Measuring and honing the Chrysler 2.4

The construction of the Chrysler 2.4L VIN S engine (2004 to 2007) severely limits the options for engine builders seeking to return one to serviceable condition.

Since this two-piece cast iron cylinder block cannot accommodate overbore procedures, special attention must be paid to measuring and honing.

According to the AERA Technical Committee, the lower bedplate portion of the block should be properly torqued to the upper block while any cylinder bore measurements are being observed. One should also note the same is true for all cylinder boring and honing operations. Follow the steps listed below to create a desirable cylinder wall finish.

Cylinder Bore Honing

1. Used carefully, the cylinder bore resizing hone, recommended Chrysler tool C-823 or equivalent, equipped with 220 grit stones, is the best tool for this honing procedure. In addition to deglazing, it will reduce taper and out-of-round as well as removing light scuffing, scoring, or scratches. Usually a few strokes will clean up a bore and maintain the required limits.

2. Deglazing of the cylinder walls may be done using a cylinder surfacing hone with Chrysler recommended tool C-3501 or equivalent equipped with 280 grit stones. If the cylinder bore is straight and round, 20 to 60 strokes (depending on the bore’s condition) will be sufficient to provide a satisfactory surface. Be sure to use light honing oil. Do not use engine or transmission oil, mineral spirits, or kerosene. Inspect cylinder walls after each 20 strokes. 3. Honing should be done by moving the hone up and down fast enough to get a cross-hatch pattern. When hone marks intersect at 40 to 60 degrees, the cross-hatch angle is most satisfactory for proper seating of rings (See Figure 1).

4. A controlled hone motor speed between 200 to 300 RPM is necessary to obtain the proper crosshatch angle. The number of up and down strokes per minute can be regulated to get the desired 40 to 60 degree angle. Faster up and down strokes increase the cross-hatch angle.

5. After honing, it is necessary that the block be cleaned again to remove all traces of abrasive. Caution: Ensure all abrasives are removed from engine parts after honing. It is recommended that a solution of soap and hot water be used with a nylon brush and the parts then thoroughly dried. This is usually a two-step process involving two buckets of soapy hot water. The bore can be considered clean when it can be wiped clean with a white cloth and cloth remains clean. Oil the bores after cleaning to prevent rusting.

Block Cleaning

Clean the cylinder block thoroughly using a suitable non-petroleum cleaning solvent.

The preceding was adapted from AERA Technical Bulletin 2499. Visit www.aera.org for other engine rebuilding technical and business issues.