Three Letters Re: Choosing a BOV

Hello Jim, et al,
Reading Choosing a BOV by “Brian B in Iraq”, there are a few inaccuracies that I should mention. Some of the statements are definitely subjective, but I’ll leave those alone and just deal with the factual stuff:
Regarding this statement: “These “first generation” Cummins trucks used a Bosch rotary injection pump (called a VE pump)….” This is incorrect. The First Generation trucks used, and use, the P7100 Injection Pump. The “Bosch pump” is the VP44, used in the Second Generation trucks. There’s a huge difference between the systems, and I’m not going to go into that, since it’s a complete article by itself. Suffice to say that the author seems to have reversed the information.

Regarding this statement: “The timing gear cover on the front of the motor uses dowel pins to line up the cover when being installed. Unfortunately, in some cases this dowel pin can vibrate and back out of their spot falling down through the timing gear case causing lots of damage before ending up in the oil pan.” Again, incorrect. The dowel pin (usually called the “KDP” or “Killer Dowel Pin”) aligns the gear housing, not the timing gear cover. It does have a tendency on some engines to back out, fall into the gearset, and jam between the gear and gear housing, cracking the housing and giving [the engine] a lovely oil leak. [Preventing this is] a very simple fix to deal with, and is most commonly a problem that occurs on the 12 Valve engines, but the 24 Valve engines are most definitely not immune to it.
Regarding this statement: ” The engine coolant should be a greenish color…” The author is ignoring, or not aware, of current antifreeze formulations that are required by newer engines (heck, even my 2001 ISB Cummins uses them) such as Dexcool, which is an orange color. Some people mistake it for rust, but orange is the normal color. Note too, that there are untinted antifreeze formulations out there.

Other items in the article are minor, but these are the ones that jumped out at me.
As to my personal knowledge, it comes from owning a 1985 Suburban with an 2001 Cummins ISB and extensive modifications, older Dodge 12 Valves, a M35A2 2-1/2 ton with the LDT in it, various Kubota diesel engines, the early GM diesel, Cat, DDs, et cetera. All of these vehicles, plus plenty more, have had all the work done by yours truly. Gearheads never quit! Thanks for the site! – Czechsix


Mr. Rawles:

I’m not a chronic nit-picker, but there are many errors in the post written by Brian B in Iraq – titled “Choosing a BOV.”
This can be misleading to someone seeking information on the subject. He certainly includes a lot of good information, but some of the errors need some repair.
I’ve been a diesel mechanic and owner for 40 years and own over 30 diesel trucks and SUVs. I worked on, and drove many when new. Here are some citations from Brian’s post – and my replies.
Brian wrote: “Indirect injection systems spray the fuel into a prechamber where the combustion process begins. This prechamber is also the location of the glow-plugs for help starting the truck in cold climates. This is a very inefficient but durable design. Direct injection systems spray the fuel directly into the cylinder where combustion occurs. This is a much more reliable and efficient system.”
My reply: No, IDI is not very inefficient. Often, it comes to a 5-15% difference, but sometimes there is none. Some direct-injected diesels are less efficient than some indirect-injected diesels. Many of the newest diesels out now, for model year 2008 offer the worst fuel mileage ever – and they are using state-of-the-art combustion chambers and fuel-injection-systems. The new direct-injected Dodges and Chevys have tested at 13 MPG overall mileage, and the new direct-injected Ford at 10 MPG. Going back to the early 1980s – many indirect-injected Chevy diesels averaged 16 MPG and Fords 13 MPG.

