The International Cessna^® 170 Association

George the problem with your story is you think the Savvy method would/could have increased the compression in your case, to an acceptable level. I have my doubts it would/ could have.

I know plenty of highly thought of mechanics who would have advised you to simply run the engine another 10 hrs without doing anything. And then do another compression check. Just to rule out aligned ring gaps don't you know. How many times have people heard this advice. Is it sound advice? How many have followed it? Show of hands now.

The safest thing is to just completely disassemble everything inspect then reassemble. If you discount the possibility of introducing an issue due to faulty disassembly and reassembly, add new parts sometimes fail prematurely. Many folks would not have flown a newly installed cylinder from TX to MI.

George, I don't have an issue with your changing out your cylinder and aren't we all surprised to find damage we didn't expect. I've been involved with the removal and replacement of probably more that 20 cylinders in the last year or so for low compression. Not one was found to have any obvious damage, most had cooked and stuck rings. Something this Savvy method might correct without much disassembly and so I find it interesting. I also don't find fault with someone who might try the Savvy method. Savvy has a huge following and you don't get there by giving out lots of bad advice. Having said that I usually roll my eyes when I hear Savvy is involved.

George, you've picked a nice weekend to visit Carlisle. A little bit cooler that usual in the morning but next week it's suppose to be back into the 90's all week which you're probably use to in TX.

https://www.csobeech.com/files/TCM-SB03-3.pdf

Would most agree that this is reliable guidance for assessing and maintaining Continental Cylinders? Given the potential of low compression results during annual inspections, I would think this Service Bulletin would be of interest to owners as well as mechanics. (I am not criticizing SAVVY by bringing this up, but think it’s worth looking at before deciding how to remedy compression problems)

Bruce Fenstermacher wrote:…

. Many folks would not have flown a newly installed cylinder from TX to MI.

….

I did not immediately fly to MI after the cyl change. After the cyl was installed, I flew the airplane overhead my field for 1.5 hrs…landed and inspected for leaks, etc. After that flight, a week later we flew to MI, WI, and back to TX.

I agree it is only guess-work if the savvy-flush would have provided any increase in compressions…. we will never know. The No. 2 ring was actually stuck and was only freed after I manipulated it after disassembly. It’s unknown if a “flush” would have freed it and improved compressions…but if Busch’s theory is correct…it MAY HAVE… resulting with the possible addt’l risk I described.

I’m still curious as to how anyone would be confident that all the solvent would flow past the rings and into the crankcase….and none of it past valves, guides, and into intakes/exhausts…. OR how any clearing of debris past a stuck ring would actually “free” a stuck ring. I suppose what is imagined …is that cleaning the pistons/rings/cyl-walls of debris/carbon/etc …may result in a stuck ring becoming free again. I think that is …. “imaginative”… and not only inconclusive but also risky.

(And, by the way…. if solvent gets into the INtake manifold it will be far more hazardous (IMO) than if it gets into the exhausts…. Anyone who is knowledgeable about broken rings, pistons, or failed valve-heads…. knows one of the major hazards is that the broken pieces can gain access to the intake manifolds and then travel into an adjacent cylinder! ! If that solvent gets into an adjacent cylinder…and the engine is subsequently started…a hydraulic lock and serious damage may occur. (PS: Considering the construction of the c145/O300 this is admittedly not as likely as other model engines… but as a repair-procedure, it certainly is an oversight to be universally-recommended.)

Only physical disassembly and visual inspection will safely determine if it is a stuck ring…and if so,… if it can be freed…IMO.

voorheesh wrote:https://www.csobeech.com/files/TCM-SB03-3.pdf

Would most agree that this is reliable guidance for assessing and maintaining Continental Cylinders? Given the potential of low compression results during annual inspections, I would think this Service Bulletin would be of interest to owners as well as mechanics. (I am not criticizing SAVVY by bringing this up, but think it’s worth looking at before deciding how to remedy compression problems)

A compression check, in the case of TCM per this bulletin or the current M-0 is required for annual inspection. In addition we now borescope every single engine at every maintenance opportunity which includes in many cases 50 hr oil changes, all 100 hr inspections and for any reason we are diagnosing engine issues.

I'm sure Busch wouldn't order this flush, prior to a careful inspection via compression check and borescope be performed and analyzed. I certainly would do one before I considered a flush.

GAHorn wrote:

Bruce Fenstermacher wrote:…

. Many folks would not have flown a newly installed cylinder from TX to MI.

….

I did not immediately fly to MI after the cyl change. After the cyl was installed, I flew the airplane overhead my field for 1.5 hrs…landed and inspected for leaks, etc. After that flight, a week later we flew to MI, WI, and back to TX.

I did expect George, you tightened the last bolt and blasted off immediately for MI. I should have been more descriptive. Many folks wouldn't have flown a new cylinder far without some time on it such as 10-15 hrs. Give the new cylinder on the block some time to gain knowledge of what it is it's suppose to do, and the owner more trust that it will, no doubt.

Most new Cessnas are flown straight from the factory to destinations all over the planet.