Noise Comparison Beta vs. MD7a

I’m fortunate to have pretty good hearing.  While I can’t hear a dog whistle, at age 40, I still find old school CRT type televisions annoying because I can hear the scan frequency.  My wife, and most adults I’ve asked, have no idea what I’m talking about. 

It comes at a price though – I’m sensitive to noise in general.  With two notable exceptions, I find most machine noise to be annoying.  Being a mechanical engineer and former auto mechanic, machine noises that sound like something is loose or malfunctioning, or just shouldn’t be, are the worst. My old tired MD7a with it’s “missing the third jug timing” was one of those. (The MD7a has the cylinder timing of a 3 cylinder, with one of the cylinders missing.) So after reading all of the forums and sales literature about how quiet the Beta is, I was very excited to find a good deal on a Beta.

MD7a

So the Beta is installed and the jury has rendered a verdict.  Although I have access to it, it didn’t occur to me to take before and after noise measurements with a sound meter, so my phone will have to do.  Quantitatively, the Beta is quieter, but nothing to….well shout about.  Qualitatively, it sounds to this designer of machines for the last decade as a 2 cylinder diesel should, if a little

Beta 14

noisier than I would like. Here are some videos. That said, no effort has been made to add sound insulation (yet) in Sojourn and in fact feels like a lot of vibration is getting transmitted through the hull and reverberating in the open space in the lazarette. I’ll revisit this when I get to sound insulation on my rather lengthy to-do list.

Oh, and the two notable exceptions: A Ducati 900 Super Sport and Packard V-1650 often heard in a North American P-51 Mustang flyby.

Galloping Ghost at Reno (3 min video.) The video doesn’t do it justice.

Sojourn’s Exhaust

The Beta’s exhaust comes out on the opposite side of the prop shaft  as the old Volvo and thus my muffler.  I needed a tail pipe that went up about 8 inches, to starboard 9 inches and aft about 17 inches to the muffler. Moving the muffler is possible, but not attractive as it would encroach on storage space in the lazarette. To solve my geometry problem, I designed a tailpipe in Solidworks consisting of a flange, a bent piece of 1-5/8 stainless exhaust tubing, a 1-1/4 pipe nipple, and a 1/2 pipe nipple.  I made the flange myself and had Stan at Stan’s Header’s in Auburn bend the tube. I cut the threaded ends off the nipples and milled a hole in the larger.  I then welded the parts together.  Voila.  After wrapping it with some exhaust lagging, the hole exhaust project cost me $125 and about 2 hours. 

As I’ve said before, I purchased Sojourn as a learning project and am getting my money’s worth.  On that note, I was surprised to find that my old tail pipe actually had evidence of rust, to the point of rot, from the outside than the inside. In fact, if you look closely, there is a hole in it. I have also noticed that every time I started the engine, that the exhaust lagging would steam.  I’ve since learned that the lagging is hygroscopic (has an affinity for water) which causes it to absorb water from the air, of which there is much on a sailboat. Hopefully the stainless will last longer than the carbon steel did.

Other’s who have converted to Beta, will likely recognize that Beta recommends a 2” exhaust for this installation.  I decided to try to save a few hundred dollars and reuse the old exhaust.  If the 1-5/8 doesn’t keep me within allowable back pressure, I’ll have to upsize.  Stay tuned.

Four Feet Closer

One of the fringe benefits of my job is access to a rather well equipped machine shop.  The shaft line on the Beta sits about 1.9 inches lower than it does on the old Volvo and therefore the new Beta needs to sit 1.9 inches higher.  Beta Marine advertises that they have a solution for this, but having already purchased this on the secondary market, visions of hundred dollar bills danced in my head.

I found a piece of 6 inch aluminum C channel and drew up some feet in Solidworks around this material.  I cut it into 5 inch lengths and a few hours on an mill and this is what I ended up with.

I was worried that the timber under the engine beds would be rotten after 37 years, so I wanted a good hold to the fiberglass itself.  I decided that six #14 stainless wood screws should do the trick.

Despite a cold soggy morning, the afternoon turned out to be delightfully sunny and almost, dare I say, warm. Annie and I headed to the marina to install the new hardware. 

To my pleasant surprise, nice dry pink wood chips came out of all 24 of the drilled holes.  I wonder what species they used that might have pink wood. If six screws was going to be enough in rotten wood, this felt very reassuringly solid.  After screwing down all four feet, I rigged the engine to the Halyard for the last time and set the engine on the new feet.  So, Sojourn is four feet closer to having a running Kubota power plant.

Sojourn’s Repower Underway

I’ve embarked on a sojourn of a different sort – repowering Sojourn. As I write this, she leans slightly to starboard in her slip, burdened by 340 pounds of cast iron sitting on her cockpit seat.

I had planned to get a chain fall, some additional muscle and some other tools to remove the old Volvo MD7A, but the decided to go down and get started. I disconnected the control cables, wiring, exhaust, fuel and cooling hoses.  I then removed the bolts from the motor mounts and prop coupling and the motor was free, save the forces of gravity and being something of a square peg behind a round hole – or was it the other way around? By calibrated eyeball, the opening was about 2 inches shorter than the distance from the bottom of the flywheel to the top of the valve cover.  Further, the flywheel was too low in the hole to get a three-jaw puller on it.

