TR4/4A Oil oil everywhere revisited

[Foura]

Here we go again. After a VERY long stay at the mechanic's workshop, I finally got the car back. He said that he had had it running for some time with no evidence of oil leaks. I took it home and refitted the seats and trim and the new 2 piece Racetorations gearbox tunnel. Took it for a run and it seemed to be running well.

I got out the degreaser and the pressure washer and cleaned the remains of the 6 litres of leaked oil from underneath the car. I took it to a different workshop to have the Goodparts roller rockers fitted. Discovered that we need longer pushrods (.2") so they are being made. They put it on the hoist to have a look at my problem with the front universal joint hitting the tunnel and guess what? MORE OIL!!!

Given that the blowby problem should have been fixed with the new pistons and liners, I can only assume that I still have a problem with inadequate ventilation. The previous mechanic removed the Triumph PCV valve and fitted one off a Japanese car. I recall reading a thread where the writer had tried many different solutions to crankcase ventilation including catch tanks. He concluded that the most important issue was having vacuum in the system. I have had a catch tank without vacuum and it made the problem worse. I notice that Racetorations has a catch tank which appears to have pipes from the rocker cover and the crankcase to a catch tank which is connected to the intake manifold. Does anyone have experience of this or a similar system? I am getting a bit desperate!

 

[Foura]

I decided to try yet another PCV valve so I ordered a second hand one from a local supplier. When it arrived it was off a TR250 and would not fit the 4A. So I started again. I had bought a vacuum gauge and established that I had 20" of vacuum from the manifold to the PCV valve but the reading between the valve and the rocker cover was zero and there was still substantial pressure coming out of the rocker cover with the filler cap removed. The PCV valve was a new one which had an anti-backfire valve in the base. I recalled that my original one did not have this and I still had it. So I switched the metal valve, the spring and the diaphragm from the new valve into my old one and fitted it. Success!!! I now have 4" of vacuum between the valve and the rocker cover and noticeable vacuum at the oil filler.

Took the car to work yesterday (a 48 mile run) and checked it when I got home. No oil leaks from the engine. BUT! Now the gearbox that supposedly had new seals front and rear is leaking. Will I be going back to that mechanic? Not in this lifetime.

 

[TomMull]

I think I can safely say that these transmission leaks are not an uncommon problem. I have a TR4 OD transmission in my TR3 and it does a wonderful job of rust prevention aft of the engine. I wonder if this and yours could be also the result of pressure build up. From what I understand, the earlier TR3 transmissions had a vent, the later ones did not. (The original transmission from TS73117 has no vent that I can find).
https://www.britishcarforum.com/bcf/showthread.php?54833-Gearbox-Breather-Hole
So a couple of questions: Am I correct? Has anyone added a vent? Does anyone have a later TR3/4 transmission, particularly with overdrive and a few thousand miles on it, that does not leak?
Tom

 

[malbaby]

Brian, are you sure the oil is only coming from the front and rear seals.
Also, there has been a lot of discussion regarding the need or otherwise of venting the gearbox.

 

[RJS]

Huh,

From 2008-2010 I went through a period of oil leaks by a faulty PCV and crankcase pressurization. I am curious what this anti-back fire valve you speak of looks like. I tested four versions of the Smiths PCV valves (number stamped on lid):
-FVP 2001/02: original on my car (designed for 1964-1965 TR4)
-FVP 2001/02: used from eBay
-FVP 2003/10: new from one of the big three
-FVP 2003/11: used from eBay
I swapped springs, diaphragms, pintels, etc. Nothing worked.

The car pulls 20" Hg vacuum at the intake and has 180psi compression. My final conclusion was that the PCV in 1966 was a poorly engineered solution from the get-go (a band-aid for the new US emissions laws) and never actually performed properly. Plus, with the high compression, I suspect I have excessive blow-by that the stock PCV can't handle(?).

Since then I have run a hose off the valve cover, over the carbs, which vents in air below the chassis. No oil leaks and the motor runs/idles better than it did before.

Bob

 

[CJD]

The PCV valve is actually a switching mechanism. At idle, when the vacuum is high in the manifold, the plunger in the PCV valve is drawn by the suction against the opening and plugs the valve. Then only a small metered amount of air can get through the valve through a tiny hole. This is necessary so the vacuum in the manifold does not draw too much air/oil from the crankcase. When you accelerate, the vacuum in the manifold is lower, so the spring in the PCV draws the plunger away from the opening and allows the full passage of what little vacuum there is to the crankcase. The point of all this is that different engines require a different size metering orifice when the car is at idle. Given the volume of crappy parts I have bought from the big 3 the last few years, it doesn't surprise me if the PCV valves supplied have incorrect metering orifices. The solution would be to do what you did...just keep looking for a std replacement that draws the correct amount of air at idle. They will all work about the same on acceleration.

