Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing PCV Valve question and dipstick oil leak

Many thanks gents! To answer the above questions:

1) My car does NOT have a breather on the rocker/valve cover, but it does have the vented oil cap.

2) Oil pressure readings using the in car quadrant gauge (which still has the dedicated oil line) runs around 50 psi (midpoint), at least it doesn't look to be running high.

3) My car DOES have the convoluted breather pipe on the left hand side of the engine block (about 1 1/4 inch in diameter, with a beveled end)...can this get plugged? Any tips on how to clear it?

Many thanks!

I dug out my old Triumph TR3 hardback manual, and had a look through it, there is a diagram that indicates the same oil filler cap type of which you posted a pic of, and suggests that the cap is an air intake with arrows in the diagram indicating the airflow downward through the engine, and out through the breather pipe in the block, which Arwyn describes in his post..

I guess if you have high crank case pressure for whatever reason, if you remove the filler cap while the engine is running, you may feel some degree of airflow exiting from the oil filler tube..

Thanks Luddite...I'm going to take a look up the breather pip with the car on a lift...maybe it's blocked with sludge. But I'm wondering how to clear it. Best idea is probably to remove it from the block - no? Looking at the exploded views of the Triumph motor, it's not clear to me how the crankcase breather is removed? It's not threaded - is it just pressed in place? Is there a set screw?

Just looked again at my old book, it looks like there is a bracket mounted at the level of the sump to block joint also a small bracket welded to the vent pipe, through which there is a nut and bolt fixing between both brackets holding the pipe in place.. It seems the air flow through the filler cap and out through the breather is encouraged by venturi effect (?) caused by either the engine fan and/or when the car it`s self is being driven....

I guess it is possible if there is crankcase pressure build up, then there may be some blockage but it would seem to be a very simple system to be blocked up enough to cause a build up of pressure to blow oil out of the dipstick hole..?

So I'm posting some images below, things I noticed this morning while fettling the car:

1) I do have a road draft pipe (pic below). The road draft pipe s putting out some air with throttle - however MOST of the air is coming out of the oil filler neck under throttle, not from the road draft pipe, though the road draft pipe does have airflow (air blowing out of it) under throttle, it's probably 25% of the flow from the oil filler orifice.

2) Without the dipstick in, oil is just spraying out in a fine mist from the dipstick hole (see pics below).

So...it *seems* like the road draft pipe may be partially blocked (Am I correct here - or is something else going on?). When I look up into the draft pipe from below the car, it's appears to be open and clear from the part I can see - but it may be blocked on the takeoff from the block that I cannot see. How would one go about clearing the pipe? How it is removed? I see the bolt holding it in place, is it just a pressure fit into the block? If I remove the oil pan, will I be able to check the opening of the road draft tube from the inside? Is that a better approach?

Frankly - the evidence I have is that the block is being vented - though perhaps not efficiently. The oil pressure a 2k RPM is around 50-60 (using the quadrant gauge), I don't think there is excessive crankcase pressure, or else oil pressure would be high. I'm quite tempted to just use the rubber plug I have around the dipstick to stop oil from splashing out and just live with this...I don't think I'm at risk for additional leaks with normal oil pressure...again would appreciate any additional thoughts.

I certainly appreciate everyone's help here!











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I suspect TR engines leaked oil when new and by the time they had covered a sporting few miles, just as with Brit m/cycles at shows, if they did not have drip trays under their perfectly dry engines, they were likely to have no oil in them... (-:

You could be chasing your tail here.... I never ran an engine to see if oil might splash out through the dipstick hole, though logic seems to suggest to me that the sump being where the oil is stored and that there is a crankshaft spinning around at engine revs oil dripping down from the galleries in the head to the sump, chances there would be a fair amount of oil being splashed around. My guess is that any one piston returning to BDC might be expected to create some degree of crank case pressure, though I expect that to be countered by whichever other piston is on it`s way to TDC, however with all that metal flying around and splashing oil about some degree of crank case pressure seems bound to be created... ADD to that scenario the possibility of blow-by in a marginally worn bore/piston rings during compression and eventual ignition, then it seems simple to imagine more crank case pressure will exist....?

