Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 How to break your M3W in 3 easy steps

All that crud being pushed into the air intake does nothing good for the engine.

The oil in the tank drains down into the sump over a period of inactivity, it's an S&S X-Wedge problem and some engines are worse for this than others. If you haven't started the engine for a long time it is well worth checking the oil level in the tank, if it is down DO NOT TOP IT UP. If the level is down more than an inch from it's normal level, remove the drain plug in the engine case sump (Allen head) and drain the oil into a clean container. Refit the plug and return the oil to the tank. Start the engine and run it for at least a few minutes. Turn it off and let it settle for a couple of minutes, check the oil level and replenish if required.

I would think that if your cam belt is cleaned off it will be fine. The crankcase vent system burns off the fumes and puts a slight negative pressure in the system so that seals will not leak so easily. It has a calibrated 0.1" orifice and really doesn't need any modifications to improve it. It works fine as long as the sump isn't full of oil when you start it.

One other problem that can occur and is easy to check is a blockage to the tank vent line, the thinner hose from the top of the tank to the upper of the three hoses that connect to the front, lower RH side of the engine. Disconnect both ends and blow through the line occasionally (put a bottle over the other end to catch the "mayonnaise"). This will be more prone to blockage if you use the car in cold conditions a lot, it needs to get hot to vaporise the condensed water out of the oil system. If this line blocks it can lead to oil tank ruptures and leaks, particularly with the early dipstick type tanks.

If you are a member of the MTWC there should be an article about the M3W oil system and it's problems in the next issue of the Bulletin magazine.

The period of inactivity is the most likely culprit. This just happened to mine as well, after several months of inactivity due to the pandemic. Albeit not as much, but I did have oil seeping out of the engine casing and oil filter and did get oil into the air filter. The oil seeping out of the engine casing and oil filter quickly stopped but I had to change the air filter and oil and oil filter to get all the issues resolved, including an intermittent check engine light that had popped up along with the oil.

Hope you get it all sorted out soon!

It's basically an old motorcycle engine.

Anyone who's familiar with old British bikes will know that if you leave them standing for a while, the engine in the oil tank will drain back into the engine sump.

I'd suggest checking the oil level before starting the engine. If it's lower than when you put it away, then drain the sump before starting the engine.

Luckily it happened at idle whilst parking, so doesn't look like anything made its way into the engine.



Thanks planenut, really informative and useful to know. A very good point around checking the oil level as that way you aren't guessing how long it has sat for and whether or not its safe to start!
I had them check and blow through all the oil lines (so they had to drain the tank) and it all seemed fine, clean as a whistle thankfully.

You know I completely forgot to finish my application form for the MTWC! I shall do it now.



Looks like a fairly common problem, quite a relief as for a moment this morning I thought something terrible had befallen it!



Thanks, steep learning curve these!

I know that my suggestion will sound very dangerous, but I have a similar issue with my older 1976 Harley Shovelhead. The oil tank is located above the oil pump/crankcase and after a "bit" of time my crankcase will fill up with leaked/bypassed oil from the oil tank.

I realize that this and when it's sat for a couple weeks, I use a cookie pan under my crankcase breather that I ran to the rear under my transmission and then through a 90 degree rubber boot towards the ground. But for long storage, like this winter, I use a hose pinch off clamp on the oil pump feed line.

eBay Hose Clamps

But the scary thing is this, IF YOU FORGET TO REMOVE IT BEFORE YOU START THE MOTOR, IT WILL BLOW THE MOTOR UP...

So I hand a tag on my handlebars next to the start button that says to remove the clamp before starting. Kind of like the red flags sport airplanes use on the pitot tube for the air speed etc.

Based on all the issues that seem to be occurring on the M3W with wet sumping during driving intervals, I would consider some type of a shut off valve for the oil feed line that will not allow the motor to start until the valve has been removed or switched open.

Just a thought, but for just a few buck/pounds, you could stop the oil bypassing the pump and filling the crankcase with oil.

I have three harleys and two of them dump a lot of oil out the air filter breather if they set for more than a month.
I mean a lot of oil.
I have had 2 harley shops and an other bike shop try to fix the problem. I am being told thats what some harleys do.
So now i make sure i start them up at least one a month.

Thanks both, perhaps running it more often is the better option.
How long do you run them for? I always worry about condensation forming in the exhausts but equally running it up to temp at idle could take a long time!

Although I suppose being air-cooled, this is less of an issue to a water-cooled engine.

NickCW---recall you have a relatively early car (?) - looks like your cam cover does not have the spacers that ensure the cam belt does not get too hot.

Very early, number 28 if I recall!

It does have the spacers, (has had pretty much every upgrade known to man) hence why the belt got covered..