O470K cylinder options

[Skylark60]

Seeking advice

Cessna float configuration

I have a low hour Nu-Chrome top end and number 1 & 2 cylinders have fell to the low 60psi range in short order

I have a single point EGT in number two stack and run around 1300 deg, 50 deg less than peak and at about 13gph

I am considering replacing the two rear cylinders and want to know if I should go chrome, nickel or steel?

I would also like to get opinions on operating temp ranges

I would very much appreciate any advice, thank you in advance

[Strega]

There are a few places that can "repair" your cylinders.

http://www.harrisonengine.com/aircraft_ ... rvices.htm

I think there are a lot of people that become confused about "chrome" cylinders.. I dont like them personally.. but some do. Remember that chrome cylinders are usually old, and have had the bore re-newed by the chrome process

my 0.02 would be to buy a set of new steel or nickel jugs, a bit of cost upfront, but better in the long term.

One thing that people tend to forget about, (and is apparent with cars these days) is the tighter you keep the top end, the cleaner your oil will be be; the cleaner your oil stays, the better the bottom end will last. (have you ever seen a plane that 20 mins after you change the oil its blacker than coal? worn out top end blowing combustion gasses into the oil) This is not conducive of the bottom end and lifters/valvetrain lasting to tbo.

Your EGT seems ok to me, but another thing you can do is put in a set of gami injectors (flow balanced) to keep all cylinders running even.

[cgzro]

Where are the leaks? Rings? Valves?

How many tests have been done? Hot ? Cold?

How did you break in the cylinders? How many hours since TOH?

[iflyforpie]

I hate chrome, personally. Maybe they do better on the water with moisture.. but we always go steel and rarely have problems. It seems like every chrome cylinder I encounter has problems with leak downs, oil consumption, and excessive oil temps from blowby... though admittedly, lots of these are from improper ring seating and break in.

For operating temps... I like 75F rich... 100 is overkill, 50 isn't enough unless you have an engine monitor (the leanest cylinders aren't always the ones you think they are).

[Skylark60]

Thank you for the advice

The cylinders were tested during annual and I assume it was a hot test

I am not sure what was done to check leaks however it seems strange that the two back cylinders are the ones out of normal - to my limited knowledge and thought process it seems to suggest overheating?????

Are there issues or considerations with mixing nickel or steel jugs with chrome?
Which would handle the heat better?

Thanks again