twopointwo
twopointwo New Reader
4/28/14 2:32 p.m.

I'm in the process of rebuilding the head on my F2T, and I've encountered some things I've never seen before.

The cam is steel, and rides on aluminum bearing surfaces which are the native aluminum head and cap material, no replaceable bearing surface.

The head side of the bearing looks great, no concerns there. The cap side, however, I have some questions about.

The bearing surfaces seem dull in some spots. Not rough, or in any way marked, just not as shiny. I've seen people polish these with aluminum polish, but wouldn't the polish heat up and become something I didn't want on a bearing surface in operation? Is there any other way to polish them? Or am I making a big deal over something inconsequential?

Also, one of the oil holes has a slight amount of roughness on one end of it. How would I best go about removing that roughness? 2000 grit paper very gently?

This is my first full head rebuild, so maybe some of these answers are rather obvious.

James

djsilver
djsilver New Reader
5/1/14 10:46 p.m.

That's a very common setup for DOHC aluminum heads. On inverted bucket lifter setups, the bottom stays shiny because the valve springs are always pushing the cam upward against the cam caps. As long as the surface isn't gouged you'll be okay. Roughness around the oil holes can be lightly blended but don't get carried away. Just follow the FSM and don't over-torque the caps!

series8217
series8217 Reader
5/28/14 2:35 a.m.

Polish is fine. Just make sure you remove it all when you're done polishing. Use a solvent cleaner.

You can use 1200 grit or 2000 grit to smooth out the oil hole. If it were steel I might say peen it, but there's a real risk of bulging up the edges if you do that.

Really though, it's not a big deal. On my DOHC V6 Chevy the cam bearing surfaces had some pretty significant machining marks in them, but no wear on the cams, and nothing out of the ordinary at all really. The factory just didn't bother polishing them down much after boring them out.

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