Words of Wisdom

November 07, 2007

Topic #2

Buying used diesel engines:

Today's topic will elaborate on brands of diesel engines suitable for industrial, automotive and marine applications.

My favorite diesels are mostly of Japanese design. They tend to build them rather well with long lifespans. Isuzu, Kubota, Mitsubishi, Yanmar are the most popular in the US. I have been working with various models of these brands for many years with mixed results. Over the last 20yrs these brands have gone through a transition to provide better engines especially concerning exhaust emissions and reliability, parts availability etc. It seems to me that the companies are teeming up providing engines across their model lines to fill in where some lack models that comply with the new Tier system. The Tier system started in 1998 with the Tier 1 in 2000 and the Tier 2 in 2004. In early 2008 I believe the small diesels will be meeting Tier 3. The Tier compliance labels are required on all diesel engines built to US standards. If you run into ones without this label then it is either before the Tier regulations or a non compliant engine. I have not seen any large changes except in actual noticeable smoke. Fuel is a big component to meeting these regulations. I find for example the high rpm Kubota and Yanmar generator sets emit excess smoke if run on old #2. They seem to run best on the new low sulfur fuels. The L series Yanmar and the Kubota mini 5 series ie the Z482E and V722E we have in our portable 3600 rpm diesel generators are perfect examples. The Yanmar diesels seem to eat any quality fuel we have dumped into them without any problems. These are only the 3000 rpm or less including the 1800 rpm diesels. 

The Isuzu engines are one of the cross branded engines now using in the smaller sizes variants of Yanmar TNV engines. In  the past Isuzu used their own designs exclusively with great results. We have found them in various brands of equipment like light towers, skid steers, compressors etc. These are characteristic of having individual injection pumps for each cylinder. Never even consider their earlier units with overhead camshaft. There was a KR and KC engine that should be avoided (crap). The only older engine in the smaller sizes the C240 used in truck reefers and other applications were of bulletproof design. Kubota had had mostly nice models as had Yanmar. The Yanmar L series an aluminum one cylinder design is a good engine as I have rebuilt several. The Chinese picked up on this design back in the 90s and are dumping clones on the US market. They may look like the Yanmar L series but not half as good and most do not meet emissions. 

Yanmar has made inroads into the marine market big time. They have been using their own and other brand engines like from BMW and Toyota. I have seen some really bad examples of what happens with some of these non Yanmar engines when overheated, overloaded, and misapplied.  Most are light weight for non commercial boats. It is obvious when non of these are in any industrial equipment. Yanmar has some great little marine diesels superior to anything else out there especially for auxiliary power. They now offer and we built using a series of marine generator drive engines that are as good as any land based system. We have them in commercial applications with excellent results. The Yanmar TNV series for industrial and backup power are another good example of a durable system. The best thing about these engines is that Deere uses them in their small equipment so service and parts are readily available. The small  Isuzu and Deere engines being Yanmar have the same advantage. Kubota is in a similar situation with service centers all over the place. We end up purchasing Kubota parts from a local retailer for quick repairs.

Mitsubishi diesels are just starting to become more available in my area for fabrication of new equipment. They are simple engines of solid design. A few fabricators like Westerbeke have been using them for years. They do not make this well know so as to make parts more proprietary to their applications. Vetus and others are using them with good results. With my resistance to the most modern electronic designs these small diesels have gotten my interest as an easy machine to work with. Luckily all of the little ones have retained their simple mechanical components. Hopefully this does not change any time soon.

Next we will go over US and EU models.