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Discussion Starter #1 (Edited)
I have spent some time to prepare the engine block for HG installation, I have used a razor blade to remove the residuals, then scotch-brite with WD-40 Non-aerosol to scrub remainings, the entire surface is pretty smooth, I don't feel any nicks if I run razor blade, also it passed the feeler gauge test for any directions.

However, there are still black spots here and there, they look just like discoloration to me. Shall I go ahead use some sort of sandpaper (say, 400 or 600) to remove those as well? Or can I live with them?

The picture below shows a typical area, the valleys are magnified somewhat, though. Even the marks surrounding the water hole are just marks, of no thickness. I tested a small area with brass wire brush and acetone, they just can't be removed.



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283202
 

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You need to either Blanchard grind it or take to vertical lathe or somehow else make sure it is perfectly plane. As in - has no bumps and valleys.
Just looking at it, you can't tell.
That's when shops place it into holding fixture, level it and do what needs to be done.
I know only one DIY way of doing this - finding LARGE grinding wheel and running it in circular motion (like Blanchard grinder does) on head mating surface. Ensuring that grinding wheel moves perfectly flat and smooth on head.
Metal warps from heat, you know. And you want to have perfectly smooth surfaces to mate. Same, actually, goes for the block.
Of course, you cna just slap gasket onto it with bunch of high temp goop and call it a day...but that's why it costs what it costs at machine shop. To resurface the head.
 

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Here's a suggestion.
Find piece of glass several feet long. They tend to be perfectly straight edge.
Set it on head surface crosswise, lengthwise and anglewise.
If you see any light coming through between glass and head surface, that's where it's warped.
You could use straight edge but shit nowadays is made in China and tends to be not that much straight itself.
 

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Discussion Starter #4
You need to either Blanchard grind it or take to vertical lathe or somehow else make sure it is perfectly plane. As in - has no bumps and valleys.
Just looking at it, you can't tell.
That's when shops place it into holding fixture, level it and do what needs to be done.
I know only one DIY way of doing this - finding LARGE grinding wheel and running it in circular motion (like Blanchard grinder does) on head mating surface. Ensuring that grinding wheel moves perfectly flat and smooth on head.
Metal warps from heat, you know. And you want to have perfectly smooth surfaces to mate. Same, actually, goes for the block.
Of course, you cna just slap gasket onto it with bunch of high temp goop and call it a day...but that's why it costs what it costs at machine shop. To resurface the head.
Thanks! The cylinder head was sent to a professional shop for re-surfacing, but the engine block is still on the car;-) I did run a straight edge test with a feeler gauge, the flatness is fine, what I am concerned is cleanness... I guess I'll keep fighting for a cleaner surface anyway...
 

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LONG solid metal bar, as straight as you can find, wrapped into semi rough sand paper, so that you can run it flat on the head.
Circular motion again. You can use profile metal, if you want to. It's lots of elbow grease, but gives good results. Large flat sanding arbor, installed onto cordless drill will also do and much faster, as far as you manage to keep it flat on the surface. Arbor like for DeWalt grinder, 10 inch diameter I believe.
Sorry, I missed you are asking about block, not head. My bad.
You are going to hone cylinders, right?
 

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Discussion Starter #6
You are going to hone cylinders, right?
That's a question! Without taking out the block, is it even possible to hone the cylinders?
I do not plan to take off the block, too much work for a car with 418 miles! Besides the car run really smooth before the overheating, blown head gasket issue, so I am betting that the engine would last another 60K or so without honing cylinders, I can be awfully wrong!
 

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Of course you can. Any parts store will loan you honing attachment for a drill. You likely think of lathing cylinders and then honing. No, just hone. Like Mr Miyagi said - slowly up, slowly down...
Done it. You just want to give it refresh.
Also, when you went to all those lengths and still don't have head on.
Drop oil pan and pull pistons out. replace crank bearings and rings, clean oil passages in pistons.
Wrrroooommmm....
 

