Topic: FCD Piston Rings vs Conventional Steel Rings

[Mkubs]

Hello all,

My name is Mat. I've been a long time reader of this forum but am a first time poster. This forum has been immensely helpful when I was rebuilding by 78 CB750K, and I couldn't be more grateful.

I'm here today because I wanted to ask for opinions regarding ductile iron casted piston rings (FCD) and if anyone has used them in the past? I'm currently in the market for some new rings and wanted to get some feedback before I make the purchase. I've been scouring the internet for a little while now and havent been able to find anything that would help in the decision making process. On 4into1.com, it is stated that the FCD rings are superior to the OEM steel rings. I have found articles on the benefits of ductile iron over grey iron, but I have not found anything to suggest they are better than the OEM steel rings.

Any insight or opinions in the matter would be greatly appreciate 

Thank you!
Mat

[Mkubs]

Bump 

[Mkubs]

Alrighty, one more bump and then I'll leave you guys alone.
I guess to help answer my question....

Would you buy these....https://4into1.com/piston-ring-set-standard-13011-392-004-cb750-1976-1978/

OR

These....https://www.vintagecb750.com/search/?q=piston+rings
[scroll down to standard size piston rings for CB750K 1978 (should be the second item)]

Thank you,
Mat

[uksparky]

The 4 into 1 rings will work fine.... going back to my automotive engine days fitted many a iron ring....... how many miles  these rings will last before using oil... they should last 200,000 miles ....OEM grey steel rings or chrome 225,000 miles

[lrutt]

The 4 into 1 rings will work fine.... going back to my automotive engine days fitted many a iron ring....... how many miles  these rings will last before using oil... they should last 200,000 miles ....OEM grey steel rings or chrome 225,000 miles

Automotive miles in a water cooled low revving engine are a LOT different that MC miles in an air cooled much higher revving engine. Rings heat up a LOT more in an MC due to higher piston speed, higher engine temp, etc.

[Mkubs]

The 4 into 1 rings will work fine.... going back to my automotive engine days fitted many a iron ring....... how many miles  these rings will last before using oil... they should last 200,000 miles ....OEM grey steel rings or chrome 225,000 miles

Automotive miles in a water cooled low revving engine are a LOT different that MC miles in an air cooled much higher revving engine. Rings heat up a LOT more in an MC due to higher piston speed, higher engine temp, etc.

Thank you both for the replies! I greatly appreciate it.

Based on what lrutt is saying, I should go with the OEM piston rings as they would hold up better to the beating of the CB750 engine.