Short Term Bypass System


More details to be included later, including a bill of materials and discussion.

The first diagram is for normal operation (not bypassed). The second diagram shows the fuel system in a bypass mode. Diagrams courtesy of Dale Price(Diesel Service West)

Click on diagram to display an enlarged version.

Intended Use

A system such as this can be used to run two engines off of one fuel filter. The intent is not to run both engines at full throttle, only to allow both to be run off one filter while the other filter is being changed. There is always the possibility that stopping an engine to change the filter will result in not being able to restart that engine. This is not likely, but is a possibility. The parts to do this should not cost more than about $200, which is about 1/15 the cost of Racor Dual Filter system for both engines.

A similar setup can be used with the Racor 900 and 500 filters. The component sizes would be correspondingly smaller. Any assembly like this should be assembled carefully to avoid air leaks, plenty of sealant and tighten fittings snugly. Brass fitting would most likely have the longest life. Other variations would include the use of spin-on filters like the Racor 400 series, or even a single engine setup using two filters. If using a third filter it could be smaller, like a 900 or 500, or a spin-on only intended to be used for the short period during the bypass.

The disadvantage of this kind of installation is more individual components with the corresponding chances of air leaks. Also, when the bypass is active neither engine can be run much above a moderate rpm for fear of pulling a vacuum that would shut down one of the engines.

Don't misunderstand, it's not that I recommend this, but at least reading this over may give you ideas and help clarify and teach you something useful about fuel systems.


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