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When you replace piston rings with new ones, no need for repair sizes, just stock size, they will come with new leading edges. That is just enough to seal cylinders as they will be slightly larger diameter than old rubbed off rings.
But clean ring groves real well.
 

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Discussion Starter #10
Of course you can. Any parts store will loan you honing attachment for a drill. You likely think of lathing cylinders and then honing. No, just hone. Like Mr Miyagi said - slowly up, slowly down...
Done it. You just want to give it refresh.
Also, when you went to all those lengths and still don't have head on.
Drop oil pan and pull pistons out. replace crank bearings and rings, clean oil passages in pistons.
Wrrroooommmm....
Never knew that deglazer can work with the pistons on! I'll give it a shot! Thanks for the tips...
Getting the pistons re-ringed is tempting, but I'm not sure if I want to go that far...
 

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Firstly stop using WD-40, for anything the stuff has no useful purpose except maybe removing glue residue. Get yourself a carbon gasket scraper and clean the surface as much as possible, the pits and the like won't be removed. Chase the threads with a thread chaser and make sure they are 100% clean and intact, thread in a new head bolt to into each to make sure the threads are good.

Clean the block surface several times with lacquer thinner and a maroon Scotch-Brite pad, then clean it again. Take two old head bolts and cut the head off of them then cut a slot with a hack saw so you they can be turned with a flat blade screwdriver. Thread these into two opposite outer locations these bolts will make mounting the head much easier. Follow the factory service manual instructions to the letter when bolting up the head.

On the block surface, generally a composite/graphite HG is forgiving enough where small pits won't be an issue it is probably more important for the block to be perfectly flat. There is some risk in not having the block resurfaced but I've done many using the above method never had a problem. If you do have the block resurfaced then it will have to be stripped that opens up a can of worms such as replacing bearings, rings, or even pistons. On cylinder honing it takes a highly accomplished machine shop to duplicate the factory clearance precision most are not up to the task you're better of leaving the cylinders alone and putting in new standard size OEM rings, or you can create a cross hatch pattern with a flex hone tool.
 

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Take the rings off the pistons slide them down the bores enough to go past where they DO NOT CONTACT the cylinder walls at the top of the bore. Measure the ring end gap and compare to original specs and MAXIMUM SPEC. Use the old rings to give you a base measurement.
Now try a new ring in the bore and measure exactly the same way as the first. Compare that measurement to the original ring. How much of a difference? That's your ring wear, comparing the original to the replacement.
Measure the new ring and the old at the very top of the cylinder above where the ring cam in contact with the bore, the distance from the top of the top ring and the top of the piston measured from bottom to top.
That's the part that never saw contact with the rings. Compare that with your other measurements. If it is of any significance in the different measurements from the top of piston ring travel and above that where the ring did not touch the cylinder wall, this is your cylinder wall taper and it gets serious quickly.
Piston to cylinder wall clearance is about 1.5 thousandths inch (.0001.5) Not sure about the metric number. I would not warranty the top of that engine in its present condition, way to risky as far as head gasket failure, then what?
You want a second try free? Nah> I'd have to pass as far as doing it for you. I might try it myself on my car. Last thing I did like that was an exhaust manifold on a 1981, where I slat, but slathered some high temp silicone, on the gasket to fill rust voids in the manifold and it was an easy job compared to this one.
Bottom line, I might try to not mess with the block, knowing it may end up spewing oil out the tailpipe and I have to replace it, or do what I should have done and rebuild it properly.
It's a different strategy when you take someones money and promise them a result, versus a simpler approach, WITH POTENTIAL CONSEQUENCES.

Considering this look at the overall picture of the sum total of everything the car needs and then decide how much time you might waste, if you allow the mating surfaces of the head gasket-head-block to be compromised. There is no right or wrong decision, just one with higher risks of failure.
 

