Help me identify this Lycoming cylinder....

[William]

Hi all I've pulled my cylinders to install new 9:1 pistons and rings. Only problem is the logbook was missing when I purchased this engine. I've already overhauled the lower end but figured I would freshen the cylinders now. I've already did a valve job to the cylinders and now it's time to hone and add the new pistons and rings. Now to the problem, my cylinder has both a blue strip and a orange stripe. Can someone identify this cylinder as chrome or nitride so I can be sure to purchase the proper rings. The cylinders are standard size and measure fine with the dial bore gauge.

Thanks
Bill

[az_gila]

This is from ECI -

Lycoming or ECi replacement Cylinders for Lycoming Engines: Color Codes for the outer fin tip area between spark plug and cylinder barrel or color band between the flange and lower cooling fin are:

Standard Size Barrels:
? Engine Gray or Unpainted - Plain Steel or thru-hardened Airmotive Steel
? International Orange - Chromium type bores
? Two (2) Silver Stripes - CermiNil Process and/or Nickel+Carbide Bores
? Blue - Nitride Hardened Steel

Oversize Barrels:
? Green - Plus .010 Inch
? Yellow - Plus .020 Inch

Color codes for fin area between spark plug and rocker box are
? Engine Gray, Blue or Unpainted - Short Reach Spark Plugs
? Yellow - Long Reach Spark Plugs

Could it be that the blue is just overspray from somewhere since it's location is incorrect?

[William]

Originally Posted by az_gila

This is from ECI -

Lycoming or ECi replacement Cylinders for Lycoming Engines: Color Codes for the outer fin tip area between spark plug and cylinder barrel or color band between the flange and lower cooling fin are:

Standard Size Barrels:
• Engine Gray or Unpainted - Plain Steel or thru-hardened Airmotive Steel
• International Orange - Chromium type bores
• Two (2) Silver Stripes - CermiNil Process and/or Nickel+Carbide Bores
• Blue - Nitride Hardened Steel

Oversize Barrels:
• Green - Plus .010 Inch
• Yellow - Plus .020 Inch

Color codes for fin area between spark plug and rocker box are
• Engine Gray, Blue or Unpainted - Short Reach Spark Plugs
• Yellow - Long Reach Spark Plugs

Could it be that the blue is just overspray from somewhere since it's location is incorrect?

Hi Gil

Thanks for the response. It could be except all 4 of the cylinders have the blue and orange stripe in the same place.

Bill

[Mel]

The "blue" I've seen has always been on the fins where your orange is.

My guess, and it is just that, is that the cylinders were originally nitride and have since been chromed.

[William]

Originally Posted by Mel

The "blue" I've seen has always been on the fins where your orange is.

My guess, and it is just that, is that the cylinders were originally nitride and have since been chromed.

This is my guess as well. I know that nitride cylinders use a chrome top compression ring and chrome cylinders use plain steel rings. Let me take a picture of the top compression ring and see if this can help with the identity of the cylinder plating material.

Thanks
Bill

[rocketbob]

Well the stripe is orange and the bore looks chrome to me. A cast iron ring will shatter if you smack it with a hammer. Removed of course

[William]

Originally Posted by rocketbob

Well the stripe is orange and the bore looks chrome to me. A cast iron ring will shatter if you smack it with a hammer. Removed of course

Here are a picture of the rings. I put the ring on the steel shoulder of my work bench vise. Gave the ring a hard hit with the hammer and the ring only broke in 2 pieces. Is this what would be expected from cast iron rings?

Thanks
Bill

[rocketbob]

Correct. Those are cast iron rings. They appear very worn.

[William]

Originally Posted by rocketbob

Correct. Those are cast iron rings. They appear very worn.

Awesome Bob thanks for your help! Thanks Everyone else for your help as well! Vansairforce family comes through again!

Bill

[Doug]

I have no expertise with engines but - the base flange seems thin. Is this correct for a 9:1 CR engine?