Camshaft Bush Machining: Line-bore or just reem?

On my 1967 Atlas, the camshaft is knackered. The bearing surfaces are scored and ridged, and the lobs are a tad too shiny at the tips. My (late) father suspected foul play. The alternative is that he did something stupid and inadvertently nuked it.

Que sera-sera. Anyway... while rummaging through the boxes of bits, I found a brand new PW3 non tacho camshaft and some new bronze bushes from RGM. He said that it'd need line boring to get the centres perfect. However, that didn't stop him from boring out several attempts in the lathe and trying to reem or hone them himself. I counted about 8 failed attempts that I found in the boxes of stuff.

I was speaking to a local retired engineer. He was under the impression that i was overthinking the whole concentricity thing. He said that boring and honing should be enough. He thought that the bushing holes would've been fairly concentric from the factory. He proposed mounting the case halves sideways in his milling machine and boring down.

Is this good enough? Or do I wanna send it off to a proper engine shop and have them line hone it?

I've searched the forum and can't find any threads about this specific issue. I might be using the wrong key words. I appreciate any input on this. Even if it's telling me I've completely got the wrong end of the stick.

Ze old




And ze new

They do not need to be line bored but they do need the final cut to be with the cases assembled. This can be a reamer with extension so the bushes are cut aligned, also referred to as a piloted reamer.

kommando said:

They do not need to be line bored but they do need the final cut to be with the cases assembled. This can be a reamer with extension so the bushes are cut aligned.

Click to expand...

Ohh okay. I did over think it then. This is a lot smaller in my head now. Once I get that sorted, I can go full send with assembling the bottom end of the engine

Thanks

I am unfamiliar with the PW3 camshaft. Is it supposed to be a reweld?