Engine Rebuild

[Eddie]

Here's the gap in the new oil ring.

 

[mark777]

Man......you could fall through that gap! Just another reason why I like the Yanmar, engine oil compensating for the loss of compression.

Mark

 

[ChuckT]

That looks to tight to me.

I think that the rule-of-thumb for ring gap in a gas engine (it may be different with diesels) is one thickness of the ring. And you could file down the ring ends (square please & don't do it with the ring in the bore!) to make the gap wider.

FWIW
cvt

 

[mark777]

ChuckT,

If you look at Eddie's first attachment, the ring gap (@ 10 o'clock) indicates a minimum of 0.200, and the engine most probably was hydraulicing to make compression and keep running. Hence excessive oil consumption.

His second attachment, the ring gap (@ 3 o'clock red arrow) is closer to 0.018-0.020 which appears to be standard in the diesels I've worked with. I don't have the shop manual handy, but diesel is near double the compression of gasoline engines.

Mark

 

[Eddie]

14 hours of strong mowing since rebuild and it is still completely full of oil. I actually am able to get some black smoke when I load it instead of blue. Runs stronger too!!!!!!

 

[arthr31]

great! q: after you load the engine, how soon does the black smoke dissapate? either way, nice to read that things are running well!!

 

[Eddie]

It is just a temporary thing, like when I have it in high gear and gun it with the foot throttle, I get some black smoke instead of blue. It smells like diesel instead of something funky.