mikerocosm Posted March 6, 2013 Report Posted March 6, 2013 Good morning, everyone! My recently acquired M20E shows somewhat elevated EGTs and CHTs on Cylinder 1 (compared to the others: they are all still quite low [low-mid 300s F], most of the time). The engine runs beautifully, starts easily, and is generally a pleasure to fly, but naturally, I'm after perfect, so I'd like to bring this one cylinder running warmer than the others into line. At the front of the engine, inside the cowling, are three "baffles" that appear to have been added at some point, and to what end, I am uncertain. The other Mooneys I've looked at don't have these, so naturally, I'm wondering why they're there, and if they can be removed. As you can see from the attached photos, there is a small "baffle" in front of cylinder 3, and a matching one in front of cylinder 1, PLUS a third -- even larger -- one in front of the head-end of cylinder 1. (Please forgive the quality of the photos: these were some I had on hand and not purposefully shot for illustrating this question.) What do you think? Was there an outbreak of these at some point in the past 50 years? Could they reflect this airplane's cold-country past? Dare I remove them (I can find no logbook entry for them.)? Best regards, Mike Quote
Oscar Avalle Posted March 6, 2013 Report Posted March 6, 2013 I have them too. It looks to me that they may help direct the air into the doghouse...Never thought of removing them... Quote
KSMooniac Posted March 6, 2013 Report Posted March 6, 2013 I too think they're normal.... they could've been replaced which is why they look newer or added-on. You should check your parts manual as it has an exploded diagram of the baffling/engine installation. (at least mine does for the J!) For better cooling and speed you might add the LASAR cowl closure mod. Quote
N601RX Posted March 6, 2013 Report Posted March 6, 2013 They are air dams. My F only has them on the #2 cylinder. They force the cooling air to flow down through the fins instead of just across the top. Quote
Lood Posted March 7, 2013 Report Posted March 7, 2013 Although I have an F, we share the same engine/cowling setup and I don't have them. Your reference to cylinder #3 puzzles me a bit though? #3 is the rear cylinder, on the pilots' side. The left front cylinder in your picture, with the smaller baffle is #2. My guess would be that these baffles are intended to get more airflow passing over the two front cylinders in order to get more air flowing through the back cylinders. The latter are normally the problem when it comes to heat issues on this engine. I would remove the outer baffle on #1 and see what effect it has on both #1 and #3 and I second getting the Lasar cowl closure. It's cheap and put and end to all my temperature related problems. Lasar and some users even reckon that you can score a knot or two. Quote
Sabremech Posted March 8, 2013 Report Posted March 8, 2013 Just to clarify lycoming 0-360 cylinder numbering and location, #1 front copilot side, #2 front pilot side, #3 rear copilot side, #4 rear pilot side. The baffles seem strange to me. I don't see them in the service manual or IPC, but that doesn't mean they're not part of a Mooney service bulletin. Interesting none the less. Nothing like that on my 66 C Model. David Quote
mikerocosm Posted March 8, 2013 Author Report Posted March 8, 2013 These baffles seem to be an inconsistent, but often-used feature. I wonder if they were added at the factory after test-flying and observing what went on with a particular engine-airplane combination (an artifact of the hand-made aircraft . . .)? Under any circumstances, I'm disinclined to remove them without a really good reason to do so. Mike Busch's AvWeb article on engine cooling indicates that monkeying around with the baffling is usually a bad idea, and he's the guru until even better advice comes along. Still, I'd sure like to drop the temps in that one cylinder a little. (One would think that the front two would be the cooler of the set, after all..) Thanks for all the responses! (Lood: my statement, "you can see from the attached photos, there is a small "baffle" in front of cylinder 3" was a typo or brain fart on my part. I should have called that cylinder 2.) Mike out Quote
jetdriven Posted March 9, 2013 Report Posted March 9, 2013 Trimming the top off that baffle lowers CHT. We did this and a few other things to equalize CHT across the 4 cylinders. The ones you have are not original, and look scabbed on. Quote
N601RX Posted March 25, 2013 Report Posted March 25, 2013 Mooney service bulletin M20-182 allows extra baffles to be added to a couple of the cylinders. Quote
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