What's the deal with the rods? - Diesel Forum

**mlsteele** · 10-29-2012, 08:36 PM

I was reading on another forum that the rods in the 6.7 are weak. What is the deal with this?

KJ Smith · 10-29-2012, 11:03 PM

Quote:

Originally Posted by mlsteele

I was reading on another forum that the rods in the 6.7 are weak. What is the deal with this?

You should ask on that other forum.

In the year and a half that I have been keeping up with this forum, this is the first I have heard of weak rods.

Adventure Rider · 10-29-2012, 11:22 PM

Quote:

Originally Posted by KJ Smith

You should ask on that other forum.

There's another forum?

**mlsteele** · 10-30-2012, 06:55 AM

Yeah if you goto Powerstroke.org you will see the topic there. I could not read it all due to all the bashing that was going on. It was like a bunch of female dogs fighting. That is why I came back here and ask the qusetion. Most of the guys that use this site know what they are talking about and there is little to no conflict. I look at a few different forums but always come back here for the real answer.

KJ Smith · 10-30-2012, 08:11 AM

I have noticed that people on this forum don't have as many issues with their trucks......

06ram610 · 10-30-2012, 10:04 AM

There is one guy that bashes them all the time....no one else seems to have issues. I believe there was one report of a company running 100hp sticks, compound turbos and a hot tune that bent and broke some rods. Just drive the truck and don't worry.

**mlsteele** · 10-30-2012, 10:40 AM

Well good. That is what I was planning to do anyway. This is the best forum out there and I will probably stay away from the others from now on

luke0204 · 10-30-2012, 10:55 AM

I can think of one guy on this site that had a catastrophic failure with a stock 6.7L, although in my local area I've heard of a few more. These trucks are made work at the level they are at, modded and abused 6.7's seem to fail fast.

06ram610 · 10-30-2012, 11:00 AM

While I think they are possibly a little weak when modded. How much more do we need than 400hp/800tq. I have been doing the same pulling since my first cummins which was 235/460. I think the days of the heavily bombed engines are coming to an end. All of the manufactures are looking at ways to keep the aftermarket crowd from becoming the warranty crowd....maybe they figured out how with weaker rods. Oh well, I never modded either of my dodges and don't plan on modding this one, so I'm not worried. Most of the failures have resulted from the valves, which ford has fixed anyway.

RedF-350 · 10-30-2012, 04:22 PM

Did Ford fix the valves? If so when?

06ram610 · 10-30-2012, 04:32 PM

I believe so...I don't remember the exact issue, something with heat treating I believe. I have seen or heard of any 2012 total failures. I'm sure there have been a few, any time you produce 500,000 engines something is going to happen from time to time.

Dak · 10-30-2012, 06:25 PM

Quote:

Originally Posted by 06ram610

I believe so...I don't remember the exact issue, something with heat treating I believe. I have seen or heard of any 2012 total failures. I'm sure there have been a few, any time you produce 500,000 engines something is going to happen from time to time.

I thought the vavle problems were on the c&c's... Different turbo altogether.

06ram610 · 10-31-2012, 09:07 AM

I didn't think the valves had anything to do with the turbo, but yes the cc trucks have had numerous issues with turbos. We have a 550 at work that needed a turbo at 5000 miles. But it has since been replaced and runs great.

Dr.Evil · 10-31-2012, 11:34 AM

The problem that trashes a cylinder in the 300/600 rated engines in the C&C trucks is a valve face cracking issue. Once they crack enough the exh valve head breaks and the piston beats the piston top & underside of the head up with the chunks of the valve head. Normal repair for those is a complete new engine. I've been watching the discussion on another forum for close to a year now. A company bought six new '11 F550's and had catstrophic engine failure on five of the six engines by 20,000-30,000 miles. The sixth engine was still running with ~50,000 miles last post I saw, has had a turbo replaced, and the typical transmission reflashes done, and was getting about 5-6 MPG grossing 19,000#.

I never have heard an official reason why the 300/600 engines had a problem and the 400/800 engines in P/U trucks haven't other than "They're different". A person would think an engine making 33% more HP & torque would run hotter but maybe the single turbo on the 300/600 engine runs higher EGT's due to less airflow through the engine. That's just a SWAG on my part, the reps from FMC supervising the engine replacements and return of the blown engines weren't talking.

ohman_stm · 10-31-2012, 03:39 PM

Gents, to properly frame the "rod issue", and avoid unwarranted paranoia regarding the 6.7 engine, the fact is that yes, there was an instance of the rods bending, breaking and cracking, but it was on a modded 6.7, as 06Ram10 stated. That engine was obviously tuned beyond the thresholds that Ford engineers designed the engine to deliver.

For me, 400/800 is sufficient to get the job done, and my truck does it in spades. For those looking to "tune/juice up", I get the impression the 6.7 isn't as accommodating for that configuration (like the 6.0 and 6.4 are), unless you reinforce some of the internals of the engine to sustain, i.e stronger connecting rods, etc... Which begs the question, why do you need more power over stock?

As a naturally aspirated owner, I am 100% happy with this product. Drive the truck and enjoy it!