To split or not to split...

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Panshovevo
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To split or not to split...

#1

Post by Panshovevo » Sat Sep 04, 2010 2:24 am

I pulled the top off my pan recently, as it was getting harder to start, and when I checked the compression, found it was low. The ring end gaps were way out of spec, probably due to some rust in the cylinders. The bike sat for a while before I bought it.
The top is getting the valves and seats touched up, and the cylinders ring-finished and new rings. Now, I have to decide whether or not to pull the lower end apart.
I have no reason to believe that there is anything wrong down below. The rods are snug. The motor was redone by Dudley, in New York, around 1995, according to the last owner. I had never heard of Dudley, but a local pan guru speaks well of him.

There are several reasons to not split the cases without good cause, but there is a little oil seepage that appears to be coming from the split line, and the external surfaces look rough where the leaks have not kept them protected. It would be nice to have the lower end look as fresh as the top is going to.

Any thoughts?

Edited to add that another reason I'm considering a full teardown is to add a left side oil seal. Anyone had any experience with the aftermarket oil seal for the sprocket shaft on a '50?

Regards,
John



Bosheff
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Re: To split or not to split...

#2

Post by Bosheff » Sat Sep 04, 2010 5:22 am

If it ain't broke, don't fix it....bosheff

Billpan58
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Re: To split or not to split...

#3

Post by Billpan58 » Sat Sep 04, 2010 5:49 am

im still running lower end my friend built in 1980,had top redone 7 years ago we all marveled at the rods, how snug they felt and ease it rotated, ran 50 miles today, will ride up north tomorrow. leave it alone if it feels good.s and s wheels,,,stock 74 ,low comp. build

kitabel
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Re: To split or not to split...

#4

Post by kitabel » Sat Sep 04, 2010 1:42 pm

You're kidding, right?
Take it apart to clean it?
What will you do when it still leaks?

Panshovevo
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Re: To split or not to split...

#5

Post by Panshovevo » Sun Sep 05, 2010 4:42 am

kitabel wrote:You're kidding, right?
No, actually, I'm not kidding. When I'm kidding, I'll be sure to let you know by the use of the following words: Just kidding folks.
Example:
XXXXXXX is a smartass. Just kidding folks.
Take it apart to clean it?
Do you know of a way to bead blast the cases while assembled and the cylinders are off without contaminating the internals?

What will you do when it still leaks?
Lets see. It leaks now. If I don't pull it apart, it will still leak.
I'm not a professional Harley wrench, but I have a fair amount of experience with Lycoming and Continental aircraft engines, which also have vertically split aluminum cases, are air cooled, and vibrate. There is a reasonable chance that I can eliminate some, if not all of the leaks.
Therefore, I'll be further ahead than I am now.

NightShift
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Re: To split or not to split...

#6

Post by NightShift » Sun Sep 05, 2010 2:48 pm

Bosheff wrote:If it ain't broke, don't fix it....bosheff
Dear Bosheff,
And if you take it apart, its broke!

But on the other hand a lot of rods get tighter before they blow because the races are shrunk from heat. Feeling rods is like guessing whats at the bottom of a bucket of paint.

You gotta have faith I guess,

Panshovevo
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Re: To split or not to split...

#7

Post by Panshovevo » Sun Sep 05, 2010 3:31 pm

But on the other hand a lot of rods get tighter before they blow because the races are shrunk from heat. Feeling rods is like guessing whats at the bottom of a bucket of paint.
By that point, the lower ends of the rods will most likely have discolored from the heat. Looking for that is part of my procedure.

A friend recently had an S&S 124 lower end in his shop that had been run out of oil. The rods were discolored and had vertical shake. It badly needed a complete overhaul, but the customer wanted to do only what had to be done to get it running so he could dump it. I strongly suggested that my friend stay away from it, but as he was only doing the wrist pin bushings for the "wrench" who was doing the rest of the job, he felt he was safe.
If you happen to run across a chopper for sale in Okeechobee, FL, with an S&S 124 with a fresh top end, run like hell, unless it's really cheap. At least pull the timing plug and look for severe discoloration on the flywheel.

Still looking for feedback on the Colony left case oil seal for early pans.

mbskeam
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Re: To split or not to split...

#8

Post by mbskeam » Sun Sep 05, 2010 4:29 pm

Still looking for feedback on the Colony left case oil seal for early pans.
these work....
got this on my bike, not a drop of oil.....

as to splitting the case, ....

since it is all roller brg. pull it apart, take a look at what you have, clean up the cases....
just a few hrs of work

yes I'm still alive....LOL

51Hog
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Re: To split or not to split...

#9

Post by 51Hog » Sun Sep 05, 2010 4:33 pm

Lycomings have nothing to do with a v-twin as you will find out.
A v-twin will shake at X rpm, no matter what you do to it.
A Lycoming can be perfectly balanced as it is an opposing 4. (The 0290, 0290d2, and the 0320s are the ones that I have experience with.)
If there is an out of balance problem with them, it is usually the prop, --or the machine shop has a problem (The feds would shut them down).
I have wondered how the silk thread between the case halves would work on the v-twins.
I just assembled my 51 pan lower end per specs in the book and have no leaks.

Where does one stop?
Since the top end is off, --May as well split and reseal the case.
Since the case is open, -- May as well do the bearings.
Damn,,,, May as well split the wheels and do the pins and rods while we're at it.
At least, that was my scenario. I zero timed the engine and now have no doubts as to its condition.
Runs great, and my pan is one of a very few that does not "Mark It's Spot" Unless it sumps, then it makes up for not having any leaks all at once.
Dale

Panshovevo
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Re: To split or not to split...