Again it seems the design engineers of the time expected their engines to wear yet still be in use with perhaps 50k miles covered thus the chances were that they expected crank case pressure to be an issue increasing with time...? That perhaps being the case then to save blowing gaskets and seals venting the crank case seemed the logical way to go...?

Back at the time the engine was designed many manufacturers used a vent pipe in the block which exited the block and just pointed down at the road surface. That the TR unit you have has a pipe that initially points upward before a sort of "U" bend arrangement, suggests to me that at the time it was thought best not to spray oil on to the road, and/or, in a worn engine what were the chances in time it would blow much of it`s oil out through the breather on a long run, and thus risk engine damage.... That being a possibility the design may have been such as any oil being blown into the pipe would have to travel up against gravity, the hope being that the majority of the oil would run back down into the sump...? That being a possibility the convoluted shape of the pipe then acting as a precursor to the air/oil separators more modern engines now have...?

I guess over the years and dependant on usage and maintenance either good or not so much, oil can end up considerably contaminated with sludge which can foul things up a tad. pulling things apart can lead to even more leaks.. The much younger me would remove the oil cap, attach a long tube to the breather output, and just blow through it to check just how much resistance might be felt, not suggesting you should do that, but that is entirely up to you...

As has already been suggested by Grumpy, a compression check will perhaps provide a clue.... being an elderly unit, ideally the readings should be reasonably similar across all four pots, though if one is a lot less than the rest, you may have found a possible culprit to higher than "normal" crank case pressure build up...?

However one pot with reduced pressure could be down to an exhaust valve seat/face issue.... There are tests for just such an occurrence, though perhaps you have more than enough to consider for the moment..?

Good luck, more so in that I have not read over this to check I have not made any blunders.... (-:

Where is Arwyn or John when you need them...? (-:

Many thanks Luddite! This all started with my noticing that I'd have about 2-3 tablespoons of oil under the car about every 2 weeks. I tend to drive the car 4-5x per week for about 30-40 minute stints per day. This led to a dye check with the assumption that the front or rear main seals were the culprit. When both turned out OK and the dye isolated the source to the dipstick...I was a relieved and then drilled a hole through a small rubber cork, and pushed the dipstick through said cork...and that appear to have essentially cured the problem.

Thanks to the input from you and others, I feel fairly confident that the crankcase is venting sufficiently - and will probably just continue to drive and enjoy the car!

Great that you have confidence in your typically Morganesque fix and can enjoy driving your Morgan without concern Crowbar...

It may be typically "Morganesque" - but it also may be wrong

When I first started down this old car pathway/obsession, I would perseverate a lot on things like oil leaks, rattles, etc. I spent hours and hours trying to deal with the bevel box whine on my M3W to no avail. Now I just try and live with this stuff and only fix what's truly broken, and in my mind, those are only things that render the car unsafe or undriveable.

Cheers to all - many thanks for the advice!

It can`t be wrong if it works for you...(-:

Having been on Morgan related forums since the mid 90`s I have read of all sorts of modifications and expectations thereof, often with great effort and a load of money spent to "improve" on the original rendering the Morgan close to dangerous to drive on the road, the search for more power on old engines oft leading to overheating and so much more..
On the other hand there have been some mods created by some very talented members of various forums over the years, which seem to have been adopted by the MMC in times past..

Changed days in the litigious society we have created, where any modification can invalidate an insurance claim if one`s insurance company is not informed thereof..etc.etc.etc.
It would take a very expensive claim and/or a very skilled insurance engineer to spot your "cork"... ? (-:
Owning a M3W too suggests you are a man who likes a bit of a challenge in life...(-:
Happy Morganeering Crowbar, and may all your Morgan issues be resolved to the stage where they bother you no longer.... (-: