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Painted Connecting Rods?

General engine tech -- Drag Racing to Circle Track

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BOOT
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Re: Painted Connecting Rods?

Post by BOOT » Fri Jun 26, 2020 2:09 pm

REM polish
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Re: Painted Connecting Rods?

Post by Krooser » Fri Jun 26, 2020 10:35 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
Polished rods were a common deal in the 60’s.

I did a 330 Olds several years ago and polished the 403 rods.... might even do it to my new SBM...
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Dan Timberlake
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Re: Painted Connecting Rods?

Post by Dan Timberlake » Sat Jun 27, 2020 10:37 am

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
===========.

If the part is properly shot peened then polishing is OK ONLY if less than 10% of the compressed layer is removed.
This 10% limit on material removal after peening is similar to what used to be stated in older revs of MIL spec 13165. (rev C cancelled).
I think it was 10% of "intensity".
"Properly" shot peened is defined in MIL STD 13165 Table VI ( intensity) .
If the goal of polishing is to improved fatigue resistance , why bother ?
polish after peening .jpg
peening vs polished .jpg
forked conn rods .jpg
crankshaft peen .jpg
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Re: Painted Connecting Rods?

Post by Dan Timberlake » Sat Jun 27, 2020 10:44 am

swampbuggy wrote:
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.
The dimples will be shallower on rods made of harder steel.
My recollection is many garden variety stock rods peened to the proper Almen intensity .008 - .012 A looked more deeply dimpled than say, Carillo rods.
All "looked" shot peened, as strictly opposed to the satiny finish of fine glass beaded.

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Re: Painted Connecting Rods?

Post by Steve Haaf » Sat Jun 27, 2020 11:28 am

I`ve always beamed and polished stock rods and then shot peened after, to put a hardened surface back on where I polished.

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Re: Painted Connecting Rods?

Post by MadBill » Sat Jun 27, 2020 10:36 pm

Yes, if polishing is in the plan it should always be done before shot-peening.
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