Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 One cylinder running hotter than the other

This just started recently

My understanding is that the rear cylinder (left side facing engine) always runs cooler than the front cylinder, certainly has on mine that's taking ProTune readings.

If it were up to S&S, I would guess that they program a bit more fuel to the rear cylinder, right side. That would keep it cooler as less air gets to it in a motorcycle.

Actually in cars, the driver's seat is ground zero for right and left. I know in the UK it may be near side or far side. Not sure which is which though in that scenario. So for use US guys and the European guys, sitting in the driver's seat, left is left and right is right. The S&S would be front cylinder left side and rear cylinder right side. It can get confusing when you refer to LOOKING at the car from the front for left and right.

Not sure if timing can be adjusted for less advance between the cylinders or not, but I'm sure fuel can be adjusted, at least on Harleys they are. Theoretically, there should be no difference in cooling capacity between left or right cylinders in a M3W. Oil cooling is routed the same for each head, so that is probably not a cause. Not that it would help, or that it's really a problem, you might try one heat range cooler spark plug in that head and see if the temp equalizes. But ever if that did help, that's only a band aid, not a cure.

The problem with all the information we get from bikes and cars today, knowing can be a problem. In the old days no one complained of Harley's engine oil running hot. But when they put oil temp gauges on the bikes, everyone was complaining about how hot their bike was all of a sudden. I realize that on the M3W the exhaust pipe was the determining factor to lead one to investigate cylinder head temps. Other than the different color on the header pipe, sometimes you're better off with your head in the sand... Out of sight, out of mind. Back in the mid-60's and through the 70's, we had a marina in Michigan and sold snowmobiles in the winter. Early on there were no speedometers on any snowmobiles. Everyone had their seat of the pants dyno saying they were running 70 and 80 mph. THEN a couple years later snowmobiles had factory speedos. Lots of people retrofitted their older snowmobiles with new speedos. Guess what, their snowmobiles all of a sudden weren't running as well as they had before. Like I said, some times ignorance is bliss...

Trust me guys, I'm not saying that you shouldn't find the cause of the extra heat, but other than the header coloring, it's probably not doing any damage.

I'll get off the soap box now!

Have a great week guys!!!

Get the exhaust pipe bufflers drilled.
That is good for the engine and reduces cylinder temperature.

Have already done that. Everything was fine until last week, then one side started running hotter.

Dan, just to help you out: Nearside is the Left Hand Side when sitting on a horse (the normal side to mount from) or in a car etc

You may want to pick up a fuel line kit from Emil at Morgan custom.net. It has many benefits extorted here on the forum and his website.
Stabilizing the pressure and adding a better implemented return would eliminate a variable of spikes and troughs in injector pressure that may be contributing to your perceived problem.

Has anybody done an actual test to monitor "variable spikes and troughs in injector pressure"? Or is this a mélange of marketing hype and delusional thinking?
How does a "better implemented return" fix a perceived problem?

Fuel pressure is controlled by a pressure control valve built into the fuel filter. This fuel filter / pressure regulator combo functions perfectly in millions of vehicles, how does it become insufficient to the task when used on a Morgan?

Until I see serious test data on the subject, I would suggest looking elsewhere for a solution.

As both the timing and mixture are controlled by the ECU and the engine is running OK then any severe imbalance is likely down to a sensor. Its unlikely to be timing as both cylinder sparks are triggered off the same rotation sensor.

First I'd suggest you check the exhaust manifold bolts to make sure you don't have a leak.

Then, measure the header temperature with an Infrared thermometer to find out whether its a real problem or the left just appears to be running significantly hotter. Ideally measure another M3W to see what the normal readings should be.

Second, check the spark plugs which should be about the same colour. If not either the left will be lighter so running lean or the right will be black and running rich.

As its a closed loop system the prime suspect would be the O2 lambda sensors in the header. An easy test is to swap them side to side and see if the problem transfers. If it does replace the relevant sensor..

Header bolts are tight.
Switched the lambda sensors, no difference.
Using Ir ten sensor about 100 f difference side to side don't know if that is a significant diff or not. Just noticed that the pipes on right side getting colored while left is not in the same amount of time. This was not the case a couple of weeks ago.