'78 Westfalia T2b Bus

New Engine

After a real long stuggle with overheating issues (see below), it turned out, that a used camshaft was responsible for high cylinder head temperatures and low power resulting in dropped intake valve seats and deformed cylinder heads. While I'm comfortable in doing top-end rebuilds (i.e. changing cylinders, cylinder heads, etc.), doing a bottom-end rebuild that involves splitting the engine case is something that I'd prefer being done by professionals. I was recommended that Gerd Kummetat in Gelsenkirchen is the rebuilder of choice.

I had the core of the engine shipped to his shop, where it was disassembled, cleaned and checked for wear. Since the shop specializes in tuning type1 and type4 engines, I was tempted to add some hp to the engine. It now has a higher compression due to Porsche 914 flat top pistons and the cylinder heads feature larger sodium filled valves. It's all balanced (flywheel, pressureplate, crankshaft and fan) and has a full flow thermostat in combination with a huge front oil cooler mounted below the front axle. All the sheet metal and the fan shroud were sandblasted and powdercoated. The only rusty part is the exhaust, which will be hopefully changed to a stainless steel 4-in-4-in-1, soon. Gerd Kummetat is a very nice guy and I could spent 3 days at his shop and assemble all the non-core parts to the engine while he was supervising. Really learned a lot that is not written down in any manual!

Historic Licence

In 2010 my bus got a historic licence! At least some reward for the time and money spent in keeping it running and doing all the restoration work. All interior is original, with minor modifications to nicely accommodate two persons on longer vacation trips.

These images have been taken prior to me taking out the engine once again since a dyno test reveiled that it has only 52hp instead of the 70hp a stock 2.0 liter engine with dual carbs should have. A teardown of the engine finally showed that a badly worn camshaft caused severe “breathability” issues which lead to reduced power and overheating issues.

Wideband 02 Sensor Install

In order to examine why I'm ruining one set of cylinder heads after another I decided to finally get myself a wideband O2 sensor to measure the air-fuel-ratio (AFR). Prior to this I ruled out all apparent sources that could cause overheating, e.g., air leaks in the intake section, timing, valve clearance, leaking brake booster, etc. Hooking up the LC-1 is not easy in an aircooled bus since space is confined and the stock exhaust does not provide a suitable “header” to weld the bung to. Therfore I ordered a 4-in-1 exhaust that has a few inches of space to accommodate the bung and sensor. Note that the sensor is not a cheap narrowband sensor, but a Bosch wideband type.

It turned out, that the engine is not running lean under all types of load, but cylinder head temperature (CHT) is still way too high. Experiments with larger main and/or smaller air correction jets did change the AFR, but CHT was rather unimpressed. While I was fiddling with the carbs anyway, I properly adjusted and synchronized them according to the Bentley manual. The engine runs much smoother now, but the temperature problems remained unchanged.