Author: Charley

The last major task remaining before reassembly begins is addressing the main and rod bearings. An earlier post includes pictures of the #5 main bearing, the tail bearing on the output shaft, which is in bad shape. The four main crankshaft bearings are in decent to very good condition. I reinstalled the bearing shells and placed the crankshaft back in the main block. I then torqued the caps and used Plastigauge to measure the bearing clearances. Surprisingly, all the clearances are between .003 and .008, which on a 3.5″ shaft is not bad for a machine of this vintage.

I’m very fortunate to have a well known babbitt specialist just 15 minutes from my house. George owns Harkin Arcola Babbitt Repair. He has been to my shop a few times to size up the bearing situation. We decided to not re-pour the main bearings other than the damaged #5 shells. This is fortunate because this is the shortest bearing. The others are up to 11″ long. George is going to attempt to make minor repairs to a few of the shells that have small cracks.

However the rod bearings have much more serious cracks in the babbitt so these will be re-poured. I am working on building a jig to hold the bearings during the babbitt pouring process. More on this in a following post.

One big item that has been gnawing on me for some time is the #1 bearing cap. This is the cap that was cracked and repairs by another shop only made matters worse. I discussed this in the prior post. After a lot of discussion, George and I decided to leave the cap as-is. I am not able to maintain perfect and repeatable alignment but we decided on a method that should get the cap located close to where it should be and within reasonable tolerances. Worst case, if it doesn’t work, the cap is easily accessible after the engine is reassembled and other attempts at repairs can be made. The only thing I have to do is make cap bolts. Two of the existing bolts are stretched and bent. I bought some 1″ hex rod and will be working on these in the lathe this week.

We had a visitor in the shop last week. Kurt Krueger restored a Kahlenberg a few years ago and donated it to the Door County Maritime Museum in Gills Rock. I’ve been communicating with him for five years but we had not met in-person. Kurt decided to make the trip from eastern Wisconsin and stayed with us for a couple days. Even though I couldn’t completely escape from work commitments, he worked in the shop doing a number of very helpful things. Kurt is a wealth of information and very generous with his time. Below is a picture of Kurt (in the back) with his engine:

One huge difference between Kurt’s restoration and mine is that his engine started as a rusted hulk in awful condition after having sat outside for decades. My engine was kept in fairly good condition with minimal damage from the elements. He had many parts that had to be fabricated from scratch because the originals had basically disintegrated. Just getting his pistons out of the cylinders was a challenge.

Kurt assisted me with repairing one of the fuel injector pumps, the cracked manifold and made a big number of gaskets that I will need soon.

I’ve been deliberating on what to do with the crack in the exhaust manifold. Welding seems to be out of the question, or at least not without a lot of risk. Tapered iron plugs was another option but I was having trouble getting comfortable with that repair method. Since the water isn’t at a very high pressure level, I considered doing nothing at all and just letting it leak. But that might lead to longer term issues. It might be considered a hack by some (including me) but we decided to grove out the crack and fill with epoxy. I’m hoping this repair lasts but I could always go back to the tapered iron plugs. It passed the pressure test.

I’ve had the disassembled fuel injector pumps on my bench for a few months. There is one pump for each cylinder. An injector pump is a block of brass that has a plunger piston operated from the governor tower. There are two valves in the block, input and outlet fuel. One of the valves was stuck in the seat deep in the block. I had it soaking for a couple months but it refused to come out. There is very little to grab on the valve. Oddly, all the valves had a slot cut in the top to allow lapping to be done with a screwdriver but the one that was stuck did not have such a grove. We decided that the only option was to drill a hole in the bottom of the block directly underneath the valve so we would punch it out. This worked well but that valve was stuck in the seat pretty good. There had obviously been water in there and some rust had frozen it in place. We cut a new groove in the valve, cleaned it up and lapped it back in place. We then tapped the drilled hole and sealed it with a brass screw. All three pumps feel like they are working but of course will need to be tested.

The last task in my way before the main bearing work is the number one bearing cap. The repairs done by the shop a couple years ago are turning out to be more harm than good. The caps are held in place with 4 bolts and 2 taper pins. I did not discover until recently that the shop drilled out the tapered holes so I’ve lost the ability to accurately locate the bearing cap. Fortunately they did not drill out the block but just the cap. I’m considering bolting in place and reaming oversized holes into the block. There are some challenges with this that I won’t go into right now but short of finding another bearing cap, I’m out of ideas. I will see if my bearing guy has any other ideas.

