When we bought our '75 TR6, the only breathing tube left in the car was a
hose going from the stock valve cover to an old Castrol oil bottle residing
where the charcoal canister belonged. Once we got the car running somewhat
reliably, we found that the head gasket was weeping in a 3" length along the
drivers' left side of the motor.
We replaced the head gasket this past spring and also put the ARP head studs
in, hoping to eliminate the problem (the car has a 10:1 CR). Nope, didn't
fix it. The sucker still leaked.
Our next theory was that the engine is designed to run under vacuum
conditions, something we lacked because of our oil can breather. If we could
hook the valve cover to the carbs (dual Weber downies) or the manifold, that
would release the pressure forcing the oil out and cure the leak. So, this
past weekend, Al (my hubby) attached one end of a hose to the valve cover
and the other to a PCV valve. The PCV valve then went to the manifold's
banjo connector for the brake servo. What the heck, see what happens, right?
Sunday was an autocross approx. 45 minutes south of us. We hooked up our
shiny, new, just-finished-building autocross trailer to the back of the TR6
with its shiny, new, just-finished-building hitch and were on our way.
"Honey, do you smell oil burning?"
"Yeah, and look, our oil pressure is going down!"
"Maybe we should pull over..."
We got to the next rest area and sure enough, the engine was covered in oil.
So was the entire underside of the car and most of our shiny, new (now
slick) trailer. Of course, we had a spare quart of oil for such an
emergency, so we put that in and headed for the next exit to turn around and
go home.
We had to buy another quart to put in at that exit. That put us back in the
safe zone and we limped back home. When we parked it in the garage, the poor
thing had oil dripping off of the entire underside, even the tailpipes. I'm
not looking forward to getting all that stuff cleaned off the car!
What caused it? The car has been leaking, but never enough to lose oil
pressure, even when running hard at autocrosses. We're not sure why. It's
possible that having the PCV hooked up to the manifold and the car under
load (pulling the trailer) affected the pressures inside the engine enough
to really let the oil flow. Maybe the head gasket finally gave in
completely. This weekend's test is to put the oil bottle system back in and
take the car/trailer out onto the highway and see if it happens again.
We'll let you know...
Wendy Hart
1975 TR6
1976 TR7
----- Original Message -----
From: "Paul J. Burr" <tigerpb@ids.net>
To: "Triumphs (E-mail)" <triumphs@autox.team.net>
Sent: Wednesday, September 13, 2000 9:50 PM
Subject: Weber downdrafts and TR6 PCV system
>
> OK Gang, here's the dilemma.
> My newly acquired '74 TR6 was outfitted by the previous owner with the
dual
> Weber down draft carbs and a nice alloy valve cover. So far so good. But,
he
> completely eliminated the PCV system, which makes for to much pressure
under
> the valve cover. This in turn makes the oil want to seep out under the oil
> filler cap.
> Any of you folks run into this problem?
> My first choice would be a vented and filtered oil filler cap. But, the
> alloy valve cover has as a 2" I.D. hole in the cap. A quick check of the
> parts catalog shows the biggest cap of this type is @ 1 3/4".
> Anyone have a source for these oversize filler caps?
> My next plan of attack would be to cast my vanity aside and remove the
fancy
> cast valve cover for the stock one sitting on my work bench. I can then
fit
> a vented cap. Next, I could fit a PVC valve to the vent hose on the valve
> cover.
> My next problem is where to plumb the opposite end of the PCV valve.
> Should I fit it to the it to the manifold? Or, should I use a "T" fitting
> and plumb it into the base of each air cleaner?
> Any suggestions would be welcomed.
> Paul Burr
>
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