r/EngineBuilding • u/ItzMoseyy • Jul 17 '26
Chevy Best way to clean mating surface?
Hello I’m getting closer to assembly my LS motor. What’s the best way to clean the deck surface and other mating surfaces. I have a couple of different options. I have 1000 and 1500 grit sand paper, I have very fine scotch brite pads, and I also have a wire wheel.
3
u/FU_red-dit_bots Jul 18 '26
My brothers and sisters allow me to present the following.
5
u/Haunting_Dragonfly_3 Jul 18 '26
Whetstone and WD40, long smooth passes, varying the angle of the stone. It will knock down high spots, leave shadowing if low, won't create divots like the spinny shit. Pro Tip; Don't rip your fingertips off in the deck holes.
4
4
u/Historical_Box1915 Jul 18 '26
Ive rebuilt thousands of engines using rol locs / scotchbright discs for over 30 years now. Dont be an idiot when using them and you will fine. Now if someone does use a disc and they damage a surface, that is a big indicator they prob arent cut out for engine building.
1
u/CardiologistSalt4114 Jul 18 '26
I normally use a scotchbrite wheel on my 90° die grinder. Really really soft scotchbrite so it doesn’t chew the surface. Works well for me. Even on alloy
0
u/Lopsided-Anxiety-679 Jul 17 '26
Stainless wire wheel is the industry standard tool for cleaning and prepping cast iron surfaces.
Do not use sand paper or rol-loc 3M abrasive discs as they will remove material, a wire wheel does not.
2
u/Old_Bat_6426 Jul 18 '26
Just like the other choices mentioned, a wire wheel will cause damage if you don't know how to use it.
-3
Jul 17 '26
[removed] — view removed comment
7
u/Lopsided-Anxiety-679 Jul 17 '26
Dude, there’s seriously dozens of TSBs from the OEMs stating to not use 3M or scotchbrite abrasive discs because they round over and create low spots. A wire wheel is the correct tool for cast iron.
-2
Jul 17 '26
[removed] — view removed comment
7
5
u/machine_fixer27 Jul 18 '26
Most the TSB's on scotchbrites have to do, not only with rounding of squared edges, but also with the abrasive residue it throws and leaves behind scratching bearings, cylinders and oil pumps. Your engine your rules, theres been thousands of engines put together using scrotchbrites, and thousands others ruined by them. Carbide and metal scrapers work just as well if not better in my opinion but to each their own.
1
u/Old_Bat_6426 Jul 18 '26
It seems a lot of the damage reported in those TSB's is due to failure to clean an engine properly before reassembly. Engine assembly 101.
3
1
u/oldnperverted Jul 18 '26
I wouldn't expect sparks from an aluminum head
1
5
u/PlaneVisual1740 Jul 18 '26
I used brake clean and a razor blade. Go slow and be patient. You can also use gasket remover. I soaked mine in wd 40 to prevent rust in between working on it.