One of the last big pieces to get attention was the exhaust manifold. It received a first-pass cleaning before it came off the engine but has been sitting on a cart ever since. I gave it a good cleaning and prepped it for painting. After the primer was applied it became obvious that what I thought was a casting mark is actually a crack below the middle clean-out port, most likely from a freezing water jacket based on the location near the bottom.

I loaded up the manifold for a trip to the welder. (It’s heavy. It squatted my 3/4 ton truck pretty good. Guessing maybe 600 pounds.) He thinks there is some risk in welding and suggested a tapered plug repair. I’m going to install the end plates, seal the openings and do a pressure test. Looking at pictures in hindsight shows a little bit of leakage evidence but no idea how long the crack has been there. The pressure test will tell me if I need to do something about it. Just waiting on more gasket material to arrive for the end plates. (Like a lot of things right now, some materials are hard to get. Been waiting two months for the large gasket material I need.)

A few months back I was debating whether to paint the engine or let it stay in its vintage patina. I was leaning towards keeping it as-is but changed my mind. There was a lot of peeling paint of various generations plus blobs of other paint most likely from the interior of the fish tug. And quite a bit of rust. As a (hopefully) running engine going forward, it’s going to get coated in oil anyway. Regardless, I’m committed now. The main color is “cast coat iron” with a darker machinery gray for various other components like the oilers, flyweight housing, heads and maybe a few other things. I also decided to not attempt painting the foundation but might change my mind on that one.

One of the subassemblies I worked on recently was the dial control. This runs from the throttle/timing control back to the air starter valve. Surprisingly, the timing shaft and control cam are serialized. Overall, it was in pretty good condition. This assembly is also interesting because it is obviously designed later than the engine. There were at least three types of control systems available. This one is the “C” family so probably the third generation. It includes cap screws, flange nuts and zirk fittings, things not seen anywhere else on the engine.

The air intakes were up next. They were disassembled and given a thorough cleaning before painting. These are interesting mechanisms. Being a valveless two-stroke engine, intake air is drawn in through the crankcase. The air intake valves are similar to a modern reed block. In this case the reeds are round brass disks. The disks are held closed by a series of coil springs. Vacuum caused by the piston moving upward pulls the reeds open to draw in air. I’m not sure how the engineers arrived at using disks but it is clever and simple. It is also very easy to work on. There are two of these per cylinder, one on each side of the cylinder base. Once again I was lucky to find the intakes in good condition. There were a couple of springs to replace but the brass reeds were fine.

Currently on the bench is the air starter distributor. This times the compressed air to each of the cylinders for starting. The air distributor has one of the few ball bearings in the engine. Unfortunately the bearing is in rough shape from rust. I did a search based on the information on the bearing and surprisingly the company is still in business (Aetna Bearing). I ordered a replacement for $37 direct from the manufacturer.

I still have quite a bit of cleaning and painting including a few large items like the exhaust manifold and transmission case. The weather has been very conducive to painting so I’m trying to get as much done this month as possible. I’m not trying to strip down to bare metal but to just get the loose paint off and smooth it out a bit. Below are the intake port inspection plates and the only castings with the “Kahlenberg” script.

I visited the “Albany Pioneer Days” threshing show this past weekend. I had heard there was a Kahlenberg on display and sure enough:

This is a B-series engine which has a 10″ bore. Mine is a A-series with 8.5″ bore but otherwise a lot of common parts. I got to see it run and talk with the curator. Another good source for information! It’s very enjoyable to talk with other Kahlenberg people.

It’s been a quiet summer for the Kahlenberg. We’ve been spending a lot of time outside and in the garden along with a couple of week-long vacations and family get-togethers. Most recently I stripped the foundation base to its bare minimum. I decided to not pass up the opportunity to give the base a thorough cleaning so it was loaded up on a trailer for a trip to the self-service car wash. I washed the underside at the car wash and then brought it home, flipped it over with the crane and power washed the top/inside. The bottom of the foundation had a much thicker buildup of grime so I didn’t want that crud in the driveway

The cylinder bases also received a power washing but these were manageable enough to be by myself in the driveway. The trailer made a good platform.

