"Cleaning Up" C5 Suspension Components

[Mkelcy]

I'm installing a 21st Century subframe on a 1968 Camaro which subframe uses C5 Corvette forged upper and cast lower control arms and the forged steering knuckle/upright.

I was planning on grinding off the forging/casting flash and having the arms anodized. One plater I spoke to suggested that the flash (which is about 0.125" wide and as much as 0.125" thick) was "structural" and that grinding it off would weaken the parts.

It just didn't "compute" for me that an OEM engineer would rely on flash for required structural integrity of a part, but I don't want to create an unsafe suspension simply for slightly better appearance. Any thoughts/experience?

[ProStreet R/T]

I don't see the casting flash as being structural, but the surface finish very well could be. Just don't polish the arms and everything should be fine.

[79T/Aman]

that is not casting flash but the forging parting line and IMHO it should be left alone or just sanded smooth.

[ProdigyCustoms]

Everyone polishes them, it is just fine

[todd8541]

Its nothing. It's created by the forging process. They dont completely remove it in the factory because it is too costly to do so.

Also it is actually better to have a smooth surface than a scratched or gouged surface. The scratches and gouges create stress risers and creates cracks easier. The thing is dont remove too much metal when polishing. Don't remove a .25" or so haha.

Todd

[Mkelcy]

Thanks for the responses. I thought it would be okay to clean them up, but wanted to check with those who would know.

[protour_chevelle]

Just like engine cranks.... Its easy to tell from a cast and a forged crank before the forging/casting line is removed. Afterwards it takes a bit more to tell the difference.

-Matt

[zbugger]

I've seen it done many times on hotrods. It shouldn't be any issue really.

[Mean 69]

Its nothing. It's created by the forging process. They dont completely remove it in the factory because it is too costly to do so.

Also it is actually better to have a smooth surface than a scratched or gouged surface. The scratches and gouges create stress risers and creates cracks easier. The thing is dont remove too much metal when polishing.

Yep. Parts crack at, always, stress risers. Smoothin' is a good thing, but as stated, don't go too far. Heard of polishing connecting rods? Same deal.

Structural. Give me a break. Humbug, the dude that told you that is a moron.

M

[ProdigyCustoms]

Yep. Heard of polishing connecting rods? Same deal.


Xactly!

[silver69camaro]

I agree, polishing can be a good thing to minimize stress risers.

The forging line cannot be a key player in structural regidity because the parting line is "uncontrolled", meaning the physical aspects of one parting line will not be the same for all parts made. And without 100% QC testing (which GM doesn't do), it would be a very unfavorable process to add strength.