428 RAP, RAP, RAP
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From: ROCKVILLE, CT.
428 RAP, RAP, RAP
Ah yes the joys of owning an old truck!
Just when it gets to the point of running about as good as I can get it to I start hearing this noise. At first I was hoping it was just the rocker assembly that had loosened up ( happened before ) but that ain't it.
It is definitely coming from either the #5 or #6 cylinder. It is most pronouned at idle. I'm guessing here ( rpm ), but I will say the noise totally disappears at 1500-1800 rpm.
This leads me to think it is either a noisy lifter or a crack exhaust manifold or bad gasket.
The engine is running fine but I can't bear to take it on the road until I resolve what is making this noise.
Today, I am going to see if I can find a crack or obvious gasket failures on the exhaust manifold.
Any tricks on determining what the culprit is ?
Just when it gets to the point of running about as good as I can get it to I start hearing this noise. At first I was hoping it was just the rocker assembly that had loosened up ( happened before ) but that ain't it.
It is definitely coming from either the #5 or #6 cylinder. It is most pronouned at idle. I'm guessing here ( rpm ), but I will say the noise totally disappears at 1500-1800 rpm.
This leads me to think it is either a noisy lifter or a crack exhaust manifold or bad gasket.
The engine is running fine but I can't bear to take it on the road until I resolve what is making this noise.
Today, I am going to see if I can find a crack or obvious gasket failures on the exhaust manifold.
Any tricks on determining what the culprit is ?
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Senior User
Joined: May 2010
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From: ROCKVILLE, CT.
RAP
Well, I couldn't check the exhaust manifold. Was pouring rain all day.
Any other advice out there?
If we're talking noisy lifter, is there anything that can be done shy of pulling the lifter?
I figure if I need to pull the lifter I should probably replace all 16 and the cam. That is somethig I really don't relish. Am I thinking straight?
I really didn't want to do anything with this engine until I could afford a total rebuild. At the same time, I need to be able to use it as a second vehicle and hauler at times.
Is it okay to replace the cam and lifters alone?
Any other advice out there?
If we're talking noisy lifter, is there anything that can be done shy of pulling the lifter?
I figure if I need to pull the lifter I should probably replace all 16 and the cam. That is somethig I really don't relish. Am I thinking straight?
I really didn't want to do anything with this engine until I could afford a total rebuild. At the same time, I need to be able to use it as a second vehicle and hauler at times.
Is it okay to replace the cam and lifters alone?
Fleet Mechanic
Joined: Nov 2010
Posts: 1,501
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From: Axtell, TX
Have you run a compression or leak down test? I've had cracked and burnt valves that seemed to quiet down with a little rpm, though I think it's mainly just being covered up by other noise.
The first thing I'd do besides checking for black residue around exhaust gaskets is checking clearances. Do you have the adjustable rockers? Check to make sure the clearances are right. Set to "0" lash and then back off 1/2 a turn. If somehow you have the non-adjustable rockers then it's a more work to check clearances and you'll have to adjust pushrod size to change them.
If you have to replace the cam and lifters I'd recommend replacing the springs as well. You don't want a failure because you didn't want to spend the extra 120 bucks on springs. Just get the complete kit (cam/lifters/springs) if you have to. If something were to happen it makes warranty claims much easier.
The first thing I'd do besides checking for black residue around exhaust gaskets is checking clearances. Do you have the adjustable rockers? Check to make sure the clearances are right. Set to "0" lash and then back off 1/2 a turn. If somehow you have the non-adjustable rockers then it's a more work to check clearances and you'll have to adjust pushrod size to change them.
If you have to replace the cam and lifters I'd recommend replacing the springs as well. You don't want a failure because you didn't want to spend the extra 120 bucks on springs. Just get the complete kit (cam/lifters/springs) if you have to. If something were to happen it makes warranty claims much easier.
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From: ROCKVILLE, CT.
Have you run a compression or leak down test? I've had cracked and burnt valves that seemed to quiet down with a little rpm, though I think it's mainly just being covered up by other noise.
NO. I've heard of it but never done one. I had the compression checked last year and it was 155-165 across all cyl. I don't think the noise is being covered up. I think it actually goes away.
The first thing I'd do besides checking for black residue around exhaust gaskets is checking clearances. Do you have the adjustable rockers? Check to make sure the clearances are right. Set to "0" lash and then back off 1/2 a turn. If somehow you have the non-adjustable rockers then it's a more work to check clearances and you'll have to adjust pushrod size to change them.
