engine block surface prep for oem mls......600 grit?
 

OK so I have a rebuilt head going on my old block with 125,000 on the clock. It had a mls on it but the block was pretty nasty and the machinist that did the head said it had been off before and someone resurfaced it. So I don't know what they used or prep but it looked like black build up like silicone. I scraped it with a razor blade and it still had some pretty nasty shit and a little bit of pitting. So I grabbed a machinist edge with some 200 sand paper to get off the nasty and then some 600 to shine it up. Is this sufficient and should I go ahead and copper spray it and install the head? Here's a couple pictures.
https://cimg3.ibsrv.net/gimg/www.mia...c65bcde534.jpg

https://cimg5.ibsrv.net/gimg/www.mia...d46def9e63.jpg

https://cimg9.ibsrv.net/gimg/www.mia...6e1d67c887.jpg

https://cimg5.ibsrv.net/gimg/www.mia...d177c04ea1.jpg
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I would surface that block and remove all the pitting, and make it flat. I like head gaskets that don't leak.

I put a machinist edge on it and it sits flat at all points across the face, and I can not fit a feeler gauge under the edge anywhere. But pitting is pitting. I was thinking about copper coat on the gasket and going for it, but I wanted some feed back and opinions on the idea. I opted not to install the arp studs see what the consensus is first.

If it doesnt grab your fingernail it is probably fine. If it does, resurface. MLS gaskets need a perfectly flat layer to seal against. If it is the least little bit warped resurface. Flat and smooth is key with mls.

The copper will probably work, and you may be fine from the photos i see.

If it were my car, i would resurface, and i am a dipshit that usually wouldn't. Just because of your third photo. That is the only one that makes me cringe.

Edit: I don't like to fuck around with mls gaskets. They can be testy. Best to give them what they want, a smooth flat surface.

That said, if you plan on rebuilding at some point, and you dont mind doing the work again, run it. If i were 20 and non turbo i would.

Surface it now or surface it after you've thrown a head gasket and 6-8hrs of your time at it, your choice.

that pitting doesn't look good at all

I'm not a machinist by any stretch, but I've always been told that MLS gaskets are not tolerant of badly surfaced heads. Even without the pitting, belt sander finishing is supposed to be no good.

--Ian

More work and money..... well I don't like the answer I got so I'm going over to CR to ask those guys!

Well I guess I'll give Nathan Gerolamy a call tomorrow and get a quote.

Surface the deck, no other option.

what is all that goop in the cylinders for?

I would guess it's there to catch the crap that came off when he sanded the deck surface and prevent it from getting into the oil pan.

--Ian

​​​​​​​^^^ this. I had to figure out a way to use up that bearing Grease, it actually advertises 350-degree drop point like it's a good thing:facepalm:

this^^^^^^^^^^^^^^^^^ sums it up, point blank.

Like everyone else in this thread said you should really have it decked, it will be well worth in in the long run.
It cost me $75 to get my cylinder head pressure washed and resurfaced, I don't think a block decking would cost much more than that.