The Piaggio porter and Daihatsu Hijet share the same diesel engines funnily enough seeing as they are the same van! Actually if you look at you chassis plate on a Hijet you’ll find it says Piaggio at the top. They were all made in the same factory in Italy under licence from Daihatsu. Anyway they don’t seem to be the most hardy of engines, made by Lombardini who are a big commercial engine supplier across Europe, they make engines often found in plant equipment, generators, boats etc.
The engines installed into the Porter/Hijet are the 1.2 and 1.4 engines of the Lombardini series “LDW FOCS”, the 1.2 is noted as the LDW1204P and the 1.4 LDW1404. The 1222cc LDW1204P is a 4 cylinder 8 valve unit which makes 75Nm at 2200rpm with a massive 33.2bhp. The 1372cc LDW1404 is also a 4 cylinder 8 valve unit packing 35.2bhp with 84Nm at 2000rpm. Neither are exactly the most powerful of units but are great diesel power plants for the little Hijet.
You are most likely to have stumbled across this page looking for solutions or help with your broken hijet! They seem to often fail from knocking or ratting engines, or oil loss and compression loss. Being such a small simple engine they are easily removed and rebuilt but the hardest part is finding workshop manuals for information such at head bolt tightening torque measurements, timing marks and other specifications. Here are a couple of links which may help your cause! Firstly we have the full manufactures engine manual – “Manuale Officina LDW” – luckily translated into english LOMBARDINI DIESEL ENGINE MANUAL LINK while this other side offers a full Lombardini engine component webshop with an online database with reference diagrams Daihatsu Hijet Piaggio Porter Diesel Engine Parts Shop. Hope this helps you out and don’t forget to join the forum where you can pick the brains of others who may have walked in your shoes with the Lombardini Diesel engine.