Author Topic: Rebuilding my Upshur vertical single  (Read 497 times)

Online Art K

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Rebuilding my Upshur vertical single
« on: October 06, 2019, 08:51:04 PM »
Hi everyone,
Some of you who were at the Zanesville engine show know that I had my Upshur single apart for repairs. Over the last year or so I had been noticing that it was running worse & worse. Before the show I took the head off to see what was wrong and found about a 16th of an inch of carbon built up on everything in the combustion chamber. Then yesterday I took apart the crankcase, this is what I discovered.

The Piston looks much worse in the photo than it really is. But as you can probably see the rod journal is very rough, and the rod bearing is oblong about .040". There are scuff marks on both sides of the connecting rod from it hitting the cylinder. Also it shifted up enough to hit the center of the cam.

This Is what it looked like in its prime. I think at the least a new rod and crank are needed. I had redesigned the head already, had hoped to have that in time for the show but the computer for my mill died so that has been postponed till my computer guy has healed up from surgery after his vacation. No I didn't ask.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline cheepo45

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Re: Rebuilding my Upshur vertical single
« Reply #1 on: October 07, 2019, 02:38:52 PM »
My Upshur horizontal has been rebuilt several times.
I just polish the crank as much as I can, and trim the rod cap faces and ream or rebore the rod to the proper clearance.
You may have to add some clearance to the sides of the rod so it doesn't hit the cylinder.
That gets me another 5 years or so.
 Scott ;)

Online Art K

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Re: Rebuilding my Upshur vertical single
« Reply #2 on: October 07, 2019, 05:19:01 PM »
Scott,
I've been running it for ten years and this is the first time I've had to open her up. The rod is past any reworking and the rod main is .002 under w/o any cleaning up at all. I am considering replacing the bearings as well, although they may be ok. The photo doesn't show how visibly oblong it is.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline cheepo45

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Re: Rebuilding my Upshur vertical single
« Reply #3 on: October 07, 2019, 07:52:15 PM »
I think you are correct in making new parts with the crank at -.002.
It's kind of cool to actually wear out one of your creations.
I run my IC engines all day at the shows. My Upshur is on its 6th set of rings and its third cylinder!
I hope your rebuild goes well.
 Scott

Online Art K

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Re: Rebuilding my Upshur vertical single
« Reply #4 on: October 07, 2019, 11:41:44 PM »
Here's a better photo of the rod. By the way I have no idea what grade of aluminum this is. It was what ever I had laying around. Is there a specific grade of aluminum I should use? I am considering using a bearing of some sort on this, though I'm not sure it's worth the effort.

After all in the ten years it's been running I discovered it would run 7400 RPM.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline awake

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Re: Rebuilding my Upshur vertical single
« Reply #5 on: October 08, 2019, 12:35:34 AM »
Art, I am just beginning to learn, with the hope of making an IC engine in the next year or so. That to say that I hope my question is not hopelessly ignorant or muddled by using the wrong terms ... !

Is the aluminum rod running directly on the crankpin? I think that is what I am seeing / understanding. What about the small end of the rod - is that also aluminum running on steel, or is there any bearing material (bronze?) there?

Also, how has the big end of the rod been lubricated?

Again, I hope I'm not out of line (or out in left field) by asking - just eager to learn ...  :cartwheel:
Andy

Offline Dave Otto

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Re: Rebuilding my Upshur vertical single
« Reply #6 on: October 08, 2019, 12:42:42 AM »
Wow that is some pretty serious wear!
I would think that 7075 might be a good choice but someone with more experience in this area may have a different idea.

Dave

Offline cheepo45

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Re: Rebuilding my Upshur vertical single
« Reply #7 on: October 08, 2019, 01:14:00 AM »
Wow! That rod is worn!
That must have sounded interesting at 7000+ RPM!
 Scott

Online Art K

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Re: Rebuilding my Upshur vertical single
« Reply #8 on: October 08, 2019, 01:35:02 AM »
Awake,
No you aren't in left field. It was designed to run aluminum on steel, apparently it has fairly good lubricant qualities as a bearing. There is a center drill hole at the end of the cap which lubes the crank. Any question is a good? I think bronze would wear better but be more of a PITA to make.
Dave,
I will have to see if I have any. I have lots of aluminum that isn't labeled.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Online Art K

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Re: Rebuilding my Upshur vertical single
« Reply #9 on: October 08, 2019, 01:43:59 AM »
Also I might add It was originally designed with less cooling. I modified that when I was told it would idle all day but overheated when the RPM was higher. I did at one point in time run it at about 6000RPM for 20 minutes and melted the Perry carb I was using, it didn't ever stall from overheating. I must admit in the last few years it hasn't run very well, now I know why.
Art
"The beautiful thing about learning is that no one can take it away from you" B.B. King

Offline Brian Rupnow

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Re: Rebuilding my Upshur vertical single
« Reply #10 on: October 08, 2019, 01:01:41 PM »
Art--All of the aluminum I use is 6061 heat treated to T6. I think that is very common aluminum. Aluminum runs fine on steel crank throws, with good lubrication until it doesn't. If you want to run a bushing on the big end, make it two  separate shells of 660 bearing bronze captured in the aluminum rod. I have never spent a lot of time worrying about the small end of the rod, as that pin only swings back and forth in an arc. I give it a liberal squirt of oil on first assembly and then don't generally think any more about it.

Offline awake

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Re: Rebuilding my Upshur vertical single
« Reply #11 on: October 08, 2019, 05:37:35 PM »
Very interesting. I would not have thought ali on steel would last very long at all. I have much to learn ...

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Andy