No adjustment
If you have to replace the cam and lifters I'd recommend replacing the springs as well. You don't want a failure because you didn't want to spend the extra 120 bucks on springs. Just get the complete kit (cam/lifters/springs) if you have to. If something were to happen it makes warranty claims much easier.
NO. I've heard of it but never done one. I had the compression checked last year and it was 155-165 across all cyl. I don't think the noise is being covered up. I think it actually goes away.
The first thing I'd do besides checking for black residue around exhaust gaskets is checking clearances. Do you have the adjustable rockers? Check to make sure the clearances are right. Set to "0" lash and then back off 1/2 a turn. If somehow you have the non-adjustable rockers then it's a more work to check clearances and you'll have to adjust pushrod size to change them.
No adjustment
If you have to replace the cam and lifters I'd recommend replacing the springs as well. You don't want a failure because you didn't want to spend the extra 120 bucks on springs. Just get the complete kit (cam/lifters/springs) if you have to. If something were to happen it makes warranty claims much easier.
Fleet Mechanic
Joined: Nov 2010
Posts: 1,501
Likes: 1
From: Axtell, TX
Lifter preload and valve clearance
That's how the Ford manual says to check clearances with non-adjustable rockers. You'll need Ford tool T58P-6565-A to bleed the lifters down.
If you have it pinpointed to a specific cylinder then I would start checking everything that relates to it. Check your pushrods for clearance with a good flashlight. Are they hitting the intake manifold, drainback tins, or valley tray? Check valve springs for broken damper, broken spring, or loose seals.
Lastly pull the lifters and inspect. It can be done with the intake on with a clothes hangar bent just right. You don't want the kids around for that though, the words they hear will warp their little minds for good!
lol
Hope it helps.
That's how the Ford manual says to check clearances with non-adjustable rockers. You'll need Ford tool T58P-6565-A to bleed the lifters down.
If you have it pinpointed to a specific cylinder then I would start checking everything that relates to it. Check your pushrods for clearance with a good flashlight. Are they hitting the intake manifold, drainback tins, or valley tray? Check valve springs for broken damper, broken spring, or loose seals.
Lastly pull the lifters and inspect. It can be done with the intake on with a clothes hangar bent just right. You don't want the kids around for that though, the words they hear will warp their little minds for good!
lolHope it helps.
Lead Driver
Joined: Oct 2004
Posts: 8,062
Likes: 35
From: Central Oregon
Have you checked the fuel pump? A weak spring on the arm of the fuel pump will sound alot like a lifter and it will go away about 1500rpm's
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From: ROCKVILLE, CT.
On the positive side, it will sure beat dealing with replacing the lifters, springs and cam, or even a manifold / gasket.
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From: Middle Tn.
If you do have a sticky lifter I've had luck in the past adding a can of Marvel Mystery oil to the oil. It will dissove any varnish in the lifter and won't hurt the engine. Read the directions on the can.
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From: ROCKVILLE, CT.
Talk about white smoke!!!
I think I might give it a try if I can eliminate the other variables first. No sense in doing it unless it really looks to be a lifter and if it works maybe it will save me from having to pull the top end. At least until I'm ready for the rebuild I want to do.
Hotshot
Joined: Jul 2005
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From: Middle Tn.
The Marvel oil was designed for this purpose and you can leave it in for the whole oil change. Read the directions. I don't think that will be in the directions for the tranny oil.
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From: ROCKVILLE, CT.
EXHAUSTED
Well, I had a couple of mechanics listen to it and both leaned towards an exhaust leak.
Here are a couple of things I found when driving it Saturday:
The tapping / popping has gotten louder. She pretty much runs the same but I haven't really gotten on it to notice a difference under load.
When I increase power ( in park ) the noise diminishes a great deal and almost disappears altogether around 1500-1800 rpm's ( guess )
When in gear and driving it is loud and does not abate except whhen I let off the accelerator and coast. Then you don't hear it at all
If it was mechanical in nature wouldn't it remain regradless of acceleration / deceleration?
I can't get a clear view of the underside of the exhaust manifold to get a visual confirmation of exhaust leakage.
Here are a couple of things I found when driving it Saturday:
The tapping / popping has gotten louder. She pretty much runs the same but I haven't really gotten on it to notice a difference under load.
When I increase power ( in park ) the noise diminishes a great deal and almost disappears altogether around 1500-1800 rpm's ( guess )
When in gear and driving it is loud and does not abate except whhen I let off the accelerator and coast. Then you don't hear it at all
If it was mechanical in nature wouldn't it remain regradless of acceleration / deceleration?
I can't get a clear view of the underside of the exhaust manifold to get a visual confirmation of exhaust leakage.