One was thrashing, all of them idled like they had a dead cylinder. The one we actually drove sounded good but idled real rough but ran good down the road. I saw that truck come back up on Craigslist a few months later and they had to do a valve job on it lol. Truck had no emergency brake either!

 

Most of y'ouse guys probably think that nothing is happening re Dad's engine. But, that's not the case, as some of you know, since there's a lot going on in Oiling System Mods over on the 335 Series forum. We are working out several small mods to improve the flow of the system, having validated that Tim's mods raise the overall pressure in the system, which is a problem most of these engines have. And, by the way you'll be happy to know that I've introduced a whole new group of FTE'ers to my "attention to detail" (which seems to have something to do with being able to overanalyze things).

Last I reported I had sent Tim a spreadsheet with all my wants for engine parts. He sent me a note early this morning so I know he's working on it, but he's had some other things come up and doesn't yet have the answer. But, we'll get there and the main thing is to get the pistons and cam bearings so the machine shop can do their thing, and I'm confident he'll get at least those on their way to me in early March.

 

Got the rods ready to go to the shot peener tomorrow. Took the rib off of all of them and smoothed everything. Sure was messy as I wound up having a lot of debris. And it took a while to develop a good process, but here's what finally worked best:

1. Clean the rod and cap to get all the oil off
2. Remove the rod bolts
3. Use a carbide burr to remove the ridge, moving quickly so no divits were created
4. Go to a hard stone in the die grinder to smooth the ridges the burr left
5. Use a 60 grit flap wheel to smooth it even more
6. Go to a small 120 grit flap wheel to get into the corners, smooth the edges of the beam, etc
7. Clean the whole thing up in the blast cabinet with aluminum oxide at 50 psi

 

Gary, are those wrist pin bushings? I didn't realize anything later than the FE used them.

 

No, I just protected the bore and it looks like a bushing.

 

So, you're telling me that you reamed out the factory size hole in the rod and installed a protective sleeve inside of there? interesting. Tell me more.

 

No, Matthew, as I'm sure you understood I protected the wrist pin bores with a plastic sleeve so the abrasive wouldn't etch the bearing surface.

Looking back, I realize I should have explained my rationale for a couple of things. One was the idea of smoothing the surface of the rod so that less oil attaches itself to the rod, which should decrease the weight. I could tell that oil had been adhering to the rods previously as the areas that had more roughness had more varnish - and in the case of the rods from the $40 engine there was a lot of varnish. So I wanted to remove as much texture as I reasonably could without spending an inordinate amount of time. And, when I got through with the rods they were shiny in many places.

But then I realized that on rods 2 - 8 I'd skipped a step that I did on #1 - a light pass with aluminum oxide to remove all the embedded oil and other yuk that the parts cleaner and brake cleaner didn't get out. But, then I worried that doing so, even at low pressure, would destroy the smooth surface I'd gotten - until I remembered that the next step is shot peening. I'm confident that blasting the rod with steel shot at a velocity high enough to change the strength of the surface layer of the rod will flatten the light texture given in the cleanup phase. And, then I realized that cleaning them will also ensure that the yuk which was down in the pores won't get embedded in the surface.

So, off to the blast cabinet they went, and they came out a uniform satin gray. My expectation is that the minor surface roughness will be flattened in the shot peening step, and the rods will come back pretty smooth. We shall see!

 

(edited for brevity)Gary,
Nothing is going to "change the strength of the surface layer of the rod"
The steel is still the same.
It is not case hardening, work hardening, or doing anything to "change" the steel itself.

Shot peening simply puts the surface in compression.
Steel is stronger in compression than tension, and cracks due to the reciprocating action are far less likely to start at that surface.

Look how and where rods break.
It is from the action of the crank trying to fling off the mass of the rod and piston.
A tension failure.

Nice work though!
The rods will come back burnished, because (basically) that is what shot peening is.

 

So, "Shot peening simply puts the surface in compression.
Steel is stronger in compression than tension, and cracks due to the reciprocating action are far less likely to start at that surface." Doesn't that say the surface is, therefore, stronger? Doesn't that "change the strength of the surface layer of the rod"? I am confused. Seriously.

But, thanks for the

 

I guess I should have said it doesn't change the composition of the steel in any way.
It does not result in a surface with more carbon in solution, like case hardening would.

It changes the mechanical properties of the surface because of residual stress.
But the surface is not "stronger" by any real measure.
(maybe I need to better understand 'strength')

The UTS is not changed, nor E
What IS changed is the starting point where the load is applied.
Normalized or annealed material will start at 0.
With a shot peened object, the same load is applied but the starting number is some negative value, at the surface.

I should also have said, shot peening is plastic deformation, just like burnishing.
The rods are going to come back textured not polished.

 

Ahhh! I think we are on the same wavelength. I wasn't expecting the composition of the material to change, just the strength of the overall rod.

As for the surface texture, I don't think I've ever seen a shot-peened part. Or, at least known what I was looking at if I did see one. Anyway, for a finish I'm expecting it to do to a much larger extent what any media does when hitting a part at high speed - close the pores up and create small craters the size of the shot. But, since any one area will get hit thousands of times it'll be the last round that will leave the marks I'll see. So, as I think about it, they may well look similar to how they look today - a satin finish over an underlying sheen of the smoothed and beaten metal. Yes?

 

Yes, satin or stippled surface.
Many gears and springs are shot peened.
In fact they wouldn't survive long if they weren't.

Polishing to reduce windage is another thing entirely.

 

In the 80's I worked in a foundry machine shop; before the castings came to us for machining they were fettled, & most were shot-blasted.
The texture on cast iron & steel was pretty much the same as sandblasting (using the size beads we were, anyway......about .020" IIRC)

 

I think I found the right place to have the rods shot peened. The guy said they looked very nice - until he got to one with the copper on it. At that point he said that will have to be stripped off as the copper is soft and will absorb some of the impact of the shot so the peening effect won't be as planned. Further, it has to be chemically stripped as doing it via media blasting will erode the metal outside the copper and when the copper finally comes off you will be left with differing thicknesses. And, they have the chemical stripping capability since they frequently copper-plate portions of a piece before treating it.

So, I left them with him to strip as well as peen. It'll probably be two weeks or so before I can pick them up, but he assured me these rods won't come apart.

 

Ken - He didn't say what sized shot he will use, but he did say that is determined by the thickness and metallurgy of the part. I do think the shot will be heavier than .020" as he did say the vacuum on a blast cabinet isn't enough to pick the shot up, that it has to be gravity-fed from overhead. So, since I think mine would pick up .020" shot surely it has to be bigger than that?