4.0l Ohv complete rebuild, still makes same knocking noise

[broncc]

So this sounds like something I'm sort of familiar with on mine. Here is a list of things to check that might help;
-vacuum leaks
-if your egr system works at all
-if your egr valve has good flow
-fuel pressure
-fuel filter
-pressure regulator
-did you have your injectors rebuilt?
-MAF condition
-exhaust leak before o2 sensors
-o2 sensor age

 

[Nick Ranger - Private Eye]

So this sounds like something I'm sort of familiar with on mine. Here is a list of things to check that might help;
-vacuum leaks
-if your egr system works at all
-if your egr valve has good flow
-fuel pressure
-fuel filter
-pressure regulator
-did you have your injectors rebuilt?
-MAF condition
-exhaust leak before o2 sensors
-o2 sensor age

No vacuum leaks, no egr, fuel pressure is in spec, new fuel filter, new pressure regulator, new injectors (Standard - made in USA), new maf, no exhaust leaks, new Bosch O2 sensors.

 

[Nick Ranger - Private Eye]

@Nick Ranger - Private Eye ,
I want verify that I understand you:
• you reused the stock bore pistons with 340k miles
• you did not bore the cylinders, they were honed
• the machinist polished the crank
• using a used (unknown hours/miles) ignition module

You used all new valve train (lifters, rods and rockers):
• did you do a complete overhaul of the rocker arms?
• did you measure the lifter preload?

Have you tried premium gasoline?

Yes,yes,yes, and yes. Complete overhaul of rockers meaning I disassembled the rocker arm shaft and mount assemblies completely, hot detergent tanked them and scrubbed all passages with wire brushes until all debris removed. I did not remove the plugs in the ends of the rocker shafts because my engine was pretty clean in the oiling areas, no sludge or unusual buildup. I did not measure lifter preload as I was not aware of that procedure. I have not tried premium gasoline though I have run several tanks of fresh gas now with chevron Techron, fresh filter.

 

[broncc]

What spark plugs are you using? Are they all the same color after running?
Do you have a sprung clutch that could be clanking around?

 

[Nick Ranger - Private Eye]

@Nick Ranger - Private Eye ,
Hello,
LIFTER PRELOAD:
Engines that use hydraulic lifters use a "lifter preload" adjustment to keep the valve train working at optimum.

It is not accomplished the same way as the valve lash adjustment, as with solid lifter (which produces a gap); it is an amount of adjustment PAST the push rod contact with the rocker, which forces the push rod into the lifter a specific amount (range, usually somewhere between 0.020" to 0.080", depending on the engine) of the lifter's plunger travel.

Great to hear that you did a good job cleaning up those rocker arms . It may be worth the small amount of time/effort/expense that it takes to determine what actual length of push rods your specific 4.0l now requires.

Well the other thing that hasn’t been confirmed is that the valve assembled and tip height is correct. They said they reground the seats in the new heads because new Chinese castings can be inconsistent (but did not lap because “nobody does that anymore, they’ll self lap on breakin”) and reground the old valves on tip and seat. It is assumed that they set the assembled valve height to spec and the total valve height but when I put a straight edge across the tops of the valves, the exhaust valves were all lower than the intakes by maybe a mm (0.039”). Since all the rockers, lifters, and pushrods are the same, and the rockers ride on a common rail, the valve train preload should be the same across all intake and exhaust valves.

 

[gaz]

@Nick Ranger - Private Eye ,
In a system with an adjustable valve train, each valves rocker/pushrods are adjusted independently, because they must be; this is a benefit since each independent set is unique.

Your idea that all the preloads will be equal is impossible, what is more likely is that they are all incorrect.

"Since all the rockers, lifters, and pushrods are the same, and the rockers ride on a common rail, the valve train preload should be the same across all intake and exhaust valves."

The point is that a this non-adjustable valve train is a poor design, employed either to increase fuel use, decrease performance or both. Without using adjustable rocker or push rods, the only remaining avenue is to measure the amount of push rod needed to obtain the correct lifter preload. Without the correct lifter preload, the valve train will not be optimized and will make noise, this condition will only become exaggerated over time...unless you absolutely nailed each of the 12 sets, by mistake. Figure the odds of that

 

[franklin2]

@Nick Ranger - Private Eye ,
In a system with an adjustable valve, each valves rocker/pushrods are adjusted independently, because they must be; this is a benefit since each independent set is unique.

Your idea that all the preloads will be equal is impossible, what is more likely is that they are all incorrect.

"Since all the rockers, lifters, and pushrods are the same, and the rockers ride on a common rail, the valve train preload should be the same across all intake and exhaust valves."

The point is that a this non-adjustable valve train is a poor design, employed either to increase fuel use, decrease performance or both. Without using adjustable rocker or push rods, the only remaining avenue is to measure the amount of push rod needed to obtain the correct lifter preload. Without the correct lifter preload, the valve train will not be optimized and will make noise, this condition will only become exaggerated over time...unless you absolutely nailed each of the 12 sets, by mistake. Figure the odds of that

Most all the older Ford engines starting around 1965-66 had non-adjustable valvetrains. Ford puts them together with it all figured out, and from the factory it works. When you have machine work done or modify the engine, you have to rely on the machinist to keep it all correct. The newer GM LS engine also have non-adjustable valve trains.

The cologne engines are unicorns when it comes to Fords, since at least up to the 2.9's, they had adjustments on the rockers. Ford did have a few engines now and then that were adjustable but most were not.