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William Maslin wrote:
> In article <3AB7A6E4.B7581A78 att >, Marc Warden <marc.wardenatt> wrote:
>
> > Dave W wrote:
> >
> > > thinking of re-ringing '88 golf gti
> > > is it essential to hone the bores and can it be done by hand.
> > > ps, how much are honing tools approximately.
> >
> > You should check the bores to see if their dimensions are within spec.
> > Even with a super honing job if the bores are worn too much, the engine
> > won't be much good and you'll throwing money away.
> >
> > Otherwise, William G. provided you with good advice about hand-honing
> > cylinder bores.
> >
> > You want to use a good quality hone. When I hand honed engine bores I
> > used (borrowed from work) a Sunnen hand hone setup along with a 1/2hp
> > electric drill motor (it is unlikely a smaller drill motor will be able
> > to turn the hone -- I was honing a large V8 cylinder block and have hand
> > honed up to 12" bores in cast iron bearing stanchions usign that same
> > 1/2hp drill motor).
> >
> > Use plenty of good quality honing oil and clean, clean, clean the block
> > throughly after you are through.
> >
> What about those honing tools that look like a round wire brush with
> abrasive balls on the ends of the bristles? I saw a picture of one being
> used in a Haynes manual I've got (can't remember what car/truck the manual
> is for). I got the impression that it was more idiot proof to use than
> the three stone honing tools.
>
> Bill maslincvm.msstate
>
> 78 Rabbit...since new! 82 Convertibles(s)...since 93 95 Golf GL...since 11/99
In a previous career (journeyman machinist) I did a lot of honing and never once
used the tool you describe, the one like a wire brush with abrasive balls on the
ends of the wires. My guess is that this would barely remove any surface dirt
because to hone something significant pressure must be exerted by the honing stones
to actually allow the abrasive to cut and remove metal.
I used (or at least I remember having in my tool box) a 3-stone honing tool (or two)
but I can't remember how it worked out, though I suspect it would face the same
limitation as the 1st tool you mentioned.
For cylinder bore work (and high-precision bearing stanchion work -- precision
required a half a thousandths (0.0005) within the nominal size (approx. 12") I used
a Sunnen portable honing setup with 4 stones and a rachet center feed which feed the
4 stones out in unision and allowed me to preload them to when I first started up
the hone, it was all I could do to hang on and keep the drill motor from spinning me
instead of the hone.
Had to be this way or the stones would have not cut any material but just loaded up
and glazed/galled the bores and ruined the bores in the process.
For measuring I had a dial bore gage setup with a 'tenths' dial gage.
A dial bore gage was very nice (and I used one for almost all of my honing/boring
jobs).
It was especially nice for the cylinder honing (but frankly was indespensible for
stanchion honing as well, because of the very tight tolerances) because one could
get a very clear picture of the bore's topology (roundness, taper, and size).
The Sunnen setup was not very difficult to use and in fact I think it was probably
as about idiot proof as any other setup, and maybe even more so. The setup did take
something out of you, that is, it was kind of strenous work, because in the case of
the cylinder bore honing in order to get the proper cross hatch pattern, I had to
move the hone up and done in the bore very quickly. In order to not take too much
material out of the bore and bring the cylinder wall/piston clearance out of spec, I
had to get the pattern into the finish and remove as little material as possible.
In the case of the bearing stanchions (and I honed lots of other bores too, too many
to list or even remember) there was the additional drag of the large hone stones.
Once I got the initial machining marks out of the surface, got the initial surface
roughness out of the bore, the stones made full contact with the bore surface and I
had to really hang on to the drill motor. It has additional handles, extensions, so
one could counter the twisting force the honing drag imparted to the motor. I had to
move the hone back and forth to make sure I took even amounts off the front and back
of the bore and take out any taper that the boring operation imparted to the bore
(though the bores were pretty round after the finish boring operation).
I had the proper type of stones (silicon carbide IIRC) and some good honing oil that
kept the stones open and cutting.
In the case of the engine bore honing, I managed to get the right surface finish and
still keep the size in tolerance. The engine just purred when I got everthing back
together.
And in the case of my professional honing, I never once took a bore oversize.
Sincerely,
MarcW.
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