This is long and may interest you mechanics
 

I was on my way to pick up a piece of equipment and was on a long grade with my 6000 lb goose neck trailer in tow. I had my chip tuned with Edge Products Evolution tuner set at the #1 setting, which is suppose to be the tow setting. I don't remember the speed or rpm, but it was not over limit. All of a sudden, it sounded like I had blown out part of the exhaust manifold. I did not notice any loss of power, but pulled over immediately, popped the hood, and found blow back coming out of my intake cleaner. First thought was that I'd sucked a valve, but the engine was still running and no other noises. Seemed to be pretty smooth running too. After all, seven cylinders still firing.

I took a chance and drove on, a little slower by choice, to my destination where I dropped the trailer. Still didn't seem like any loss of power. Now I shut off the engine not knowing if it would start again.

I pulled codes with both my readers and nothing came up. So I pulled the Y tube from the turbo and heads and turned over the engine to see if it would crank. It did, and it started. Nothing has locked up. The blow back was coming from the right bank.

So is what's going through your mind what was going through mine? Intake valve melted away? Glow plug blow out? Injector? I figured this is a little more than I want to handle since I don't have a shop built yet to do the work in, and it rains here a lot. So I have her towed to a shop. Tell them the scenario and they start by pulling the right valve cover.

They start pulling the push rods out, and the 2nd cylinder has a bent push rod, and a broken one. I believe the intake push rod was the bent one. I don't think the mechanic paid attention to the valve position when he removed the rockers. But what I'm thinking is the bent rod wedge in the channel and held the intake open just enough for the blow by.

Now I'm worried about the valves, piston and cylinder wall. So I give the OK to pull the head. They do and find nothing wrong with anything else. The valve are fine, the piston and cylinder wall is fine. The lifters are fine.

We're all scratching our heads. The mechanic has no idea what caused the push rods to bend and brake. His only suggestion was a clogged or dirty injector which he would clean to make sure.

So she goes back together and I have new push rods put in, both sides. They start her up and she runs fine.

Any ideas out there as to what may have caused this? I'm still scratching my head.

First off, don't use the Edge if you don't have at least a Pyrometer....

Usually push rods bend due to overrevving, Did it downshift right before this happened?

That is intirely possible. I don't actually remember at this point, but when I think on it I want to remember it did. CRS has been setting in for some time now. All the other push rods are prefectly straight.

Yes, I do need a pyrometer. It's on my todo list as I just picked up the Edge (used) and did send it in for reprogramming. Now I see on their web site the have new units with pyrometer and boost. Know anything about these?

If you hang around FTE very long most well advise you to sell the Edge, and get some good custom tuning. TW tuning, Dp tuner, BTS tuning, Tyrant diesel Tuning, just to name a few. The Edge is better than stock, the custom tunes are way better than the Edge.... either way you need gauges.

I assume your truck is an automatic? Bending pushrods ussually happens on more heavily modded trucks.

It's possible the rocker arm loosened up or somehow bent. The pushrod popped off the rocker causing your failure. Or the pushrod just failed. Your very lucky that the valves are OK. I would find it hard to believe it had anything to do with tuning.

Bent or broken pushrods aren't a common problem but do happen from time to time on 7.3s even on stock trucks. Two on the same cylinder is a little strange but one could have been bad before too. A bent one can be hard to notice with the injection and combustion noise and as you've found out the truck still runs fine

When this happens it usually is a good idea to take a real close look at the rockers and their hold down parts. They have been known to bend and crack at the same time the pushrods bend.