Repairing damaged manifold stud and smoothing surface

[JHZR2]

I d been working this on my cheapo used belt sander. I think I got close over the weekend. 6x48 isn’t quite long enough for this part which is 19.5” iirc. I try to keep it off the roller on the end but generally I have to just swap directions and then sit it perpendicular to the direction the belt turns to get the center.

I also started to work a crisscross pattern versus all straight. I’m not sure what’s best but I figure a “crosshatch” of sorts might be best.

Now that I have a plate that is a flat reference surface, it’s much easier. Using a straightedge or box level was more challenging to look at the gaps. I haven’t put feeler gauges on it yet but I think it’s decent though the gap may be different top to bottom.

You can maybe make out the remnant gaps better in these:

At some point I’d like to swap over to my 120 grit to do a final sand.

 

[JHZR2]

@Trav hoping you can help me to know when to stop.

I put the Empire Abrasives 120 grit on the sander. It cuts way, way more aggressively than whatever Chinese used 80 grit was on the machine when I got it.

It would have been great to have this when I started working g on the surfaces. To do a final finish it’s essentially too much for my low skill abilities. I keep making things worse!

How good is good enough?? I’m trying to be better than a 0.008” feeler gauge. That’s hard. There’s always some spot that my 0.006” slips in. But I can’t remediate it without messing another spot up.

That last picture I barely touched the sander with the egr port and it took a nice chunk out. Hoping that seals it I’m really screwed! I’m fearful it nicked it too much and there’s no sealing surface.

I should have farmed this out. I know folks said to at the start. I wanted to learn but I think I’ve done a disservice and wasted more time than I care to admit.

 

[JHZR2]

FWIW the gasket looks like this:

 

[spasm3]

I'm not sure a hand held belt sander can do this to the level you would like. I does look good. I have done aluminum cylinder heads, and aluminum oil pump covers on a sand paper attached to a piece of glass. I don't think that would work well with cast iron, might take forever.

 

[D20]

Instead of heating the stud, try heating the area around the stud to bring the block's threads away from the stud. Although heating the stud does break surface rust tension, it also enlarges the stud. Heating around the stud will open it up a little. If you cannot do that, try heating the stud again, then quickly shock it with cold water. It may take several attempts.

If you can do both heat techniques outlined above, perform the hot-cold shock attempt on the stud, then move to heating around the stud.

I believe they will come out.

 

[JHZR2]

I'm not sure a hand held belt sander can do this to the level you would like. I does look good. I have done aluminum cylinder heads, and aluminum oil pump covers on a sand paper attached to a piece of glass. I don't think that would work well with cast iron, might take forever.

It’s not a hand held, it’s a 6x48 machine on a stand. Machine shops have bigger versions of what I have.

Here’s an example:



I kept working it, using Prussian blue on my surface plate. Surprisingly, it indicated that the high points were around the end cylinders, despite the warp putting them up off the plate before,

I am worried about this one end cylinder. I’d have to remove probably 1/8” to get a lot more gasket contact surface.

At this point it is about what it is. I have the turbo flange better than 0.006”, and the five cylinders are less than 0.006” on the top side, with the bottom side as it would be mounted to the engine having <0.008” on 1, 3, and 5, and 0.011 or maybe a bit more on cylinder 2 and 4.

I wasted about an hour and a half and got no improvement.

Instead of heating the stud, try heating the area around the stud to bring the block's threads away from the stud. Although heating the stud does break surface rust tension, it also enlarges the stud. Heating around the stud will open it up a little. If you cannot do that, try heating the stud again, then quickly shock it with cold water. It may take several attempts.

If you can do both heat techniques outlined above, perform the hot-cold shock attempt on the stud, then move to heating around the stud.

I believe they will come out.

They came out a while ago. Nothing got them out but diamond ball mills and eventually picking the final bits out. They’ve been drilled and tapped for helicoils.

 

[spasm3]

It’s not a hand held, it’s a 6x48 machine on a stand. Machine shops have bigger versions of what I have.

Here’s an example:



I kept working it, using Prussian blue on my surface plate. Surprisingly, it indicated that the high points were around the end cylinders, despite the warp putting them up off the plate before,

I am worried about this one end cylinder. I’d have to remove probably 1/8” to get a lot more gasket contact surface.


View attachment 350717View attachment 350718

At this point it is about what it is. I have the turbo flange better than 0.006”, and the five cylinders are less than 0.006” on the top side, with the bottom side as it would be mounted to the engine having <0.008” on 1, 3, and 5, and 0.011 or maybe a bit more on cylinder 2 and 4.

I wasted about an hour and a half and got no improvement.



They came out a while ago. Nothing got them out but diamond ball mills and eventually picking the final bits out. They’ve been drilled and tapped for helicoils.

Oh sorry i didn't realize you were using a stand sander!

 

[JHZR2]

Hope I’m nearing the end on all this. Not sure if I am.

First, the irregularity. Everything is better than 0.006” except this one spot which is more like 0.012”:

What is good enough for a gasket like this:

I could keep going after it on both sides and addressing the high points I get with Prussian blue dye, but to what end?

The other issue is this:

As you can see, it would take a lot of material removal to get this flat.

I used some Prussian blue on the gasket, and found this:

So I feel like there may be a little stagnant pocket of hot combustion gas that circulates there. A flow irregularity. Heck, that may have been what caused at least some of the leak problem to begin with. Maybe it will just plug up with soot and oil too.

I got some photos to show how it looks with the gasket against it:

 

[JHZR2]

(Continued)

As compared to another cylinder:

Maybe it’s just too much to think about, or doesn’t really matter.

So:

1) is that 0.011” going to be an issue given everything I’m showing?

2) is that erosion at the one cylinder manifold hole going to be an issue for sealing and/or future erosion?

3) what kind of final surface treatment should I give this? Make it criss-cross, or hit it quickly with a high grit random orbital perhaps? Or are the lines good enough?