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 still present on cylinder walls which indicate less than .002 inch wear. Why are you putting rings in it. The cyinder walls look almost brand new with some hear discoloration next to a head bolt. So rings should still be in good shape.
 
I recommend you mark the top of the piston in relation to the discoloration in the cylinder. You may need a piston due to a casting defect or possibly a wrist pin has rubbed the cylinder wall.

If the top ring is seized in its groove, there is some kind of physical damage that has been caused in the past by a solid item inserted through the spark plug hole to check piston height. (I've seen a person ruin an engine doing this).

Keep in mind that the are mass produced consumer engines, so machining tolerances are not strictly checked on every engine.
 
You can't see the light scratches just above the dark spot. You can't feel them but they are just starting to scratch the cylinder wall. Very light, no depth yet. I was hoping they would show up. I'll get some sizes in the next day or so. Looking for my i.d. micrometers and telescoping Gauges to check the bore size, it should be perfect. I was thinking of new rings and light honing of the bore. I was concerned about what was going wrong to start this issue?
 
If the piston ring end gaps are still within tolerances, there is no reason to replace them at 300 hours. I have reused piston rings many times before providing that they were still good.
 
Any idea why the dark area formed and what may be causing the start of scratching? I was thinking something in the rings dragging up and down to cause the scratching.? But why the dark area, heat?
 
Auto Doc's said:
I recommend you mark the top of the piston in relation to the discoloration in the cylinder. You may need a piston due to a casting defect or possibly a wrist pin has rubbed the cylinder wall.

If the top ring is seized in its groove, there is some kind of physical damage that has been caused in the past by a solid item inserted through the spark plug hole to check piston height. (I've seen a person ruin an engine doing this).

Keep in mind that the are mass produced consumer engines, so machining tolerances are not strictly checked on every engine.
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Thanks, marking the piston is a good idea. Does a wrist pin extend that far! I have to check that out!
 
I did not see where you gave us the exact engine number so we can focus on your exact design better.

Just on a speculation, I would say the cylinder is running lean and getting hot. There is a lot of "coincidence" that the hot spot of the cylinder liner is in line with the head bolt location.

The other possibility is that the cooling fins were loaded up with grass clippings and preventing proper air flow.

Are all of the cylinder tins in place? I've seen people remove them before to clean better and then just leave them off. All cooling tins have to be in place.
 
Auto Doc's said:
I did not see where you gave us the exact engine number so we can focus on your exact design better.

Just on a speculation, I would say the cylinder is running lean and getting hot. There is a lot of "coincidence" that the hot spot of the cylinder liner is in line with the head bolt location.

The other possibility is that the cooling fins were loaded up with grass clippings and preventing proper air flow.

Are all of the cylinder tins in place? I've seen people remove them before to clean better and then just leave them off. All cooling tins have to be in place.
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I bought it new Husqvarna ts348xd with a Kawasaki fr730v. All tin and all air flow covers are in place. Never ran stripped down. Was very clean until this winter, I found a mouse nest under the covers but no run time on it.
 
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