CHTs 30-40 degrees higher on right-hand side

[chris_01]

Flying with my new EDM830, I can finally see more details about my engine.
What has hit my attention is that Cyl 1/3 (right-hand side of the engine) is consistently running 35-45 degrees hotter than cyl 2/4.
Looking at reasons for this, I found that some part of the ducting at the front inlet to lead the air stream over the cylinders was missing. I fixed it yesterday and tried out but it didn't make any noticeable change to the situation.

The temperatures in climb out are going up to 400 and above on 1/3 if I don't reduce power or increase speed. In level flight, 1/3 are between 360 and 380 degrees and 2/4 accordingly some 40 degrees below that.

It is the O-360-C4F - does anyone have a good idea where to continue troubleshooting? Maybe it is a known problem? Maybe someone fixed it and could share?

it's just bad to know that the previous owner had been flying 300 hours after overhaul with only the factory gauge on cylinder 2 - which is on the left-hand side and one of the cooler ones........

[andy]

Make sure the front baffling is oriented up and against the cylinders. If it's down below the cylinder, air pressure will push it down and route the air down below the cylinder instead of cooling it.

[chris_01]

Yep - it is up and against the cylinder, no way pushing it downwards.

before the circled part was missing - actually it looked like cut-off or so:


I added the black part of rubber. Ignore the silver-tape - that's off again.




the temperatures are in this range - the shown number just after t/o and then levelling out to between 380 and 320:

[AndrewK]

Does your engine have the vertical baffle near the middle top of the case to help direct air to the right or are those only installed on the 6 cylinder engines?
What about the aluminum baffles between the cylinder barrels?

[chris_01]

The vertical that basically separates left from right and the Aluminium baffles at the bottom of the cylinders are there and let the looking good.
Also - the baffles which are installed are doing their job, I.e. seal nicely with the cowling, bent forward, no gaps etc.
Visually, it looks normal../

[gdflys]

The black forward baffle you added on mine goes all the way to the crankcase. It is kind of a pain in the neck to get around the alternator and bracket when removing but that's a big pressure loss hole. Does the same baffle on the other side go all the way to the crankcase?

[chris_01]

thanks - if someone has a picture of this, going up to the crankcase, it would be helpful I guess. On the other side it is fully closed to the crankcase as per factory, that's OK so far..

[gdflys]

I looked through my many pictures and don't have one of that. I'll try to get out to the airport and take one today.

[chris_01]

no stress, not really urgent..

This forum is amazing - thanks a lot for the big source of information and very knowledgeable and constructive help rather than spinning off into never ending off-topic discussions etc. like in many other places on the web.

[gdflys]

No problem at all. I needed to go out and pet her anyway. Like I said this will make it harder to install and remove the lower cowling which is most likely why your's is missing. It was either removed or broke off. I still need to split mine to go around the oil temp sender lead from my EDM-830.

Right forward baffling by gdflys1gregflys, on Flickr

[chris_01]

very cool - thanks a lot, will do so on the weekend if I manage.. At least my Maule is Virus-free...
The lower cowling is anyway a mess to mount and unmount due to the hoses etc, which I'd have to re-new also at some point. The list of things to be done is long, but first things first..

[Andy Young]

Check out my post (with photos) in this thread:

http://maulepilots.org/forums/viewtopic ... light=cowl

Scroll about 3/4 of the way down the page to see photos of my mod. It’s on an IO-540 but the concept should apply.

My cowl had been broken and poorly repaired in the area you are seeking to seal. I wanted to get that area sealed up nicely, but also make cowl removal easier. So I made a piece that fills the gap and holds a piece of baffle seal, but is easily removable.

[flyusn99]

Chris,
I had the exact same problem as you are describing. The picture of my baffling also looked exactly like yours (only my issue was on the pilot side). On a hunch I gently pushed the baffling downward so it allowed the cooling fins on the cylinder more airflow and the first flight I dropped the CHT by about 50degrees on the lead cylinder and consecutively less on the trailing cylinders. Not saying this is the only cure all, and your mileage may vary but it'd be worth a shot. Take one flight with the front baffling pushed down and see what it gets you. It solved my issue...

James

[flyusn99]

Re-reading the original post, the way to get the baffling to go down if you don't have enough clearance while the cowling is in place on is to remove the cowling and as you put it back on use your fingers to orient the baffling material down as the front comes up into place. Hope this solves your issue.

James