7.3 IDI Knock

[southpole560]

you damn jarhead (with all due respect intended from a veteran)
open the hood.
inspect exhaust manifold carefully for soot.
around exhaust ports.
all around exhaust manifold.
if you are 100% in your mind that its not an injector.
i suspect either an exhaust leak, which is my drunk unprofessional opinion.
or a collapsed lifter.
a rod knock or a wrist pin will have a lower frequency sound.
definitely AFTER the short block issue.
your lower end sounds ok.

if it is a valve, or a spring, take care of it ASAP, and dont drive it.
the slugs can take a beating to a certain extent.
but do not royally F it up.

do i need to break out the UCMJ on that ass?

There's no way it can be a lifter. I just replaced those and the pushrods. It has the same exact knock to it that the old ones had. I have looked around the exhaust manifolds and have only seen a little bit of caked oil from when the valve cover seals were leaking. But I replaced those since then. I will inspect it again for cracks. Also, I have no idea how many miles those injectors have on them. They definitely do not look like the factory ones. They have "ZP301" engraved on the side of them. I will take a video sometime of it under the hood. Before I cleaned the motor off, my friend told me that it looked like pep boys threw up all over it because there was a lot of caked oil. Mostly from slight gasket leaks and a small power steering pump leak. I thought that was pretty funny when he told me that. And no disrespect taken at all! Hear it from my buddies back home all the time haha.

 

[IDIoit]

another video with the hood open, request chit admitted to the chain of command.

 

[bobs_idi]

Try running some additives through your fuel. (ATF, diesel kleen, 2-stroke oil), whatever you're comfortable with.
If not injectors, I'd say a valve or spring.
Good luck Marine.

 

[southpole560]

I've ran a bunch of lucas through it and a bottle of diesel klean before. Both at different times lol. They seem to make no difference I will take a look at the springs again. They seemed to be fine last time I looked at them though. I'm pretty sure the sound is coming either from or very close to the #5 cylinder. And I wish they would take a look at my leave request sooner! lol

 

[IDIoit]

And I wish they would take a look at my leave request sooner! lol

youd have better luck asking to be deployed again. lol

 

[southpole560]

youd have better luck asking to be deployed again. lol

I wish lol

 

[crash-harris]

you damn jarhead (with all due respect intended from a veteran)
open the hood.
inspect exhaust manifold carefully for soot.
around exhaust ports.
all around exhaust manifold.
if you are 100% in your mind that its not an injector.
i suspect either an exhaust leak, which is my drunk unprofessional opinion.
or a collapsed lifter.
a rod knock or a wrist pin will have a lower frequency sound.
definitely AFTER the short block issue.
your lower end sounds ok.

if it is a valve, or a spring, take care of it ASAP, and dont drive it.

+1 and sober, lol.

 

[FarmerFrank]

Ok I didn't read through the whole thing so my bad if is been said.

I had a 7.3 that had a "tap" with 220k on it. I did the same, injectors, checked rockers, timed it and it would quite down when #3 was cracked. Also after a fresh oil change and 2 quarts of Lucas it would really quite down for maybe 500 miles. I figured it was a wrist pin.

I finally said screw it, I'm riding this pony till it dies. After 10k miles it still ticked and I parked the truck for other reasons. Ended up selling the heads and found a surprise, a cracked piston. So what what ones hearing might have been piston slap and a wrist pin knock.
Take it for what it's worth. I had a replacement engine and didn't care of this one windowed a block.

 

[southpole560]

Ok I didn't read through the whole thing so my bad if is been said.

I had a 7.3 that had a "tap" with 220k on it. I did the same, injectors, checked rockers, timed it and it would quite down when #3 was cracked. Also after a fresh oil change and 2 quarts of Lucas it would really quite down for maybe 500 miles. I figured it was a wrist pin.

I finally said screw it, I'm riding this pony till it dies. After 10k miles it still ticked and I parked the truck for other reasons. Ended up selling the heads and found a surprise, a cracked piston. So what what ones hearing might have been piston slap and a wrist pin knock.
Take it for what it's worth. I had a replacement engine and didn't care of this one windowed a block.

I've been starting to wonder if it's a cracked piston. Maybe even a slapping piston but it sounds like it's at half the speed the tach says. If this is the scenario, what should I do? Most new diesels are expensive and require smog. I've heard really good things about the 7.3 IDI but it would probably cost a lot for another engine or a rebuild. I would do it myself but I just don't have the time or the tools with me here :/

 

[Greg5OH]

you suuure its not an exhaust leak? does it get louder under load? If yes-exhaust leak
i dont THINk its a bad injector as those seem to knock more than tick/hiss.
Could be a bad valve, but most of the time its something really simple and the engine is just fine structurally.
Dont panic yet.
So many times in my foxbody I though ok yup, there goes my rod bearing, or ok bad lifter...it was jsut an exhaust leak..again, just different spot.

 

[IDIoit]

does your base have an auto pool? i know point magu does.
hueneme does, yours should!
you can find deals on IDI's just gotta keep an eye out.
ive bought 3, an N/A for 300
an entire truck for 500
and a 94 turbo complete for 600.

maybe theres one in the CESE yard...lol

 

[southpole560]

you suuure its not an exhaust leak? does it get louder under load? If yes-exhaust leak
i dont THINk its a bad injector as those seem to knock more than tick/hiss.
Could be a bad valve, but most of the time its something really simple and the engine is just fine structurally.
Dont panic yet.
So many times in my foxbody I though ok yup, there goes my rod bearing, or ok bad lifter...it was jsut an exhaust leak..again, just different spot.

I'm not sure if it's an exhaust leak. How would I check for those? Just look for cracks in the manifold? And the noise stays exactly the same, possibly even quieter on higher revs. It just goes faster. Also if I put the throttle on can hear the knock like in the video. If I'm going and then all of a sudden release the throttle, the knock gets very quiet. You can still hear it fails tly but it's just barely there. Once I put the throttle back on, you can hear the knock again.

 

[southpole560]

does your base have an auto pool? i know point magu does.
hueneme does, yours should!
you can find deals on IDI's just gotta keep an eye out.
ive bought 3, an N/A for 300
an entire truck for 500
and a 94 turbo complete for 600.

maybe theres one in the CESE yard...lol

A pov auto pool on base? Never heard of it lol. There are a few wrecking yards about an hour away from pendleton and also a few by 29 palms. I've only been to one near 29 palms since I'm here for a shop rotation. Saw a few IDI's but I didn't know the engine status and they looked like they had been sitting for awhile.

 

[freebird01]

this sounds dumb but have you checked your rocker arm bolts?

it sounds exactly like mine right after i put the motor together and had a loose rocker arm bolt...

 

[southpole560]

this sounds dumb but have you checked your rocker arm bolts?

it sounds exactly like mine right after i put the motor together and had a loose rocker arm bolt...

Yes. Torqued them all down to specs.