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i was getting cht readings of 412 degrees,way to high,i read a post to put two washers together,and stick them between the #3 cyl,and the aluminum baffel,this gave me a opening of about 1/8 inch,behind cyl 3. more air flow,i was at my witts end with the high cyl temp,what an easy fix,did the job temps are now 370 in the summer months,cowl flaps closed in cruse.

Hi. Just purchased a really nice M20C and I noticed I have about 1/2" gap between my baffle seal (attached to the aluminum baffling) and the front cowl at the bottom below the spinner. This gap seal is obviously intended to fit into the slot in the cowl but it's way too short. This gap goes the full width of the aluminum baffle. I'm experiencing high CHT temps but only in climb. It's a apparent this material has not been changed in decades -if ever. Can someone tell me the specs for this rubber seal and maybe a source for it? Is it a kit or just roll stock? Thanks. Joe PS just had the LASAR cowl enclosure installed but doesn't seem to have any cooling effect.

Mooniacs, Flying my M20F with an IO360a1a, turbo normalized (ray jay)...went for a little scenic cruise yesterday and here's what happened: 1) Oil was just above 6qts, so I figured I'd add another qt before the next flight 2) Leaned for taxi, rolled to the threshold, and did my run up. First click on the mags and the engine loses 200 rpm, runs rough. Ok on the other mag. Ok on both. So I rev up to 2200 rpm, lean for best power, hang for 30 seconds and check the mag again. Still rough. I repeat the leaning/fouling rectification procedure and this time it works, everything is fine and dandy. However, I notice cyl #2 has crept up to 405. I pull the power back, but since its hot as hell 90degrees, high DA 8500ft, and not a lot of cooling, I don't see much of a drop. I think to myself, let's roll and see what happens. 3) So I line up and go WOT and #2 goes up to 420. I abort. Head the FBO. Drink an iced tea. Add a qt of oil. Wait 20 mins. 4) I try again. No fouled mag check. Temps all stay low (350-370). I go WOT no turbo (24inches, 2600 rpm, but the rpm takes 5 seconds to spool, kinda hangs at 2400 for a bit then get to 2600 on the roll), I hit 410 on climb out on #2 but that comes down quickly after I nose over and speed up to 115 for cruise climb (full rich, no turbo, 24/25). At 8000 feet, I add the turbo just to see how it affects the temps, all good. I lean. All good. So, what happened? EGTs were all fine around 1290-1360. Could I have stressed the cylinder that much during the plug foul operation to make that one cylinder that hot? If #2 had the fouled plug, I would expect the CHT to be lower...#1 340, #2 420, #3 380, #4 340... I don't have the GEM computer to download any data so you'll just have to go with the above. Mind you, my #2 is always the hottest by about 20 degrees compared with #3 and by 30-40 degrees compared to #1 and #4. Interesting that 1 and 2 are both in front, and that 1 has more baffle around it and it looks like #2 is intentionally missing a few inches baffling (#1's go straight across the entire length of the cylinder and #2 has a 3 inch gap between baffle pieces). Also, #2 is about 70 hours new, I so I get that the higher temps could be a break in thing. About 20 hours ago I replaced the mineral oil with 100Wplus. Thanks for your thoughts! B

Hi folks, I have been seeing high CHT temperature on cylinder #1 over the last year and am having trouble nailing down the culprit. CHT often exceeds 400 degF in cruise when running 100 degF ROP when it used to operate well below that. We are having to run super rich (150-200 degF ROP) and often fly with the cowl flaps open. We have recently changed this cylinder due to a small crack at the spark plug hole discovered during the annual inspection, however, this high temperature issue was apparent before this replacement. I also notice that the EGT on this cylinder is the lowest of all. Here is what has been checked so far: 1) CHT probe #1 swapped with #3. No change in readings. 2) Air cooling baffles checked - ok 3) Fuel flow divider recently checked - clean 4) New injector installed - no change 5) Fuel lines tested last year for even flow from divider to injectors - ok 6) Intake system checked - no leaks 7) Exhaust system checked - no visible issues 8) Mag timing checks out ok 9) Spark plug is black showing we are running rich (matches with what we are doing to keep CHT below 400) Anyone engine gurus out there have any advice? Brenden 81 M20J Calgary

i am getting high cht temps on cyl 3,, 417 degrees the highest,,,this just started and i have done everything but pull the cyllinder,jpi 930 is brand new,all cyl are good.changed spark plugs,changed probes,cleaned injectors,still high,any thoughts,baffel is new also,,just stumped,dont know if the new jpi 930 is bad, just have to switch probes around,,any comments welcome