REMOVAL & INSTALLATION
Use the following service procedures as a guide for your engine. Machine shop work requires special training and equipment, it is best to send the cylinder head assembly to a reputable machine shop for this kind of repair.3.3L Engine
See Figures 1, 2, 3, 4, 5, 6, 7 and 8
The valves are arranged in line in the cylinder heads and inclined 18°. The rocker arm shaft supports are cast integral into the heads.
- Remove the cylinder head. Mark all valves and rockers for reinstallation with a felt-tip marker or similar pen (do not scribe the components).
- Situate the cylinder head so the valves will be free to move downward. You'll need a valve spring compressor tool such as Chrysler Valve Spring Compressor Tool C-3422-B with adapter 6412.
- Compress the valve springs until the valve retaining locks can be removed from the valve stem. Release the tension on the springs slowly and remove the valve spring retainers, valve stem seals and valve springs.
- Before removing the valves from the heads, remove any burrs from the valve stem lock grooves to prevent damage to the valve guides. Identify the valves to ensure installation in their original locations.
- Coat the valve stems with clean engine oil and insert them into the cylinder head.
- Check the valve tip-to-spring seat dimension (A) after grinding the valve seat or face. Grind the valve tip to give 1.950-2.018 inch (49.541-51.271mm) over the spring seat when installed in the cylinder head. Check the valve tip for scoring; if necessary, the tip chamfer should be reground to prevent seal damage when the valve is installed.
- Install the valve spring seat spacer on the head.
- Install new cup seals on all the valve stems and over the valve guides. Place the valve springs and spring retainers into their positions on the cylinder head.
- Compress the valve springs with the valve spring tool and install the retainer locks. Release the spring compression slowly. Make certain that the valve locks are seated correctly in the lock grooves.
If the valves and/or seats are reground, measure the installed height of the spring's dimension (B), making sure the measurement is taken from the top of the spring seat to the bottom surface of spring retainer. If the height is greater than 1.56 inch (40.6mm), install a 0.0313 inch (0.80mm) spacer in the head counterbore to bring spring height back to the normal 1.53-1.59 inch (39.1-40.4mm).
- Install the cylinder head to the engine.
See Figures 9, 10 and 11
- With the cylinder head removed, compress the valve springs using a special tools C-3422-B, 7068 and adapters 6525 and 6537 or equivalent.
- Remove the valve retaining locks, valve spring retainers, springs and spring seat/stems seal assemblies.
- Before removing the valves, remove any burrs from the valve stem lock grooves to prevent any damage to the valve guides. Identify the valves in order to ensure installation in the original location.
- Coat the valve stems with clean engine oil and insert them in the cylinder head.
- If the valves or seats have been reground, check the valve tip height (A). If the valve tip height is greater than 1.7185 inch (43.65mm) intake and 1.8102 inch (45.98mm) exhaust, grind the valve tip until it is within specifications. Make sure the measurement is taken from the cylinder head surface to the top of the valve stem.
- Install the valve seal/spring seat assembly over the valve guides on all of the valve stems. Ensure that the garter spring is intact around the top of the rubber seal. Install the valve springs and retainers.
- Compress the valve springs with a valve spring tool, install the locks and then release the tool. If the valves and/or seats are reground, measure the installed height of the springs (B). Make sure the measurements are taken from the top of the spring seat to the bottom surface of the spring retainer. If the height is greater than 1.5256 inch (38.75mm), install a 0.030 inch (0.762mm) spacer in the head counterbore under the valve spring seat to bring the height back within specifications.
- Install the head.
See Figures 12, 13, 14, 15, 16, 17 and 18
- Clean the valves thoroughly and discard burned, warped or cracked valves.
- Remove any carbon and varnish deposits from inside of the valve guides with a guide cleaner.
- Check the valve stem tip for pitting or a depression (A).
- Check for wear and ridge wear (B).
The valve stems are chrome plated and should not be polished.
Check for even contact (at face center) with the valve seat (point C) as follows:
- Inspect the valve seat with Prussian blue® to determine where the valve contacts the seat.
- Coat the valve seat very lightly with the Prussian blue®, then set the valve in the head.
- Rotate the valve with light pressure against the valve seat. If the blue is transferred to the center of the valve face, contact is satisfactory. If the blue is transferred to the top edge of the valve face, lower the valve seat by grinding it with a 15° stone. If the blue is transferred to the bottom edge of the valve face, raise the valve seat with a 65° stone.
It is best to allow a professional automotive machine shop to grind the valve seats. The correct tools and skills needed for this job are beyond most anyone but a professional machinist.
- Measure the valve head margin. The valve margin should be 0.031 inch (0.794mm) for the intake valve, and 0.0469 inch (1.191mm) for the exhaust valve. If the margin is out of specifications, replace the valve with a new one.
Measure the valve stem guide clearance as follows:
- Install the valve into the cylinder head so that it is 0.551 inch (14mm) off of the valve seat. A small piece of hose may be used to hold the valve in place.
- Attach the dial indicator tool C-3339 or the equivalent to the cylinder head and set it at a right angle from the valve stem being measured.
- Move the valve toward and away from the indicator. Ream the guides for valves with oversized stems if the dial indicator reading is excessive or if the stems are scuffed or scored.
- The maximum allowable dial indicator measurement for the intake valve stems is 0.009 inch (0.247mm), and 0.016 inch (0.414mm) for the exhaust valve stems.
Service valves with oversize stems and oversize seals are available in 0.005 inch (0.15mm), 0.015 inch (0.40mm) and 0.030 inch (0.80mm) oversize. Reamers to accommodate the oversize valve stems are as follows:
- For valve guides with an inside diameter of 0.3198-0.3208 inch (8.125-8.150mm), use the 0.005 inch (0.15mm) oversize reamer.
- For valve guides with an inside diameter of 0.3297-0.3307 inch (8.375-8.400mm), use the 0.015 inch (0.40mm) oversize reamer.
- For valve guides with an inside diameter of 0.3454-0.3464 inch (8.775-8.800mm), use the 0.030 inch (0.80mm) oversize reamer.
- Slowly turn the reamer by hand and clean the guide thoroughly before installing the new valve.
Do not attempt to ream the valve guides from standard directly to 0.030 inch (0.80mm). Use a step procedure of 0.005 inch (0.15mm), 0.015 inch (0.40mm) and 0.030 inch (0.80mm) so the valve guides may be reamed true in relation to the valve seat. After reaming the guides, the seat run-out should be measured and resurfaced if necessary.
Valve refacing should only be handled by a reputable machine shop, as the experience and equipment needed to do the job are beyond that of the average owner/mechanic. During the course of a normal valve job, refacing is necessary when simply lapping the valves into their seats will not correct the seat and face wear. When the valves are reground (resurfaced), the valve seats must also be recut, again requiring special equipment and experience.