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The lower intake manifolds on some Ford vehicle models are not fitting correctly after machining
Engine Builders: Some AERA members have reported that the lower intake manifolds on some Ford vehicle models are not fitting correctly after machining. To reduce the likelihood of coolant contamination of engine oil, a revised, thicker intake gasket is now available for the 3.8L and 4.2L Ford car and truck engines. These models have VIN codes 4 and 2 and were manufactured between 1996 and 1998.
To align the lower intake when these gaskets are installed, install and tighten the #3 and #4 center bolts first to facilitate the installation of the remaining bolts.
To complete the installation of this manifold, follow the sequence shown in Figure 1. Torque all bolts in sequence to 71 in.lbs. (8 Nm). Then, rotate all bolts in sequence another 90 degrees.
Engine Builders: Ford 3.8L and 4.2L V6 engine timing cover gaskets tend to leak coolant, externally or internally, after extended service.
To reduce the likelihood of coolant loss and/or oil contamination, Ford recommends:
1. Carefully remove all old gasket by hand scraping the timing cover and block. Avoid using any abrasives.
2. Tighten the timing cover bolts. The socket head cap screws should be tightened to 16 ft.lbs. (22 Nm) and all other bolts should be tightened to 20 ft.lbs.
Exceeding these revised torque values may result in timing cover damage and/or coolant loss.
Engine Builders: Since the valve lash on 1993-’99 GM 3.1L VIN M engines is fixed, changes in valve train dimensions may prevent valves from seating. To restore hydraulic lifter function in these engines it may be necessary to shim the rocker studs with GM p/n 88894006 or equivalent shim.
Each GM shim is .010˝ (.254 mm) thick. Do not use more than two shims per rocker as misalignment could result. If more than two shims are needed, valve or valve seat replacement may be required.
Engine Builders: Any 1996-2002 Mack E-Tech engine valvetrain failure that results in excessive valve lash or subjects the lifter body to rotational force, may dislodge or rotate the H-ring of the valve lifter out of alignment in the lifter bore. Failures that can cause this situation include a broken rocker arm, broken rocker shaft, broken rocker shaft mounting bolts, etc. When such a failure has occurred, the H-ring must be checked to see if it is dislodged in the lifter bore.
Before an H-ring is replaced, proper fit in the lifter bore must first be determined. To determine if the H-ring is dislodged and lacks proper fit in the lifter bore, Mack recommends the following procedure be used while the cylinder head is still installed on the engine.
1. Place a length of welding rod that is approximately 15˝ long down the pushrod bore so that it rests on top of the H-ring on the outboard side as shown in Figure 2.
2. Place a straightedge on the cylinder top rail surface, in contact with the welding rod.
3. Mark the welding rod at the point where it makes contact with the straight edge.
4. Perform the same check on a cylinder that is known not to have suffered the valvetrain failure and mark the location on the welding rod. Compare the measurements with the original mark made on the welding stick and determine the H-Ring dislodgement as follows:
• If the H-ring at the location of the valvetrain failure is the same height to within 1/16˝ higher as compared to the cylinder not affected by failure, it can be concluded that the H-ring is not dislodged.
• If the H-ring at the location of the valvetrain failure is 1/16˝-1/8˝ higher than the cylinder not affected, the H-ring position is properly located.
• If the H-ring at the location of the valve train failure is more than 1/8˝ higher than at the cylinder not affected, the H-ring is dislodged and needs to be replaced.
The H-rings are an interference fit with a range of .0006˝-.0020˝ in the lifter bore. In some cases the standard size H-ring, p/n 718GB36, may fit too loosely in the bore. For those instances, an oversize H-ring is available (p/n 718GB36P2, which is .0015˝ oversize or p/n 718GB36P3, which is .003˝ oversize). The oversize H-rings are identified by dots formed into the bottom surface of the ring next to the flat. The “P2” version is identified by a single dot and the “P3” version is identified by two dots as shown in Figure 3.
An oversize H-ring is to be used only when the lifter bore in the cylinder block is oversize. Using an oversize H-ring in an undamaged lifter bore will result in an interference fit that is too tight, and will cause the H-ring to collapse. EB