To expose the flywheel, I tied the main halyard to the alternator bracket and hoisted, tipping the engine up, giving me the clearance I was hoping for.  The three jaw puller I borrowed from work must have weighed 45 pounds and seemed adequate to remove the wheel from one of those earth movers you see on Big Machines. After applying most of the muscle and all of the cajones I had, it would not budge.  I had screwed so much energy into it that I was having visions of it popping off and subsequently harpooning the forward bulkhead.  In fact, I damaged the crankshaft stud pretty badly.

Plan B was to remove the valve cover, rockers and injector lines. Now, at least, it was a smaller peg.  And, it was halfway out of its hole.  I decided to keep going.  I tightened the halyard a little more and gave it a tug.  The engine practically popped onto the battery box.

The impatient man in me wanted to keep going so the engineer did a seat of the pants calculation.  340 pounds.  7/16ths halyard. 5 inch winch. 12 inch handle. Some friction. – about 70 pounds of armstrong.  I figure I give it at least 50 pounds of armstrong on the last crank when hoisting the sail.  A 7/16 line, even as old as this one should have 1000 pounds of breaking strength. I went for it.

The impatient man re-rigged the halyard, tied a line between the end of the boom and the halyard to keep the engine from swinging toward the mast and proceeded to crank the winch.  As soon as it pulled free of the battery box, the whole boat listed to starboard with the engine swinging likewise.  I think I heard a goose in a very good Homer Simpson voice say “Dohhhh!”  The impatient man tied a line between each of the cabin top winches and the halyard.  This worked very well. I continued cranking the winch as the old Volvo emerged from the companionway.

Before I knew it, Sojourn’s old engine (and perhaps someone’s new anchor) was sitting on the starboard cockpit seat and there was an  empty hole under the cockpit.

Too Good to Be True

I’ve both found screaming deals and wasted time and money on Craigslist.  But, on balance, I have had a favorable experience. This deal…well, time will tell. 
Sojourn’s 13 horsepower, 1974 Volvo Penta MD7A is tired. She smokes when cold.  She doesn’t start without a can of assistance if the outside temperature is below 50.  Incidentally, I fearlessly bought her with two thoughts in mind.  First, that I can rebuild nearly anything.  Second, this is a hands on learning experience.  I didn’t fully appreciate the scope of the second.  The jury can decide which of those the cost of Volvo parts applies to most.

Video of Sojourn’s old MD7A

So, for the last couple of months, I’ve been monitoring Craigslist to get a feel for future repower possibilities. I wasn’t planning on acting before next winter, just getting a feel for the market and possibilities.  Then, to my surprise, a Beta14 showed up one morning at an attractive price.  I nearly sprained my pinky hitting send on my reply email! A few hours later, I was standing in front of it. Beauty is in the eye of the beholder.  I’m an engineer and a sailboat owner and it was shiny and red and beautiful!
The alleged story was that it was under powered for the 36 foot boat it had been installed in, which seemed at least logical.  After gathering a battery, a cable, a fuel line and discovering that the switch was corroded there was one glorious puff of black smoke and then musical, mechanical, diesel purring.
All of the fluids looked as one would expect in a brand new engine. I only had three reservations which, in the end, didn’t prevent me from buying it.  1. Was it stolen? 2. It had some unusual corrosion, at least to my amateur eyes. 3. Last, but not least, was it too good to be true?
On the first point, the transaction took place at a business with lots of employee and non employee onlookers, so I dismissed it.  On the second, I chalked up to salt air.  On the final, this is where it gets interesting.
I brought it home, fired it up and started going through it.  At first, it appeared it might even be a better deal than I thought.  I found the date of manufacture sticker.  10/10 – only 4 months old.  I also noticed that all of the paint was still on the pulley grooves.  I ran it until the thermostat opened.  The previously virgin looking oil turned a little milky.  I’ve seen this before in engines that don’t get fully warmed up often enough, so I wasn’t alarmed.  I changed it, brought it back up to temperature with no more milk.  I also noticed that the pulley grooves were now partially black – this motor didn’t have much time on it at all.

Next, I moved on to the electrical.  The alternator didn’t work. They say a picture is worth a thousand words.  It only took me a minute to realize this picture was saying “gurgle gurgle gurgle.” I took it apart to find the conductors between the brushes, the regulator and the diodes were gone!  There were only rusty nubs where the conductors used to penetrate the substrates of the various components.
Experienced sailors no doubt have filled in the blanks.  Later, my friend Ben, an experienced sailor, confirmed the worst of the three scenarios running through my mind - the boat had sunk during or after repower.  He had in fact concluded that upon first inspection, but felt is was still a good deal and didn’t want to burst my bubble so he kept it to himself.
So, in answer to the third point, yes.  My fantastic craigslist find, in all likelihood, went down with a ship.  Time will tell if it turns out to be recovered treasure.