Now is the opportunity to paint these large pieces. I masked off what was necessary and delivered a couple coats of cast iron gray.

I’ll finish up cleaning and painting the cylinders but there are plenty of other tasks to do. I have a lot of gaskets to make and the gasket material I need has been backordered for two months. This fall we will be doing the babbitt work. More on this to come.

It’s never been clear in my illustrations how the transmission separates from the crankshaft. There just isn’t good detail and resolution in the transmission parts drawings I have. But the tip-off was in one of the tools provided with the engine (which I don’t have but it’s in the parts manual). The lift ring attaches to the front of one of the outside through-bolts. I fabricated a crude lift ring from a nut and eye-bolt with the mig welder. Despite hours of staring at it trying to figure out how to remove the darn thing, the transmission came off easily.

Last up was the crankshaft itself. Once the transmission was out, I removed the crank pin oilers and the bearing caps. Out she came without any drama. Not surprisingly, it’s darn heavy. To put the size in perspective, the length of the crankshaft is 7’-2”.

It took a couple hours to give the crankshaft a good first cleaning. The number two bearing has a lot of wear and left quite a bit of babbitt material on the shaft but otherwise it appears to be in very good condition. Four of the five crank bearings will need to be rebuilt along with all three rod bearings. This babbitt work is penciled in for the fall.

Next up is to get caught up with cleaning. I’ve taken off a lot of parts recently both big and small. Each cylinder is held on with 10 bolts, 7 nuts and 2 taper pins. Each one gets cleaned in the parts washer, wire wheeled and lubricated for storage. The cylinders and bases also need to be thoroughly cleaned and I’ve only completed one set so far. They are really nasty with caked on oil sludge. I wish I had a nice big automatic parts washer. Lots of paper towels, mineral spirits and WD40. After cleaning, parts get doused in PB Blaster or they will start rusting within an hour. I will also do some painting if it makes sense to do so before assembly. Lots of gaskets to make too.

Following up on a prior post, I made a replacement part on the lathe for the piston rod bearing alarm.

It’s been a lot of fun to figure out what everything is on the engine, particularly the little details. Lots of clever engineering. But I’ve been stumped by this one:

It protrudes into each crankcase above and a bit offset starboard from the crankshaft. Not shown is a jamb nut.

I’m sure there will be some old-timers who will see this and immediately say ‘you dummy, of course that’s the …. ‘. But I couldn’t figure it out. It didn’t touch the crankshaft. It couldn’t be anything electrical. Obviously deliberately offset with the ability to position as desired. It took a buddy coming over to have a couple beers in the shop to figure it out. By rotating the crankshaft he recognized that the piston nearly touched the brass “probe” at its lowest travel point. The outside bass rod is shaped like a whistle but it appeared to be solid inside. Then the light came on. It has to be a whistle.

Some may frown at this but I was curious. I could not resist the temptation to prove it. I rotated the “probe” (I still don’t know what it’s called) so the pin was at the top. Then I rotated the crankshaft and sure enough it sheared off the inside pin leaving a hollow body. Normally the inside brass rod is adjusted so it just barely clears the piston. If there was significant wear in the rod bearing there would be additional travel in the piston and it would shear off the inside pin. The outside brass pin that has the whistle cut is actually a tube with another pin pressed inside. That inside pin has a small beveled edge so air (crankcase pressure) could pass through and alert the operator of a problem before a catastrophic failure. I tried it with compressed air and the whistle is loud!

A brilliant and simple solution to an engineering challenge.

I have not seen this feature on the other Kahlenbergs I’ve looked at and it isn’t in my parts diagrams nor referenced in my copy of the operating manual. The crankcase is cast with provision for this specific mount point so it obviously came from the factory this way. Perhaps it was an option or something found on earlier engines (mine was made in 1946, not exactly early but about midway through the manufacturing life). The one I tested likely would not have worked because the internal hollow body was packed with corrosion and crud. That may be why I haven’t seen others.

I will remake the inside brass piece by threading and counter-sinking a 3/8″ brass rod.

