Polishing side beams

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1980RS
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Re: Polishing side beams

Post by 1980RS »

BCjohnny wrote: Sat Nov 27, 2021 7:12 am
rocketracer380 wrote: ....... and do they need to be shit peened afterwards
Yes, but it can get a bit messy

'Shot' works much better .........
I was going to say something but you treed me on it. :lol:
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Dave Koehler
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Re: Polishing side beams

Post by Dave Koehler »

Back before China rods this process was a standard shop service.
It was either this or Carillo and those were only considered by the well heeled.

It was spoken to by BC but the biggest mistake I saw others do was try to cut the beams perpendicular to the rod face.
This removes far too much material. If you look at the forging line you will often see that one side is dominant.
It sits higher or however you may describe it.
Sand the parting line to blend the dominant side toward the other.
You end up with a somewhat curved look.
Saves a lot of time this way also.

With enough practice the time comes down and it almost becomes an art.
I had a few that requested a high polish like you do before sending something out to chrome.
Seemed silly even at the time but as long as they paid for the extra labor it got done.

It also doesn't hurt if you have multiple rods to choose from to pick those that the forging line and dominate side are similar. After weight check of course.

As mentioned it makes little to no sense to do this these days when a presumably better material and machined repeatability is available.
That is unless it's sitting in a container on the pacific coast and the race is next week. :D
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Re: Polishing side beams

Post by PackardV8 »

It also doesn't hurt if you have multiple rods to choose from to pick those that the forging line and dominate side are similar. After weight check of course.
For true, Dave. Also needs to be emphasized old forged OEM rods are all over the place on center-to-center length. Correcting this to make them identical is a time consuming bitch and requires a barrel full of used rods. If they've been previously reconned, throw them away, as .010" difference in length is not uncommon.

Guys recently into engine building may not appreciate how magical it is to open a box of pistons and they're guaranteed to be within 2 grams on weight and .0002" diameter. The box of new aftermarket rods are dead nuts center-to-center and on weight and the big ends are round!

Having said that, we still weigh and measure everything, as shite happens. It's still magical when it's all as it's supposed to be without all those hours of grunt work.
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Dave Koehler
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Re: Polishing side beams

Post by Dave Koehler »

Yeah, Haven't had to bitch about aftermarket pistons including OEM replacements for quite a while.
On the other hand I got a set of Sealed Powers the other day that made me groan. :?

CNC bar stuff, alum. or steel is usually a dream to deal with.
The aftermarket "budget" rods can be a crapshoot.
Sometimes they are close and other times it appeared to be packaged by 2 different people on 2 different days.
While overall weight might be acceptable one end or the other will be too far off.
Trust but verify on all of it.
What hasn't improved is God help you if you need to get a replacement anywhere close to the original in respective weights.
I politely growled at Eagle in their early days and convinced them to get their own scales in house.
Originally they just took the word of the Chinese and sent them out. Took about a year but they began to settle in.

Big ends and crank dimensions are another story when I am allowed to check.
Most of the time I have to hold my tongue and hope the builder has some brains.

Rod CtoC .010 variation might be a good day. When it is performance time the best way is to bush the small end to correct it.
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Re: Polishing side beams

Post by BCjohnny »

If it's any help, I suppose if I was a 'hobbyist', with no resizing equipment but a simple balancing fixture, wanting to rework some OE rods it would go something like this ........


If it's a V8 you'd want to start with a dozen or more 'identical' rods

Split 'em all down, keep as pairs, weigh and visually assess ...... leave the bolts in

Optionally measure from BE to SE arc to arc ..... it's one of the few times a vernier caliper has value ....... and make a note of each beams relative 'length'

Taking everything into account pick the best nine or ten

Do your tittivating, rough balancing as you go, but leave them slightly chubby not anorexic, take the bolts out, wire the pairs together and get them peened

Take them to your machinist with the new bolts of you're choice unfitted, impress on him what you're trying to achieve and (if you did this) with the r/l of each rod written on each beam ask him when he shaves the faces to resize, to correct variations as best he can ..... the latter will likely be ignored and anyway there's a limit to what can be done

If they can check for straightness too all the better

After you pick them up ..... there'll probably be a disclaimer on the invoice ...... final balance, re-measure the r/l and if the pistons have any pin height variation 'match' them to the rods as best you can


Lot of work, your time would probably be better spent doing a few hours overtime in your day job and buying aftermarket, unless you have no choice or want the experience
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Re: Polishing side beams

Post by jed »

Just to round out things to do to increase longevity of rods is to cryogenic treatment and or metal-lax the rod, cap and bolts.
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Re: Polishing side beams

Post by Schurkey »

Where would a person go to get rods shot-peened?

I'm not in the market...but if I was, I'd have no idea where to send 'em. I bet there's no one within three hundred miles of me that does shot-peening; and I only say that because the Big City might have someone and they're 325 from here.

I see folks claiming their parts were shot-peened; and when I drill down enough to find out that it was their local machinist who did "the block, the heads...everything got shot peened", I have to explain that shot-blasting parts to clean them is not shot-peening parts to make them stronger.
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Re: Polishing side beams

Post by Dave Koehler »

Bill Jones is a ST source for actual shot peening if he still does it.
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MadBill
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Re: Polishing side beams

Post by MadBill »

Metal Improvement has many facilities around the US and Canada; you could Google the nearest one.
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