The vent in the TR3 gearbox is in the tail housing. It would not be hard to add it to the TR4 box if you need it.

 

[Foura]

The valve that I now have looks like the one in the first picture. The newer one that did not work looks like the second one. It has the anti backfire valve that I mentioned in the base and is identified as 5. Plate valve. This is held in place by the Orifice plate which is not removable. In the one that is working, the orifice plate is not fixed but sits in a recess in the main body and is held in place by the spring under the valve pin. There is no plate valve. in both valves, the orifice plate has four "fingers" that locate the valve pin and allow air movement rather than a single hole that appears in the second picture.

I did try the pipe from the rocker cover to the atmosphere when the problem first occurred but it did not work. I am convinced that the designers of these engines knew what they needed in terms of ventilation. Hence the road tube on the crankcase plus the suction from the rocker cover up to the TR4, then the suction through the PCV valve (when it works!) in the 4As.

 

[malbaby]

Brian, your comment..."I did try the pipe from the rocker cover to the atmosphere when the problem first occurred but it did not work".....what was the outcome...still oil from the pipe?
"RJS" and I run a tube to atmosphere without any problems.
IMHO the PVC valve is only useful to pass emission regulations, not to force ventilate the crankcase.

 

[Foura]

Malcolm, the outcome was the same - oil coming out of the dipstick hole and the rear seal at a great rate. I had disconnected the PCV valve and run a piece of heater hose from the rocker cover early in the trip, and it still pumped out 6 litres in 1800 miles. As I mentioned in my previous post, the Triumph engineers obviously decided that the crankcase on the 2-4 series TRs needed ventilating with both the road tube from the crankcase as well as the tube from the rocker cover to the air cleaners. The rocker cover vent alone was not sufficient to ventilate the crankcase. When it was no longer legal to ventilate to atmosphere, they tapped into the greater vacuum of the intake manifold to ventilate both the rocker cover and the crankcase, but then had to control that with the PCV valve. I can only point out that I don't have any leaks now that I have a working PCV valve.

Does your car have the J tube to vent the crankcase as well as the rocker cover tube? What ventilation does your V8 have? I recall that most early V8s have vents on both banks.

 

[Foura]

(Hopefully) final progress report!

We have just been to the annual Triumph National Rally for a week. Great fun and superbly organised. We covered 1300km including 23 laps of the Barnawatha racetrack (including one spin....).

The car did not leak any oil nor did it use any. So it seems that the critical thing is to have a working PCV valve. Now I just have to work out why the speedo cable is not working. Right angled drive?

 

[Geo Hahn]

...Now I just have to work out why the speedo cable is not working. Right angled drive?

Do you have overdrive? That would probably mean a right angle drive is present.

In my experience the right angle drive was cleverly designed so that in case of a speedo freezing up the angle drive ($$$) would break and save the cable (¢¢¢).

If it is a broken angle drive or cable you will want to be very sure the speedo head is moving freely before you try a replacement.

 

[malbaby]

Malcolm, the outcome was the same - oil coming out of the dipstick hole and the rear seal at a great rate. I had disconnected the PCV valve and run a piece of heater hose from the rocker cover early in the trip, and it still pumped out 6 litres in 1800 miles. As I mentioned in my previous post, the Triumph engineers obviously decided that the crankcase on the 2-4 series TRs needed ventilating with both the road tube from the crankcase as well as the tube from the rocker cover to the air cleaners. The rocker cover vent alone was not sufficient to ventilate the crankcase. When it was no longer legal to ventilate to atmosphere, they tapped into the greater vacuum of the intake manifold to ventilate both the rocker cover and the crankcase, but then had to control that with the PCV valve. I can only point out that I don't have any leaks now that I have a working PCV valve.

Does your car have the J tube to vent the crankcase as well as the rocker cover tube? What ventilation does your V8 have? I recall that most early V8s have vents on both banks.

My TR and V8 Ford only vent from the rocker covers, no additional venting.
I can understand your frustration with the oil problem that seemed to defy common logic.
Glad to hear that you now have enjoyable motoring.