THE SHOP

Performance & Hotrod Business - April '15

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April 2015 n Performance & Hotrod Business n 91 pipe rubbing on another engine bay com- ponent, which would lead to an eventual rupture of the pipe wall. Newer vehicles are equipped with more and more plastic components in the engine bay. While this saves weight (and likely money), it also provides yet another compromise. A few newer trucks are using plastic CAC piping (Power Stroke 6.7-liter, Duramax 6.6-liter), primarily on the cold side of the system. As we've seen with the use of plastic on engine cooling systems, the repeti- tive oscillation effects of temperature and pressure can degrade the plastic, leading to an eventual failure. Diesel intercooler cold-side piping is not usually exposed to such high temperatures as a radiator would be; however, it will still see a great deal of pressure, especially if the truck has been modified. We are already beginning to see failures of these plastic pipes, and we are working diligently on an aluminum solution (6.7- liter Power Stroke already released). Installing new boots on your existing intercooler pipe seems like a simple task, but many installers forget one important step, cleaning the pipe. The CAC system on your car or truck is not a perfectly clean pathway. Blow-by oil and fuel byproducts make their way into the track, coating the internals of the pipes, boots and intercooler. Often, this oil can make its way underneath your boot, coating the sealing surface of your pipe. When installing a new boot, be sure to clean the surface with some form of sol- vent. Be certain that no oil residue exists on the sealing surface. If you are having issues installing a very tight boot, a few home products can come in handy. Spray the surface with hair spray and try to slide the boot on the pipe. The spray will be slick and then dry once installed. You could also use a small amount of dish soap, which will also make the surface slick during install and then tack up when dry. Boot Contamination & Breakdown Now that we've covered the pipes, we can move onto the main culprit for leak issues: the CAC boots and couplers. So why do these units fail? They should last forever, right? For a period of time, manufacturers were including EPDM rub- ber boots on their CAC systems. Rubber is inexpensive, and provides the flex needed for movement within the CAC system. That being said, there are far better mate- rials to use for boot construction. Three primary factors weigh into the wear that will lead to eventual boot failure. Temperature EPDM rubber is generally well-known for its heat, ozone, and weather resistance April 2015 n PRECISION ENGINE n 11

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