Using a Sunnen Hone to bore?

[coffeeguy]

I would like to open up steel cylinder bores in a 2.5l merc. Some are just in the limits but are out of round a little and some are up to 0.002 out of limits.Can I use a Sunnen hand held hone to open up and straighten the bores.
This would require removing 005" and 0.010"of material depending on the wear(one new cylinder too)?
If possible what stones would I want to use?

[FORBESAUTO]

Need to bore it. What will happen is you’ll wind up with taper in the cylinder with the bottom being smaller than the top. The stones will spend less time at the bottom of the cylinder because of the floor limiting your downward stroke.

[rock]

We have a shop in town that only uses the Sunnen for 2 stroke. This is an automatic machine with a dwell for blind holes. I wouldn't want to remove that much material by hand.

Rock

[outasite]

Have many hours on a sunnen CK10. With the correct stones and proper bottom dwell time a near perfect bore can be obtained. It would be possible to do with the handheld BUT not without a way to limit depth you would be crashing and breaking stones constantly. Not to mention only guessing at the bottom dwell time.Carefull use of a good dial bore gauge would keep ya honest.

[Dave S]

I did a tohatsu that way .015 took forever......them jap bores are hard. It was an open hole so I could pass thru. I would not do a Merc blind hole. Give it to a pro. And a nudda thing on a 2.5 top guided motor.......004 slop will give you rod bind at the crank bearing. That what breaks the plastic cages..... JMO.

[Motv18]

It can be done, but to much room for error.

Coarse steped to finish stone.

The hand hone really isn’t made to move slow. And to me constantly moving stones out is a pain.

Totaly awesome for removing bit marks and makeing the hash.

[coffeeguy]

If it was mounted in a mill where the depth and speed could be set?

[outasite]

A floor drill press comes to mind.The right stones are the key,lots of kerosene and light oil mixed.And don't forget to champher your ports.Go slowly! One chance to get it right.

[Chaz]

The job will be only as good as the tools you use to acomplish it. When you say Sunnen, you add quite a bit to the price tag going in. But if you already own a H.D. type of frame like the AN-815 then yes you can do the job. If not then something like a Goodson GH-2555 is a couple hundred dollars cheaper and uses AN stones .

https://goodson.com/collections/cyli...-portable-hone

You will need a set of 150's for stock removal ...

https://goodson.com/collections/sunn...ning-stone-set

A set of 220 bottom pressure to keep .. or get it straight twords the end ...

https://goodson.com/collections/sunn...ning-stone-set

A set of 280's to finish the hole

https://goodson.com/collections/sunn...ning-stone-set

Like was said above, you'll want a mix of oil and kerosene or mineral spirits / JP-1 / diesel .Use lots of it , the stones need to be washed clean to work properly.
Set some kind of stop or put a mark on the shaft. you will only need to get the hone caught in the bottom one time to know your wrists weren't meant to turn in that direction.
You'll also need a 3" to 4" micrometer and a dial bore gauge. Measure 4 places as you go . Top thrust , top 90* bottom thrust , bottom 90 *
There will be a lot more stuff you will want , if you get into it . But those things mentioned would be a minimum "starter kit" to do a good job ..

[Dave S]

Soapy water.... then oil to finnis up.

[Chaz]

Soapy water.... then oil to finnis up.

My hand's too big ..

The Mrs. uses a sponge from the dollar store ..

The kid slotted a piece a .500 molly tube put the loop from the stem of a long twisted handle bore brush in the slot, tacked the end shut, puts it in a battery drill > kinda throws it in the hole and pulls the trigger .. not to enthused about cleaning parts ..

Finnis oil ... like this .. ???

[Dave S]

Chazzz crazzzy.... I can't stop lafffin....Darrrn....

[Dave S]

that be the flag.....

[powerabout]

have to admit when I started my apprenticeship the guys had already made full bore size stoppers for Merc and OMC's to you couldnt do damage when you bottomed out.
Not hard to make but very useful