Wellseal or Hylomar

[billwill]

I've now go some of both Wellseal and Hylomar so what are their respective merits & which joints are best done with Wellseal and which with Hylomar?

I've just tended to use Red Hermetite in most places in the past.

[benymazz]

I believe that all 3 are relatively interchangeable but if someone knows more than me I'll edit this post to reflect that. The only thing I seem to recall is that wellseal is marginally better for close-fitting gaskets and hylomar is good for just about everything else.

No doubt Rohan will be along shortly to sing the praises of Loctite No.3 aviation gasket cement it's good stuff, I've used it in many places and haven't had any problems with leaks.

-Ben

[Chrispy]

I used the no.3 aviation gasket cement with good success after taking Rohan's advice. Pleasantly surprised with it actually!

[rgh0]

They are all similar I believe, I prefer the Loctite No3 Aviation gasket cement as a paper or cork gasket dressing as its more available locally than Hylomar or Wellseal.

For metal to metal joins such as front chain cover to back plate I use modern anaerobic gasket forming / sealing compounds of which Loctite make many variations depending on surface flatness and degree of flexibility required.

cheers
Rohan

[69S4]

I've now go some of both Wellseal and Hylomar so what are their respective merits & which joints are best done with Wellseal and which with Hylomar?

I've just tended to use Red Hermetite in most places in the past.

I hope you've been keeping up the Red Hermetite tradition of using buckets of it on every joint. You used to see it oozing out everywhere as evidence that the engine had been apart. Got through a few tubes of it myself back in the day

I've had better results with Wellseal than Hylomar. It does seem to seal better although it's a lot more 'messy' to use than Hylomar. My current Wellseal tube is a half used sticky mess propped up in the corner whereas the Hylomar tube is clean enough to keep in the box and not much used now. I do use both but probably 10x as much Wellseal.

One thing I have been using for metal to metal joints is Threebond 1184. It's a semi drying rubbery sealant that's factory specified (as Hondabond or Yamabond) for sealing motorcycle crankcases (I've been rebuilding a few recently) and I've been wondering about its suitability for the TC front cover as it'll take up minor irregularities. Anyone used it for that?

[2cams70]

Threebond sealants in general are very good. On a par with Loctite and in some cases better. Almost every Japanese car and power equipment manufacturer specifies Threebond. Japanese cars generally speaking do not leak oil.

[JonB]

Slightly confused by Rohan's comment of them being basically the same. Wellseal is like a sticky liquid - think treacle. Does it ever set? As for the others, are they not like silicone bath sealant to handle?

[2cams70]

You are far better off using a high quality gasket paper and cutting your own rather than using the crap precut gaskets typically supplied these days made from the lowest cost paper and trying your luck with some added goop.

The exception are the cork gaskets. Use quality cork/foil laminate precut gaskets instead of the typical crap cork/synthetic rubber granule mix pre-cut gaskets.

Only use goop as a last resort. Almost all gasket paper manufacturers recommend NO goop. Granted though the Lotus Twin Cam is not an optimal design. Use some goop on the cork gasket between the timing chest and head. For there I use Loctite HiTack on the bottom face and Loctite 534 on the top face. Loctite 518 anaerobic works on the metal to metal timing cover joint but a minimally applied quality silicone would probably do just as well if not better. The problem with the Loctite 518 is that it's not very flexible and adhesion is only so so. OEMs mostly use silicone on metal to metal joints such as this rather than anaerobics for this reason.

Oh and don't forget - use a torque wrench!!! Even on those small 1/4" UNC bolts. If there are cork gasket's involved only torque the bolts up ONCE to the set figure in a criss cross pattern. You will find if you go over the bolts again with torque wrench the bolts will turn more due to compression of the cork gasket. Don't be tempted to go over the bolts again just for reassurance or you WILL over compress the gasket and it WILL extrude.

[nigelrbfurness]

I use Welseal on cork and head gaskets and Hylomar on metal-to-metal joints, always very happy with results.

[saildrive2001]

Having had a leak from my fuel sender mounting on my fuel tank, I am now about to refit it & looking at the past postings it looks like Hylomar is the preferred sealant to use. Would you use a cork gasket along with the hylomar?

[billwill]

Having had a leak from my fuel sender mounting on my fuel tank, I am now about to refit it & looking at the past postings it looks like Hylomar is the preferred sealant to use. Would you use a cork gasket along with the hylomar?

My recollection is that the flange mounted in the tank is relatively flimsy and so the probability of it being nicely flat is small so I reckon you do need a cork gasket there and coat it with suitable gunge. I recall, last time,I made my own cork gaskets for the tank from a cork floor tile.

[vxah]

I use https://www.chemico.co.uk/jointingcement.html

[2cams70]

Having had a leak from my fuel sender mounting on my fuel tank, I am now about to refit it & looking at the past postings it looks like Hylomar is the preferred sealant to use. Would you use a cork gasket along with the hylomar?

Use no sealant. Use a new cork gasket and make sure the mating surfaces are clean and flat as possible. The reason a cork gasket is used is because it's very compressible and accommodates uneveness relatively well. Tighten screws evenly. Do not overtighten or gasket will extrude, flange will warp and create leaks. Never had problems with leaking cork gaskets on fuel tank senders using that method.

[elans3]

I'd agree with the above, but in joints where you know that the surfaces aren't perfectly flat (pitted, scored, scratched etc,) I use Permatex Ultra Grey https://www.ebay.co.uk/itm/Permatex-821 ... SwSdFbNinj
Given it as a tip by the US guys on the 105 section of the Alfa Bulletin Board (I have a couple of Alfa Twincams too)
Hylomar a little old hat now, (and I used to use it exclusively), and I never liked red Hermetite..
The Ultra grey only needs a very thin covering to seal, so a tube lasts a long time, and I don't have any leaks !

[rolbydo]

I used Wellseal on the gaskets and had no problems.