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Kalmar Ottawa Yard Tractor


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On 10/17/2017 at 9:23 PM, DRIPTROIT 71 said:

I've been wanting to build an early 70's one of these myself. I'll be watching this one close, especially the fifth wheel lift. Great start so far!

Great minds think alike. i just acquired 2 parts manuals for the 1970 Ottawa Commando 30. I'll try it one of these days. In the meantime, I'll keep watching this one come together. It looks good so far, great idea, great thread!

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3 minutes ago, Repstock said:

Great minds think alike. i just acquired 2 parts manuals for the 1970 Ottawa Commando 30. I'll try it one of these days. In the meantime, I'll keep watching this one come together. It looks good so far, great idea, great thread!

That's probably close to the model that I want to build. The company that my dad worked for in the late 70's and early 80's had one. It was powered by a gas v-8 (Ford I think), and had dual thrush mufflers on it. I hope to build a replica of that one.

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  • 2 months later...
  • 7 months later...

Getting back to work now that winter is coming and the yard work has tapered off.

Took the plunge and glued the suspension to the frame to get it up on its wheels. Found an engine in the parts box that may work but I'd like to identify the source and maybe find a shorter tranny if i could. Any ideas what engine this is?

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Tie rod is temporary, as my plastic one didn't work out, too flimsy. To be honest, the plastic frame and suspension parts are pretty fragile. Now I see why Charlie likes brass!

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Mocked up. Need to raise the cab and put some louvres on the hood (I'm thinking 0.030 quarter round strips, though lots of little pieces involved) and then if it looks okay sand to its final shape

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Bonus tip - found you can melt styrene into a silicone mold, though under the fume hood or die. First attempts, original part on the left.

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The engine is definitely a Cummins. For a transmission you may consider the automatic out of the Louisville kit. I've only been around an old Ottawa yard truck and it was an automatic. I don't know what year model you are trying to make, but some of the older Ottawas ran 3208 Cats similar to the engine in the Lousville as well.

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On 2018-11-11 at 9:22 PM, PierreR89 said:

To me the enigne looks like it is the Cummins that is in the autocar a64b kit just beacuse of the exhaustmanifold without turbo.

The Freightliner DD/SD kits also has the non turbo Cummins NHC 250.

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  • 2 weeks later...
On 2018-11-11 at 3:52 PM, DRIPTROIT 71 said:

Another option for an engine is a 6bt Cummins. Trailer Trash Customs offers one for $18. It appears that most of the yard trucks used smaller engines.

Thanks for the tip! Due to foreign exchange rate and shipping as well as postal strike up here I took a stab at making my own 5.9L Cummins 6BT.  Always wanted to try making an engine, and what's better than a big six!   I'm finding some dimensions and parts can be hard to figure out. Fuel pump and accessories will likely come from a spare Mack parts kitI have on hand

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Looks like you've got the beginning of a great looking engine.  Lots of things can be added using tubing and strip stock.  I like using small bits of round stock for bolt heads for the smallest areas.  some of the others can be replicated with plastic hex shaped strip stock as well.  If you've got one of those Northwest Short Line choppers you can make a lot of them from the hex stock.  Brass wire and even small solder wire make good fuel lines etc.  I like that engine!  Nice detail!  

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Thanks for the detailing tips, Charles! Never tried detailing an engine before, so we'll see how far I can go with it.   While playing with the engine (had to revisit drawings and pics to get the proper block width), for a break I worked on the 17" lift mechanism, mocked up here:

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I didn't consider how to limit the travel of the pistons so that the lift stops before the pistons come apart, so I may have to re-do them with an internal stop or come up with something else...

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Is the piston on the lift mechanism the same diameter as the inside of the cylinder?  There is a way of making an internal stop to the mechanism if you have room inside the cylinder to add an additional piece to the end of the piston.  BTW if you make the piston out of aluminum tubing you can polish it bright and you won't have to paint it.  I can post a how-to if you like.

Edited by Chariots of Fire
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12 hours ago, Chariots of Fire said:

Is the piston on the lift mechanism the same diameter as the inside of the cylinder?  There is a way of making an internal stop to the mechanism if you have room inside the cylinder to add an additional piece to the end of the piston.  BTW if you make the piston out of aluminum tubing you can polish it bright and you won't have to paint it.  I can post a how-to if you like.

Good advice, and as the cylinder is two pieces of concentric tubing, I can redo it with an inside tubing segment sliding inside the outer one, with fixed stops at either end. I will have to redo the top mount and also will see what is available for the piston, I think it's maybe 0.080"  running in a 0.100" hole.  Thanks for the advice!

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Bob:  Here is what my cylinder looks like.  It is a section of aluminum tube inside a section of brass tubing with telescoping sections of brass tubing inside.129.thumb.jpg.6e47e8c1ea3c3bfc620aab5f21ab96ef.jpg

The section of aluminum tubing fits inside a piece of brass tubing that is 2 sizes larger (in a telescoping sense).  I will do a sketch that shows it rather than try and describe the process but the piston slides smoothly in and out and does not wobble.  It also cannot come out of the cylinder due to the stop that is at the end of both the cylinder and piston.

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