APPARATUS REBUILDING

APPARATUS REBUILDING

APPARATUS/EQUIPMENT

“Enough has been written about the dollar issue. But dollars should not be the only consideration. Dependability, reliability, safety and downtime must be considered as well.”

Let’s face it, the only reason we are becoming involved in rehabing, repowering and reconditioning our fire apparatus today is money. A lack of it! Even with an economic turnaround, the economics of rehabing, repowering and reconditioning will not be quickly forgotten by the decision-makers in government who control the purse strings. We may as well learn as much as we possibly can about it.

The first thing that needs to be addressed is a definition of terms. The reason this is so important is that we hear these terms used and do not always know what they mean, like “heavy duty” and “deluxe.” Without definitive guidelines, you really do not know what they imply!

The most commonly used terms are “repower,” “rehab” and “recondition.” Rehab is a combination of repower (engine and transmission replacement) and reconditioning (disassembling the complete unit, cleaning, replacing all parts subject to wear, reassembling, painting and testing).

Reconditioning a vehicle is basically an attempt to bring the vehicle back up to original specifications with the same original components, whereas rehab is an attempt to upgrade the vehicle and bring it in line with the present state of the art.

Repower can best be explained as a rehab of the drive train. The primary purpose is to replace a gasoline engine with diesel. The balance of the work required on the vehicle is generally a spinoff as a result of the engine change. It is in repowering that we face the greatest potential for mistakes. This is true whether repower is part of a total rehab job or simply a repower.

Let’s look at reconditioning, repowering and rehabing individually for the purpose of identifying the considerations that should be addressed before a decision can be logically made on the feasibility of any one of the three.

RECONDITIONING

As mentioned earlier, reconditioning is an attempt to bring the vehicle back up to original specifications using original components. Therefore, it is the least complicated to address. The most important question to be answered is whether it is practical to recondition the vehicle. Areas which need to be addressed are:

1. Will this vehicle continue to be practical in our department during its extended life cycle? If you are not currently happy with the vehicle regardless of the reason or reasons, you should not extend the misery. Reconditioning will not reengineer or otherwise change its characteristics.
2. Will parts be available during the extended life cycle? Many factors come into play here. Age of the vehicle, number of this type originally built, whether commercial or custom chassis and the original manufacturer. You should look for similarity with the current market of the vehicle subcomponents, brakes, suspension, steering, engine, transmission, pump, transfer case, differential, electrical system, cooling system, etc. All of these should be reviewed in some detail before a logical decision can be made. You are more likely to have parts available on a custom manufactured vehicle than a commercial vehicle of equivalent age. The original manufacturer will be a big factor here. Talk to Deople with like equipment to help estabish current parts availability and commitment to provide service. Keep in mind the quality of the vehicle and its subcomponents when originally manufactured. This should play a major role in the decision.
3. How has the cost of operating this vehicle compared with others of equal age and usage? Experience has shown that a reconditioned vehicle will cost a minimum of 10 to 20 percent more to maintain than a new vehicle. If the vehicle has had a history of mechanical problems, etc., reconditioning will not reverse the trend! Get rid of it and start over.
4. Is reconditioning this vehicle cost effective? What will it cost to replace? What is the vehicle worth? How long will it last when reconditioned? Hpw much will it cost to recondition? What will it be worth when we eventually sell it? What will it cost to replace at that time? All are important questions that should be answered before a decision can be made.

REPOWER

The considerations for repowering include the same questions we addressed in reconditioning. The difference as mentioned earlier is that in repowering we will upgrade the drive train to take advantage of the benefits of a diesel engine.

There are obvious advantages to this such as greater fuel economy, longer life, more torque, higher horsepower, longer maintenance intervals and less downtime compared with gasoline engines. Repower is an alternative for existing vehicles. The parts are readily available. Although the process is not too difficult, it is complicated and should not be considered as simply dropping in a new engine.

