Surface preparation of 1FZFE deck surface prior to Head Gasket replacement. How smooth (RA Finish) does it need to be?? (1 Viewer)

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Starting this thread in an attempt to get in one place expert opinions on how to prepare the deck surface of a block (other than sending it off to a machine shop) when replacing the head gasket. For the purposes of this discussion we will assume that the deck is within the Toyota spec for FLATNESS ie: not warped, because if the deck is warped than the only answer pretty much is to send it off to a machine shop or replace the block

Below is a link to video made by an experienced machinist showing how to hand lap a block deck. It may seem a bit slow in spots but listen to what the person is saying and try to stick with it until the end.

Some people may say the amount of detail/work in the video linked below is not required. But the point of showing the video is to use that information as a starting point; ie: do we go that far, and if not, how far do we have to go, and how best to go about it??

Here it is:





So basically looking for people to share their expert opinions based on their experience/training to answer these basic questions as it relates to preparation of the 1FZFE block deck prior to installation of a new HG:

1) How smooth (surface finish RA) does the deck need to be for a Composite (OEM) head gasket versus a MLS (multi-layer steel) gasket?

2) How does the average person (without a $2000 contact surface roughness profilometer) determine the finish of the deck?

3) If the deck is not smooth (commonly seen corrosion pitting for example) what tools/techniques can be used to get it where we want it without causing more damage?

4) And what techiniques/tools should not be used (steel or brass wire wheel, fine versus course wire, Roloc pads, 3M Scotch Bright pads Red versus Green #96---)?
 
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Here's another video discussing how to clean up the block deck:



And another:




Take home consensus from all the above:

Probably not a good idea to use a rotary tool (wire wheel, sanding disc, Roloc pad, flexible rotary abrasive fingers, or any pad that will leave abrasive dust behind (unless precautions are taken to catch/clean up the dust??)

The Super Scraper carbide tool appears to be one tool that can be used (carefully) to remove old gasket material and surface rust (ie: anything higher than the deck surface)
 
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Following your thread with some interest.... When I did the HG the first time on our '97 @ 119k, I used a straightedge and feeler gauge to check block flatness. All measure to spec after I had done the scraping and some cleanup with the scothbrite pads our machine shop used for metal cleanup. Block flatness was better than what manual said it needed to be. But, I could still see the 'stains' or light imprint of the old gasket contact areas in many areas. I couldnt feel it with my finger nail but I could see it. I did not own a surface finish gauge back then so have no idea what the RA was. The concensus back then was it was good enough - I did not pull the block and have it decked. I purchased new Toyota head bolts and the lasted HG from CDan - the latest and best at that time. With a complete rebuild at a machine shop of the head, I put the engine back together.
@ 183k, I lost the HG again! By then, everyone was now using ARB stud kits, mls gaskets, etc. Looking back, the surface finish was likely the issue that lead to the 2nd HG failure. A stud kit might have helped but that block surface was likely course enough to be a problem.
Starting up the project again with the plan to get the block prepped this time - full engine rebuild. So, interested in what others have to say.
 

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