electropolishing

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

John - 16 Oct 2004 01:24 GMT

I was wondering. Has anyone ever electropolished the metal-to-metal,
lubricated surfaces in an engine, like the main, rod, and cam bearings,
lifters, etc. and what were the results? I know it's been used on intakes
and exhausts with good success, but I haven't heard of it being used on
engine wear surfaces. Maybe since they have specified clearances and are
lubricated, there's not much benefit?

Signature

John
ThunderSnake #59
If you Reply, be sure and remove the " (DELETE_THIS) " from the email
address.

Reply to this Message

Mark - 16 Oct 2004 03:52 GMT

Polishing wouldn't work on the cylinder ring seal because it uses oil and
compression to seal. Rings and the cylinder wall need to seat or break in
together and polishing would delay that. You can't polish the bearings
because they're made up of soft metals and are better off with a dull
surface to help oil adheasion anyway. The crank is often polished but I
don't think the extra cost of micropolishing would be worth it except for
racers. Valve stems come polished from the factory. The only benefit, if it
were possible to polish every wear surface in the engine, would be at
startup. Exept in extreme cases the wear at startup is minimal, though.

>I was wondering. Has anyone ever electropolished the metal-to-metal,
> lubricated surfaces in an engine, like the main, rod, and cam bearings,
> lifters, etc. and what were the results? I know it's been used on intakes
> and exhausts with good success, but I haven't heard of it being used on
> engine wear surfaces. Maybe since they have specified clearances and are
> lubricated, there's not much benefit?

Reply to this Message

John - 16 Oct 2004 07:39 GMT

> Polishing wouldn't work on the cylinder ring seal because it uses oil and
> compression to seal. Rings and the cylinder wall need to seat or break in
> together and polishing would delay that.

Agree here.

>You can't polish the bearings
> because they're made up of soft metals and are better off with a dull
> surface to help oil adheasion anyway.

I'm not so sure about this. Oil adhesion would be good for startup. I know
some oils have tackifiers added to improve this, but after startup when oil
flow is established, it seems to me that the less defects in the two metal
surfaces the lower the friction and less heat generation. The two metals
need to be about the same hardness so the softer one doesn't get etched by
the harder one, don't they? Less surface defects means less points for
propagation of failures too. But I can also see that when the size of the
defect gets very small relative to the clearance between the oil flooded
parts, it may not be too beneficial.

>The crank is often polished but I
> don't think the extra cost of micropolishing would be worth it except for
> racers. Valve stems come polished from the factory. The only benefit, if it
> were possible to polish every wear surface in the engine, would be at
> startup.

Doesn't this kind of disagree with your previous statement? I can see both
sides too, I just don't know where the break point is as a finer, and finer
polish is obtained.

>Exept in extreme cases the wear at startup is minimal, though.

Signature

John
ThunderSnake #59
If you Reply, be sure and remove the " (DELETE_THIS) " from the email
address.

Reply to this Message

David M - 16 Oct 2004 11:59 GMT

>> Polishing wouldn't work on the cylinder ring seal because it uses oil
>> and compression to seal. Rings and the cylinder wall need to seat or
[quoted text clipped - 12 lines]
> two metals need to be about the same hardness so the softer one doesn't
> get etched by the harder one, don't they?

No. The bearing shells are soft. As you said, they
are supported by a 0.001" (or so) film of oil.

Signature

David M (dmacchiarolo)
http://home.triad.rr.com/redsled
T/S 53
sled351 Linux 2.4.18-14 has been up 28 days 12:24

Reply to this Message

Backyard Mechanic - 16 Oct 2004 04:29 GMT

> I was wondering. Has anyone ever electropolished the metal-to-metal,
> lubricated surfaces in an engine, like the main, rod, and cam bearings,
> lifters, etc. and what were the results? I know it's been used on intakes
> and exhausts with good success, but I haven't heard of it being used on
> engine wear surfaces. Maybe since they have specified clearances and are
> lubricated, there's not much benefit?

What would the benefit amount to, if there WAS one?

Engines already last far past the lifetime of the body if maintained... and
most owners get lax in maintenace once the body starts to go anyway....

Reply to this Message

Mark - 16 Oct 2004 04:51 GMT

It wouldn't be noticeable to us street machine guys. :)

>> I was wondering. Has anyone ever electropolished the metal-to-metal,
>> lubricated surfaces in an engine, like the main, rod, and cam bearings,
[quoted text clipped - 9 lines]
> and
> most owners get lax in maintenace once the body starts to go anyway....

Reply to this Message

John - 16 Oct 2004 07:04 GMT

> > I was wondering. Has anyone ever electropolished the metal-to-metal,
> > lubricated surfaces in an engine, like the main, rod, and cam bearings,
[quoted text clipped - 7 lines]
> Engines already last far past the lifetime of the body if maintained... and
> most owners get lax in maintenace once the body starts to go anyway....

There's benefits to electropolishing in some applications. I'm just looking
for some help in this particular application. Kind of like thinking out
loud and seeing if someone helps you.