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You need to decide whether you're doing a HG replacement or engine rebuild. My opinion - if the engine ran fine before with no out of ordinary oil usage, and you want it to keep doing the same, leave the pistons and rings alone. HG is the weak point on these engines, everything else is bulletproof as long as you keep feeding it good oil.
Once you start replacing the rings, deglazing bores, why not check the bearings? Before you know it, you'll be doing a full engine rebuild.
As for deck surface, the important surfaces are where the combustion chamber ring is right around the bore - this is the only area that seals the bores, not the whole head gasket. Similarly, there are lines around water jackets, head bolts, and the oil passages. The areas where you see pitting on your deck is where coolant comes in contact with the block and it basically doesn't matter as much. What's in your pictures looks perfectly serviceable for what you're going for.
 

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Once you start replacing the rings, deglazing bores, why not check the bearings? Before you know it, you'll be doing a full engine rebuild.
That's been me, I wanted to do the job the "right" way so I stripped the block took it to a machine shop. Long story short they didn't hone the cylinders accurately enough the engine developed piston slap it got to the point where you'd think I had a diesel. Dismantled the engine the pistons skirts were grinding away on the cylinder walls.

I've put in new OEM rings into old blocks didn't touch the cylinders rings broke in fine the engine ran perfectly no oil burning. Agree with you on leaving the bottom end alone unless there is a specific problem.
 

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I have spent some time to prepare the engine block for HG installation, I have used a razor blade to remove the residuals, then scotch-brite with WD-40 Non-aerosol to scrub remainings, the entire surface is pretty smooth, I don't feel any nicks if I run razor blade, also it passed the feeler gauge test for any directions.

However, there are still black spots here and there, they look just like discoloration to me. Shall I go ahead use some sort of sandpaper (say, 400 or 600) to remove those as well? Or can I live with them?

The picture below shows a typical area, the valleys are magnified somewhat, though. Even the marks surrounding the water hole are just marks, of no thickness. I tested a small area with brass wire brush and acetone, they just can't be removed.



. View attachment 283202
particularly where the HG gasket sits & seals, you should continue to remove any remaining material. (I would, if here) Follow up with a type "A" scotch bright scuffer pad, then do final wipe down & clean / prep, before HG install.

For example: the material on the inner cylinder wall seal surface, sitting in the middle of the pic - should be removed: the surface should look as smooth as the surface to the left / and right, of the high spot area.
Even though it may "feel smooth" - there is still material present: and it should be removed.

If left on the block: that material may not affect anything / or cause any issues.. or it may end up being a leak path / failure point: after the HG install. Impossible to tell you. A 50/50 chance, either way. Flip a coin.

Which is why folks highly recommend getting the block surface "as clean as humanly possible", before the HG install.

The areas to the left / right of the high spot, do look in clean condition - I would have no problem installing a HG on that surface, if here. *Looks like you are making good progress: just some more sanding and " elbow grease" is needed. Best wishes for a smooth repair.
 

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I had a head gasket fail in Beaver Dam, WI. Had mother-in-law bring up my spare head gasket, and I changed it in the police parking lot with the tools I had. Scraped the gasket surfaces with a utility knife blade. Still running on that repair.
Message: don't overthink this into scaring you off a repair.
 

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Huh? The pistons need to come out he said, right?

Are those on the block minor pitting or just old gasket imprint image?


Never knew that deglazer can work with the pistons on! I'll give it a shot! Thanks for the tips...
Getting the pistons re-ringed is tempting, but I'm not sure if I want to go that far...
 

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For deglazing the piston must come out. And if the crank stays then you need to protect it from metallic debris falling on it.

You then clean the cylinders with ATF and white rag until no metal dust is seen on the rags. Otherwise the dust will grind things up for you fast.

I think he was talking about the carbon ring at the top of piston travel that may be blocking you from taking the piston out?
 

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You absolutely cannot do any machine work without removing the crank no shop will do that. After any machine work the block is throughly washed to remove all traces of metal particles failure to do this will ruin the crank and bearing or worse.
 
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