The Restoration of Big K

I’ve run the Kahlenberg a half dozen times since last fall. It is a bit challenging to run on a trailer because there is no counter-balancing and it shakes rather severely. I moved it to a heavier gooseneck trailer this year which has helped but it still feels somewhat precarious running it this way. I’ve also decided that I’m not overly interested in keeping the engine long term, especially given that I don’t have indoor space for it. I made an A-frame and covered the whole rig with a tarp over the winter but this isn’t going to be practical in the long haul. I’ve been asked many times about putting the engine back into a boat but this isn’t realistic for me. It would have to be a large boat that would come with great expense. I’ve reached out to a handful of maritime museums in locations where the engine has spent part of its life (Bayfield, WI, Benton Harbor, MI, and Gills Rock, WI). I’d like to have the engine be available for others to see in maritime context with relevant local history. It would be nice if it were displayed in a way where it could be occasionally run. The sound of a running Kahlenberg is what got me interested in this in the first place. But I understand that running it takes additional resources that a museum may or may not have. We will see.

There are a handful of things I need to address to make it run more reliably long-term. Nothing major, but what I’d call typical shake-down kinds of things. I then want to make a better quality video of the engine running. Stay tuned.

Getting the fuel strainer fixed (again) was the last thing to do to get the Kahlenberg ready to run. Here are pictures of the finished engine. Yeah, there are a few more things to do (such as machining main bearing drain plugs) but these are cosmetic and/or minor.

It’s been nearly seven years since I started this project. Time to see if it runs!

first run video

There you have it.

Here is a better, less chaotic video of the third run for the gang at BoatArt:

third run video

In preparation for running, each of the systems needed to be checked – air, fuel, oil and water. I started with fuel and quickly ran into a problem. I used a small gas tank for fuel. The system is gravity fed to a fuel strainer and from there to the fuel injector pumps and the torch tank. The fuel strainer had been split from water and freezing. This was covered in a prior post a few years ago. The first shop that did repairs unfortunately did a poor job. The fuel strainer was brazed but the body was badly warped. I had to do a lot of fine hand grinding to get the bronze cap to fit as the body was oblong. When fuel was added from the tank, the strainer leaked badly from many places.

Luckily I now have Crow Custom Cast Welding available to me to make proper repairs. Buck cut out all the brazing and properly repaired the cracked areas. I did not have high expectations of the strainer being repairable but Buck does amazing work. I don’t have a good picture of the finished product but it looks literally as good as new. The shape sprung back to round so the bronze cap fit again.

With fuel now in the system the injector lines were primed, which took a bit of time. I was able to verify that my injector calibrations were correct and performing as expected. It was then time to fire up the torches. The #1 torch had to be disassembled and recalibrated (and will need to be done again).

I check and calibrated all the oil pumps. I also still needed to overhaul the two oilers. I had purchased new ones but these turned out to not be satisfactory so I ordered some new material to make new site glass. The old oilers have some issues but they should work good enough.

Next up was the air starting system. The original air tank from the boat was mounted on the trailer and plumbed in with new hoses and fittings. It quickly became obvious that there was a problem with the air distributor. I tore it apart and discovered I had not sealed the lower shaft properly. This was kind of a head slapper. Once it was correctly packed, it worked as good as new.

But then the next problem reared up. I was told that 150psi of air would be needed but I had not given it a lot of thought. None of my compressors, including my big shop compressor, go above 135psi. The engine would painfully pull through two compressions but not fast enough to start. I bit the bullet and bought gas powered compressor with a cutout of 175psi. The engine wasn’t going to start without it. I mounted this onto the trailer as well and tied it into the big airtank for a total of about 170 gallons. Now I could get a few good revolutions at a speed good enough to start.

I used a 55 gallon plastic drum as a water reservoir. I’ll need to come up with some kind of cooling system for continuous running but this will work for now.

Time to see if it runs!

At some point in early August I realized there weren’t a lot of parts left to put on the engine and that it was actually going to get done. I kicked into overdrive and worked most every spare minute. I created a final punch list, which was a little bit of reality hit as the list was still pretty long. But I could smell it.

