Channel chrome break in

stknrdr · Post by **stknrdr** » Tue Jun 03, 2008 12:51

Any suggestions for breaking in my three "new" channel chrome cylinders from Gibson? (A-75-8F) I obviously don't have a CHT gauge. I've already swithched to straight mineral oil.

Thanks,

Tim

Captgrumps · Post by **Captgrumps** » Tue Jun 03, 2008 14:52

Way we always broke in chrome cylinders was to run them wide open for about 4-5 hours. If you baby them the rings will never seat. With a chrome cylinder make sure you Don't have chrome rings. If you do you might not make the 4-5 hours.

Doug

Post by **joea** » Tue Jun 03, 2008 19:05

Have always heard the same as Doug, run them wide open. Then land the plane and DO NOT TOUCH THE PROP. Let it sit and let the rings and cylinders cool off right where they are.

Next day fly it and see how it feels. A CHT gauge would help but you can usually feel when it settles down.

Joe

Nathan K. Hammond · Post by **Nathan K. Hammond** » Tue Jun 03, 2008 23:30

Wide open for an hour at a time, for the first 5 hours. Don't baby it, and don't dilly-dally around on the ground before or after. Get it running, down the runway and in the air quickly. It needs high temps, but more importantly, high cylinder pressure to seat the rings.

Oil consumption will tell you when they're broke in.

nkh

stknrdr · Post by **stknrdr** » Wed Jun 04, 2008 12:35

Thanks guys! I hadn't heard about the chrome rings or not moving the prop.

I do remember my Dad telling me when I was a kid:

"Tim you stay away from that wheelbarrow! You know you don't know nuthin 'bout no 'chinery!"

So, am I supposed to let the engine go to dead cold between one hour flights?

Do I want the oil temp redlined?

Forgive my ignorance, but I want to do this right.

Post by **joea** » Wed Jun 04, 2008 16:45

I would let the engine sit for a couple of hours at least and go "dead cold" between flights.

Other ideas?

marklamon · Post by **marklamon** » Wed Jun 04, 2008 19:22

joea wrote:I would let the engine sit for a couple of hours at least and go "dead cold" between flights.

Other ideas?

I agree with letting it go dead cold between flights. We speed the process up a little by putting a fan blowing in the air intakes . Mark

Nathan K. Hammond · Post by **Nathan K. Hammond** » Thu Jun 05, 2008 00:58

You don't want the oil above redline but it could very easily reach 200'F-205'F while you're running around at full throttle. If it goes above redline, land and let it cool off and go again. You may have to plan your flights early in the morning or late in the evening for the cool air. It was 93'F in ATL today.

You should be able to place your hand on the engine before running it again. So if you're like my father; thats about 10 minutes after you shut down.

nkh

gusc · Post by **gusc** » Wed Jun 25, 2008 19:18

My system for engine break-in is to;

Start it for a minute to check for leaks. double check oil level.

Push it to the end of the runway, make a quick mag check and take off.

Climb in a medium steep climb, watching oil temp to keep above high normal to near redline, to about 4000'. This climb provides the real break-in.

Cruising at full throttle is ok if you have a cruise prop, but if you have a climb prop if won't help much.

Regardless of the prop type fly until the oil temp drops to normal. It should be high for just a few minutes to as much as 30 min. Make a power descent and landing, don't idle any more than you absolutely have to.

I agree about not flying it again until the next day.

Chrome may break in and it may not. I've had them take 50-250 hrs to never. They will always use more oil than other types.

This is not the gospel according to Cont, this is just my way developed over the years.

stknrdr · Post by **stknrdr** » Thu Jun 26, 2008 11:01

Thanks for all the advice.

Flew it Sat and Sun for a total of 2.6 hours. Climbed to 5500' w/ oil temp to 205 deg. I think we followed all the advice to the letter.

Will repeat this weekend after an oil change.

115 mph indicated in cruise is a hoot. A-75 w/ climb prop. Air was super smooth.

Tim

gusc · Post by **gusc** » Thu Jun 26, 2008 20:43

Tim'

Your ASI is probably a bit off. A climb prop will actually slow you down at normal cruise RPM but your fuel consumption will also drop. I had an A75 on my first Champ and this was my experience. Your actual AS is probably around 80. It can be checked approximately with a GPS.

For fun use though I prefer a climb prop and will get one if I ever need a replacement.