so after a host of problems over the last week, frozen,gelled fuel, replaced water pump that was not 6 months old, 2 dead batteries, bad icp sensor, bad cps, finally got everything up and running last Sat. so truck is up and running good again and not 45 min into running it after all of the F-ing problems i get into the throttle just a little for about 10-15 swconds, let off and i hear this god awfull whump, whump, whump..... I pulled the truck over and checked things out, then i hear the sound comming from the intake/air fliter... finally got around to pulling the valve covers today and this is what i found, a bent pushrod on cyl. #4.

Thanks for all of those who have helped me over the last week.,

 

Crikey, any idea what cause that?

 

u just pull them all out? to check? theres no adjusting anything right just re tqin it down

 

Dang, how high is your drive/ manifold pressure? I am really sorry to see that man.

 

Thats a bummer, one heck of a week your having..

 

over reving?

 

not really, never got over 3k rpm,

boost is right about 40 psi max.

no I had checked the others just by grabbing ahold and trying to move them by hand, all the others felt tight. and yes no adjustment, just tighten down... I did re tourque everything and install new GP's while in there tho...

 

Any recommended aftermarket push rods that are more stout?

 

Yeah, but if your drive pressure is excessive and you haven't swapped out your valve springs that may have caused them to float and bend the push rod.

 

I have a client (w/95' PSD) who just experienced the same problem. He replaced bent push rods and broken rocker arm to the tune of $500.00 at our local Ford dealership that has a sharp diesel mechanic. Started up the motor and yep, bent the new ones. Turns out he had a bad valve (the scope of work didn't include head diagnosis).

I'd make sure the head was good before dropping in another push rod and getting similar results.

 

Too late, already dropped a new one in this afternoon, put it back together and took it out for a spin, ran it out pretty good and nothing gave as of yet,,.. keeping my fingers crossed, although i do have another set of heads in the shop.. so worse comes to worse ive got an extra set.

 

What about a sticking valve due to wet stacking? I recently came upon a link by dieselmann which went over the subject of bent rods due to that. It made sense to me how it occurs, so that could be another possible theory. Here's the link:

dieselmann's editorial

 

With computer controlled injection, wet-stacking is all but eliminated. In fact, I've never heard of it happening in the new generation diesels.

To the OP: Can you look at the back pressure? AE or a Scan Gauge can do this. I'm getting 35ish psi boost for 50psi or so of back pressure. It's a little high, but not even close to 2:1. Ideally it should be about 1:1 (as in for 40psi of boost, 40psi of back pressure).

 

If you need I have about two complete sets of push rods and all kinds of crap in the shop. Let me know if you need anything!

I also have another set of 910's on my old heads...

I would be looking to a set of springs... Ya dont need push rods, just better springs.

 

Thanks for the offer Joe, I have a scrap engine in the shop i stole one of the pushrods from, yes i will be looking into doing springs sometime soon, what do you want for the 910's? I drove by your house the other day and saw the white beast sitting next to your shop is it still down?