Cylinder Honing - Supplemental Service Procedure
87ford16
Article No. CYLINDER HONING - 6.9L DIESEL -
87-17-10 NEW SUPPLEMENTAL SERVICE PROCEDURE
LIGHT TRUCK: 1983-87 E SERIES, F SERIES
ISSUE: TSB 87-3-19 provides a service procedure for 6.9L diesel engines having high levels of oil consumption (less than 900 miles per quart after the first 7,500 miles/12,000 kilometers). A new supplemental cylinder honing service procedure has been developed to aid technicians in performing Step 14 of TSB 87-3-19.
ACTION: If re-ringing and re-honing are required, use the following supplemental service procedure. After re-ringing and re-honing, the engine will need a 7,500 mile/12,000 kilometer break-in period.
1. Before taking the engine apart, remove exhaust manifolds and check all exhaust ports. Look for build-up of heavy oily carbon deposits on one or more exhaust ports. This will show that a concern exists on only these cylinders.
2. When removing the valve train components, keep rocker arms and posts in order to prevent mixing parts. Mismatched rockers and posts will result in rapid and excessive wear.
3. Before removing the pistons, scrape carbon build-up from top of cylinder walls. Push each piston and rod assembly out; carefully making sure that the big end of connecting rod does not hit and damage cylinder wall.
4. Remove piston rings from each piston checking for upside-down installation of the rings or missing oil ring expander.
5. Soak pistons in detergent and water solution for no more than two (2) hours.
Figure 6:
Figure 7:
6. To refinish cylinder walls, obtain a "flexhone" for a four (4) inch bore engine with a 120 grit rating (no color code). This type of hone looks like a wire brush with carbide balls on the ends of the bristles, Figure 6. Also, get a full 12- ounce container of Ford "Rust Penetrant and Inhibitor" (D7AZ-19A501-A). This spray contains colloidal graphite and has a black appearance. Get an electric, or air-powered, drill motor with adjustable speed. A speed of about 100-120 RPM is required. If this speed is not available, REPAIR WILL NOT BE SUCCESSFUL, Figure 7.
NOTE: It is necessary to remove "bolt-on" piston cooling jets before refinishing cylinder walls.
It is NOT necessary to remove the crankshaft or "press-in" piston cooling jets to refinish cylinder walls, however it is good practice to oil the rod journals and wrap them in a shop towel and tape.
Figure 8:
7. Spray cylinder wall and hone cylinder wall for about three (3) seconds while stroking up and down twice a second. Remove the hone (ALWAYS REMOVE WITH HONE ROTATING), and wipe a portion of cylinder wall. Inspect the crosshatch pattern comparing it to the neighboring (untouched) cylinder. The crosshatch angle should be 45~, Figure 8.
NOTE: Comparison with an "untouched" bore is the best check, provided the engine has not been repaired before. If the pattern is "flatter" than called for, increase stroke speed or slow down rotation speed. The hone will not damage the piston cooling jet and honing to the very bottom of the cylinder is not required as the piston ring travel stops well short of the bottom of the bore. The hone must be partly removed from the block at the top of each stroke.
Continue honing the cylinder (after adjusting your technique to get the required 45~ crosshatch) for between 10 and 15 seconds, while an assistant continuously sprays the graphite spray at the cylinder wall. Do not spend more than 12 seconds (25 strokes) per bore. Wipe cylinder bore clean and inspect. The bore should have a satin-like sheen with a clearly identified crosshatch pattern of 45~. Compare with an untouched bore to confirm correct angle. Repeat for remaining cylinders.
8. Wash all cylinders with mild soap and water (like dish washing solution). Air dry with shop air and IMMEDIATELY oil cylinder walls to prevent corrosion.
9. The pistons which were soaking should be clean and ready to check. Note depression in each piston. In the center of this depression, is the pre-combustion chamber flame exit slot.
This slot ends about 1/8 inch from the edge of the piston. Inspect this area of the flat piston crown for pitting or melting. Erosion in the area is often caused by oil consumption (oil burning on the surface of the piston). Damaged pistons should be replaced.
10. Air dry and oil all pistons. Install piston rings as follows:
a. Slightly spread oil control ring expander and slip into lowest groove with the "gap" in the expander located 90~ to the piston pin ends.
b. Install oil control ring over the expander, setting the gap 180~ from the gap in the expander.
c. Gently spread the second ring and install in the second groove with the gap spaced about 120~ away from the oil ring gap.
d. Install top ring with the gap located 120~ from the other gaps.
NOTE: The second ring will be deformed if spread too wide. The two (2) dimples on the ring show the top of the ring.
11. Install two (2) 9-inch long pieces of 3/8 inch fuel line on the connecting rod bolts to protect the crank journals and to aid installation.
12. Install each piston carefully into the same cylinder from which it was removed. Use lots of oil on rod bearings, cylinder walls, etc., to prevent corrosion and provide initial lubrication.
13. Install "bolt-on" piston cooling jets.
14. Reassemble remainder of engine using the procedure in the Light Truck Shop Manual. The first oil fill may require up to two (2) quarts more oil than specified to refill oil cooler.
NOTE: A good practice is to change oil and filter at 1000 miles/ 1600 kilometers to remove any contaminants from the repair process.
Order the BRM Flex Hone GBD4-1/8 directly from:
Brush Research Manufacturing Co., Inc. 4642 East Floral Drive Los Angeles, California 90022 (213) 261 -2193
PART NUMBER PART NAME CLASS
D7AZ-19A501-A Rust Penetrant and AM
Inhibitor
OTHER APPLICABLE ARTICLES: 87-3-19, Supersedes 87-8-15
WARRANTY STATUS: "INFORMATION ONLY"