[TR] TR2-3-4 Engine and Rad Taps

Sun May 2 16:26:37 MDT 2021

Well Steve, it solves the mystery but not the problem. What I understand
from your explanation is that you manufacture a product that is not going to
perform its intended purpose. There is no indication on the Moss online
catalogue that these petcocks will not function as petcocks - or that
leaking is guaranteed. 

I've installed 3 of these, 2 radiators and one block, and in each case I
took them apart and polished the cone and seat, none of them have leaked. If
I can do it, I don't see why the manufacturer can't.  

Bob

From: Steve Kirby [mailto:sackirby at chinaautogroup.com] 
Sent: Sunday, May 02, 2021 2:16 PM
To: Kinderlehrer; 'Brian Thomas'; triumphs at autox.team.net
Subject: RE: [TR] TR2-3-4 Engine and Rad Taps

I can provide the definitive answer to this question because my company
makes these aftermarket valves for Moss Motors (who probably resells them to
everyone else in the world).

The response "they all leak" is absolutely correct.  In fact, the problem is
so pervasive and resistant to all attempts to solve the problem in
manufacturing, that Moss no longer sells a functional valve.  What they sell
has no internal drillings, it is just a plug.  It is made to look like the
original for authenticity purposes, but does not function (and hence does
not leak).

If you disassemble one of these, original or repro, you will see that there
are no seals.  The "sealing" is accomplished by a tapered metal stem fitted
into a similarly tapered metal body.  The two parts are "clamped" together
by virtue of the external spring and depend totally on a very tight and
concentric fit between the two metal parts.  This valve was designed well
before cars had pressurized cooling systems.  And yes, they always leaked.
But back in the day, before people started using distilled water and high
quality antifreeze with effective anti-corrosion additives, the valves
quickly plugged up with corrosion and, voila, stopped leaking.  When they
were opened and reclosed, they leaked again, until the corrosion re-plugged
them.

If you are dead set on trying to make one leakproof, get some valve lapping
compound, disassemble the valve, and "lap" the two parts together for an
hour or so, until the two surfaces are as smooth and concentric as possible.
I have seen this work on occasion.  Basically you are perfecting the seating
of the stem in the body.

If you just want to stop the valve from leaking and don't care about the
function, you can remove the valve and plug or solder the inlet port.

Jaguar used this same valve as a block mounted oil drain tap, with a bit
more success due to the higher viscosity of oil vs. water.  Several British
motorcycle companies and Indian used this valve as a fuel shut off (and you
can imagine how that worked!).

Hope that solves the mystery.

Steve Kirby

President

China Auto Group

22831 Avenida Empresa

Rancho Santa Margarita, CA 92688 USA

Direct:  (949) 261-8208

Fax:  (949) 767-5949

Cell:  (949) 903-0957

Skype: steve.kirby29

www.chinaautogroup.com

From: Triumphs <triumphs-bounces at autox.team.net> On Behalf Of Kinderlehrer
Sent: Sunday, May 2, 2021 10:40 AM
To: 'Brian Thomas' <thomasb at queensu.ca>; triumphs at autox.team.net
Subject: Re: [TR] TR2-3-4 Engine and Rad Taps

Hi Brian,

Moss's response to the leaking issue was "they all do that". It's been many
years since I had this same issue. I solved it by taking the valve apart and
polishing the parts. I don't remember how I polished them, maybe it was
compound or 1500 grit wet/dry sandpaper.  Some PTFE on the threads that go
into the block or radiator also helps. Anyway, no drips since.  I had to do
this on 2 radiators. 

The other alternative is to use a "modern" petcock.

Hope this helps,

Bob

From: Triumphs [mailto:triumphs-bounces at autox.team.net] On Behalf Of Brian
Thomas
Sent: Sunday, May 02, 2021 9:11 AM
To: triumphs at autox.team.net
Cc: Brad Smith (britspcars at gmail.com)
Subject: [TR] TR2-3-4 Engine and Rad Taps

Hi,

I'm having great difficulty getting either of the drain taps in the TR2 to
stop leaking.  I've tried various used taps from my 45+ year "collection"
without any success.  The taps leak mostly out the drain hole but some also
where screwed into the block/rad.

I recently ordered a pair of new replacements from Rimmer with high hopes
but after install, both leak from the side opposite the lever - see pic.
This is with antifreeze in, rad cap off and no pressurization.  I've asked
Rimmer for comment, but they are closed until Tuesday (bank holiday Monday).

The pic is shows the engine install with the spring portion "up" - that's
what it tightened to.

Has anyone had success with current offerings from the various vendors?  I
see Moss also offers them - others?  TRF doesn't currently have them. 

I'm about to give up and try the Don Elliot solution sealing the taps where
they thread into the block/rad.

Appreciate any suggestions.

Stay well and cheers,

Brian

_____________________________________________________

Brian Thomas                            E-Mail:
<mailto:Brian.Thomas at QueensU.Ca> Brian.Thomas at QueensU.Ca

92 Wyona Lane                          Phone:  613-385-1947

Wolfe Island,  Ontario                Toys:  54 TR2,  56 TR3,  67 TR4A,  

Canada  K0H 2Y0                                   01 XKR,  75 John Deere 920

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