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Well, while you're here check out my cylinders I just borescoped and let me know what your thoughts are. I'm doing this primarily because I've been experiencing higher oil consumption in the past +6 months of 1qt/3hrs. (Yikes) Only fill it to about 6qts and tend to change oil every 25-30hrs. No metal in the filter in the past 3 changes and oil analysis comes back normal for my 1430hr engine. I've also had abnormally high oil temps with low to normal CHT's. (Granted I live in ABQ but never seen oil nearly red line before). My initial thoughts are increased blow by due to frozen or broken oil rings hence the oil use/ higher temps. I just completed the oil control ring flush yesterday but haven't ran it yet. So, check out the pictures in the linked albums and let me know what your thoughts are. I believe I see a good amount of lead deposits on some of the cylinders and oil pulling as well. Below are the bottom spark plugs for reference too. Nothing crazy or out of the usual for residual oil from my perspective. https://photos.app.goo.gl/p4o59zXnJ8sN8smbA https://photos.app.goo.gl/wdjMyvKrDWE2V5wA6 https://photos.app.goo.gl/AXtSkn4HXR5t8Atr9 https://photos.app.goo.gl/pAVCbk2QWQgWpvoF9 In the meantime, I'm trying to pull the vernetherm to test if it's working correctly but it's being a real PITA. The return line from the oil cooler is getting in the way so seems like I'll have to pull that as well. I'm also trying to re-install the oil regulator so the bypass holes line up correctly but will need a new crush washer for that. (Mines the non-adjustable kinda adjustable with washer type.) Let me know what youses think! -KC

OK; this is a continuation of my engine saga of apparent excessive oil use here: Upon further investigation, we now found excessive oil coming out of the air-oil separator of my IO550G (see STC# SA02033AT, http://www.cessna170.org/OilSeperator/OilSep.html#Install). In fact, after 15 hours of flying after my last oil change, I had a black "cake" on my nose gear doors -- which came from the vent of that air-oil separator. Note that I don't see any oil on my hangar floor. One explanation is that I have excessive blow-by, creating pressure in the engine, which perhaps is overwhelming the air-oil separator? But I am grasping at straws here: Is there another explanation? Maybe the life time of those air-oil separators is limited (mine is 11 years and probably 1300 hours or more old, or so). Clearly I am blowing oil overboard, but mostly while flying and hot it seems. What puzzles me is that I had the problem (excessive oil usage, about a quart every 3 to 4 hours), then it went away for no apparent reason for one 35-40 hour oil change cycle, and now it is back. Does anyone know under what condition this air-oil separator would start blowing stuff overboard, instead of returning the oil to the engine? Really puzzled by all this -- and obviously trying to avoid experimental top overhauls (all the compressions are pretty good still).

I've only had my 231 for 10 months now, putting 170 hours (more than it's flown in the last 8 years combined) and have been working out the years of poor maintance on the aircraft. Thankfully she only has 1600 total hours on her. Today I finally nailed down the 1/3 to 1/2 quart per hour oil consumption issue I've had from day one. I checked the usual suspects; Compressions, turbo, oil seperator, all good. Not until I replaced a cylinder intake gasket that I saw a possible cause. Oil pooled in the intake port and a coked up intake valve. I checked two other cylinder, same story, but no oil in the induction system, bone dry. After checking the TCM IPC, easy fix I thought, change the seals on the intake valve guides and let's see if we can make TBO. Cylinder after cylinder I found that no seals were installed. I called TCM to see if they were required on -GB engines as listed in the IPC . Yep, required per the Tech Support guy. After getting a seasoned Tech Guy on the phone I found out that they started installing the seals in the mid-80's. My cylinders are factory installed in January 1981, and have never been replaced. 1600 hours, wow, never heard that about a TCM ENGINE. The previous owner must have really babied the engine for the 25 years he owned it. Seals are installed now, can't wait to see the results. I'll see if I can get 200 more hours then upgrade the engine to an -LB. Any thought on cleaning the coked up valves? TCM says to disassemble the cylinders. Really?

Anyone have a flight time, fuel consumption, oil consumption, etc. log that you're particularly happy with?