Engine Vibrations - you should also look at:
1. Is your propeller clean and balanced? Also, check the wear in your cutlass bearing the next time you are on the hard.
2. Is your propeller shaft aligned to the reverse gear? Remove the 4 cap screws, separate the flanges and measure the gap. I recall that anything over .004 inches is considered a misaligned.
3. While the flange is free, make sure it doesn’t wobble on the propeller shaft. The flange is held onto the shaft with two set screws that are a180-degrees apart. That means the shaft diameter and the hole in the flange must have zero clearance to be true.
4. Make sure your motor mounts nuts and bolts are tight. See below - no matter what, they get loose!
5. Do you have a copy of Bud’s service manual? If not, get one. (We keep ours next to the family Bible !) He has a article that addresses bonding the fiberglass engine pan to the hull. Do it! I went one step further by adding 3x6x1/4 inch SS plates under each motor mount to distribute the weight of the engine on the engine room pan.
6. Check engine-to-motor mount brackets. I’ve seen several MD‘s that developed cracks in the casting on the lower - aft - starboard side. In the following picture you can see where I welded over the engine casting at the location marked - A.
Also, most MD mounting brackets are attach to the motor with two bolts. I modified my brackets to capture three bolts. The picture shows the 2x1/2 inch flat-bar (B) that reaches the third bolt on the starboard side.
Capturing the third bolt on the port side takes a little more imagination. Here’s what my aft-port-bracket (see below at "C") looks like after I put away the stick welder.
Even with all these modification, I was surprised to find - that some of my 1/2 bolts that hold the motor mounts and SS plates to the pan - still worked loose over time. Keep your wrenches handy!
MD Longevity: Everybody has an opinion and an .....
Some sailors swear by Volvo MD’s and others swear at them. I’m somewhere in between. I also pray that mine keeps running; praying is better than swearing, and praying is cheaper than a Beta!
CAPRICA came with an 1977 vintage MD11C, raw water cooled, with unknown hours. Several years ago, I purchased a used MD11C that was pulled by a fellow Westsailor in Florida because of raw water cooling problems. I got it for a song, but had to ship it from FL to VA, get my MD11 out of CAPRICA, move both engines down into my basement workshop, turn two old engines (with a bunch of new parts) into one, and then had to reinstall the resulting engine into CAPRICA's new engine room. There are dozens of stories in that last sentence, but I’ll limit my comments about longevity to my own $0.02.
BTW, I’ve been running the “new-old-cobbled-together-rebuilt” engine since 2006 without problems.
1. Change the oil ! Do it often, every 50 hrs or twice a year - always after a winter lay-up regardless of hours or time. Use oil for diesel engines, API service CD or better. I use 30 weight and Fram PH-16 filters.
Keep your eye on the oil pressure. The dip stick O-ring is a weak link in maintaining oil pressure.
2. Clean fuel, clean fuel filters, clean fuel screens. I never had a problem. I use marina diesel, farm diesel, gas stations, Seven-Eleven’s ... Volvo’s eat anything, whether it’s combustionable or not!
3. Adjust the valves at least once a year.
4. Cooling - Oh NO ! ! ! ! the dreaded raw water cooling ! ! !
This will make or break an MD. The whole idea is to keep the water going though all the water passages.
I’m not a fan of Volvo technology in this area. The water path splits at the engine; one path goes through the exhaust manifold and the other through the cylinders heads and jackets. The path through the exhaust manifold is always open. The path through the cylinders is “dammed” by the thermostat when the engine is cold. When the engine gets hot, the dam opens and the water is supposed to flow through both paths. The problem is: if the cylinder path is restricted with rust or dirt, the water take the path of least resistance and just goes through the exhaust manifold. Another words, there isn’t positive pressure pushing H2O though the cylinder cooling path!
First - get the correct thermostat. I seem to recall the MD2s use the 72-degree version, not the 84-degree version (available from NAPA auto parts), or is the other way around?
Second - change the water pump impeller at least once a year, whether it needs it or not.
Third - un-plug and flush the reversing gear water jacket at least once a year. The raw water comes from the ocean -through the strainer -and into the reversing gear; then it goes to the H2O pump and beyond. The water jacket around the reversing gear is like a kitchen sink trap; it collects (and fills up with) all the sediment that makes it past the strainer.
Fourth - there are three little brass stop-cocks on the engine; one for each cylinder (lower starboard side) and another under the exhaust manifold. I took them out, and drilled out the holes to accept 3/8-inch bronze plugs. Now when I winterize, and the plugs come out - instead of a little dribble of seawater - I get a gush of water and all the junk that collected in the cylinder water jackets.
Fifth - eventually, the exhaust manifold needs to come off. I do this every 3 or 4 years. Each cylinder has three rectangular shaped openings. Right next to the middle opening, there is a 3/8-inch hole, labeled - “D” in the picture below. It’s where the cold water enters the cylinder head and tends to clog with exhaust soot and carbon build up. You can drill out the gunk, but be careful, as the back end of the hole abuts to the injector sleeve. There is a gap between the back of the hole (tube) and the injector for the water to pass into the cylinder head. You need to clear that space with a coat hanger wire or something. Do this for each cylinder.
Sixth - Here in Virginia, most people winterize for Dec - Mar weather. Rarely does it freeze solid but .... whether I’m on the hard or in the slip... I always leave the engine cooling system full of antifreeze. It’s my opinion (based solely on faith) that antifreeze inhibits rust scale that forms when O2 and wet iron interacts.
My simple(?) engine winterization involves:
- Flush the reduction gear.
- Remove the engine coolant plugs to drain all the junk.
- Reconnect everything.
- Run engine until temp gauge cycles.
- Disconnect raw water feed at strainer and place it in 5-gal bucket of anti freeze.
- Run engine until temp gauge cycles several times.
- Visit boat every week and dream about spring!
Disclaimer:
I’m not a diesel mechanic.
I’m not an expert about anything.
I’m an avid DIY-er driven by the empty boat kitty.
My opinions are based on my own mistakes and my limited successes.
Always seek Bud’s wisdom first !
And when all else fails, at 550 lbs, MDs make a good mooring anchors !?!
Ed & Karen Hlywa
CAPRICA #687