Dowty washers?

[Bryan Boyle]

Thinking out loud...but was watching some vids from UK based TC engine shops...and the subject of sealing the valve cover studs came up...and the suggestion was offered that dowty washers were a lot more effective in providing an oil-tight seal than the normally-spec'd selocs. 

Anyone have any experience using that style?  I know they're used in high-pressure (well, higher than std. atmospheric) sealing...but, thought I'd throw that out for what it's worth.  Seems to me that it may be a better sealing technology than selocs.

Just thinking out loud, as I said...

[BDA]

I don’t really have an opinion about which is best. I expect the seloc washers are perfectly adequate but there are surely good substitutes. McMaster Carr has these (https://www.amazon.com/Glarks-Stainless-Neoprene-Sealing-Assortment/dp/B07GB15DS9/ref=sr_1_15?keywords=dowty+washer&qid=1671417085&sr=8-15). In other similar applications, I’ve used Earl’s stat-o-seals (I think they’re actually made by Parker) but they would work fine (https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=stat-o-seal&_sacat=0). I’m sure there are lots of other similar solutions but if it were me, I’m not sure that selocs wouldn’t be the path of least resistance.

[Bryan Boyle]

I don’t really have an opinion about which is best. I expect the seloc washers are perfectly adequate but there are surely good substitutes. McMaster Carr has these (https://www.amazon.com/Glarks-Stainless-Neoprene-Sealing-Assortment/dp/B07GB15DS9/ref=sr_1_15?keywords=dowty+washer&qid=1671417085&sr=8-15). In other similar applications, I’ve used Earl’s stat-o-seals (I think they’re actually made by Parker) but they would work fine (https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313&_nkw=stat-o-seal&_sacat=0). I’m sure there are lots of other similar solutions but if it were me, I’m not sure that selocs wouldn’t be the path of least resistance.

I may be overthinking it, but...the thought of having a dry cam cover is not out of the realm of hope after I get done with what I've queued up, and these rubber coated star washers, to me, just seem to be a half-hearted (though it might have been the bee's knees in 1962...) solution at best.

I've used stat-o-seals on aircraft hydraulics and they work well (you do have to put an AN960 flat and then the nut on it); I may root around the hangar parts room this week while I'm in NJ and see if they've the right size for the cover studs and grab a handful (and give the owner some $ for the privilege).

Did some digging around in McMaster...and found these:
https://www.mcmaster.com/dowty-washers/

Considering the threaded stud ends are #12 size (.245"), the 1/4" size would be 5 thou ID smaller, which would grip the threads a bit, helping to create a better seal (theoretically).  A pack of 10 is not expensive; worth a try, I think.  The worst that could happen is I still have a leak, right?  I've already installed the screw-on oil cap upgrade that Ray sells and that area is staying dry.  Also thinking that putting in the scavenging separator and plumbing it into the airbox at the carbs (where there was a tube from the head that is lost to time) will reduce the pressure up at the top end, and cut down the weeping.

Right now, though, I'm fighting removing the woodruff key at the end of the intake cam; it's truly in there holding on for dear life, so I can get the snap ring off, and put the new seal on the cam.  Then it's off to retorquing the cams in place with a good smear of assembly lube, and measuring the clearances, and figuring out if/what different shim sizes I need to have to set the valves properly.

[BDA]

It has been a long time since I had a TC motor but I don’t remember a problem with oil leaking from the seloc washers and it’s not something I hear people complaining about so you may be overthinking this. Maybe someone with more direct experience can comment.

WRT stat-o-seals, a washer between the stat-o-seal and the nut would be proper practice but it will seal against the bottom of the nut. I’m using one now on my car in that manner and I have no issues. (Actually, thinking about it, if you used a washer, wouldn’t you theoretically have a leak path up the threads and out between the washer and the nut? - maybe I just broke my OCD meter!j

I saw those dowry washers at McMaster Carr but I wasn’t sure if they neoprene part was proud of the metal part. It probably is but I have experience with stat-o-seals and so I’m more comfortable with them.

[Bainford]

Dowty seal is an interesting suggestion. I use them at work by the thousands. Generically, they are referred to as bonded seals or bonded washers (at least, in this industry), though colloquially, we just refer to all such seals as 'dowtys'. Navy submarines are full of them (at least, UK built boats, and boats with UK built systems, such as the Canadian Vic Class subs), sealing the high pressure hydraulic and pneumatic systems and seawater systems, all critical sealing applications. They are available in a large range of sizes and a variety of sealing arrangements and options (in to out, out to in, in and out, self centering, etc) and a variety of materials for the metal portion(steel, stainless, NAB, brass, aluminum, etc).

If both sealing surfaces are smooth and flat, and reasonably perpendicular to the fastener centreline, a dowty should work great. Having said that, though, I have yet to experience any leakage through my sealocs.

[EuropaTC]

Fascinating. I'm always amazed at the breadth of knowledge on this and other enthusiast forums.

Y'know I think this internet thing might catch on.....

[Bryan Boyle]

Fascinating. I'm always amazed at the breadth of knowledge on this and other enthusiast forums.

Y'know I think this internet thing might catch on.....

Imagine trying to do what we set out to do without it?  I remember my first attempt at renovating a Europa in '81.  Had Ray to talk with, and hung out at Marco Competition in Montclair NJ talking with Ralph and Carlos (for those who remember...).  But, absent that...the occasional article in ReMarque.  Amazed that I got 444R back on the road!