What's the preferred gasket cement for the inner timing cover? Blue hylomar or Wellseal on the gasket?
I use Wellseal applied with a small brush and use SRM gaskets, which fit much better than the more commonly available ones.
I agree I use wellseal on all my bikes and works great and you dont see blue squirting out all over the engine.
Hi,
Blue Hylomar.
Used Wellseal on the engine casings once it was still dripping out a few months later.
Best wishes...
I use wellseal on crankcase halves , both jap and brit, and blue hylomar (sparingly) on other gaskets or sealing faces.
As long as you don't lather it on it's fine.
Works for me....but not for everyone.
Pete
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.
Blue Hylomar was an excellent product until it was changed. I now find it impossible to spread thinly and evenly, it seems to dry in an instant. Anyone had success with a tube bought in the last few years?
Hi Richard,
I am fan of Blue Hylomar and I find that as a tube is used it seems to get a bit thicker and harder to spread. I would imagine that each time the tube is opened some of the solvent evaporates. I always put the top back on a quickly as possible and perhaps I will buy smaller tubes in future to help to reduce wastage.
It sometimes helps to remove the bit that has gone off at the top and get through to the 'fresher' stuff.
Dave.
Hi Richard,
As Dave wrote, plus it has a best before date.
You might be using the bulk standard Blue Hylomar not the original Rolls Royce designed Hylomar Aerograde, a superior product.
Best wishes...
Yes! Definitely Aerograde if you can get it.
Dave.
Much more expensive though. Does it have a shelf life like the Blue? Phil
You can buy the aerograde in Cromwell outlets....only had to get some coz i ran out of my "aquired" Rolls Royce aero stuff from the RAF.
Pete
Hi Phil,
The Aerograde also has a shelf life.
Best wishes...
Hmmm...
Just been looking at it online. Medium grade. Says for thickness up to 0.03mm. So that's just over one thou. That's a pretty thin layer of compound. Or am I mistaken somewhere?
Phil.
Hi Phil,
Face to face joints such as main casings will be fine. Other joints using gaskets in the world of engineering are designed to be used without products but old casing surfaces can be dire so a light smear of product takes up the discrepancies.
Not saying this is correct, others might have their own methods:
I clean the casing mating surfaces, filing off any high spots with a dead smooth fine (rubbing the teeth with chalk first, stops the aluminum clogging the teeth), apply a thin layer of Hylomar to the gasket, fit the gasket Hylomar side to the engine, once fitted, smear the other face of the gasket with a thin layer grease, let it soak into the gasket, then a thin layer of Hylomar to the other case and assemble together.
If you want a joint without a gasket because the mating surfaces are really bad I would suggest silicone RTV. Again apply a layer of silicone RTV to the engine and grease to the other case then assemble, lightly tighten and allow to semi set before finally pulling together.
There can be issues with product entering the oil, so you need to balance up the quantity of product to stop leaks against the risk of excess entering the oil system.
Best wishes...
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.
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
Quote from: chaz on 28 Jan, 2021, 08:07
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
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...
I confess: maybe I do sometimes overthink things.
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
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