Brian wrote: “For those of us who have decided on a diesel powered vehicle, you’re now faced with choosing from three different manufacturers. GM, Ford, and Dodge.”
My reply: No, that’s not the case if looking for older vehicles – which seems the be the main point of the original post. Isuzu turbo-diesel Troopers, International Harvester turbo-diesel Scouts are certainly still to be found. I own several. Also, smaller rigs e.g. Isuzu PUP 4WD trucks with 2.2 diesels, Chevy LUV 4WD with 2.2.diesels. Chevy S10 diesel trucks, Ford Ranger with Mazda 2.2 diesels, Toyota diesel trucks, etc. Also a lot of little Chevy 4WD Trackers that have been converted to 1.6 Volkswagen diesels – a real easy swap – but not factory made like the rest. Also very popular are 1/2 ton trucks with Cummins or Isuzu 3.9 liter diesels installed. Many companies now offering the conversion-service. This results in a 1/2 ton 4WD truck that can get close to 30 MPG highway, and over 20 MPG around town. In Europe, the same swap is very popular with Land Rovers, Range Rovers, and Toyota Land Cruisers.

Brian wrote: “GM, for a brief time, installed diesel engines in their half ton trucks, but they are rare and hard to find.”
I find them all over, and 1/2 ton GM diesel trucks were never rare. All the Oldsmobile 5.7 diesels in the 70s Chevys and GMCs were 1/2 ton but the engines were terrible. [That changed.] Starting in 1982 with the Detroit Diesel-designed 6.2, GMC and Chevy sold thousands of 1/2 ton K5 diesel Blazers, 1/2 ton C10 and K10 diesel pickups, 1/2 G10 diesel vans, and 1/2 C10, K10, and V10 1/2 ton diesel Suburbans. The US Army bought 24,000 1/2 ton diesel Blazers in 1984 [and designated them CUCVs], and more later on. GM sold over 10,000 civilian diesel 1/2-ton Blazers in 1982 along with 1/2-ton pickups, Suburbans, etc., and continued to sell them until 1991 when sales dropped off to 92 for Blazers. In 1988, Chevy came out with a new generation 1/2 ton truck with the 6.2 diesel using a new body style, serpentine belt system, and independent front axle. The heavier trucks were not changed at that time, nor were the Blazers or Suburbans. During the 1990s, GMC and Chevy sold 1/2-ton trucks, Blazers, etc. with the 6.5 diesels.

Brian wrote: “A turbo will give you more power and better mileage so if you can find a turbo charged motor that’s the route to go.”
My reply: No, not true with all. A turbo raises effective compression ratio – and – enables an engine to burn more fuel and make more power. With most turbo diesels driven on the road, the result is less fuel mileage and more power. Years back, turbochargers were more commonly referred to as “altitude compensators” and were used to restore power at high altitudes – not make more power a lower altitudes. A diesel with no turbo loses 1% of its power and fuel efficiency for every 328 feet it’s driven above sea-level.

Brian wrote: The older mid-80’s trucks will likely have a 4-speed manual or 3-speed automatic, none of which have an overdrive gear to save on fuel consumption.
My reply: Again, not true with all. All GMC and Chevy 1/2 ton diesels if equipped with automatics had a .7 overdrive via the 700R4 transmission with lock-up torque converter. For standard shift, all the 1/2 ton diesels were available with the New Process 833 four-speed manual with overdrive. I own four of them. Later , around 1988, GM offered NV3500 five-speed manuals with overdrive in the 1/2 ton trucks.

Brian wrote: “The GM trucks and Suburban’s also had one additional limiting factor, the front independent suspension, which improved ride quality and handling substantially, but the tradeoff is off-road capability and the ease with which you can install a lift kit on the vehicle.”
My reply: No, not true with many. All the GMs had solid front axles until 1988. Then, only the 1/2 trucks went to independent. The 3/4 and 1 ton trucks, as well as all the Blazers and Suburbans kept the solid front axles until the 1990s.Brian wrote about Ford diesels: “by 1994 a 5-speed manual was standard and a 4-speed automatic was optional. These trucks are pretty bulletproof and maintenance friendly and get marginal fuel mileage. A 4×4 3/4 ton 7.3L turbocharged truck will likely get around 15 mpg average and go 200,000 miles between overhauls”
My reply: Yes, they were rugged trucks except the fairly new Ford four-speed automatic overdrive – the E40D. It was prone to problems – very expensive ones and still is unless it receives many updates and improvements.
Brian wrote: “Beginning in 1989 Dodge began installing a 12-valve 5.9L I6 diesel produced by Cummins with mechanical direct injection. In 1991, Dodge added a turbo charger and intercooler as standard equipment”|
My reply: No, the turbo was not added in 1991. All the Dodge trucks with Cummins diesels were turbocharged since the first year – around 1989. Dodge did sell 1/2 ton and 3/4 ton trucks for one year in 1978 with a Japanese Mitsubishi 6 cylinder diesels – but that is something completely different. That engine was 243 cubic inches, i.e. 3.9 liters.

