Diesel honing stones

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accurate engine
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Diesel honing stones

Post by accurate engine »

What stones are you using in your CV616 to hone diesel blocks. IE 5.9L Cummins and 7.3L Ford. What kind of load are you getting for the proper finish? New to the CV-616 and I want to get things right. Any help is appreciated!
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Re: Diesel honing stones

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Base finish would be good to have on hand, ehu518, ehu412, ehn512
518 should work for the 7.3, or 412 for a coarser finish.
Cummings B is fairly hard, so, 512 or 412

the ehN is 3.5" long stone so should be used for cylinders 7" or longer, but you can grind back the top to shorten them and have an extra soft 220grit, which CAN BE handy. i find is needed more and more often as blocks just keep getting harder and more flexy. Stone length should be no more than half cylinder length, You can shorten them but you can't stretch em!

I like to bring the cylinders pretty much all the way to size with one of the above, then do 7-9 strokes with jhu623, a conservative plateu finish.

Far as pressure used.......not enough it glazes, too much breaks down the stones too fast and has no real advantage.
The less pressure you can use and "get away with".... the less it will heat and distort the cylinder, and you just have to figure it out, it depends so much on the stones used VS the material, and the RPm and stroke rate.....ect, I don't know what to tel you there.
I find myself switching to softer stones as I get closer to size, partly to save time, partly to save stone wear. each step closer I get the load is lower.
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Re: Diesel honing stones

Post by accurate engine »

Sounds great. Thanks for the info. What RA do you end up with? I used the 518 to size then topped it with the 623 stone at 6 strokes. AERA stated a finish of 60-120 RA. OMG! I called them, they sent a mitchell manual download about using an 80 grit to size and then 285 grit to establish crosshatch........WOW! :shock:
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Re: Diesel honing stones

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RA....i can't comment.
Yes i too have read that from cummins, and wasn't sure what to make of it.
I assumed it would make more sense if they described exactly what kind of honing head and abrasive was used, or it might not. With a ck-10/ 616 going straight from 123 roughing stone to 623....is not going to produce a consistent finish IMO, or at least not in any way I know how.
I can say finishing many hundreds of Cummings B blocks as I described, over the past 10 years there have been no reported problem, although there were a few problem childs in the early days, using methods.... not described.
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Re: Diesel honing stones

Post by accurate engine »

Thank you for your time.
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