

[robincroft]

In my experience using any sealant that can come adrift and enter the lubrication system is fraught with danger. Many times I have stripped engines only to find bit of silicon sealant floating about within engine cases. I am a fan of Wellseal as it does not set and can do little harm, used with a gasket it is excellent. Of course it cannot bridge large irregular surface discrepancies but usually as previously mentioned with care faces can be improved. Silicon is fine for applications that are in a self contained environment such as a chaincase or gearbox. Good olde British vertical joint faces are never simple to keep oil tight but with good preparation success can be achieved.
Robin

[chaz]

dont know where you get your wellseal from but every tube Ive ever used has set and if not wiped off you are left with a hard brown residue on the casings, inside and out.
Fluff Brown, who used to build FB AJS Stormers and Cotton Telstars and TriCot  bikes new, always used a clear bathroom sealer