Volvo MD17D Mounted on Down Angle ?

[caseymichael]

I sail a 1985 Najad 343 with Volvo MD17D engine, and have been considering repowering versus rebuilding because of the age of the engine and the cost of Volvo parts. Taking some measurements to start to determine what might fit best, I realized for the first time that the engine seems to be mounted with the aft end down about 7.5 degrees. The engine mount angle is in addition to the "natural" 7 degree down angle of the MS2 transmission. Basically, the fore and aft mounting brackets attached to the engine are about level when the Volvo drawings for the engine show the aft brackets a good but higher than the forward ones.

Any other experience like this?

[Viking Sailor]

I also have a MD17D. The mounting rails for it are basically level. Thus, the transmission end is lower then the flywheel end of the motor. I don't see any downward angle associated with transmission.

[Sandero]

Mine is mounted level.

[Dame.n.Jess]

I have an MD1, Mine is sitting level on the floor of the workshop now that I have removed it from the boat...

Damien

[redhead78]

Casey, whatever engine you choose, look at the tech specs, first at basic height and width. Size is usually not a problem as the older engine and trans were beasts. Once that is done build one of these, it will make life much easier. I noticed in my search some of the engines offer specific down angles on the trans.

[redhead78]

oops pic did not load, I,ll try again. Red

[Play Actor]

I'm replacing an MD 17C with a Yanmar 3JH5E. The MD 17C ahs the same mounting brackets that are shown in your drawing and photos, but it does not have the down angle transmission. My old beds are inclined at 15 degrees to match the prop shaft. I'm rebuilding the beds to get to an 8 degree incline, and I'm using a transimission with a 7 degree down angle.

Oddly, because the aft brackets on the Volvo are so much higher relative to the crankshaft than the front brackets, I will end up keeping the aft end of the beds at about the same level, while raising the front end slightly.

Sketching a side view of the old engine with the new engine superimposed on it, showing the line of the beds and the distances from the mounts to the shaft flange in rough scale, including all of the angles, is helpful in figuring out how to make it all fit. Also, as a previous post suggested, building a mock-up of the new engine is a great way to get an understanding fo what's happening. I made mine out of 2" by 1/8" aluminum angle, which I will reuse for other little projects. Pictures are on the blog below.

[redhead78]

Bud, I don't know how far along you are on the beds or if they are done. As I thought about the cutting down of my rails,( about a thousand times in my head) all my figures were based on ending up in the mid range of the adjustable motor mount. If you are the least bit unsure, err on the low side. When you are all done with the new rail beds if they are too high you are screwed. If you are a little low you can always shimm up. Red

[Play Actor]

Thanks, Red.

Good advice. My father used to say, "If it's too short, you can always splice it, but if it's too long, there's nothing you can do."