Flathead V-8

[gbritnell]

 If a person has a kiln then the next step can be done one of two ways. The rings need to be protected when heated so that a scale doesn't form. To do that they can be wrapped in stainless foil or because I don't have a kiln I coat them with a Boron powder. For these small rings and fixture I use 2 propane torches. They provide enough heat for the job. With larger rings and fixture one should probably use an oxy-cetylene torch.


 The fixture is brought up to about 500 degrees or until everything starts to turn blue. Being careful with handling and avoiding breathing the fumes I use a plastic spoon to coat the fixture. The Boron powder is extremely fine and as it's sprinkled onto the fixture is starts to bubble and smoke. Using some pliers I rotated the fixture to get a nice coat on everything. This is what it looks like when it has melted uniformly on the fixture.


 

[Don1966]

That is too cool George. Love all the photos gives a perfect lesson on how it's done. Much appreciated my friend.

Don

[gbritnell]

 Now it's time to bring it up to annealing temperature. I originally followed Trimble's method to the letter when I first started making rings but as I practiced and read about the process there seems to be some dissension about what temperature to use. It seems like Trimble's temperature is too high but when I started out it seemed to work ok.
When I made the fixture I counterbored the inside of it so I wouldn't have to heat as much metal and I could get the torch up inside to evenly heat everything. I heat until everything is a dull red, 1000-1100 degrees? If it doesn't work you can always redo it.

 Once the fixture has been heated it is then allowed to cool on it's own. I have an old glass cooking pot that I boil water in for cleaning flux after silver soldering and also for removing the heated Boron material. The fixture is immersed in the boiling water and rolled around until all the scale it removed. It's hard to believe but the boiling water takes it all off.




 This is the fixture after boiling. The oil rings were removed and everything was cleaned up for the comprssion rings.

[gbritnell]

The compression rings were installed with the .078 rod and the process was repeated.
You can see in the following pictures that both the oil and compression rings have taken a set. Had then not been heated enough they would have sprung back to their original shape when removed from the fixture.

[b.lindsey]

Looking at that picture with the boron coating all over it looks horrendous to clean. Pretty neat that just boiling water does it.

Bill

[gbritnell]

 When the rings are first made and snapped open one would think that they would then fit in the bore, as they are made size for size, but such is not the case. Each ring requires a small amount of filing on the end gaps to get the rings into the bores. For these rings I try to shoot for .002 end gap but one extra stroke on the file and sometimes you end up with .003. With three rings on the piston and installed with the gaps at 120 degrees they seal very well.
I have never made oil rings this small before so it's going to be a learning experience when installing them.

 With automotive and motorcycle rings one just takes the ring, opens it and slides it down over the piston, or you can use and ring expander. With these little suckers you have to very carefully finesse them into place. The hardest one is the lower compression ring because you have to get it past the first groove.

gbritnell
 

[b.lindsey]

Could it be slid into place from the bottom of the piston instead, thus avoiding the upper groove? Just curious.

Bill

[gbritnell]

Hi Bill,
Then I'd still have to get it over the oil groove.
George

[b.lindsey]

I misunderstood, I thought you meant the oil ring, I got it now.

Bill

[gbritnell]

My mistake Bill. I meant the lower compression ring. I changed the text.
George

[petertha]

Thanks for sharing the pictures & step-by-step details, George!

- where do you buy Durabar?

- re the non-scaling compound you show, one thing I'm not clear on. Once the part is up to 500F temp & coated like in your pic, is the procedure to immediately carry straight on heating to elevated target temperature? (ie. if you were to let the coated assembly cool a bit for whatever reason, that would somehow compromise the coating protection?)
- does the coating layer basically stay put in that glossy state (doesn't tend to flow away)
http://www.brownells.com/gunsmith-tools-supplies/metal-prep-coloring/heat-treating-accessories/non-scaling-compound-prod1122.aspx

- do you happen to know what the difference is between Non Scaling Compound (what you used) & Brownell ATP-641 = Anti-Scaling Compound? I got the impression with this stuff you coat it at ambient or only slightly warmed, then take it right up to elevated target temp. Some of the knife maker types use this in full hardening/quenching procedure
http://www.brownells.com/gunsmith-tools-supplies/metal-prep-coloring/heat-treating-accessories/anti-scale-coating-prod23076.aspx

[fumopuc]

Hi George, thanks for showing your ring making process. I like your fixture. Just checked it in the net, this Brownwells non scaling compund is also available in Germany.

[gbritnell]

Hi Peter,
First of all here is a description of Durabar.
http://www.matweb.com/search/datasheettext.aspx?matguid=05f0795918314796a689d72341c96e90

As Durabar is a trade name I purchase a comparable product from this supplier.
http://www.speedymetals.com/c-8388-round.aspx

I'm sure it is available world wide.

When I use the anti-scaling powder I heat the part until it turns blue, as I don't have any good way of determining the actual heat. It has to be hot enough so that when the powder is put on it will start to melt. I have never interrupted the process by letting the part cool but once coated it's a glass like coating so I don't think it would affect anything. I'm not familiar with the other product. When I got into making my own rings many years ago this was the only product that Brownell's had listed. The quantity that I got will last me all of my life and longer. To coat the ring fixture for this project only took about 3 or 4 tablespoons. I use a little extra to cover the inside of the fixture also.

If you go to the following link there is some very useful information on making rings and the different processes that can be used.
http://www.modelenginenews.org/techniques/piston_rings.html

gbritnell

[steamer]

Is the anti scaling powder boric acid?

Dave

[gbritnell]

Hi Dave,
All I know is what it says on the label. It contains Boron and to take precautions when using it. I did a search and found many applications but not a particular content.
gbritnell