It was time to get the engine on a trailer. I didn’t want to add any more weight because my lifting mechanism wasn’t suitable for the completed engine (about 7200 pounds).

Once on the trailer, we installed the transmission. I don’t know what it weighs but it is heavy.

Next up was the flywheel. I had not got around to painting it prior to now. It needed a good cleaning and a light sanding. It came out looking good.

The engine came to me with some missing pieces on the throttle so there was still some machining to do. A conspicuous piece is the throttle handle. I was told this broke off a long time ago. There was a large bolt in its place but I wanted it to look original. A few years ago, I dimensioned one in the Gills Rock maritime museum so I had something to work from. Although lacking patina and wear, it came out looking good.

I had to make the metal stop behind the throttle lock. Again, I had dimensions from one in the maritime museum.

I’m not very artistic but I wanted to set off the cylinder cleanout port covers. There are very few parts which have the Kahlenberg name on them but these are prominent on the engine so I took the time to highlight the lettering.

Throughout this entire project, which included a house move and having the Kahlenberg parts in storage for two years, I’ve done a good job keeping parts organized, labeled and together. But I’ve known for quite a few weeks that I was missing two connecting rod nuts. I hadn’t misplaced anything else but I picked a heck of an item to lose. Each rod bearing is double nutted on each side. There are six short and six tall nuts. Two of the tall ones were not with the others. I spent a lot of hours scouring the shop but no luck. Regardless of what happened, I needed to replace them. Since they are hidden in the engine, I was going to buy new ones even if they didn’t exactly match the originals. But at that point I discovered the nuts have a bastard thread. They are 13/16″ thread with 11 threads per inch. Even Victor Machine, which in their catalog has 13 different thread sizes for a 13/16″ tap, doesn’t have one for 11tpi. I have no idea why Kahlenberg would have used such an odd thread (there might be a German engineering joke in there somewhere). I had no choice but to make my own. Please excuse the chatter in the threads. My boring bar was too small for this job but I didn’t feel like waiting to order a new one

After 6.5 years of slogging along (or making no progress at all for long periods), the engine is quickly coming together.

The governor tower is the one area that I’ve been most concerned about since taking it apart six years ago. It is complicated, my documentation is thin and my memory is worse. Luckily I had taken many pictures during disassembly and did a fair (but nowhere near perfect) job of labeling parts. It went together shockingly well. I only had to backtrack a couple of times. The engineering is really good. Things fit and work logically on the engine. I think that is one of the things that makes it beautiful!

I finished rebuilding the last water pump and installed those.

The last of the bearing tasks was to finish machining the rod bearings. We decided the best way to do this was on the big mill. It took over half a day but we got them done. I then had to radius the edges and cut the oil groves, which I was able to do on my own smaller mill. Can you tell I’m a former wood worker? I used a router bit in the boring bar to cut the radius. Not pretty but it worked.

Next up were the pistons.

And the heads.

The caps for the pre-combustion chamber are, like may parts on the engine, water cooled. I found gaskets with what seems like the correct properties at McMaster-Carr. I hope they work. The old ones are in tough shape.

I forgot how much plumbing is on the engine. Oil, fuel, water and compressed air. There were a few lines that needed repairs but most are in good condition. Again, I’m grateful for having the discipline to properly label all the plumbing lines.

This morning I attached the exhaust manifold. It’s heavy. I then was able to finish up the plumbing. There isn’t much left to do and I’m about out of parts. I’m rigging up a temporary fuel tank which must gravity feed the engine. The injection system then needs to be calibrated. I might be able to get the engine on a trailer and ready to run in the next week or two. It is a lot of fun to watch it come together.

The last step before starting reassembly was to finish making the oil groves in the main bearings. I did a lot of research on this topic without gaining a good solution. For the oil channels, I used a Dremel with a small round engraving bit. These were done freehand as I could not come up with a good way otherwise. It appears these were done freehand at the factory but by a much more talented and experienced person. They aren’t pretty but they will be functional.

