Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Engine Trouble?

Evening,
I wonder if there are any M3W gurus that could advise on the following please.

I purchase my 10K mile 2012 M3W in September and I only got to drive it a handful of times before Winter set in (I will only drive it in fair weather). Therefore I haven't had that many hours to get that familiar with it (so I am not 100% sure if it has always been like this or something has changed recently).

Since thw Winter came in I have been regularly running it in the garage to keep the engine well lubricated, and therefore ironically I am getting more familiar with the car over the many times I have spent watching the car idling.

Anyway standing behind the car I have noticed that the left exhaust put,put,puts away rhythmically but the right exhaust has a more stranger labored sound. When i first heard it i initially though it was some kind of exhaust rattle, but bracing the exhaust with my foot didn't alter the sound.

Here is a short video of the sound, showing the difference.

https://photos.app.goo.gl/EcCWURySb3S3S6oP9

Any advice would be most welcome. Have I got a problem?

Two other quick facts of info...

1) The M3W has a G56 ECU, but returning to stock ECU makes no difference to the sound.
2) The sound happens throughout the rev range, not just idle.

I don't think you have any problem at all with that, TADTS as they said at Lotus. All very normal with the left exhaust nice and rhythmic and the right fluffing a bit at idle. This has been noted long ago and no real convincing answer supplied, other than the fact that the intake manifold isn't great and it's probably a bit of an interaction between the two cylinders messing the mixtures up a bit. It seems to be more pronounced with a free flowing exhaust as well. You could always treat it to a new set of plugs, NGK Iridium DCPR7EIX work well.

I think your exhaust system may actually be a Morgan Stage 1 rather than G56 as it has square cut rolled ends, G56 are usually slash cut with no rolled ends...and larger expansion boxes. Both systems are a good upgrade from the very restrictive standard system.

I agree with Planenut this is nothing to worry about, but I too have never found any definitive explanation about why it is so. My conjecture is that it's related to the cam timing of the original spec (emissions) cams. Those who have fitted aftermarket cam kits might be able to comment if they continue to experience this behavior with the new cams.

These engines aren't really happy when idling, and frequently running the engine for short periods, as opposed to getting them fully up to temperature is not recommended for any engine. In the case of the M3W, frequent short term running can lead to an air/oil emulsion clog in the breather hose between the oil tank and crankcase, leading to various maladies. And don't to forget these engines need airflow to cool, so running them up to full temp while stationary without overheating them is a dangerous guessing game.

The engine will live longer if it's left to slumber until the next time you can take it out for a proper drive. Just sit in it and make "vroom-vroom" sounds until the time comes

The cams don't make any real difference either, just the same with standard 548's as 569's. Not sure about 618's but they are not really road use. I know that some have delved deeper into the fuel mixtures and airflows when trying to get the Emerald ECU to work better than the unlocked S&S ECU and have concluded that separate inlet manifolds are really required to make both sides of the V-Twin work perfectly.

It maybe isn't perfect but it's not a big issue either. Once running under load on a dyno, both cylinders seem to work together and the exhaust sensors balance up well. With the Urban Cooling Kit fitted the temperatures seem to stay reasonably stable, for an air cooled engine. I would say it's certainly not a good idea to idle the engine too long without the Urban Cooling Kit but not so bad with it fitted. Ugly as it is, it does a good job of controlling the temperatures within limits but agreed that it is better to run the car than sit it stationary. Overheating kills air cooled engines.

If you don't run the engine regularly in storage, check the oil level before attempting to start it. If it's low don't top it up. Drain the engine sump and return the oil to the tank, then start it.

I have an Emerald ECU
And I made an extra dashboard to control a lot, but also the Air-Fuel ratio of the two pipes.

I had the same difference in the exhaust pipes as you and many others are mentioning.

I found out that it was extremely difficult to get a stable and equal Air-Fuel ratio.

Studying the problem I found information that even with perfect engine valves there is always a little back pressure in your pipes.
When there is within a meter after your O2 sensor an air-leak this can still cause trouble with your Air-Fuel-ratio.
The two - front and aft - pipes are connected with a simple hose-clamp with each other.
That can give an air-leak.

First I bought on amazon the
MOCNT Pipe Connector Exhaust Collar 65mm Band Exhaust Pipe Stainless Steel Clamp Double Exhaust Sleeve Fitting Length 87mm
€ 29,49
And fitted it on the Starboard exhaust pipe.
I got far better results.
Then I installed a second on the other Port pipe and since then I have no problems with irregular Air-Fuel ratios and got rid of the differences you mentioned.

I am not sure if this is the solution, but I can tell it makes your exhaust pipe fully closed.
Give it a try and when it not works for you, for sure your exhaust pipe looks more nicer than with that ugly hose-clamp.

In the same article, wrapping the pipe was discussed to keep the gasses in the pipe as much as possible on the same temperature till 1 meter aft of the O2 sensor.
So I did that too.
There is a lot of discussion about wrapping - your S.S. pipe will rust ( ? ) etc. - but for me it helped.

The Morgan 3 Wheeler is designed for fun driving but also the joy of improving what MMC designed.
So enjoy experimenting.

The early 90° V twin Moto Guzzi's (750 cc and up) had a balance pipe between the horizontal sections after the downpipes and before silencers. The 850 Le Mans also had this, but sported another balance pipe welded between the two downpipes such that they formed a single assembly. I always understood the mutual exhaust pulses improved scavenging between cylinders.

I remember Krazy Horse developing similar for their Stage 3 converted M3W as below.

A krazy horse indeed... Thanks for posting..

Thanks for all the advice

. A bit of a welcome relief to find I haven't got engine issue!

Richard, Harley V twins on which the S&S engines were originally based had a balance pipe (just below the air filter housing) for that very reason you mentioned. I had a Dynaglide when they first came out and to give it a cleaner engine look (ie no balance pipe in the usual place) they hide the balance pipe at the base of the down pipes just before the exhaust very close to the frame and put a black plastic shield over to cover its existence, so it blended in with the black frame.

Might not be a factor here but the cat in my RH exhaust came loose in the pipe. When I took the silencer off it dropped out. I equalized both sides by knocking the LH cat out. I did a bafflectomy on my car, a 32mm hole in the front baffle.