Electropolishing uses rectified current (DC) and a blend of chemicals in an
electrolyte bath to remove flaws from the surface of a metal part. It's
normally used after mechanical polishing has reached it's limit of the
finest abrasives available (500 grit +) to yield the highest quality polish
available. Since it uses chemicals and not mechanical abrasives, it's
equivalent to sanding/polishing on a molecular level. There is no higher
degree of polish available than electropolishing. It leaves a
microscopically smooth surface that is highly reflective and has a bright
surface. It improves seals, lowers friction, and improves heat and light
reflection. It's the ultimate "mirror finish".

This is all in the direction of goodness when it comes to less defects in
metal surfaces, lower friction, higher RPM, and more horsepower. I just
don't know how much is gained when the dimensions of the surface
imperfections get much, much smaller than the specified clearances between
metal-to-metal wear points and it's bathed in an oil film anyway. You may
reach the point of diminished returns and it's not worth the effort. Mark
has indicated this is the case.

Signature

John
ThunderSnake #59
If you Reply, be sure and remove the " (DELETE_THIS) " from the email
address.

Reply to this Message

John - 16 Oct 2004 07:10 GMT

I forgot to add. Since electropolishing works by setting the metal part in
a bath, it's great for areas that are difficult or impossible to reach with
tools and fingers, like intakes and exhausts!

Signature

John
ThunderSnake #59
If you Reply, be sure and remove the " (DELETE_THIS) " from the email
address.

Reply to this Message

Backyard Mechanic - 16 Oct 2004 18:10 GMT

> I forgot to add. Since electropolishing works by setting the metal part in
> a bath, it's great for areas that are difficult or impossible to reach with
> tools and fingers, like intakes and exhausts!

So... you're saying you would use polish intake runners?

How about head intake passages? Hmmmm?

Reply to this Message

CobraJet - 16 Oct 2004 18:15 GMT

> > I forgot to add. Since electropolishing works by setting the metal part in
> > a bath, it's great for areas that are difficult or impossible to reach with
[quoted text clipped - 3 lines]
>
> How about head intake passages? Hmmmm?

hehehe

Signature

CobraJet
Thunder Snake #1

Reply to this Message

John - 16 Oct 2004 21:30 GMT

Your first sentence isn't totally clear to me, and since the second sentence
keys off the first, it isn't either. Hmmmm?

If you are asking, would I use electropolishing to polish intake runners and
head intake passages. The answer is yes and no. I would use it to debur,
but not polish. Like I said, it's great for those hard to reach places.

"Electropolishing" is a somewhat misleading name for the technology. A more
descriptive name is "reverse plating". It actually removes metal, therefore
the name "reverse plating". Imagine a metal surface. On a microscopic
level it looks like peaks and valleys. If it's right out of the foundry,
it'll be rough and the distance between it's peaks and valleys will be
large. If it's just been mechanically polished to 2500 grit finish, it'll
be smooth and the distance between it's peaks and valleys will be small. No
matter the size of the peaks and valleys, electropolishing basically knocks
the peaks off. It kind of mows off the top of the peaks first, then mows
off a layer from the flat part that was just under the peak, and on and on
and on. The longer you leave it in the bath, the more metal it removes.

So, if you start with a rough intake manifold and you leave it in the
electropolishing bath a short while, it deburs it to a semi-rough surface
that is good for creating turbulence, helping to further atomize fuel, and,
hopefully, having a more homogeneous fuel/air mixture when it hits the
cylinder.

And for exhaust ports, you'd mechanically polish those to about a 220 - 500
grit finish. Then throw it in the electropolishing bath for a long while.
It'll come out with a mirror finish! Smooth as an oiled baby's butt to
channel the exhaust out with the minimum of turbulence and backpressure.

Did this clarify the technology for you?

Signature

John
ThunderSnake #59
If you Reply, be sure and remove the " (DELETE_THIS) " from the email
address.

Reply to this Message

John - 16 Oct 2004 22:23 GMT

> > > I forgot to add. Since electropolishing works by setting the metal part
> in
[quoted text clipped - 37 lines]
>
> Did this clarify the technology for you?

I forgot to add. Deburring an intake with those long tortueous paths (you
know, the ones for low end torque) would be ideal for "reverse plating". Of
course the ones with the straight, short paths right to the intake port (you
know, the ones for high end horsepower) could be deburred this way too.

Have I answered your questions?

Signature

John
ThunderSnake #59
If you Reply, be sure and remove the " (DELETE_THIS) " from the email
address.

Reply to this Message

Mark - 17 Oct 2004 07:36 GMT

Ok John, Tell us the name of your business that does this, or are you just
an investor?

>> > > I forgot to add. Since electropolishing works by setting the metal
> part
[quoted text clipped - 60 lines]
>
> Have I answered your questions?

Reply to this Message

John - 17 Oct 2004 15:29 GMT

> Ok John, Tell us the name of your business that does this, or are you just
> an investor?

Neither, I've used it before in my job, and I was thinking it may have some
benefit in my chosen hobby. So, I started a dialog on it to see what
happens. That's all, I swear.

I've used it for sanitation reasons, mainly to minimize adherance of stuff
to metal. The surface defects get too small for things to grab on to, like
pathogens, bacteria, viruses, glue-like substances (pressure sensitive
adhesives, sealants, coatings), etc. They clean off much, much easier too.

However if anyone sees a way to get rich using it on our chosen hobby,
please e-mail me.

Signature

John
ThunderSnake #59
If you Reply, be sure and remove the " (DELETE_THIS) " from the email
address.

Reply to this Message