Tick/Knock issue with heavily modded grail

[wgr73]

Guys I'm looking to purchase a grail truck. Its pretty heavily modded with less than 2000 miles on the mods (~190k miles on truck). The owner (who is an honest and open cool guy) told me that the truck has what seems to be a fuel tick/knock at idle only audible in the cab and rear of the engine. He said it sounds like a screwdriver tapping and moves around from time to time and sometimes it disappears altogether.

He took it to a master diesel tech who I actually got to speak with on the phone. He thinks it sounds like a wrist pin. He's heard them in his 25 years of working there, said it sounds like a minor wrist pin noise. Question is:

How major is something like this? I know for my Subaru that would be considered catastrophic, but these diesels are built like tanks. But what do you guys think?





Mods:

Twin Batmowheels 62/68/12 over S480
21* Timing
Stainless Diesel Polished and port-matched Manifold
AirDog II 165 gph lift pump
Benched and maxed 215 p7100 pump
CPP 5x18 injectors
Afe Bladerunner intake manifold
Heavily ported/polished, o-ringed head
Titanium keepers and HD valve springs
5" Straight exhaust
ARP Head studs
NV4500 with a South Bend Dual Disk clutch


Any ideas? I live 1500 miles away so I can't just drive over to see it :-/ Any help would be greatly appreciated.

 

[wgr73]

*The stock lift pump has been deleted all together*

 

[spooled mule]

Someone with more knowledge than me will chime in. From the way it moves around and stops sometimes seems it would be something other than a wrist pin $.02. Have they looked at the injectors or tried swapping the #1 injector for number #6 to see if it moves cylinders with that injector? Goodluck just what i would ask them to try if it were me buying it. If they do not get it stopped you can probably get it for a song. Forgot to add have they checked the valve lash not sure if it would cause this but easy enough to check.

 

[ARbowhunter7]

An audible wrist pin sound could be more or less noticeable depending on different factors, but generally wouldn't change location.

It must be pretty loud, though, as these motors make a lot of racket at idle. Any more details?

 

[wgr73]

Someone with more knowledge than me will chime in. From the way it moves around and stops sometimes seems it would be something other than a wrist pin $.02. Have they looked at the injectors or tried swapping the #1 injector for number #6 to see if it moves cylinders with that injector? Goodluck just what i would ask them to try if it were me buying it. If they do not get it stopped you can probably get it for a song. Forgot to add have they checked the valve lash not sure if it would cause this but easy enough to check.

I have him cracking #6 for sure. I'll ask him to swap 1 and 6. Valve train seems to be good. He has heavy springs so those chatter some.

An audible wrist pin sound could be more or less noticeable depending on different factors, but generally wouldn't change location.

It must be pretty loud, though, as these motors make a lot of racket at idle. Any more details?

He said it sounds like a screwdriver tapping. And that he thinks the wrist pin may have scored if anything. Not much info other than that. It does go away once you get into the throttle. I've been reading that wrist pin sound goes away as rpm increases

 

[wgr73]

Is it a rare thing for the wrist pin to go causing this type of knock?

 

[cumminsman315]

I have experienced a similar problem, it was a customers truck that he just bought off a guy.

The knocking noise very very similar to what you describe, in the same location, would go away for a second if you got rolling and then slammed on the brakes, and also when you would put it in reverse really fast it would move from the back too the front and return to the back.

In his case it sounded like it went away as rpm increased but that could've been just other motor noises covering it up.

He chose to pull the motor before he ever brought it to me. When I drained the oil it ended up have 5 1/2 gallons in it... All bearings looked good but the number 6 rod was bent. Before I pulled the pistons out I measured protrusion, number 6 was .012 less than the other 5. Trashed the piston and scuffed the hell out of the cylinder wall.

 

[wgr73]

I have experienced a similar problem, it was a customers truck that he just bought off a guy.

The knocking noise very very similar to what you describe, in the same location, would go away for a second if you got rolling and then slammed on the brakes, and also when you would put it in reverse really fast it would move from the back too the front and return to the back.

In his case it sounded like it went away as rpm increased but that could've been just other motor noises covering it up.

He chose to pull the motor before he ever brought it to me. When I drained the oil it ended up have 5 1/2 gallons in it... All bearings looked good but the number 6 rod was bent. Before I pulled the pistons out I measured protrusion, number 6 was .012 less than the other 5. Trashed the piston and scuffed the hell out of the cylinder wall.

Wow dude, thanks for the insight on this. A wrist pin issue seems like a ticking time bomb to me. That's why I am hoping it isn't. I want to exhaust all other options first.

 

[kansasfirstgen]

check your tappets, I had a partially broke tappet that sounds about like this.

 

[wgr73]

I'll tell him about that! Thanks for the suggestion.

 

[wgr73]

Is there a way to do that without tearing into the engine?.... Tappets that is

 

[AsTroSS]

Is there a way to do that without tearing into the engine?.... Tappets that is

You can chage the tappets and cam even if the engine is still in truck ,I have done it

At first you need cam gear puller/installer (If I remember correctly cam with gear will hit radiator support) and tappet remover/ installer kit

 

[wgr73]

Ahh ok. It's too much work for the seller. He won't have time. And I can't buy a truck with a wrist pin issue. He said his mechanic is pretty sure that's what it is.

 

[ChuMaDD]

Ahh ok. It's too much work for the seller. He won't have time. And I can't buy a truck with a wrist pin issue. He said his mechanic is pretty sure that's what it is.

You can, just get it alot cheaper than he wants...

 

[1stgensleeper]

You can, just get it alot cheaper than he wants...

^this^

 

[wgr73]

I don't think he'll lower the price. That'd be good tho

 

[ChuMaDD]

You just need to sell him on how major/time consuming the work would be to fix it and the price needs to reflect on that...

 

[1stgensleeper]

You just need to sell him on how major/time consuming the work would be to fix it and the price needs to reflect on that...

^agreed^

 

[wgr73]

You just need to sell him on how major/time consuming the work would be to fix it and the price needs to reflect on that...

Thing is that he doesn't think it's a big deal. That it'll run forever

 

[Bponci]

I have seen the cam gear move before and it made a ticking noise come and go. The last one we checked by buy removing the lift pump block off plate and rotating the engine in both directions and watching the gear move back and fourth. Just another Place to check.