Should I replace head bolts when replacing head gaskets?

john in ohio said:
After pulling cylinder head number 2 this is what I found!! I was shocked to find this with only 315 hours on the machine! What is this telling me?
I pulled the engine and I have it on a work bench. I didn't open it up yet. Ordering rings and crank seals, should I also order seals for the governor?
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Crosshatching in cylinder. You should wait another 20 years when you will needs piston rings, etc. 300 hours is nothing.
 
looking at your photo it feels like we are being trolled. That cylinder appears to be freshly honed. There appears to be no wear in it since the honing. It looks like a recent DIY hone. The angles are too shallow and the stone spun round and round at the top like it was done by hand and not a honing machine as a factory would have. The deck has been rubbed with a stone too. The cross hatch is supposed to intersect around 45 degrees. That looks to be around 20 to 25 degrees, indicated someone did not maintain the speed and movement properly.

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sgkent said:
looking at your photo it feels like we are being trolled. That cylinder appears to be freshly honed. There appears to be no wear in it since the honing. It looks like a recent DIY hone. The angles are too shallow and the stone spun round and round at the top like it was done by hand and not a honing machine as a factory would have. The deck has been rubbed with a stone too. The cross hatch is supposed to intersect around 45 degrees. That looks to be around 20 to 25 degrees, indicated someone did not maintain the speed and movement properly.

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I ran scotchbrite around the top 1/4 inch. Only 315 hours on the machine! Some of the guys recommended decarbing the pistons at 300 hours. It had started blowing white smoke when I started it. After the first cut of the season it was smoking (white) full time. I was new to engines so I pulled the heads to clean up the carbon and inspect things. The photo was what I found.
 
I pulled the engine it's on my work bench now. That was what started the post. I had seen other posts about blue loctite and I had never used it before, so I was asking if I needed it and was wondering if the head bolts could be re-used. I see that is just fine and no blue loctite.
Now I cleaned the outside of the engine and I'm getting ready go mark the piston so when I pull them I can look at the skirting for ring problems or what ever else can start the light scratching and discoloration that was forming.
 
Is dark areas caused only by heat? I saw the dark spot and light scratches and thought it was ring damage!? I don't understand all the clues and hints as to what it's telling me.
 
john in ohio said:
Is dark areas caused only by heat? I saw the dark spot and light scratches and thought it was ring damage!? I don't understand all the clues and hints as to what it's telling me.
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My suspicion is since the bolt hole is there, dark area could be caused by different heat dissipation cause heat warpage of the cylinder walls causing that area to wear more. Can be cause by not using a torque plate when the cylinder is honed leading to out of round when the cylinder gets hot. Or the bolt threads could be heat treated and the heat treatment bleed through to the cylinder walls.
 
sgkent said:
the only decarbonize fluid that ever worked was the GM Upper cylinder stuff that was discontinued. I did a test many years ago of five or six different well known decarbonizing cleaners and the GM one was the only one that actually 100% softened and washed away the carbon. But smoky and stinky. Do it on a windy day so it blows away or you will live in a stinky fog for hours. The carb cleaner one soaks parts in also works but that isn't really designed to be burned. You pour it into the engine slowly at a fast idle, and then stall the engine, let it sit a half hour then restart the engine and pour the rest thru. Probably on a mower 1/8th can per cylinder would be enough. It is outrageously expensive on Ebay. Goes by GM or AC Delco Top Engine Cleaner. The Subaru stuff might be the same. For a $50 - $100 can of the stuff I can buy a head gasket, professionally clean the head(s) in my glass bead cabinet, and then clean the piston dome with some cleaner and scotchbrite. Also check the valves and lap them if needed.
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Agree with sgkent. The old GM Top Engine cleaner contained Methyl Cellosolve which worked very well. Newer stuff not so much.
 
StarTech said:
Why remove the head to de-carbonize when can use use a de-carbonize fluid?
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Hi StarTuck I happen to be reading this + I never even heard of what you're talking about decarbonizing fluid I'm just curious and then I read the post below that maybe it doesn't work that well if there's something current that does work I'd be willing to take a shot with my Briggs& Stratton OHV engine if you can recommend anything rather than take the engine apart.

Thanks,
Jim
 
With today’s unleaded gasoline carbon buildup is not an issue anymore. That mark is harmless & likely from an over torqued bolt. (**** happens).
Were there any issues while running? I would put it back together, don’t look for problems that don’t exist.
It’s likely you’ll create an issue trying to fix a non issue.
If you want to make this a learning moment by all means dig in.
90cummins
 
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