Broken crankshaft

[Hooligan1948]

I bought this camper back in November in Portland. It was making a bit of noise when I left for Long beach. The noise would best be described as a main bearing rattle at about 2000 rpm but, I was planning to build the motor when I got to Florida. I made it to Long beach with minimal issues and the rattle hadn't gotten any worse. I left it with a mechanic to do some work, (Jim's VW Service) for a couple of weeks while I returned to Costa Rica. In Mid December I returned to start my cross-country drive. Jim pointed out the rattle and thought there was a good chance that I wouldn't make it. Three thousand miles later i made it by keeping it out of that 2000 rpm awkward zone but, after a couple weeks of Florida driving it started making a racket and I pulled over to call for a tow. Here's what I found.

The cheeks on either side of that center main bearing are considerably weaker than to the connecting rod journals.

Definitely a forged crankshaft, certainly not cast.

The bearing looks like it has been overheating due to a loss of oil.

From here the cases are going to Randy's VW in Comfort Texas to check the alignment and have it machined for the rebuild.

[SGKent]

most common cause would be either lugging the engine at low RPM, or using a lightened flywheel. Type IV are pretty strong but the type 1 cranks used to do that all the time when lugged in traffic. Lightened flywheel or TC will move the harmonic spot into a journal like where yours broke. It shows signs of a fresh break and not a long time coming one.
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"Most people don't know what they're doing, and a lot of them are really good at it." - George Carlin

[Abscate]

Small keg of JB weld and You’ve got a GEX replacement OE rebuilt crank ….
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[Wildthings]

Might have been damaged in some previous engine failure and what at that time was a tiny crack got overlooked by the engine builder.

[timvw7476]

every time I even partially lug a Type IV, even dropping down a gear as I crest any hill, I visualize this.
Turns out it looks just like I imagine it.
29 years, still haven't cracked one. 1800 & 2L.
Downshift people. The crank you save may be your own.

[SGKent]

[Hooligan1948]

The fuel injection had an issue when I first bought it that two shops in Portland and one in Long Beach couldn't fix. The bus would run 85 on level pavement but any type of incline that necessitated a little more throttle, would result in bucking and hesitation that downshifting would not take care of. Sometimes I would be down to 35 mph. That's when I decided to switch to carbs going forward. I'm sure that aggravated the situation but, there was an issue that I inherited indicated by the bearing rattle at 2000-2200 rpm. My tactic was to load the motor up with 50 weight oil and STP oil treatment and to keep the rpm above 2200 rpm as much as possible. It worked.