For the relief cuts along the bearing parting line, I took a different approach. Basically, I made a small line bore with my lathe. It took a couple tries but I made a fixture to hold the bearing that was rigid and repeatable. I used a piece of 4130 tubing to make a boring shaft and let the lathe do the work. These cuts came out very nice.

Completing these bearings was a moral victory. They have seemingly taken forever (over a year and a half) but now they are done. I learned a lot about babbitt and bearings in general. But the reward for this was the kicking off reassembly of the Kahlenberg!

I spent a lot of time over the past few years thinking about how create a good platform to run the engine. My long term goal is to have it in some kind of an enclosed display trailer. Although I believe the engine will run, I hesitate to invest in an expensive trailer before knowing the true final condition of the motor. I have two leading ideas. The first is using steel to encase the existing wood crib and run the engine on the ground. This might be the simplest and least expensive. The other idea is to mount the engine at least temporarily on a flatbed trailer. I purchased a good used trailer for this purpose which can be modified to support the engine without high cost. I’m inclined to go the latter route but not sure just yet.

If I do mount the engine to a trailer, one thing that needed to be done was to turn the engine around so it could be more easily placed properly.

Step 1: Install the crankshaft. The crankshaft has been in and out 4-5 times recently but more work was needed to put it in for the final time. The engine is two stoke with each cylinder having its own crankcase. Intake air is drawn through the crankcase and forced into the cylinder by the downward force of the piston. The crankshaft seals on each end of the cylinder crankcase uses a bronze collar with a ring of heaving leather held tightly against the side of the crankcase with four springs each. I’m thinking the factory had made nice tools to hold all these seals in place for installing the crankshaft but I got by using quick clamps.

Next up were the cylinder bases.

And then the cylinders.

Next were the oilers and the air compressor. This was kind of a big deal for me because the compressor was the first item I took off the motor almost seven years ago.

I then tackled installing the 26 oil and fuel lines. This went better than I thought it might. There are more lines to be installed later.

As of today, the oil lines are in, the compressor is fully assembled, the water pumps are installed and I’ve started working on the governor tower. More on this next time.

Other than one hiccup dealing with the joint in the 2-piece boring bar, the rest of the bearings went as the first. I’m quite satisfied with the results.

Next step is to lap the bearings using TimeSaver compound. I needed a way to turn the crankshaft with the lapping compound. The crankshaft turned fairly easy with a short pry bar but this would take forever at 1/3 of a rotation at a time. One idea was to use a tractor PTO for power. For that to work, I needed a way to connect the crankshaft to the tractor. I decided to make an adapter using the keyed shaft on the flywheel end of the crankshaft.

I picked up some steel from CoreMark metals. The tube is a 3-3/4″ sleeve that goes over the crankshaft stub end. It was too tight so needed to remove some material with a boring bar on the lathe. I had to machine a key on the mill for the shaft keyway, drill for temporary bolting, fit the key and then weld. I picked up a PTO stub shaft from Fleet Farm, machined a hole in the round end plate and welded in place. I used angle to make an attachment point to hold the fixture on the shaft. Don’t judge my welding but it otherwise came out nice.

I mixed the TimeSaver with oil, coated the bearings and installed the caps. Time to see if the little Kubota could spin the shaft.

Video here.

The process worked very well. A little too well, actually. I started with too aggressive of a grit and took a little more material than I intended but the tolerances are still good. Despite being about 600 pounds and all the bearing surface area, the crankshaft can now be spun by hand. It spins just as easy with the caps on and torqued.

Video here.

Next step is to cut the oil groves. I have a few ideas but still not sure how I’m going to do this. Once the bearings are done, I can start reassembly!

We poured new babbitt for the #4 and #5 bearing shells so I was anxious to start the cutting process with the line bore. First I had to clean the shells to get the excess babbitt material removed and properly fit the bearing shell halves. I tried a combination of coarse files, disk sander and even a router (I’m a recovering carpenter). This was a bit tedious because I had to be very careful to not damage the bronze shells. I’d like to know what process was used originally at the factory to accomplish this task.

