The International Cessna^® 170 Association

blueldr wrote:Decarbonize it, deglaze the cylinders with a dingleberry hone, lap the valves, ring it, and put it back toghether with new wrist pin plugs as needed.

Might be a good idea to flush the galleys and change the oil too!

I wonder if there will be anyone to say this kind of thing in 20 years? Simple, practical solution, for a simple practical engine. These things really were designed to be fixed, not replaced.

After popping on the affected cylinder and checking the filters and before changing the oil , I would be undoing the engine mounts and lifting the engine up and pulling the sump off for a clean and inspection . You would be surprised to find what sits in the sump . I would be changing the oil again at 15 hours later also .

Five hours an a screen-sample would be a good idea.
Most things sitting in the bottom of sumps remain in the bottom of sumps. I wouldn't pull it unless subsequent samples cont'd to repeatedly show contaminants....after-all...THAT is what the screen is FOR, to collect the stuff out of the sump.

I second the suggestion of not pulling the Oil Pan too soon.

a number of things could wrong.

Dr do no harm

The engine shop miked out the cyls and one other one was at max limit so decided to order 6 new Superior cyls. Decided it was the more prudent thing versus having them all inspected and gone through. Figured I had them all off so now is the time.

Also ordered a F&M filter adapter. Will flush the engine well before putting on the new cyls.

Will install new motor mount bushings too as long as the engine is light. Those were on my next annual list anyways.

Good luck with the new cylinders Kyle!

Update....

All new Superior cylinders are on and the engine was test run for leaks.

I've got about 5 hours on it over the last few days. No oil leaks, no oil consumption and it's running smooth.

One question for those of you who have replaced all 6 cylinders - how tight or 'draggy' are those new cylinders?

When handpropping through the compressions the engine now has much more drag. I know it's hard to describe and pretty subjective, but what's been your experience? Are new rings and pistons in all 6 cylinders really that more noticable in their drag due to those new tighter tolerances?

You'd expect more drag due to the cylinders not being broken in yet, Kyle. New cylinders are honed to a slightly rough finish, which gets polished by the rings as they break in. You should have less resistance after a few more hours.

Glad to hear you have 6 new cylinders Kyle. You said the engine is dry. Must be out of oil as I don't see many Continentals (or Lycomings) that don't drip some oil I don't think you mentioned how many hours you had on your old cylinders or what compression they were making. After you get these new ones broken in good I would like to see if you notice any significant increase in performance. When I did my overhaul I was told I would really feel the differences with the new cylinders. I couldn't detect much, if any, difference. I hope you will do so.

Say hi to Becky!

Frank

Kyle Wolfe wrote:Update....

All new Superior cylinders are on and the engine was test run for leaks.

I've got about 5 hours on it over the last few days. No oil leaks, no oil consumption and it's running smooth.

One question for those of you who have replaced all 6 cylinders - how tight or 'draggy' are those new cylinders?

When handpropping through the compressions the engine now has much more drag. I know it's hard to describe and pretty subjective, but what's been your experience? Are new rings and pistons in all 6 cylinders really that more noticable in their drag due to those new tighter tolerances?

The "drag" you mention might be due to the crankcase having been re-torqued and squeezing the main bearings more tightly than previously. (I once had an engine on a Baron suddenly demonstrate excessive "drag" during hand-turning and it developed that a main bearing had "spun" during a cylinder change at a local Cessna dealer in Austin. The engine had to be replaced after the next flight because oil pressure failed due to the spun front bearing.)
The possibility with "top ovhls" is the crankcase to be improperly torqued too lightly such that a bearing might spin ... or that the bearing is displaced while the cyls are off and the crankcase is not clamped with thrubolts when someone turn the prop in the shop...unlikely in the scenario you've just described. (I realize these comments are not comforting...I just wanted you ..and others...to be cognizant of carefully following procedures.)

I prefer that when doing cylinder changes that thru-bolts be measured for torque-required when disassembly is made and that minimum (lower-range) torque be applied during reassembly to meet that previous torque as a maximum, i.e., the previous disassembly torque measurement is ideal as long as minimum spec per the manual is met and no maximum is exceeded.

Since you've already assembled and run the engine, I suggest you've already operated with the new pre=load on those mains and it is not helpful to startle you with those thoughts, so just keep a close eye on it and remain vigilant towards the possibility. If you've operated more than 5 hours now then it's probably fine. A bearing problem would likely have already shown up by now, but you might want an early screen/filter check.