Strange sound in exhaust after a retorque

A

AMS247

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I posted a similar thread a year ago, adjusted lash when I had this problem and that solved it at the time. I would have reposted in the same thread, but it was closed..

I Need help with diagnosing noise after a retorque
I swapped out my factory injectors for brand new 5x14s. At that same time, I also retorque my head studs. Most of them only moved 1/32 of an rotation if that.

I've rechecked my valves 4 times now. Originally getting them all at .10 and .20 clearance. Then I dialed it down to .009 and .18 clearance. No real change that I've noticed.

The engine, only under load will produce a weird thumping sound, which sounds like it's from the air some how. Almost sounds similar to an exhaust manifold leak on a V6 ford engine.

This happened to me before when I retorqed the head, then I went through the valves more precisely the 2nd times and it fixed the issue.

When idling, cruising at speed with light load, or when completely off the pedal I can't tell that it's making any weird noise. Only under load. Even light load of slowly taking off the noise is loud and noticeable.

Fuel pressure reads 23psi at idle, and over 30 when moving. The exhaust only expels a slight haze when cold and at idle. The engine has head studs. Compression seems fine. And no exhaust leaks from what I can see.

Here are links to Google drive of videos showing what I'm hearing. It isn't picked up well on these recordings, but when I have the volume up I can hear what I'm referring to. It's much louder in person.

12vproblem1 - Google Drive

12vproblem2 - Google Drive

Has anyone else seen this and understand what is going on?
 
So, this is the 3rd day that I've been tinkering around on this. My brain is fried on what the issue is.

I checked all my manifold bolts and some were loose. I torqued them all down to spec.

I doubled checked valve clearance at .10 and .20. Then I tried .09 and .18 to see if there was a difference. There wasn't. So then I opened it up to .11 and .22. Still the same thing.

My exhaust manifold has shrunk quite a bit. I have a new one to throw on when I throw my new turbo on, I just want this squared away first. And if my manifold was leaking, I don't understand why it would be fine for so long and retorqing the head studs change anything over with that part.

Just restating myself. I did have this issue a year ago. I checked valve clearance, re set them, and everything was sounding good after that.
 
If it happened right after an injector swap that would prpbably be the first thing I suspect. It would be easy enough to swap back to your factory ones and see if the noise goes away.
 
I was considering it, I just don't have another install kit on hand for the copper sealing washers.

And, since this has happened before without changing the injectors, just with a head retorque like this time as well. I felt it could be similar but my old solutions haven't been helping..

I'll order more copper washers and swap back in the old injectors.

I haven t really put much throttle into these new Injector as the sound bothers me and scares me.

But, even with the really light pedal control, I can feel a ton more power and I don't smell a lot of diesel on cold start ups like I was smelling with the old ones. So I was thinking that they were burning and atomizomg better to not even be a thought. And the old ones were just 180hp sticks. Nothing more to be smelling so much fuel.
 
Since you have studs, have you milled the head or the block?
Sounds to me like piston to head tolerances might be a bit tight.

Mark.
 
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Mark Nixon said:
Since you have studs, have you milled the head or the block?
Sounds to me like piston to head tolerances might be a bit tight.

Mark.
Click to expand...


When I put in studs, I swapped in a Stage 1 Hamilton head with o-rings. They assured me it was flat, and to use a standard gasket, so that's what I did.

And the sounds doesn't sound like metal contact... it's more of an air sound? That can't be heard at idle through the intake or the exhaust....
 
Doesn't it seem odd that it did it BOTH times after a re-torque, which moves the head downward, even a small amount?

Don't suppose you have the old head gasket and it's part number?

Mark.
 
Mark Nixon said:
Doesn't it seem odd that it did it BOTH times after a re-torque, which moves the head downward, even a small amount?

Don't suppose you have the old head gasket and it's part number?

Mark.
Click to expand...

Yeah, you're right. It's odd it has done it both times.. but even on the initial install of the studs. It ran totally fine.. maybe I'm in denial?

I do not... it looked like the factory head gasket though.. And from what I recall on the previous owner who had all the shop records and paperwork. A head gasket was never treated. The truck has 200,000 miles on it.
 
AMS247 said:
I was considering it, I just don't have another install kit on hand for the copper sealing washers.

And, since this has happened before without changing the injectors, just with a head retorque like this time as well. I felt it could be similar but my old solutions haven't been helping..

I'll order more copper washers and swap back in the old injectors.

I haven t really put much throttle into these new Injector as the sound bothers me and scares me.

But, even with the really light pedal control, I can feel a ton more power and I don't smell a lot of diesel on cold start ups like I was smelling with the old ones. So I was thinking that they were burning and atomizomg better to not even be a thought. And the old ones were just 180hp sticks. Nothing more to be smelling so much fuel.
Click to expand...

You can reuse the washers for a quick elimination test.
 
Adding more details that I didn't think of.

My truck is timed at 18*. When I installed the new injectors (built on new Bosch bodies) I noticed that the truck didn't start quite as easy. Still fine though. And when cold starting (currently high 30's low 40's) the truck idles lower than the old factory injectors and lopes until about a minutes or two trying at about 1100 RPMS. This didn't happen with the old injectors.
 
It kinda sounds like a valve hanging open to me. You might try going through and setting them pretty loose and see if it sounds better. I wouldn't run it much but it should be fine at idle.



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Are you sure you didn't set valve lash on a cylinder while it was in overlap?
 
AMS247 said:
They will still seal if they're all clean?
Click to expand...

Use a small torch and heat the coppers to red. You can quench or not, makes no difference to annealing copper, but it helps knock the oxide layer off to make cleaning easier. Now you have nice soft copper again ready to reuse. I've used a BIC lighter for doing the injector return line washers, but a propane torch is 100 times more convenient.
 
Easiest way to set valve lash is one cylinder at a time.

Locate exhaust and intake valves.

Then bump the engine over. Exhaust start to open, set lash on the intake.

Intake fully lifted and closing, set lash on the exhaust.

Remember EXHAUST OPENING, INTAKE CLOSING
 
While you have the injectors out, snake a horoscope down the cylinders, for a look at the pistons.

Mark.
 
Awesome, thanks for all the feedback.

I'll try all of that on Monday. I'll set the exhaust valves to say .030? See of that makes a difference since .022 didn't show a difference?

Then I'll swap injectors. I've got a map gas torch to use on them so I'll do that.

And yes for the valve lash. I did it the common way of watching cylinder #6 cross over from intake to exhaust spinning the engine CCW the doing
#1 I&E #2 I #3 E #4 I #5 E, then cylinder 1 going cross over on Intake and Exhaust and checking
#2 E #3 I #4 E #5 I #6 I&E
 
Just stay .010 intake, .020 Exhaust. No need for extra lash, just beats up your valvetrain.

What procedure did you use to set your lash?
If the way I posted makes sense, it's the easiest and foolproof way, guaranteed to be on the backside of the lobe every time.
 
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