Some engine swappers' fear of emissions regulations may often be overblown. It simply is not the challenge that many perceive. The emissions and complexity of engine swaps are actually less of a headache than a few years ago, especially when swapping post-OBDI (1996- ) GM engines into your Jeep. The PCM does now what a myriad of pumps, hoses, EGR, etc. used to do. Instead of taking horsepower away from an engine to meet emissions, the new engines burn cleaner and more powerfully.
And, not just for the purpose of obeying the law. Think of your passengers and the Jeeps following you on the trail. They'll have a more pleasant 4wd experience if they don't have to suck up dirty exhaust.
This guide is not meant to explain, interpret or notify the installer of local or national laws concerning vehicle changes, engine conversions and the emissions systems surrounding them. It is the installer’s responsibility to know and understand their local legal requirements and regulations and to make their installation conform to demands of the jurisdictions in which they live. Novak does not recommend nor condone the disabling or modification of the vehicle or any system within it that could render it out of conformance with any laws in which the vehicle may be licensed or operate. Neither Novak Conversions nor its directors, principles or employees are responsible for any changes made to your vehicle.
We recommend you consult and know your own city, county, state or countries laws. If your vehicle requires referee inspection, you may wish to establish a rapport with a referee and discuss your plans and seek advice and approval from them.
Many principalities have emissions standards, but hardly any of them bar proper engine conversions. As a rule of thumb, if you can meet the California laws, you can usually meet all of them. Many jurisdictions have significantly simpler requirements.
Like the weather, trends flow eastward from California. Not just for Californians anymore, vehicle emissions considerations play a big role for most swaps. As a benchmark, we will focus on the way the California Air Resources Board does it.
We’ve read that California law does exempt 1975 and earlier vehicles from emissions regulations. This exemption year has been pulled forward occasionally, so do your research at dmv.ca.gov.
Engine conversions, according to California regulations, are to meet the following standards:
“Engine changes are legal as long as the following requirements are met to ensure that the change does not increase pollution from the vehicle:
In California and other states, vehicles must first be inspected by a state referee station after an engine change. The vehicle will be inspected to ensure that all the equipment required is in place, and the vehicle will be emissions tested subject to the specifications of the installed engine or the vehicle into which the conversion engine is installed.
Note that there are two emission systems to consider: Exhaust and Evaporative. The former consists of burning (and reburning) the fuel and air to the cleanest state possible, and then reburning yet again through the catalytic converter in the exhaust circuit. Evaporative emissions consist of how the unburned fuel is stored and transferred in the vehicle. The principal piece of hardware used here is a charcoal canister that absorbs fuel fumes as they slowly evaporate from the tank and lines. Upon starting the engine, the cannister is purged of these fumes through engine vacuum and the temporary opening of a purge valve. Usually, one should retain the Jeep's existing canister as it already fits, and evaporative emissions management are no different for the engines involved.
Your Jeep is considered to be a “Light Truck” by most jurisdictions. As such, you can usually source your engine from a GM truck or SUV without failing your emissions certification. However, this again is according to local laws and your research is encouraged.
We welcome any contributions or clarifications to this article, including information about your own local laws. Contact us here.