The Isetta Saga, Chapter 7: The Art & Science of Isetta Engine Disassembly

In Chapter 6, we saw in pictures and words how the chassis was the first component to be transformed from rusty hulk to freshly painted beauty (if an Isetta chassis can be beautiful).

In Chapter 7, we discover the secrets to taking apart what is essentially an air-cooled BMW motorcycle engine. Then we do it two more times.


 You cannot embark on a project of this magnitude and expect to do it alone. This is especially true for tasks you’re performing for the first time. At some point, there will be the need to rely on, and to seek expertise from, those who have done these things before you. This is the theme for this Chapter, and this concept will certainly be revisited again.  

 I’ve related in earlier Chapters how glad I was to discover other hobbyists who were Isetta restorers and collectors. There was some knowledge-sharing, and just as important to me, there was satisfaction in knowing that parts availability could be fulfilled through some of my fellow Isetta fanatics. Now, as I was about to start a mechanical teardown and rebuild, I really needed some assistance from others.

 Two gentlemen who were serving the Isetta community, John Jensen and Ron Krause, were both huge factors in the success I had with my engines. Simply put, this restoration would have faced a far rockier road without them.


With the cleaning and painting of the bare chassis done, I had to decide which mechanical sub-system to work on next: engine, gearbox, rear axle, electrical, suspension, or brakes. Bodywork, which I would not be doing myself, would be postponed until most or all of the mechanicals were completed.

The decision was made to begin with the engine, as that would potentially take the most time. Also, from staring at these engines over the last few years, I still did not know how to take the one-cylinder Isetta engine apart. To be specific, I saw no way to remove the crankshaft & connecting rod from the crankcase. The case was one piece; it was not “split” the way an air-cooled VW or Porsche crankcase is. And as near as I could tell, the bottom of the connecting rod was not split either. At least I couldn’t see or feel any bolts which would hold an end cap in place. Whatever the trick, this was nothing like any other automotive engine I had worked on.

I was now subscribing to Minutia, the quarterly publication of the Microcar & Minicar Club. In a recent issue was an ad from a fellow named John Jensen (I recognized his name from the old HMI Club). He was advertising a book he had authored and self-published (come on, you think Random House was interested?) entitled “Isetta Restoration”. He claimed that the book was a detailed account of the restoration of his own Isetta. It seemed expensive at $42 in 1992 dollars, but I purchased it.

A postcard advertising John Jensen’s “Isetta Restoration” book

The memory of getting the book in the mail and opening it is vivid. The first thing I looked up was “engine disassembly”. I’ll paraphrase what was in the book:

            “The Isetta crankshaft is a two-piece affair, with the two halves pressed together through the bottom of the one-piece connecting rod, which rides on a roller bearing. To remove the crankshaft/con rod assembly from the case, you must heat up the case to a temperature of around 400 degrees F. Doing so expands the aluminum just enough so that you can wiggle the crank/conrod out of the front opening. Be sure to use oven mitts!”

For me, this was as good as “X” marks the spot on a treasure map. I couldn’t wait to try this. But first I needed to make a decision: WHICH of the three engines would I rebuild?

Yes, I was in possession of three engines, all in various states of disassembly. Taking an approach I had already used with the bodies, carburetors, and other systems, I decided to disassemble all three engines, and take stock of what I had. I cleverly labeled the engines A, B, and C. Three cardboard boxes were also labeled A, B, and C, and were positioned under my workbench. As parts came off, they went into their respective box.

Engine B’s oil pickup had been in more water than oil

At first glance, all the engines looked questionable, as they had been open to the elements for many years. With front covers and oil pans removed, the picture became clearer: the ones which kept oil in them looked better, if a bit black. And one looked like it had been lifted from the deck of the Titanic (not really, but it certainly had been in water).

Based on this visual inspection, I decided to rebuild two engines, one for my car, and one for my step-son’s. The third engine would be sold for parts, which would help fund the project.

A colleague at Volvo, Steve Kraitz, was also a part-time carpenter, I showed him a page from Jensen’s book which detailed the construction of a wooden engine stand that could be bolted or clamped to a workbench. Steve gladly agreed to build this for me, charging only for the cost of the wood. That stand was a major help with the engine rebuilds. Because the engines are so small, it was a simple matter for one person (me) to bolt the engine to the wooden stand, and then lift and bolt the stand to my workbench.

ENGINE A:

Engine A on plywood stand, about to be disassembled (stand is bolted to workbench)

 

Coked black, here are engine A’s chains and sprockets pre-cleanup

 

Snap-On puller used to pull cam sprocket; wrench stands in for leverage

As engine parts were removed, they were cleaned, labeled, and returned to the appropriate box. I now had three engine crankcases, with everything removed except crankshafts and connecting rods.

Time to fire up the blue torch.

