Dave's 1650 Project

[westofb]

I had to replace my plastic bushing as well, the pic you referred does not show it. There are 2 moving cams on the hydro, one fits over the trunion area and springs, the other (most forward of the 2) is the one with the plastic bushing, more or less a sleeve that takes the slack out of pivot point. If you look, it may be stuck inside the hole of the front cam. The new one installed takes out most of the slop in the front cam, I think the new one costs me about $9.00.

[_DX3_]

Depending on your serial number you may not have to have it.
This is a diagram at cubcadet.com for the hydro controls of a 1650:

[CC1650Dave]

I'm not home at the moment but I'm pretty sure my SN starts with 622, so that would explain that.

I found a local guy that runs a welding shop out of his garage. He welded up the trunnion bracket for free, asked me to bring a few of the bigger jobs to him when I'm ready.

So that's cool. I'll get some good pics of the weld and process (unless I make it too ugly to be shown). :0

[CC1650Dave]

Here's how it looked after welding:
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I couldn't for the life of me find my Dremel tool, so I just figured I'd pull out the files and use a little elbow grease to reshape the bracket. Probably all for the better, as it's so easy to over-do something with the high speed dremel. First I filed the flats:
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...And a few other files (I didn't use this one much - too much danger of it cutting its own path)

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And after about 20-30 minutes of working it, I came up with this:

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I reassembled the unit to check the fit, with new springs and the old seats. Everything looks great as far as the bracket/spring/seat movement, but I have a good bit of play as the outer bracket can move up and down on the shaft. From what I can tell, it looks like I'll need to add about .040" of shim between the ring clip and the bracket, and everything will be snug and smooth.

[ACecil]

Excellent job, Dave!

[Methos]

Looking great! Looking forward to your updates!

[CC1650Dave]

Finding washer-style shims for that trunnion shaft proved to be a challenge. And I didn't want to order 50 of them from McMaster Carr.

I found a 5/8" ID machine bushing at Ace Hardware that was 18 gauge. I measured it at about .047" thick, a little more than I needed. So I put it in a pair of vise grips and filed it down to about .042", and it worked fine. The trunnion is ready to go.

[CC1650Dave]

The machine shop called (finally) with a report on the engine. He said the cylinder measured just a thou or so over, and recommended we go to .010 over on the rebuild. Crank is in good shape, valve guides look good. He didn't think I needed new valves, but I was just re-reading my measurements of the stems from somewhere around page 5 of this thread, and I had them measuring just a shade below tolerance, so I'm going with new valves.

Question: What is the scoop with going with an undersized rod? I'm reading around but haven't found any discussion of "why" yet.

[Matt G.]

If the crank journal is out of spec, it will need to be turned down, and you'll need an undersize rod. If you have it apart, you may as well have it done and be done with it. In my experience, if they are still within spec, they are just barely so, and consequently won't be for too long.

[CC1650Dave]

OK, I'll check with the machinist on that.

Bad news I learned today: I think I'm going to need a new oil pan, and they ain't cheap.

You may recall that the front two motor mounting bolts were missing, and it looks like both of the rear ones were on their way out and torquing on the threads as well - because when I went to thread a bolt into them, it stopped after 1/4".

I turned it hard to clean the threads, and eventually got both of them to thread in all the way. But today I mounted it to the engine rails (preparing to weld in the crossmember) and one of them spun when I tightened it up.