#10

Post by Panshovevo » Sun Sep 05, 2010 6:40 pm

Dale,
I have had a v-twin apart before, and am aware of the differences between them and a Lycoming. However, as I stated above, they share some similarities.
I don't care how perfectly you balance a Lycoming (and I have done an IO-360 A1A to an extreme degree, way beyond factory spec, as we wanted to run the engine well above the factory specified RPM limit)), you still get vibration. You may not see it or feel it in the cockpit, but it's there. With a 5.125" bore and a 6" stroke(IIRC), and four cylinders (two power pulses per revolution), it's going to vibrate. There is no such thing as perfect balance. There are things you can do, such as tuned intake, tuned exhaust, flow-matching cylinders, dynamically balancing the crank, matching piston weight, matching rod weight on both ends as well as overall,...
The six cylinder engines that are equipped with counter balance weights on the crankshaft are better, but the weights are tuned for a specific RPM, and outside that range, vibrate like the rest of them. Of course, the sixes are naturally smoother, by virtue of more power impulses per revolution. The IO-720, with eight cylinders, is better yet.

I've been thinking about trying the silk thread myself.

What do you mean by "sumps"? When the check valve leaks and the oil drains into the cases while sitting?

mbskeam, thanks for the input on the seal.

Regards,
John

Cotten
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Re: To split or not to split...

#11

Post by Cotten » Mon Sep 06, 2010 2:01 am

Panshovevo wrote:
But on the other hand a lot of rods get tighter before they blow because the races are shrunk from heat. Feeling rods is like guessing whats at the bottom of a bucket of paint.
By that point, the lower ends of the rods will most likely have discolored from the heat. Looking for that is part of my procedure.
Panshovevo!

Races can overheat to the point of damage long, long before you can see any peacock coloring above them.

Have you never found a spun race without coloring upon the rod?
Nearly all I have encountered did not discolor the rod web, much less the beam, even when the pin had to be driven out with a hammer.

....Cotten

Panshovevo
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Re: To split or not to split...

#12

Post by Panshovevo » Mon Sep 06, 2010 4:16 am

Cotten wrote:
Panshovevo wrote:
But on the other hand a lot of rods get tighter before they blow because the races are shrunk from heat. Feeling rods is like guessing whats at the bottom of a bucket of paint.
By that point, the lower ends of the rods will most likely have discolored from the heat. Looking for that is part of my procedure.
Panshovevo!

Races can overheat to the point of damage long, long before you can see any peacock coloring above them.

Have you never found a spun race without coloring upon the rod?
Nearly all I have encountered did not discolor the rod web, much less the beam, even when the pin had to be driven out with a hammer.

....Cotten
I stand corrected Sir!

Edited to add that I don't have a lot of experience with Harley lower ends yet. I built the 96" Evo in my Wide Glide, but I used an S&S kit with the wheels already assembled and balanced. Other than machining the cases for the bigger cylinders (done on a Bridgeport without one of the nifty fixtures that holds the cases at the correct angle-won't do that again) and clearancing for the stroker crankpin nut, it was mostly a pretty simple assembly procedure.
Most of what I know about them came from old timers who have been doing it for many years. I was taught , when the top end is off, rotate the wheels, and feel for roughness, feel the rods for vertical shake and excessive side shake, and look for anything unusual, including discoloration of the lower end of the rods. Does this procedure cover all eventualities? No, but there is not a great deal more one can do without further disassembly, as far as I know. I'm always open to learning more. How can you ID a spun race without disassembly?

Thanks to all for the input. It's much appreciated.

Regards,
John

Cotten
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Re: To split or not to split...

#13

Post by Cotten » Mon Sep 06, 2010 3:45 pm

If you will all indulge me while I tell a long tale,

Once upon a time, I was working out of a street shop with a few other builders.
Every time a lower-end came in, we would take turns inspecting before disassembly.
With our foreheads furrowed and our tongues in our lower lip like a chunk of 'chaw' (tobacco),
we would wash out the rollers, fondle the rods, probe it with feeler gauges, set up dial indicators, and of course do the old palm-smack trick.

That is where you pull up on the rod with one hand, and smack the top with the other to listen for a noise that signals "rod-knock".

Upon disassembly,
we were all always right when the crank was totally tortured and trashed.
But we were often wrong when we asserted that it was "fine".

Sadly, a fresh and powerful top end can take out a lower that otherwise would have lasted many miles as a "slug".
That's just one more reason why "Rat's Where its At!"

....Cotten
PS: Please also consider the problem of straightening and aligning rods, even if the crank roller assembly is within spec.
An oblique wear pattern upon the skirts of the pistons is your best external clue to any such problems.

Panshovevo
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Re: To split or not to split...

#14

Post by Panshovevo » Fri Sep 24, 2010 5:25 am

By the way, when I look for discoloration, I'm not just looking for the "peacock" coloring of overheated metal, I'm looking for burnt oil stains as well. That is what I was referring to in the above post about the S&S 124 that had been run low on oil.

I haven't got to the lower end yet. I'm focusing on the frame first (with breaks to keep the Evo on the road and other distractions) so it can be painted, and the paint can cure while the motor and tranny get freshened.

I learned something about sprocket shaft seals the other day. I haven't been able to keep one in place on my stroker big bore Evo. Turns out I've been putting it in backwards. With a wet primary, the object is to keep primary lube out of the engine, not keep engine oil in place.
Live and learn...

Regards,
John

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