Once cleaned up, I mounted the #5 bearing shells with the new gaskets Kurt made and torqued the bolts. The shells are held in consistent alignment with taper pins on either side of the top shell.

The cutting tool is mounted in the boring bar and held with a set screw. A very accurate depth gauge is part of the line bore kit and is used to set and verify the cutting tool.

And then we cut! The rough passes took .025″ of material and at the highest cut rate, which I believe is .010″ per revolution. We had no issues with chatter. We checked measurements as we went and everything was spot-on.

We took much smaller cuts with the last two passes. We also used a finer cut of .005″ per revolution for the last cut of just a few thousandths. The bore is cut .005″ over the crankshaft diameter (3.750″).

That’s two down and three to go with the line bore.

Watch videos of the cutting here and here.

We finally carved out the time to start pouring at George’s shop in Stillwater. Wisely, he does this in a small outbuilding far removed from his house and shop. We test-fit the first bearing cap and figured out how to clamp and seal it against the pouring fixture. It took a couple caps to get the process nailed down.

First step was to remove the old babbitt by pre-heating the cap and then using a rosebud tip to carefully bring the bronze (cast iron in the case of the #5 bearing) shell up to temperature. The old babbitt was recovered in a muffin tin. George then cleaned and tinned the shell.

After that, we clamped the shell in the pouring jig, sealed the joints as best we could and slowly poured in the fresh babbitt.

After a few minutes we removed the shell from the jig. We were very pleased with the results. We got five shells done the first day (and ran out of babbitt material) with five more to go to complete the main bearings. There will also be the three rod bearings (six more pours).

I’ll get these cleaned up and installed in the engine block for cutting.

I recently realized it has been a year (and a day) since my last update. While a little work has been getting done, I’ve mostly been waiting on bearing work although it has been such a busy year I’ve not pressed the job. But now it is time to get the project back on track and moving forward. I have other projects to tackle and the Kahlenberg is taking up a lot of shop space. And I want to hear it run!

My first step in the bearing process was to set up the line boring equipment. George (the babbitt guy) has all the equipment and gave it to me to prepare. He hasn’t done a job this large so there is some new territory. I’ve already blogged about making the fixture for pouring babbitt in the large main bearings. Now I needed to set up the line bore. The bridges mount to parallel bars. The first trick was attaching the parallel bars to the block. I made a dozen clamps and bolted them to the existing cylinder base mounts which provides excellent strength around the main bearings. I had to use regular c-clamps to attach the bars near the #5 output bearing.

Once the bridge bars were securely attached, I then mounted the bridges and ran the boring bar through each bridge. Centering the boring bar required making centering plugs. I couldn’t find suitable commercial units so I made them out of aluminum. This took some time with my modest mill and lathe but they came out well. These aluminum plugs sit in the bearing saddle with the caps properly installed and torqued. This allowed setting the boring bar within, I’m estimating, a few thousandths of center through the entire nine feet.

I went back and forth adjusting the bridges but got the bar centered and running smoothly without difficulty. There is a gearbox to slowly advance the cutter which is powered by a geared motor. It is kind of amazing how easy it is to set up this whole rig for a novice like me. A clever design and very well-made. The machine was manufactured by Kwik-Way of Marion, Iowa. The manual is dated 1979 and apparently was originally shipped to the Army in Rock Island, Illinois.

Other tasks completed over the past year included making about a dozen bolts from hex stock. You can’t buy these from McMaster-Carr.

This is the jig I made for pouring babbitt into the bearing shells.

Other tasks this past year included finishing rebuilding the air starter, overhauling the three fuel injector pumps and rebuilding one of the water pumps. This pump circulates cooling water. I still have another water pump to do although the second one (starboard side) was used as a bilge pump in the boat so won’t be used now. In fact, the internal pump valving had been removed prior to my getting the engine. I’m starting to run out of things to do before the engine starts going back together, hopefully soon!