Lapping the Swiftech

[Tullphan]

I recently purchased a "pre-owned" Swiftech MC370 that i'm putting on my 1.4 T-Bird.
I can see on the bottom of the heatsink what appears to be a small rectangle...possibly where either the old core lined up or maybe where the thermal compound was?
My question is how should I lap this bad boy? Or should it even be lapped? It ain't exactly got a mirror finish...the above mentioned rectangular object & minor scratches.
If I do need to lap it, what's the proper or tried & true procedure?
Any help will be appreciated.

 

[SWScorch]

it doesnt need to be lapped; only do it if you will accept nothing less than the absolute best. Lapping takes a long time, and results in minimal performance gains. However, if you really want to, heres how you go about doing it:

Take a flat object, like a plate of glass, and put a small puddle of water on it. Lay some 400 grit sandpaper or so on it; the water will make it stick better. Sand the bottom of the heatsink using figure-8s. After a while, when you think its done all it can, switch to a higher grit sandpaper and repeat. Continue doing this until you use very high grit, say 2000 or so. When you finish it should either be a mirror finish or a smooth milky finish.

 

[bacillus]

heatsink lapping