My trusty Bernz-o-Matic was pressed into action. I selected Engine A. With the exterior of the crankcase as clean as possible (I didn’t need to add to the drama by igniting any errant sludge), I moved the flame around the front of the case. The crankcase, of course, was bolted to the plywood engine stand, so I couldn’t get too close to that either! It felt like an eternity, but after about 15 minutes or so of heating, I guessed that the aluminum had absorbed as much heat from a propane torch as it was going to.

I grabbed the oven mitt which I had thoughtfully brought down from the kitchen, grabbed the nose of the crankshaft, and worked it forward. I had to experiment with tilting the shaft to get the connecting rod to clear the opening. It looked like it wasn’t going to come out. Moments passed. The crankcase was cooling off.

POP – I must have blinked, because in the next moment, I was holding onto a crankshaft/conrod assembly OUTISDE the crankcase. Yahoo! I exclaimed (before that was a search engine).

ENGINE C:

A very filthy Engine C assumes the position

 

Armature off, engine C shows a lot of rust behind the front cover

 

Engine C’s crankshaft and crankcase separated

I stopped for now. This was too much excitement for one night. I worked on the next two engines on subsequent nights, with the same success. But the next step was still a problem in search of a solution: how was I going to separate the crank halves so that a new bearing could be installed?

The 3 bare crankcases. None showed any sign of wear or damage.

In the early 1990s, Old Cars Weekly was a viable publication in the hobby, and I subscribed to it. The classifieds in the back could be helpful, and it was here where I noticed a vague ad from someone who offered Isetta restoration services. His name was Ron Krause, and he was in Emmaus, PA, only an hour from my house. But first I decided to give him a ring:

RR: Hi, I’m calling to find out if you can rebuild Isetta engine crankshafts.
RK: Sure, just bring me the engine so I can remove the crankshaft and examine it.
RR: Oh, the crank is already out of the case.
RK: Who did that?
RR: I did.
RK: YOU are a genius.

I tried to remain humble at this inference of my intelligence level (really, I was just a tech with a blowtorch). But Ron was OK with me bringing the crank/conrod assembly to him. We agreed that I could drive out on a Saturday morning to drop it off.

The front of Ron Krause’s Isetta “dealership” (note Honda 600 at end of row)

The following weekend, I arrived in Emmaus in front of what looked like an Isetta new car dealership. Out front, there was a glass-walled showroom with several restored Isettas. Inside was a service area with cars-in-progress, along with several chassis. Ron himself was behind a parts counter, assisting a customer ahead of me. It was 1957 all over again.

Ron Krause had been a successful Honda dealer principal. As I understood it, he got into Hondas very early in the game, sometime in the early ‘70s. He prospered through all the boom years, and then decided to retire. He sold the franchise, and the new owners had to relocate when he retained ownership of the property. He kept the building where his Honda dealer was, and turned his hobby into an Isetta business. Here was yet another “character”, as seemed to be the trend among people who liked Isettas (not sure what that said about me).

I had time to wander around while waiting for him to finish with his customer, and I couldn’t help but observe that as nice as his restorations were, they were not done to 100% original standards. There’s nothing wrong with that if that’s what you want, but many of these restorations were not my preference. He especially favored inauthentic colors. A rare bubble-window convertible was a quality job except for its metallic turquoise paint. Not quite as bad was the white sliding-window convertible with blue body accents.

When Ron finally came out from behind the counter to greet me, he also went back to work on one of the chassis. While we talked, he cut an intake manifold in half so that the two halves could be re-welded with one end rotated 90 degrees. Ron made no secret of the fact that he “hated” the factory Bing carburetors. No doubt driven by his long-term Japanese car experience, he said he converted ALL his Isettas to run on Hitachi carbs. The reconfiguring of the intake manifolds was all it took for the Hitachis to bolt right up, at least according to Ron.

Restored chassis in front, Ron Krause in rear (wearing Honda smock)

He agreed to rebuild the crankshaft and con rod assembly for me, so I left it with him, but not before inquiring about other parts he might have. It felt like quite the stroke of good luck to have several sources of Isetta parts (first Isetta Johns in Rutherford NJ, and now Ron Krause) within an hour’s drive of me. Things were looking up in my quest to get this project on the road by 1995.

My signed receipt from Ron Krause, proof that he had my crank

 

Chapter 8 of the Isetta Saga will detail progress on suspension, wheels, and tires happening while we patiently wait for the Krause crank creations (moan).

All photographs copyright © 2018 Richard A. Reina. Photos may not be copied or reproduced without express written permission.

 

FUN FACT OF THE WEEK:

Today we take for granted that the Japanese “Big 3” in the automotive world are Toyota, Nissan, and Honda. Toyota built its first passenger vehicle in 1935; Nissan was building cars under the Datsun name around the same time. But Honda started much later: its first vehicles went on sale in 1963.

While it entered the U.S. market in the late ‘60s with some quirky small cars, its first mainstream success was the introduction of the Civic in 1973, which stood out as one of the few front wheel drive vehicles available in any segment. The Accord was introduced in 1976. Both the Civic and Accord have been in continuous production since their introductions in the ‘70s.

 

 

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