Wednesday, October 19, 2022

Ranger Biodiesel Swap - VW 1.6NA Engine Refresh

I debated which engine to select as a donor, and settled on the iconic Volkswagen inline-4 cylinder. There are multiple options for displacement, natural- or forced-induction, electronic or mechanical, unit or common-rail, so I spent months researching and browsing Facebook Marketplace. 

One day, I stumbled across a 1.6L NA barn-find engine from an early 80's Rabbit. The price was right (super cheap!) and it was mostly complete, so I drove to Lancaster PA to retrieve it.

The 1.6L NA engine was only rated at 55hp, and was considered SLOW even when new. This particular one was also in less than ideal condition (as you'll see), and may not run well enough to be the final donor engine for this project. Despite that, these do have a reputation for reliability and fuel economy, so it was worth the risk.

However, one major advantage of the VW 4 cylinder diesel, is that the bolt patterns and block dimensions are nearly interchangeable across 30 years of production, so fabricated adapters will be reusable. Any engine mounting brackets, flywheel adapters, or bellhousing adapters that fit a 1.6L NA will also fit a 1.9L Turbo engine. Worst case scenario, this 1.6Lwill work perfectly as a mock-up engine.


Barn-Fresh and ready to rebuild.

Quick trip to the carwash for some quality time with a high-pressure wand.


Unfortunately, a mouse had built a nest inside the cylinder #1 combustion chamber, so it was necessary to pull the head and perform a quick top-end refresh. I scraped the carbon off all 4 piston domes, cleaned the bores of all debris and corrosion, and relubricated everything to soak the rings.



I also discovered stress cracks between the intake and exhaust valves on all 4 cylinders, which is apparently a common and ignorable design flaw with these engines. I decided to grind out majority of the cracks, and polish the remaining affected material to prevent localized overheating.




Finally, I retapped all of the external threaded lugs, scraped off the loose paint and rust, degreased the block, and repainted with a fresh coat of "Detroit Diesel Green"







The top end was treated to a fresh set of gaskets and seals, a new timing belt and tensioner kit, and the intake from a later-model engine.











 

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