1800cc Type 4 engine rebuild - 74 westy

[white74westy]

[white74westy]

[germansupplyscott]

For reference this is a similar photo of an NOS Type 4 rod.

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SL

[SGKent]

well, during my time as a machinist I did I dunno, maybe 8,000 - 10,000 rods. I can see neither good quality crosshatch or scribe marks in either of those photos.

The device that measures the rods for size has a carbide point on it. The machinist spins the rods around that device by hand to check for size and runout. The hone that sizes the rod is done in a way that cross hatches the inside of the rod just like a cylinder. Usually there is a fine lite line, about 1/8" to 1/4" inside the rod big end where those carbide points rode. Sometimes unreliable shops will wash a rod, check the size and if they feel it is acceptable, sand the inside with sand paper to make it look like someone worked on it. Neither of your photos show the lines. Scott, yours has a yellowish coating on it which may be hiding yours. The other one I would measure carefully before using. Measure both sides. Some machinists will only measure one side and assume both are the same. That is not always true - a machinist that doesn't have the right rhythm may cause the rod to flare a bit like a horn so one side is larger than the other. Or if the rhythm is wrong, the rod may look like an hourglass when carefully measured, with the outside being wider than the inside or vice versa. That is hard to detect when measuring - one has to watch the stones for wear to be sure they are wearing evenly. Please measure those rod big ends.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[germansupplyscott]

The rod in my photo has cosmoline on the journal. I cleaned only the end where the cap attaches.
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SL

[SGKent]

[orwell84]

Those are some damn fine scribe marks. I could just lick them.

[SGKent]

I don't know what the factory process was in the late 60's to late 70's. Machine shops use a hone. The carbide tips leave a fine mark where they measure. The mark should go all the way around and measure both sides about 1/8" to 1/4" inside the edge. It is possible that the factory used a pass fail device to measure them - meaning a series of rods like wrist pins that they slid the big end over. If so it would be one too large won't fit, one goes in easy, and one is barely tight - sort of like we use feeler gauges. Wrist pins are fitted to the small end by feel.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[SGKent]

I found a really good youtube of how a rod is properly resized. He uses two hands to measure the rod. I used one in a way that I could measure it all the way around. You have to measure across the part lines like 8:55 - 2:55 and 9:05 - 3:05 plus 12 to 6. If the rod is pinched it will be across one side of the part lines. Then you flip the rod over and do it again to be sure both sides are the same. This guy has a really good rhythm - he has been doing it awhile. You can seem him work the outsides of the stones a couple times every few passes to keep them from wearing uneven. Otherwise the center of the stones wears faster because you pass over them twice as often as the outside, and the stones would no longer be even.


Link

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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[white74westy]

[white74westy]

Steve, thank you! I really appreciate your input. It has forced me to pay greater attention to detail, even after I have felt like I'd taken anal to another level. This is all really great information, and I hope not only to gain from it, but that others will be able to in the future as well. Once again, thanks!

Today I spent a little time chamfering the edges of the rod bearings:

After that was done, both the rods and the bearings were put back into the ultrasonic for one last cleaning, before final assembly. They are all squeaky clean and free of all debris, oil, or contaminants.

After Steve's posts today, I wanted to go back and take a little closer look at the rods. As you'll see from the picture below, there are indeed cross hatch markings from the hone. Consequently, this picture is of the #3 rod. The one in the pictures earlier in the thread are of #1. You'll also take note of the same "scribe" markings in approximately the same place/orientation as the other:

Once again, I apologize for the poor quality of the pictures earlier in the thread. For some reason, every time I would try to snap the picture, either the flash would wash the image out, by overexposing the subject, or it would go out of focus.

Anyhow, I feel pretty confident after putting on glasses and really taking a closer look, that everything checks out. The "forty yard stare" just wasn't cutting it. This getting old stuff sucks!!!

[Abscate]

Damn, I missed this one.

Have you thought about ( sorry) opening the case and doing the mod to the oil drain plug case stud to prevent the saddle breaking problem?

Case open is the time, of course. Sorry about that.
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.ssS!

[orwell84]

I sometimes watch videos like that just to see how these things are done. Once I was thinking of buying a small lathe but imagined sooner or later it would end up with a trip to the ER. The farthest I’m going down this rabbit hole is maybe a nice set of micrometers, but it’s helpful to know when something is done right.

When I brought my damaged heads to clean up the sealing surfaces of the head, he used a rotary grinder. It’s good to know the service your asking for and the machining required.

[orwell84]

[Abscate]

[SGKent]

or just own a torque wrench and use it.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[orwell84]

[SGKent]

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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Clatter]

In the end, after measuring as best you can,
The final test of rod fit will be how they feel.

Once assembled, torqued and lubed,
They should all fell the same,
And fall with a sort of slowed/dampened glide if you lift the small end and let go of it.

Any with bad measurements should stand out in the different way they feel moving on the journal.

If that makes any sense..


In the end, it's the same with the mains as well.
If you have it right, there's a certain nice feel that gives you a good feeling about it..
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Bus Motor Build

What’s That Noise?!?

[orwell84]