Those deciding to repower instead of respecifying the new equipment with diesel engines should be aware of the design elements affected when making the decision. Vibrational characteristics are different in diesels. The frequencies are lower since the engine runs or is rated at a lower speed than a gasoline engine. Noise levels are higher because the torsional vibrations in a diesel are higher. The sensitivity and characteristics of the surrounding vehicle will have a lot to do with it. Keep in mind that the vehicle was engineered around a gas engine and the diesel could increase the intensity of sound and establish what I call “sympathetic vibrations.” This syndrome can literally shake the vehicle apart – over a period of time, of course.

There are six major areas that require attention on a repower: engine revisions, drive line revisions, weight revisions, electrical revisions, fuel system revisions, and noise-related revisions. You will see that some of them overlap and must be addressed in more than one way (page 40).

REHAB

Again, in rehab you face the same considerations we outlined in recondition and repower, plus some, for now we are adding manufacturer’s improvements and updates, body and technological changes as well as new components and assemblies. It is not a simple process. In fact, it is more difficult technologically to rehab an existing unit than it is to spec out a new unit of equivalent capability.

Continued on page 35

Continued from page 35

It can be a very frustrating experience! Primarily because it is difficult to identify exactly what is or should be involved in a rehab job. There is no magic formula. Each vehicle should be judged on its own merits based on age, usage and current condition as well as past maintenance history. Also, the decision must be made as to the extent of rehab desired: How long do you intend to extend the life of the vehicle? What type of service will it see after rehab? Transferring it to a company where it will be used less may allow you to drastically cut the cost by limiting the extent of rehab necessary.

Once the decision is made to rehab and to what extent, your next move is to seek cost proposals from interested vendors. I personally believe it is far better to work with negotiated contracts for rehab rather than to use bid specifications like you would for new purchase. My reasoning is this. In a bid “you” must spell out all that is to be done, etc., whereas a negotiated contract puts the responsibility on the “vendor” to propose the needed changes. Why is this an advantage?

1. It will give you some insight into the competence of the vendor. If the monkey is on his back to prepare the proposal, the very quality of the proposal will tell you a great deal about his ability. On the other hand, if you prepare it, it tells you nothing about the vendor. Anybody can come back with a price whether they are capable of doing the work or not. Possibly the least capable vendor will submit the low bid, and low bid in this case should not be the determining factor. Quality and the vendor’s past performance are far more important.
2. It will provide you with a broader base of information on which to make decisions. When you receive three, four or five proposals, you will have also received three, four or five opinions to compare with your own. The chances of overlooking something major is reduced in the process.

Total rehab is not cheap. You can expect to spend 50 to 60 percent of the cost of a new vehicle on the process if correctly done. The price will increase or decrease from this estimate based on the condition of the vehicle and the extent of the rehab. Be careful to consider the time when you reach the break-even point in dollars. Your cheapest alternative may be to sell the existing unit and buy a new one!

The decision to repower, rehab or recondition is far from a simple process, as you can see. To say this article is all encompassing on the subject would not be fair or truthful to the reader.. I would describe it as a gross simplification of the subject! The jntent has been to focus attention on the technical aspects of repower, rehab and recondition. Enough has been written about the dollar issue. It is an accepted fact anything you do is cheaper than new replacement costs, but dollars should not be the only consideration. Dependability, reliability, safety and downtime must be considered as well. Until we find a way to convince those in the decision-making process ot the importance of dependability and safety, the average age of fire apparatus is likely to increase.

