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Technical

Highlights

 Printed on Recycled Paper

United States

Environmental Protection

Agency

Air and Radiation EPA420-F-99-045

December 1999

Office of Mobile Sources

Rebuilding Diesel Engines

To which engines does this apply?

You will need to meet these requirements if you are rebuilding an engine

that has been certified to meet certain emission standards for heavy-duty

highway diesel engines (40 CFR Part 86), nonroad diesel engines (40

CFR 89), or marine diesel engines (40 CFR Part 94). These provisions

apply generally to any certified engine, but the record keeping requirements start for the model years listed in Table 1. The label on each

engine should show its model year and size or power rating.

What’s the general principle behind EPA's rebuilding

requirements?

As a rebuilder, you in general must restore the engine to its original

configuration.

The U.S. Environmental Protection Agency (EPA) has established

requirements that apply to the process of rebuilding or remanufacturing

diesel engines. This fact sheet describes these requirements for

highway, nonroad, and marine diesel engines. Separate provisions that

apply to rebuilding urban bus engines (pre-1994 model year),

locomotive engines, and certain highway engines are not described

here.
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What does EPA consider "rebuilding"?

Rebuilding refers to a partial or complete rebuild of an engine or engine

system. This includes a major overhaul in which you replace the engine’s

power assemblies. It also includes replacement or rebuilding of an

engine's turbocharger/aftercooler system or its fuel injection/electronic

control system. For these provisions, rebuilding may or may not involve

removing the engine from the truck, equipment, or vessel. For routine

maintenance or service, you still need to avoid making changes that

might increase emissions, but you don't need to keep any records.

How do I meet the rebuilding requirements?

You must have a reasonable technical basis for knowing that you are

rebuilding the engine to its originally certified configuration for all the

relevant tolerances, calibrations, and specifications that might affect

emissions. You may use new, used, or rebuilt parts, but you should have a

reasonable technical basis for knowing that the parts perform the same

function as the original parts. You should follow the original engine

manufacturer's instructions if you change any parameter or design element. Also, be sure to check, clean, adjust, repair, or replace all critical

emission-related components as needed according to the original

manufacturer’s recommended practice. This includes the catalytic converter or other aftertreatment device, if the engine has one.

What about diagnostic codes in the engine's

computers?

Don't erase or reset emission-related codes or signals without diagnosing

and responding appropriately to the diagnostic codes. Clear all codes

from diagnostic systems when you return the rebuilt engine to service.

Don't disable a diagnostic signal without addressing the problem. This

doesn't apply to engines without onboard computers.

Can I make any changes to improve the engine?

Yes. You may make changes if you have data or some other technical

basis to show that emissions will not increase. Also, you may use different than original parts or make other adjustments if they make the engine

operate like one of the engine manufacturer's newer certified models.
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May the rebuilt engine go into any vehicle,

equipment, or vessel?

No, some restrictions apply. Rebuilt engines should return to the same

application (highway, nonroad, or marine). Also, the engine may not go

into trucks, equipment, or vessels that were originally powered by engines certified to a more stringent level of emission control. Contact us if

this is not clear from the engine labels.

What records do I need to keep?

Keep the following records for at least two years:

• the hours of operation (or mileage or other indication of age) at time

of rebuild

• the work performed on the engine

• emission-related control components you worked on, including a

listing of parts and components you used

• engine parameter adjustments

• emission-related codes or signals you responded to and reset.

You may keep records based on engine families rather than individual

engines if that's the way you do business. Keep the records in any format

that allows us to review them if we ask.

What records don't I need to worry about?

You don't need to keep information that is not reasonably available

through normal business practices. We don't expect you to have information that you can't reasonably access. Also, you don't need to keep any

records of what other companies do.

For More Information

See the following regulations for a more detailed description:

• Heavy-duty highway engines: 40 CFR 86.004-40

• Nonroad diesel engines: 40 CFR 89.130

• Marine diesel engines: 40 CFR 94.11

The provisions that apply uniquely to rebuilding locomotive engines are

described in Requirements for Railroads Regarding Locomotive Exhaust

Emission Standards (EPA420-F-99-036).
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For additional information, visit the Office of Mobile Sources' web site

at:

http://www.epa.gov/oms/

You can also contact Tom Stricker at:

U.S. Environmental Protection Agency

Office of Mobile Sources (6403J)

401 M Street, SW

Washington, DC 20460

(202) 564-9322

e-mail: stricker.tom@epa.gov

A e pplication S r ize Rang Model Yea

H l ighway a 4 l 200

Nonroad and Marine

Engines <37 kW

(50 hp)

power < 19kW

power < 25 hp

2000

19 ≤ power < 37 kW

25 ≤ power < 50 kW

1999

Nonroad Engines

≥37 kW (50 hp)

37 ≤ power < 75 kW

50 ≤ power < 100 hp

2004

75 ≤ power < 225 kW

100 ≤ power < 300 hp

2003

225 ≤ power < 450 kW

300 ≤ power < 600 hp

2001

450 ≤ power < 560 kW

600 ≤ power < 750 hp

2002

power > 560 kW

power > 750 hp

2006

Marine Engines

≥ 37 kW

d 5 isplacement < 0.9 L/cyl 200

0.9 ≤ d 4 isplacement < 2.5 L/cyl 200

d 7 isplacement > 2.5 L/cyl 200

Table 1

Implementation Schedule for Rebuild Recordkeeping Requirements