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Painted Connecting Rods?

General engine tech -- Drag Racing to Circle Track

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Krooser
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Painted Connecting Rods?

Post by Krooser » Wed Jun 24, 2020 10:48 am

[*]My old racing buddy Louie always painted the connecting rods in his race engines to encourage shedding the oil off the rods.

Just wondering if any of you guys have heard of this.... 50 year old tech!
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hoffman900
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Re: Painted Connecting Rods?

Post by hoffman900 » Wed Jun 24, 2020 10:50 am

Krooser wrote:
Wed Jun 24, 2020 10:48 am
[*]My old racing buddy Louie always painted the connecting rods in his race engines to encourage shedding the oil off the rods.

Just wondering if any of you guys have heard of this.... 50 year old tech!
I don't think it was based on anything than your buddy Louie having a hunch, which his line of thinking is / has been unfounded.
-Bob

Krooser
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Re: Painted Connecting Rods?

Post by Krooser » Wed Jun 24, 2020 11:19 am

What got me thinking about this is a discussion about H beam rods holding more oil on them than I beams.

Been many years since Louie bit the dust but he was a thinker and had a little twist to everything he did.
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Re: Painted Connecting Rods?

Post by PackardV8 » Wed Jun 24, 2020 11:29 am

About sixty years ago, the Hot Rod Magazine Annual had a furrin' engine section. One featured was an Austin Healey 2.6; a photo showed the crankshaft and connecting rods polished to a mirror shine.
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Re: Painted Connecting Rods?

Post by hoffman900 » Wed Jun 24, 2020 11:31 am

A lot of this was just done via intuition. A lot of thinking / imagining about what is happening because nobody really knew what was happening. We know better now. It doesn't mean these guys were dumb, but they really just didn't know any better and were just trying things they thought made sense (good or bad).
-Bob

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Re: Painted Connecting Rods?

Post by autogear » Wed Jun 24, 2020 11:39 am

Back in the days before corn squeezins were added to gasoline; guys used to paint a lot of stuff with Glyptal here. New Process used it as a sealant of sorts for some of their castings, so there was a LOT of it in Syracuse between NPG and GE and a lot of guys that came through those places as machinists etc kind of grabbed onto using it. Im not sure I'd trust it with ethanol laced fuel; if it came loose, who knows.

gunt
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Re: Painted Connecting Rods?

Post by gunt » Wed Jun 24, 2020 6:38 pm

Mirror polish replaced his idea , i'd say , and there's the added benefit of removing stress risers

swampbuggy
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Re: Painted Connecting Rods?

Post by swampbuggy » Wed Jun 24, 2020 10:23 pm

Yes Gunt, smoothing surfaces and polishing has proven to lessen the possibility of cracking and failure of stressed engine parts. Mark H.

AC sports
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Re: Painted Connecting Rods?

Post by AC sports » Wed Jun 24, 2020 11:54 pm

Mirror polish and no shot peen?
I always thought the surface needed to be shot peened after polishing out potential stress raisers.

Kevin Johnson
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Re: Painted Connecting Rods?

Post by Kevin Johnson » Thu Jun 25, 2020 12:11 am

Krooser wrote:
Wed Jun 24, 2020 10:48 am
[*]My old racing buddy Louie always painted the connecting rods in his race engines to encourage shedding the oil off the rods.

Just wondering if any of you guys have heard of this.... 50 year old tech!
Circle Track had a tech article about 14 years ago that found a measurable increase in output when an oil shedding coating was applied to the external surfaces of a crankshaft. See Figure 2.

https://www.hotrod.com/articles/ctrp-06 ... echnology/

There is an adjective that describes your buddy Louie: perspicacious.

https://www.dictionary.com/browse/perspicacious

~~~~~~~~~~~~~~~~~~~~

The rivulet shedding and oil droplet impact phenomena as well as aerodynamics of a high speed connecting rod would be difficult to model exactly even today.

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Re: Painted Connecting Rods?

Post by bob460 » Thu Jun 25, 2020 12:14 am

I would use isotropic treatment, it's non-directional finish which improves the surface finish and edges of machined components being used on crankshafts, rods and cams etc.............local builder swears the parts last longer because of this process.

swampbuggy
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Re: Painted Connecting Rods?

Post by swampbuggy » Thu Jun 25, 2020 5:45 pm

Here is a question i have.....Is it OK to polish a steel piece such as the sides of a shot peened steel H-Beam Con-Rod :?: Mark H

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Re: Painted Connecting Rods?

Post by Kevin Johnson » Thu Jun 25, 2020 8:01 pm

swampbuggy wrote:
Thu Jun 25, 2020 5:45 pm
Here is a question i have.....Is it OK to polish a steel piece such as the sides of a shot peened steel H-Beam Con-Rod :?: Mark H
Polish is a subjective term. Do you mean grinding away the dimpled (compressed) surface?

swampbuggy
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Re: Painted Connecting Rods?

Post by swampbuggy » Thu Jun 25, 2020 9:56 pm

Kevin, i was thinking hand sanding w/ 320-400-600. If you look at a Carrillo, Oliver, Crower, or Pankl that has been shot peened the surface is really not very rough. It is most likely a waste of time anyway ?? Mark H.

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Re: Painted Connecting Rods?

Post by Kevin Johnson » Fri Jun 26, 2020 12:07 am

:-k
https://www.sciencedirect.com/science/article/abs/pii/S014381660000083X wrote:Abstract
Laser shot peening has been developed as a surface treatment to metals. It has been shown to induce surface residual stresses comparable to those achieved by conventional shot peening, but to much greater depths. The laser technology employed is described and some test results are presented.
For a budding post graduate mechanical engineer; a lifetime of study:
https://scholar.google.com/scholar?star ... s_sdt=0,10

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