dodge 318 ?'s
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04-27-2009, 02:25 PM
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#3
04-27-2009, 05:21 PM
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Are you sure? 91 is pre-Magnum motor. I don't think they put roller lifters in them.
Just read the Alpar link, don't remember hearing they switched to roller lifters pre-magnum. I wonder what the 90 3.9 had, 5.2 was changed in 89. Would explain 200,000 without any odd noises
Just read the Alpar link, don't remember hearing they switched to roller lifters pre-magnum. I wonder what the 90 3.9 had, 5.2 was changed in 89. Would explain 200,000 without any odd noises
Last edited by lilreddakota; 04-27-2009 at 05:33 PM.
#4
04-27-2009, 05:53 PM
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Here is a copy and paste from that site posted
318 throttle-body / roller-cam engines (by Vince Spinelli and Jack Perkins)
The throttle-body fuel-injected 318 motor had a few changes for its model year (1988), which would come to the 360 in 1989.
First, Chrysler finally switched from standard hydraulic lifters (and matching camshaft) over to a roller hydraulic lifter and a new matching camshaft. The roller design allowed for a steeper cam profile, and thus a more precise valve-train actuation.
Second, the 2 barrel TPI fuel injection intake replaced the carburetor. [Webmaster note: the company was still intent on cost savings, and six more fuel injectors per engine does add up; still, others had been using multiple-port injection for some time — it had been standard in the Volkswagen Rabbit since 1979.]
Third… the heads were different; the basic casting is the same, but the fine points were not. To make better use of the fuel injection, swirl intake ports were introduced. To accommodate a slightly changed pushrod angle (the new roller lifters were taller than the standard hydraulics), the push rod guide holes in the cylinder heads were changed from roughly 0.5 inches to a published 0.66 inches (Dodge DW Series Truck Factory Service Manual, 1988). Upon measurement, this was confirmed to within an accuracy of 0.01 inches. Push rod length changed from about 7.5” down to 6.78”, and diameter shrunk from 0.360” to 0.3125” (again to accommodate the changed push rod angle).
The throttle-body fuel-injected 318 motor had a few changes for its model year (1988), which would come to the 360 in 1989.
First, Chrysler finally switched from standard hydraulic lifters (and matching camshaft) over to a roller hydraulic lifter and a new matching camshaft. The roller design allowed for a steeper cam profile, and thus a more precise valve-train actuation.
Second, the 2 barrel TPI fuel injection intake replaced the carburetor. [Webmaster note: the company was still intent on cost savings, and six more fuel injectors per engine does add up; still, others had been using multiple-port injection for some time — it had been standard in the Volkswagen Rabbit since 1979.]
Third… the heads were different; the basic casting is the same, but the fine points were not. To make better use of the fuel injection, swirl intake ports were introduced. To accommodate a slightly changed pushrod angle (the new roller lifters were taller than the standard hydraulics), the push rod guide holes in the cylinder heads were changed from roughly 0.5 inches to a published 0.66 inches (Dodge DW Series Truck Factory Service Manual, 1988). Upon measurement, this was confirmed to within an accuracy of 0.01 inches. Push rod length changed from about 7.5” down to 6.78”, and diameter shrunk from 0.360” to 0.3125” (again to accommodate the changed push rod angle).
