99 4.0 Rough idle with knocking sound.

[AkburAce]

1999 Ford Ranger XLT 4.0 V6 4x4

12,000 miles ago the heads were machined and all upper gaskets replaced as well as wires and plugs. Ever since hot or cold and only under 1k idle the truck will shake and there is a knocking sound. There is no movement in the tachometer along with having no check engine lights, I have checked maf, iac, wiring order, and any type of vacuum leak with no success unplugging the maf runs a little smoother but you can still feel a shake and the sound. It does not feel like a misfire and I've tested it under load a couple of times and it accelerates extremely clean. Extremely lost looking through a million different forums it seems and would like to diagnose more before having to pay a shop. Also am going to link a video of my truck (I can upload more) and someone else's video with the same sound. Any ideas would be appreciated.

My video:

Other:

 

[Bill4]

Hard to tell from video. I've seen belt tensioners make a horrid knocking sound at low idle.

 

[gaz]

AkburAce,

When you replaced the heads did you do anything with the valve train or did you just reuse the old parts?

Normally, when a head is replaced, I clean and inspect the valve train components for wear and the anytime the rockers arms are pulled, they need to be adjusted. ***This is where the 4.0l ohv design was screwed, Ford decided to save money and not to incorporate and adjustable valve train***.

I suspect that your rocker arm cups are worn but the surfacing on the one or both replacement heads could be throwing the pushrod/rockers out too. This is because of how the preload on hydraulic lifters is set, without an adjustment feature, the only way to have the correct length push rods is to accurately measure what size push rods your engine needs.

Deltacam of Tacoma Washington is the only company that has the hardened rocker arm inserts. That is what I recommend for rockers. They use your rockers and the service is about $150 including postage both ways.

Smith Brothers will build you a custom set of the correct length push rods; you can have them built solid or adjustable, if you get the adjustables you can stay on top of your valve adjustment as components wear, insuring the most accurate valve operation and minimal noise. The custom set of push rods with shipping will be about $150.

 

[AkburAce]

AkburAce,

When you replaced the heads did you do anything with the valve train or did you just reuse the old parts?

Normally, when a head is replaced, I clean and inspect the valve train components for wear and the anytime the rockers arms are pulled, they need to be adjusted. ***This is where the 4.0l ohv design was screwed, Ford decided to save money and not to incorporate and adjustable valve train***.

I suspect that your rocker arm cups are worn but the surfacing on the one or both replacement heads could be throwing the pushrod/rockers out too. This is because of how the preload on hydraulic lifters is set, without an adjustment feature, the only way to have the correct length push rods is to accurately measure what size push rods your engine needs.

Deltacam of Tacoma Washington is the only company that has the hardened rocker arm inserts. That is what I recommend for rockers. They use your rockers and the service is about $150 including postage both ways.

Smith Brothers will build you a custom set of the correct length push rods; you can have them built solid or adjustable, if you get the adjustables you can stay on top of your valve adjustment as components wear, insuring the most accurate valve operation and minimal noise. The custom set of push rods with shipping will be about $150.

Yes, the shop used old parts and this sounds like a reasonable explanation. The heads were sent to a machine shop and resurfaced not replaced my bad Idk if that makes a difference but I'm going to upload one more video that I would like you to look at and see if you think anything different(the sound is very faint). Also, I know I've been driving it a while without any problems and I plan on getting this fixed asap but is there anything I should worry about?
The sound is only from the oil pan and wheel wells in the engine bay you can barely hear it.
Thanks for your input.

 

[gaz]

AkburAce,

There is nothing wrong with having your heads resurfaced, also known as milling in addition to checking the valves, valve guides and seals and inspecting for wear and or damage; when milling is performed on the heads, the lower intake manifold should also be milled, to keep the ports aligned correctly. Either way it changes the the distance from the cam surface in the block to the rocker arm on top of the now lower head.

Many operators and mechanics alike will use their engines in this state. I have a problem with it as I know that when the valve train isn't in proper adjustment performance suffers and additional wear to the valve train components is inevitable.

I am not saying to rush out and buy parts but without even hearing it, I know that the maintenance you had performed "can" cause this issue.

To determine if the noise is your valve train, you can remove at least one of the valve covers, remove the rocker arm shaft and rockers and inspect the components for wear. An additional benefit to performing this inspection is that you will have the oportunity to clean your valve covers, rocker shafts (especially inside) and you can improve the top end oiling.
This is a simple process involving deburring all the parts, increasing the oil orifices 1 drill bit size and adding chamfered edges to the orifices.

Another simple area you can inspect is your oil; with 12k on the new heads it is due for at least it's 1st next oil change. When you do it inspect the oil, see how it looks and feels, see if there is anything in there that shouldn't be.

Ecessive valve train noise is an alert; I feel that it is prudent to investigate.

 

[AkburAce]

AkburAce,

There is nothing wrong with having your heads resurfaced, also known as milling in addition to checking the valves, valve guides and seals and inspecting for wear and or damage; when milling is performed on the heads, the lower intake manifold should also be milled, to keep the ports aligned correctly. Either way it changes the the distance from the cam surface in the block to the rocker arm on top of the now lower head.

Many operators and mechanics alike will use their engines in this state. I have a problem with it as I know that when the valve train isn't in proper adjustment performance suffers and additional wear to the valve train components is inevitable.

I am not saying to rush out and buy parts but without even hearing it, I know that the maintenance you had performed "can" cause this issue.

To determine if the noise is your valve train, you can remove at least one of the valve covers, remove the rocker arm shaft and rockers and inspect the components for wear. An additional benefit to performing this inspection is that you will have the oportunity to clean your valve covers, rocker shafts (especially inside) and you can improve the top end oiling.
This is a simple process involving deburring all the parts, increasing the oil orifices 1 drill bit size and adding chamfered edges to the orifices.

Another simple area you can inspect is your oil; with 12k on the new heads it is due for at least it's 1st next oil change. When you do it inspect the oil, see how it looks and feels, see if there is anything in there that shouldn't be.

Ecessive valve train noise is an alert; I feel that it is prudent to investigate.

I'm overkill and do it every 3k and it has looked like dark dirty oil no murkiness or sparkle/shavings every time. Last time I pulled the upper intake off to replace gaskets and put it back together. The truck lost compression and would not start so I took it to the shop and that's when the heads were machined. Since the head gaskets don't need replacing should I be good to take it off down to the valve covers and back together without this same problem? Weird question but it's discouraged me from pulling the motor apart ever since. Regardless, thank you a lot for putting me in a direction!

 

[gaz]

The valve covers can come off without touching the intakes or anything else.

 

[akdsrtrat]

1999 Ford Ranger XLT 4.0 V6 4x4

12,000 miles ago the heads were machined and all upper gaskets replaced as well as wires and plugs. Ever since hot or cold and only under 1k idle the truck will shake and there is a knocking sound. There is no movement in the tachometer along with having no check engine lights, I have checked maf, iac, wiring order, and any type of vacuum leak with no success unplugging the maf runs a little smoother but you can still feel a shake and the sound. It does not feel like a misfire and I've tested it under load a couple of times and it accelerates extremely clean. Extremely lost looking through a million different forums it seems and would like to diagnose more before having to pay a shop. Also am going to link a video of my truck (I can upload more) and someone else's video with the same sound. Any ideas would be appreciated.

My video:

Other:

I have the same noise. 98XLT 4X. Any progress?