Having finally discovered that the mounts that came with my Cummins engines would not work on the Roamer without modification, I took them to a local machine shop and had some work done. Meanwhile, back in February 2014, I had a fancy schmancy idea for engine beds. Unfortunately, that idea was based on a few assumptions that turned out to be wrong–like, thinking the engine mounts were symmetrical…silly me. Even more unfortunate is that I went ahead and bought a 25′ stick of 3/8″ angle and 1/4″ plate in 6061 aluminum and cut and welded my creation together…proving once again that a fool and his money are soon parted. But on the principle of making lemonade when life hands you lemons, I’m re-purposing the fancy engine beds as spacers between the vibration isolators and engine stringers.
When I first attempted to install the engines, I used a piece of tape between the stringers with a mark at the mid-point. Every time the engine touched the tape, it ripped (surprise!). The tape ended up stretching, too, so it was pretty useless as a center indicator. So now, I use a piece of aluminum angle with a mark indicating the halfway point between the outside edges of the stringers. I put a square on the angle, line it up with the mark, and then move the front of the engine until the square is centered in the middle of the damper pulley.
From the beginning, I wrongly assumed that the mounts that came with these engines had the slots at the same elevation. It turns out that was completely wrong–the front mounts are lower. Having never done this sort of thing before, I’m pretty much guessing how many spacers I need. After putting in 3/4″ spacers at the front and 1-/1/2″ at the back, I still had at least an 1/8″ gap at the bottom of the couplers. So I removed the spacers at the front and started dropping the vibration isolator bolts lower and lower to close the gap.
In the pic above, you’ll notice that in addition to there being no spacers anymore, I’ve also bottomed out the vibration isolator. See the big nut in the lower left corner of the pic? That’s the locknut that’s supposed to go under the other nut and washer on the under-side of the engine mount. Taking it out allowed me to drop the front of the engine an additional 1/2″ and get the couplers to align. But I think it’s unwise to run without the locknut. Hmmm
And then, another problem that was right in front of me made itself apparent. If you look closely at the left side of the pic below, you’ll notice (as I belatedly did) that the angle of my uber-precise engine centering gauge is hovering above the engine stringer. rather than sitting firmly on it.
It turns out that Chris Craft welded the 6061 angle to the stringer with the upright stringer plate impeding into the inside radius of the angle. This creates a gap between the angle and the plate and changes the angle between the upright stringer plate and the top of the stringer from 90° to ~95°. So, to avoid inducing stress into the vibration isolators from that 5° misalignment, I need to make a spacer that will level the stringer here. But if I do that, it will raise the front of engine, and there goes the perfect alignment of the couplers!
Dang it! Back to the drawing board!