M923A1 fuel pump to far advanced.

[Hooper]

Has anyone here had issues with what sounds like spark knock under acceleration with there NHC250? This moter only has 57 hours on it and maybe still needs to wear in but under acceleration I can hear what sounds like a faint metalic banging.

 

[Triple C]

I am not real familiar with this motor, but I used to run an 855 block 350. I think they are probably about the same. In the stone ages, when you overhauled a diesel motor like the 855 block 350hp, you ran the overhead after break in. They would adjust the valve lash and reset your injectors. It may be that you have a rocker arm or valve seat that is making a bit of noise. The time on your motor would seem to be early to adjust your valves but my guess is running the overhead would fix the problem (unless something is coming apart - unlikely.)

 

[Chain-Saw]

I had that same "knocking" noise on my first M923. See my thread about my first oil change, and you'll see I had a "partially-grenaded" cylinder liner. I sure hope you don't have the same issue on that sweet new engine. I could sometimes hear the knock in mine at idle also, and I didn't hear that on yours when it was sitting in my driveway, so it may just be a matter of breaking it in. Definitely go easy on it for a while though. Good luck.

 

[Hooper]

I had that same "knocking" noise on my first M923. See my thread about my first oil change, and you'll see I had a "partially-grenaded" cylinder liner. I sure hope you don't have the same issue on that sweet new engine. I could sometimes hear the knock in mine at idle also, and I didn't hear that on yours when it was sitting in my driveway, so it may just be a matter of breaking it in. Definitely go easy on it for a while though. Good luck.

You are right, its quiet at an idle. Talked with a Ford diesel tech and he was saying some of the mechancial fuel pumps if they are to far advanced will produce a type of spark knock sound. Thanks again for assistance getting it pickup. It was nine hours getting it home in the cold but I was grinning from ear to ear the whole time. Looking forward to testing it this summer.

 

[sandcobra164]

I've driven many NHC 250 powered trucks. I just thought that was a common "Diesel Rattle" when I stepped on the throttle. I'm not sure how your's sounds but I thought it sounded rather mean and I hope my next truck has it!!!

 

[M813A1]

Sound like you need your injectors adjusted . They can make alot of noise if they are out of adjustment .

 

[Scarecrow1]

I have a 923a1 but, I don't hear any knocking . I would have it checked out by a pro just to be safe. It is a whole lot easier to fix a problem than to replace an engine.......

 

[rangereter]

Hooper,
You could remove your oil filter and open up the pleats (sp?), in sunlight it is easy to tell if you have any abnormal metallic wear. A pocket magnet is a handy tool to id the steel from the aluminum debris. Filters are about $12...if yours does not show abnormal wear, at least your not out much.
Regards, Bob