After discovering one bad main bearing I decided that it would be prudent to get a look at all of them along with the rod bearings. There is more to the babbitt bearing story but that will come in a future post. I removed the cap for #4 behind the #3 cylinder. The top bearing half looked in good shape. I spun out the lower bearing by lifting the rear of the crankshaft slightly to take off some of the pressure. It spun out easily using a cut-down snowmobile hifax and rotated the bearing out. The lower half is okay condition but has suffered some scuffing. At a minimum it will have to be scraped but perhaps repoured.

Interesting to note that these bearing halves were repoured at some point. They are numbered #4 and #6 on both. Since this bearing is unique in the “A” series motor as being behind the last cylinder, the bearing would have originally come from a 5 cylinder engine.

Since line-boring will need to be done with any replaced bearings, it was made clear that the engine will need to be disassembled to the main foundation. For no particular reason I started with the #2 cylinder. The prior machine shop had been asked to remove the top ring ridge so the piston could be removed without damaging the rings. They didn’t do a very good job so I had to do a little hand grinding. It would be nice to have a proper reamer but finding one for a 8 1/2″ bore is tough without paying a lot of money. With that done I cleaned up the threaded hole in the center of the piston and installed an eye-bolt for lifting.

The piston and rod are heavy. I’m guessing well over 100 pounds. This one was grimy and full of carbon but overall looks very good. The rings are in surprisingly good condition. Mill marks are still partially visible. I cleaned up the rings and scraped off most of the carbon in the ring groves. I made some carts to assist with safe movement and storage of the large components.

Next up is pulling the cylinder and top case half. I fabricated a crude but functional cylinder lifting jig out of materials on-hand. These parts came off easily.

I recently removed the #1 piston. This one has a little bit of rust on it along with a partially stuck ring. The ring freed up fairly easily and I think the piston will clean up fine. I removed the rings, cleaned and lubed them. They look very good.

The rods are a three piece design with separate top and bottom bearings. The number two top bearing babbitt is heavily damaged. It looks like there may have been too much slop at some point and the ignition slamming beat on the bearing. The damage is centered around what would be just past top dead center, i.e. fuel ignition. This babbitt will have to be rebuilt. I was very surprised to see .090 worth of shims on each side. According to the manual these bearings are supposed to have .010 oil clearance which seams like a lot for 3.75″ diameter shaft. The operating engineer could remove a shim or two as the rod bearing wore. It’s really neat to see the things the designers did to make field repairs very simple.

The port-side oiler went along in a similar fashion to the starboard albeit a bit quicker the second time around.

I’m happy to report the first oiler has been rebuilt, tested and calibrated. It went back together without much difficulty. These are very well engineered. It’s obvious these are designed to be field repaired by the people who ran these machines.

I went back to the individual oil pumps and disassembled, cleaned, inspected, lubricated and reassembled. Repairs were few and minor. I got really lucky with the condition of these oilers. There was some rust and corrosion from moisture but the critical parts are all in fair to good condition.

Each pump assembly is really two pumps. The first draws in the oil from the sump through a brass filter screen. The adjustment rod sets the height of the cylinder which meters the oil pushed up the drip tube. Excess oil is returned to the sump or, in the case of one of the pumps, is used to lubricate the eccentric shaft. The operator can set the drip rate. All the lines on this starboard side oiler call for a rate of one drip per revolution of the eccentric shaft which equals 40 turns of the engine crankshaft. That would come out to about 9 drips per minute at normal rated engine speed. The metered oil runs back into the larger pump cylinder. Pumps like these had been also used in steam engines under high pressure. I’ve read these pumps can generate 300 psi.

Once everything was cleaned up I finished making gaskets. The case was thoroughly cleaned and got a light sanding to get rid of the flaking paint (2 layers). I painted the case but elected to not paint the top. The adjustment screws are peened on so these were best left alone. All are functional after cleaning and lubricating.

I’ve been working on the second oiler. It’s about 2/3 dissasembled at this point. Its condition looks similar to the first. There was a little more water in the second one but still not terrible. I don’t know if the same oil was used in both oilers but this one is much more goopy. The operation manual calls for engine oil in the port side oiler and light machine oil in the starboard oiler but I think some guys used the same oil in both. Machine oil was cheaper back in the day but I think diesel engine oil has been lower cost for some time so that’s probably what was used as a single oil in the later years.

Next up I’ll need to do something about the bad crank bearing. I need to consult with someone who knows babbitt bearings.