hone vs bore


New member
how much can you hone a cylinder before it needs to be bored. I have a block that needs to go .025 (its a limited). Can it be honed or should I send it out to be bored?
If you are going from one size to the next in piston and the wall of the cylinder is in good shape without severe scratches you can get away with honing it if you have a good hone. As for the align bore, look at the piston to see if the wear marks on both sides of the skirt are close to the same. Look at the top of the cylinder where the top ring stops each time. If there is a ridge there that is not the same all the way around, you have a cylinder that is not true to the crank and therefore you need to get it align bored. So in short, if everything looks good with the exception of a few scratches in the wall and on the piston and you are going to the next size piston, get a good gone and hone it.
If you don't have quality tools to measure the bore for out of round Dons advice is fine, but there is no substitution for doing the job correctly with the proper tools. A quality hone can fix a bore and if you are patient enough, hone it up one size. But that only applies if you are using a positive pressure hone such as a Sunnan. If your hone is a spring loaded unit that you got from the local auto parts or Harbour Freight it has NO use whatsoever in building a racing motor, throw it away. There is no way to build a quality racing motor without starting with a quality bore, not trying to discourage you from building your own motor but if you don't know the answer to these questions you are better off sending the motor out for a quality hone or bore job. Either buy the new piston from the shop doing the work or if you already have a piston send it with the block. Suggest you send it out to a kart engine builder, as they would already have a set up to get it done properly, a local machine shop probably needs to spend so much time on set up that it would be too expensive.
I have the sunnan small engine hone. I won't even use the spring ones for deglazing, there is no way to have a round cylinder with one. I prefer the ball hones for that. I was just wondering if you could hone one out that far. I had a couple of old timer engine builders tell me I was throwing money away and wanted to get a opinion from some other builders. Normally if it needs more than 10 over to clean up I have it bored. I do have the tools to check the bore for out of round. I don't want to just throw money at something. but I know if its out of round it will never make good power.
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I recently did an animal that way but the bore was in good shape and went from standard to a .005 over. The Sunnan should be able to do it just fine for a size or even 2 depending on your patience and how much you are willing to wear your stones. The Sunnan will take out taper and out of round of a couple of thousandths. Are you talking about going from standard to .025? That is a lot of honing. Are you set up for coolant?
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.005 or .010 doesn't bother me I use a truing sleve between hone jobs. mostly I use the hone to get my wall clearance where I want it. I was wanting to see what other builders thought. I'm not a pro builder, but I have been building my own for a long time. I was bench racing with a couple of guys who had raced for a long time. They thought it was funny that I was sending every thing out to be bored. I pride myself on the fact I do everything myself. I would probally be faster if I paid pros to do my stuff but I feel better running 3rd or 4th doing it all my self than if I won by paying to have everything done.
has the block every been align bored? what size is it now?

if you have to go over .010 then I'd probably bore it just because it's faster and easier to get to the size you need.

I typically align bore a new block once then If I maintain the engine I'll just use my sunnen hone to straighten the bore for the next size as needed.