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Help me identify this Lycoming cylinder....

W

William

Well Known Member
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



 
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?
 
az_gila said:
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?
Click to expand...


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
 
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.
 
Mel said:
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.
Click to expand...

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
 
Last edited:
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 :)
 
rocketbob said:
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 :)
Click to expand...

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





 
I have no expertise with engines but - the base flange seems thin. Is this correct for a 9:1 CR engine?
 
one more quick question for everyone. from what I gather these must be the old cermichrome cylinder coating. I've read you're not supposed to hone this type of chrome cylinder....is this correct. I've read you can hone the channel chrome cylinders, which I don't believe my cylinders are. so should I hone these or just put new rings and pistons in and call it good.

thanks,
bill
 
Yep I wondered if they were Cermichrome. ECI says not to reuse them. I don't know how hard they are, it may be that unless you use silicon carbide stones in the hone you might not be able to do much with them.
 
rocketbob said:
Yep I wondered if they were Cermichrome. ECI says not to reuse them. I don't know how hard they are, it may be that unless you use silicon carbide stones in the hone you might not be able to do much with them.
Click to expand...

Hi Bob ive read that eci doesn't recommend reusing the cermicrome cylinders as well. From my understanding though eci use to have a service bulletin on the procedure for honing cermicrome cylinders. This bulletin was taken down when their new plating was released. Does anyone happen to have this sevice bulletin for honing cermicrome cylinders?

Also I'm curious as to the reasoning for not reusing cermicrome cylinders after removal. Is it because part of the chrome may have worn away? From my understanding of the procedure for chromiing a nitride cylinder the bore first needs to be roughened up to allow the chrome something to bite to. If this chrome was to be worn away this would leave a rough service to wear the rings down quickly.


Thanks
Bill
 
Last edited:
The cermichrome is pretty thin. I've seen two cylinders where the the rings ate through and wore a wide spot in the softer steel.
 
They had adhesion problems and the chrome would get in the bearings and eat the entire engine. I wouldn't use it.
 
looks like I'm just going to have to bite the bullet and buy some new steel Lycoming cylinder assemblies. these cylinders should be usable by the airboat guys still.... :)
 
William said:
looks like I'm just going to have to bite the bullet and buy some new steel Lycoming cylinder assemblies. these cylinders should be usable by the airboat guys still.... :)
Click to expand...

I have 4 yellow-tagged rebuilt narrow deck O-360 chrome cylinders if you are interested...:)

Tag-front-A.jpg
 
Hi Gil thanks for the offer, but I need narrow deck O-320 cylinders. Happen to have any of those? :)

Thanks
Bill
 
Doug said:
I have no expertise with engines but - the base flange seems thin. Is this correct for a 9:1 CR engine?
Click to expand...

Hi Doug these are in fact narrow deck cylinders but they do have the plates that go on top of the cylinder flange. This plate sandwiches the cylinder flange to the crank case. It is my understanding that the higher compression pistons can be used with this type of narrow deck cylinder but not the ones that don't incorporate these plates.

Thanks
Bill
 
The orange indicates chrome and the blue stripe indicates the cylinder head was treated with the ECI IFR process.
Good Luck,
Mahlon
 
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