Brian wrote about the Dodge diesels: “The 1994 to 1998 trucks are probably the most sought after trucks. A typical 1/2 ton 4×4 truck with 5-speed transmission and 3.55 axle ratio will get 20-22 mpg and these trucks regularly go 300,000 miles before major work needs to be done.”
My reply: Dodge never -ever – made or sold a 1/2 truck with a Cummins 5.9 diesel. Also, Brian mentioned earlier the reasons to stay away from independent front axles. The 1989 to 1993 Dodges have solid front axles, and the later 3/4 ton models he refers to here have independent front axles. The older trucks get just as good fuel mileage as the newer ones and often bring more money if found in good shape.
Brian also wrote: “Unless you are really squared away and have the finances to allow it, many of us simply can not afford a dedicated BOV in addition to our regular daily-use vehicle.”
My reply: With the money I see many people spend these days on dinners, vacations, etc., I find it hard to believe that someone serious about this matter – cannot afford $500- $2000 for an extra vehicle as a project – and/or an emergency-use vehicle. If you have no mechanical skills – then you are subject to either paying a lot of money to someone who may – or may not be worth it. Or, pay more for a vehicle in better shape. That being said, I find many diesel 4WDs, in good running condition in the $1,000 price-range or less. School districts often sell Chevy 4WD diesel Suburbans in good running condition for $250-$500. I just bought a 1991 for $225. – John in Central New York.


I have been going through the BOV dilemma myself with the size of my family I can not just have one vehicle. So what I have done is rebuilt my 1 ton Chevy crew cab 4X4 in which I have sunk a great deal of money in it but it is nearly bulletproof (all but the windows anyway). The place that rebuilt my Chevy crew cab is they have great shop rates ($35 per hour) and they do a great job. My large BOV is now a 6X6 that can also be run in more fuel-efficient 2×4 mode. It has a military surplus multi-fuel engine engine that can burn just about anything: gas, diesel, biodiesel, WVO, JP-4, kerosene, perhaps even turpentine. It has 2-1?2 ton axles and brakes, and many other extras. It has a hitch for a 5th wheel (flat bed) trailer which I have stocked for Bugout at all times. My wife has an Isuzu Rodeo that I know that many of you said was a bad choice, but for the money and with the testing that I have put it through, this is [still] the secondary BOV that I have chosen for my wife. It is very kid friendly, four wheel drive, and we got the flex fuel version which means that it will burn E85 Ethanol fuel. This also has a small trailer that has my home made power plant on it. Our third trailer [assuming I have the chance to pre-position or make two trips to my retreat] is my camping trailer. It [is ia “Toy Hauler” style trailer that] can accommodate two ATVs, tool boxes, fuel and water barrels and so on.

Now, as for routes not only should you have roads picked out but also possible some off-road routes by mapping the possible detours. This is made easier by making some friends with the farmers [at key points on your route. For example, I live in the Portland-Vancouver area and my retreat is in Idaho. I have flour main road routes but I also have several back off-road detours and farming and ranching friends that wouldn’t mind if I use their gates.

Just about everything that Brian B. in Iraq said was correct except tires I would use the 37” tire because you can get those in Kevlar and there are many run-flat systems that can be used for that size. If you go with smaller or larger there are not that many options. – CDR