Repowering: Six Considerations

1. Engine Revisions
1. Cooling System
1. Larger for diesel
2. Add water filter
3. Add air shutters or fan clutch
2. Exhaust System
1. Larger for diesel
2. Turbocharged engine requires more space
3. Route to avoid excess heat
4. Route to hold back pressure to a minimum
3. Air Induction System
1. Diesel larger
2. Turbocharged engine increases size
3. Air restrictor gage should be added
4. Air leaks must be avoided
4. Engine Mounts
1. Change to match engine
2. Frame cutting should be avoided
3. Alterations to cross members and brackets should be avoided
5. Brake System
1. Vacuum will not work with diesel
2. System should be upgraded to handle added workload and weight
3. May require installation ot an engine brake
6. Acceleration Controls
1. Standard linkage will not work
2. Fuel shutdown system required
3. Emergency engine shutdown should be added
2. Driveline Revisions
1. Engine
1. Select for desired horsepower or torque
2. Decision necessary to retain or replace present components
3. Gear ratio and engine speed must be evaluated
4. Physical space limitations
5. Availability of parts and service
6. Grade climbing requirements
2. Clutch
1. Adequate size for horsepower and torque
2. Compatibility with new engine
3. Increased demand at roll-off
3. Transmission
1. Adequate for horsepower and torque
2. Automatic versus manual
3. Compatibility with new engine
4. Physical space limitations
4. Drivelines
1. Adequate for horsepower and torque
2. Clutch selection a factor
3. Torsional vibrations different
4. Alignment and degree of angle (maximum approximately 9 degrees)
5. Transfer Case
1. Adequate for horsepower and torque
2. Ratio of input shaft to impellers (pump speed)
6. Fire Pump
1. Adequate horsepower to drive the pump
2. Consider lower rpms of diesel
3. Two-stage or single-stage pump (could be a factor)
7. Rear Axle
1. Adequate for horsepower and torque
2. Gear ratio and road speed considerations
3. Weight Revisions
1. Front Axle
1. Over 500 pounds could be a matter of concern
2. Weight rating of present axle
3. May require steering stabilizer
2. Front Springs
1. Weight rating of current springs
2. Ride characteristics may be altered
3. Steering Components
1. May need a larger system due to weight
2. Gear drive ratio with lower engine rpms
4. Engine Mounts
1. Adequate for increase in weight
2. Mounted and supported without weakening other components
5. Vehicle Weight Distribution
1. Should maintain approximately 30 percent front or 70 percent rear for balance
2. Changing vehicle balance will affect handling
3. May cause brake system imbalance
4. Electrical Revisions
1. Alternator
1. Higher cranking amps for diesel engine
2. Gear ratio with lower rpm engine
2. Batteries
1. Will require higher cold cranking amps (CCA)
2. Locate so as to hold vibration to a minimum
3. Starter
1. Larger required due to compression of diesel
4. Wiring
1. Larger draw from battery storage
2. Follow all SAE (Society of Automotive Engineers) standards
5. Instruments
1. Addition of electric fuel shutdown system
2. Addition of emergency engine shutdown
3. Addition of low oil, high temperature warning system for engme protection
5. Fuel System Revision
1. Filter System
1. Dual filters required
2. Fuel-water separator a consideration
2. Fuel Tank Size
1. 50-gallon minimum recommended
2. Fill neck size 2-inch minimum to allow for diesel fuel foaming
3. Fuel Temperature Considerations
1. Low temperatures affect diesel fuel (loss of power and no-starts)
4. Fuel System Integrity
1. Air leaks will cause loss of prime and no-starts
2. Addition of return line to full tank necessary
6. Noise Related Revisions
1. Federal Noise Standards
1. 100 decibels for more than two hours require ear protection (pump operator) by OSHA
2. Sample like equipment prior to engine selection
3. Federal Interstate Motor Carriers Interior Noise Standard sets maximum 90 decibels at driver’s position*
4. EPA requirements 90 decibels over 35 mph and 88 decibels standing still for highway noise*
5. * Fire apparatus is not currently subject to these standards If you want your vehicles to comply it must be clearly spelled out in your specifications and proposals.
2. Absorptioo Shields, Engine Panels and Fire Wall Insulation
1. Care must be taken not to retain excess heat. Stationary pumping during high ambient temperatures must be considered