Subject: Re: [TR] Bad Engine Oil Leak

From: "John & Pat Donnelly" <[email-masked]>
Date: Wed, 22 May 2013 20:02:56 -0700

Hi Irv,

Something's wrong here, and I don't believe that venting to a catch tank is
the proper thing to do. The real issue in my mind is, what's changed? and
how do I validate it? 

My first thought was that the PVC value wasn't working properly, but I got a
new diaphragm from Moss, and then a whole new PCV value, and neither was it.

The leak has been progressively getting worse. I'm now thinking the valve
guides are leaking.

Johnnie

'67 TR4A

 

Your crankcase is pressurized and doesn't have enough venting to relieve the
pressure. As a result, the pressure is pushing out the oil.
On my TR4, I had a vent line from the rocker cover as well as a large (1")
vent hose coming from where the mechanical fuel pump was.
Ran both of those to my catch tank, and that did the trick.

HTH,

Irv Korey

On Wed, May 22, 2013 at 9:21 PM, John & Pat Donnelly <[email-masked]>
wrote:

Listers,

I've been battling a bad engine oil leak on a TR4A for some time. The
undercarriage gets wet from the engine to the differential. After running
for 1/2 hr the back of the engine leaves a puddle of, maybe about 1/4 cup
worth, besides the half dozen others spots that occur underneath.  The oil
is now coming out of mostly the rear seal after plugging everything else.  I
had to remove the dipstick and plug the opening with felt because that would
push oil out. The distributor pedestal bubbles out little bits where the
tach cable attaches. The valve cover cap has oil coming out of the relief
hole. A few years ago it was small stuff. Now it's embarrassing. I believe
it's internal pressure doing it.

The PVC valve is new (as was it's predecessor). The valve cover doesn't
leak. No leaks from the front engine mounting plate or the sump.

I've had the engine out 3X and .

1. Changed the rear seal to the Marx seal. 1st time I tore it by the
flywheel bolts, 2nd time verified it's intact  as evidenced through the 3rd
timed pulled.

2. Changed the piston rings. They're Deves, with openings rotated on thirds.

3. Redone the epoxy for the rear cam plug. Checked it on the third time
pulled. Perfect.

4. Checked all the rear oil galleys and they are clear, including those
going through the rear crank bearing housing.

So I decided this afternoon to do the compression and leak down tests.

Compression as follows on a hot engine dry/wet (2 squirts)

1= 175/185  2 = 175/185  3 = 175/185  4 = 165/185

My  leak down test consistent of using a Harbor Fright leak down tester,
again on a hot engine. I used a stethoscope to check for sounds.

Every cylinder was consistent in % of leakage. The only difference was that
#1 had more air was leaking through the valve cover cap, but the % was
similar to the others.

Checked the carb openings, they sounded consistent. Checked the dip stick.
Sounded consistent. No leaks in the radiator.

Maybe it's the HF Tester? The head has not had any work done to it in 15
years, I'm feeling it could it be the culprit? How do I tell?

Thanks!

Johnnie

** [email-masked] **

Archive: http://www.team.net/archive

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From: Geo Hahn <[email-masked]>
Date: Wed, 22 May 2013 20:39:05 -0700

> the proper thing to do. The real issue in my mind is, what's changed? and

My TR4 wasn't quite that bad but was oozing oil from every possible pore.
In the end I added a TR3 crankcase breather to relieve the pressure and
that greatly reduced leakage.

The crankcase ventilation provision on a TR4 is (I think) even more
constricted than the PVC on a 4A so the breather seem a prudent relief for
what was (IMO) an inadequate design.

As for the 'why' of your problem -- are you sure the rings got seated?
I'll ask (cause I do not really know) would rings that hadn't seated
reliably show up as low compression?

Geo

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From: "John & Pat Donnelly" <[email-masked]>
Date: Mon, 27 May 2013 17:18:41 -0700

All PVC valves are not equal. Got a generic one from O'Reily's. The one I
got was a really good one-way valve. Blow one way it flows, the other way is
blocks.
The factory one is sporadic at best. It opens quickly and closes just as
quick.
So I installed the generic. So far no leaks, but I have to put it under load
to see what it does.

Johnnie