WVO/SVO + 603.970 Hypothesis...

[Blevinsax]

As I was driving the other day, I had a thought about the cursed rod-bender 3.5L 603.970 that some of us have in our 350SD's, 350SDL's, and S300D's...

In a previous thread about these motors, BC mentioned that a likely cause of the bent rods in these motors is high cycle fatigue - that after a certain number of cycles (that number being different for each individual rod in each individual motor based upon its construction, use & maintenance, environment, etc. but seemingly a lower number than the time-tested 3.0L) the connecting rod gives way and bends due to the extra power being too much for it to bear. Here is the post from that thread:

Originally Posted by Brian Carlton

While it's certainly possible that certain rods are defective from the factory, if they are forged (likely), the chances of them bending in operation due to running over the design loads are minimal. In any other engine, you can run the rods just about forever and never exceed a design load.

A far more likely scenario is high cycle fatigue. It's related to loading, however, is governed by the on and off cycling of the load. The distribution of failure in high cycle fatigue is huge. One rod may fail at 4,000 hours. The next rod in the batch may fail at 40,000 hours. It's not easy to define high cycle fatigue life. Jet engines suffer from this malady and all of the rotating parts must be scrapped before the very first one of the group suffers from high cycle fatigue.

Since the power that bends the rod comes from the BTU output of burning fuel, (i.e. #2 diesel) would it not make sense that burning a fuel with lower BTU output (i.e. WVO/SVO) could create less power and therefore contribute less to the potential bending of connecting rods in these motors?

Assuming (yes, I know what happens when we ASSUME) that the high cycle fatigue theory is accurate, and setting aside all other potential problems associated with WVO/SVO use, would it be possible to say that burning WVO/SVO in a 3.5L 603.970 might help extend the life of the rods and thus the motor itself?

Hey, call it wishful thinking if you like! I just like my car and I hope I can drive it for a long time. Therefore, I am trying to think of ways to help prolong its life, especially since it saves me a lot in fuel expenses.

Sorry for the re-posting from another current thread, I just didn't want to hijack it and corrupt it into another 'rod-bender' thread!

[BioPOWER]

Biodiesel and WVO have higher lubrication properties than petro; this could help reduce friction-based stress on the rods from the pistons reciprocating in their liners.

Just my $.02 ... if it's gonna bend a rod it'll do it no matter what fuel you're burning. I also thought bent rods were related to cracked head/coolant/hydrolock issues.....?

If your 350SD has lasted 219k I'd say it's passed the test and has one of the good motors.

[greasybenz]

Originally Posted by BioPOWER

Biodiesel and WVO have higher lubrication properties than petro; this could help reduce friction-based stress on the rods from the pistons reciprocating in their liners.

Unless the fuel lubricates rods and pistons (and it shouldnt as its the engine oils job) the lubricating properties of the fuel wont have any affect. Actually the only thing that may take advantage of the better lubrication is the IP but it already gets lubricated by engine oil.

Biodiesel's solvent effects will clean the injectors though...