[hmedic]

So this all started out with a misfire in cylinder 8. Which I took to a diesel mechanic who told me I needed injectors. $5,000 later I still have a miss and a diesel mechanic telling me it must just be the motor, give him $13,000 and he will replace it . I did not do this the miss led to a Knocking, which led to a popping in the air box. The popping led to a very loud metallic knock which led me to the garage where I proceeded to tear it down. Upon tearing down I discovered a bent pushrod crushed lifter and a broken piston on the bottom side. This led to a new connecting rod, New wrist pin, one push rod, a new lifter and hopes this will solve the problem.

Put it back together yesterday, started it today to find it still Knocks. Pulled everything apart so I could see the valve train ran the motor everything appears to be fine but a definite knock from the driver side of the motor possibly cylinder 8 still. Went ahead and pulled everything apart pulled the head back off everything looks normal butt I now noticed the valve train on cylinder 8 is blacker than the rest.

I am now looking at the old piston and do see evidence of where the valves have hit the piston or left indentation where the valve is located, that I do not see on the rest of the Pistons.

Could the valve train or these valves be the reason for this whole problem?

The blackening on the valves that I am describing has always been there, but didn't suspect valves only because the bent push rod crushed lifter and broken piston seemed an obvious culprit

 

[diesel dave 99]

I heard that they have updated push rods that are shorter because if a lifter pumps up to hard the valves will hit the piston. but I have no experience with them. I would pull the other head and remove the cam and replace it and all the lifters. did you check the bore in #8. and the clearance between the piston skirt and cylinder wall?

 

[yan7gin]

Upgraded Push rod, lifter and rocker is a good idea to swap on these engine when you have it open. Since you have everything apart, i would also install the upgraded HPFP gasket cover. Open your fuel filter on top of the engine,look for signs of corrosion and look the fuel/bottom of the fuel bowl for shiny metal flake.


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[Maryland dieselnick]

Ide pull springs and see how your valves slide freely and if they feeling like a good clearance for the stem to guide. Look for coking as well.

 

[hmedic]

because i hate to be the "guy" who doesnt follow up on the post.....

Built again and appears to be working.... but still dont know why it did it to begin with.
I did not have the motor fogged or dipped or anything like that - I did this in the truck
Turns out Ford didnt know what they were talking about when they measured the piston...the knocking was the fact they gave me a standard piston and the truck really was bored .30 over like I was told, but Ford told me it wasnt. GRRRR!

So the knocking was the piston slapping all over the cylnider wall.

After all that it is back together and running - changed the oil 3 times in 200 miles and still see a little metal in the filter now the then...

I am leaking oil from the front main, but am not 100% I am putting the oi seal in correctly..there seem to be no utube or pictures to supplement this and think I put it in to far, but that is a lot of work to do this late in the game.

Does anyone have rule of thumb as to when the repair done is trustworthy!? Like I want to pull a camper for Memorial Day!