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Hi Bjorn, I was looking on ebay, and noticed a guy selling pop testers built from little hydraulic jacks. Then I did a google search on fuel injector pop testers, and found this link: How to build a diesel injector pop tester - PeachParts Mercedes ShopForum This guy shows how he made a pop...

Hi Tom, I'm near Frederick. I am certain that a manual tester could easily overcome the pressure valve in the injectors, but I wonder if it could achieve the operating pressure of the MF injector when using the thicker oils?... or the operating volume necessary when using the thinner gasoline...

Hi Tom, No, I have never put an MF injector on a tester. I have been looking for a manual test pump with my name on it, but have not found it yet. Got a spare? As I understand it, the MF injector has multiple personalities: Thick fuels will atomize because you are pushing large molecules...

MF engines don't atomize the fuel. They squirt a stream of fuel into the combustion chamber formed in the piston top. The fuel boils and splashes up into the hot air, and burns slowly. That is why the MF engine is called a Whisper Diesel engine. Keep your engine speed down, and you will...

Nope! The MF engine is NOT a spark ignition gasoline engine... Nor is it a conventional diesel engine. The special juju of the MF engine is a deep well combustion chamber bored into the top of the piston ( It looks like what you would get if the piston was made of modeling clay, and you stuck...

It isn't the indicated speedometer speed that throws the rods, it is the indicated tachometer speed. These trucks threw rods when they were doing line haul probably more frequently than they do now in our service. Check out the letter that David Doyle found where the DOD was complaining about...

Yep! The only difference between the MultiFuel, and an OTR diesel (in the rod throwing tendency) is the Military turned the governor up well past the speed that would usually be the limit for a good long operating life. Look at what they did to the gasser to make it a MF. They kept all of the...

I think you missed my point. Even though a valve spring is flexed a visible amount, the steel is still capable of handling the bending billions of times without breaking. I have taken apart many engines with multi hundreds of thousands of miles on them, and the valve springs are still the...

Nope. It is purely a maximum RPM thing. Your adjustment on fueling rate affects HP across the whole RPM range. -Chuck

That's pretty close to what we have in the MF engine right now. -Chuck

One thing I have always wished we could get access to is the reasoning behind the various decisions made in specifying this truck. There is a reason why 56MPH, and 2600RPM were selected as the maximum, and the tach's and speedometers were labeled thus. I suspect that it is like the WEP (War...

Yeah but, your entire set of pistons weighs less than one MF piston. -Chuck

Absolutely! But, when the metal isn't being stressed beyond a certain point, it can take the stress essentially forever. Consider the valve springs in an engine. They are being flexed many hundreds of times per minute, and yet they take it virtually forever. Valve spring failures are pretty...

Uhmmm, not usually. These bolts, if they were spec'd properly (and I'd bet they were), should be able to stand this service for practically forever. A well designed engine will die from friction affects (read: wear) long before they will die from fractures. -Chuck

We have seen pictures of quite a few failures, and in all cases, there are a pair of rod bolts that have snapped off. It sure looks like they are the source of the failure. In a couple of pictures that showed up on this list, there was clearly a fault crack in the rod bolt that was old... a...

Not quite. There is a big problem with highly volatile fuels like gasoline. Were it not for the special injectors that squirt a stream of fuel, rather than atomize the fuel, and the deep well combustion chamber in the piston, that keeps the fuel out of the crankcase, the MF would not work very...

One thing I have long thought is it would only take a couple of mechanics, in the rebuilding factories, that were over tightening rod bolts to create a whole lot of time bombs, just waiting [for us to go roaring down the road at 56MPH] to explode. The same goes, only even more so, for a load of...

If your intention was to see which failed first, the rod bolts, or the cap, that would be a very interesting test.... but maybe not all that useful. From looking at the results, the group consensus has been that rod bolt failure is what caused the problem. What we don't know with any certainty...