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2022/11/26 16:09:43
OhBilly97

Honda GX620 cracks and piston wear

I am in the process of rebuilding this Honda motor and just pulled all the internals today. First I noticed some cracks on the inside of the block, not sure if those are supposed to be there or not. And then second I noticed this worn off parts of the piston itself. Any input would be greatly appreciated.

I attached photos to this to view.
7 comments Leave a comment
Conrad Sigona
Photos are not visible.
2022/11/26 17:20:53
SRTsFZ6
"Cracks" I suspect are casting marks...  
2022/11/27 07:44:52
OhBilly97
I guess I should also mention that there was an extreme build up of carbon in the heads and on the pistons.
2022/11/27 08:37:57
Conrad Sigona
I would agree with SRTsFZ6 that what you're calling cracks are probably innocuous. They're not on the cylinder surface, are they? But you did mention something about wear. It would be nice to know more, either photo or description.
 
As for carbon, it can be from various causes, typically the result of unburnt fuel, for instance, poor spark or too much fuel relative to air, like when the choke is not fully open. It could also be from oil in the cylinder, usually the result of bad rings. Did the engine smoke a lot when it was still running?
 
2022/11/27 09:10:27
OhBilly97
I posted the pictures they are waiting approval. And yes It did smoke allot when it was running.
2022/11/27 15:56:03
SRTsFZ6
That does appear to be cracks... :(   
I don't see anything there that could have impacted it, prior major engine failure...
 
Re the piston, the scraping up and down shouldn't be there, some wear on the skirt to be expected but no scoring..
 
Is the cylinder(s) scored up?  That would cause oil consumption /smoking/loss of power...
 
How does the outside of the block look where there's cracks inside?
 
.
2022/11/30 11:55:52
Conrad Sigona
Yes, they seem to be cracks, likely the result of defects in casting. Whether they affect the operation is still to be decided. Do like SRTsFZ6 said: check the outside whether the cracks extend to the outside. Can you show us the inside of the cylinders? It looks like you'll find them scored.
2022/12/03 11:11:05

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