Before hooking up the engine to its various components (wiring, raw water, exhaust, fuel) I wanted to get the engine at least roughly aligned because once these components are connected to the engine, the ability to wiggle around the engine to get at the mounts becomes more difficult. Of course there was still one big component missing that needed to be connected to proceed.
The Hurth HBW 150v v-drive transmission (aka ZF15) is in theory a pretty neat solution when you don't want the engine to intrude into the cabin. It reverses the direction and angle of the propeller shaft and allows the engine to basically sit on top of where the shaft exits the hull. This is the fundamental problem with v-drives. In order to service the shaft seal (PSS or conventional packing gland) you pretty much have to remove the transmission. So before installing the transmission, the PSS shaft seal and the shaft needed to be installed. The PSS is a rubber boot with a stainless steel compression collar (rotor) that bolts to the shaft and compresses the rubber boot (bellows) so that no water can get in once the boat is splashed. Installing the bellows is a straightforward affair that only requires a bit of tenacity because it's a very tight fit, otherwise it's dead simple. Once on, 2 hose clamps secure it in place.
Next I slid the shaft out through the PSS and through the strut. Having never seen the original propeller shaft or the transmission bolted to the engine, I wasn't sure how far it would protrude into the boat so I wiggled the rotor onto the shaft but didn't clamp it down. I planned to adjust and clamp it into place later, but as explained above, access to the PSS is not good once the transmission is bolted on, but at the time I didn't know how bad.
My son and I wrestled the transmission beast aboard and jumped right into rough aligning the shaft to the transmission and engine. This is where things went a bit sideways. When I attempted to slide the shaft forward and through the transmission 'tunnel', it kept hanging up. After a bit of head scratching I got down on my stomach and looked at the bottom of the transmission from the side and saw that the rotor (from the PSS) was hard up against the bottom of the transmission housing. Damn!
We tried raising the front of the engine by adjusting the forward mounts, and while that did free up the rotor, the shaft wasn't perpendicular to the transmission face (it needs to be within .004"). This meant that the rear of the engine was too low and needed to be raised as well. Unfortunately, on the w-27 engine, the rear mount is a saddle with only one adjustment point right in the middle and it's possibly the worst location to access. Without a custom tool, there is literally no way to get a wrench on the bolt to raise or lower the engine.
Luckily, Harbor Freight is a 15 minute drive away and they seem to specialize in cheap metal things that pry stuff up. I found a 16" ball joint separator that fit nicely onto the rear mount and I was able to the back of the engine easily with one hand while I used the other to loosen the nuts (the rear mount is upside down, so to raise the engine, you need to loosen the nuts).
At this point, I removed the transmission again and removed the rotor to take that out of the alignment equation for the time being. I reinstalled the transmission and with the rear of the engine raised I was able to get the shaft through the tunnel. I plan on using a flexible coupling to reduce vibration and protect the transmission against shock loads, but I left it out for the alignment process. I loosely fastened the split coupler to the shaft and lined it up with the transmission flange. A little more tweaking of all the mounts and I was right at about .004" using a feeler gauge.
I was feeling pretty proud of myself for getting the alignment done so quickly, but that didn't last long. I pulled the coupler off followed by another transmission removal, slid the rotor back on and compressed the bellows the recommended 3/4". I decided to sacrifice 2 of the grub screws that lock the rotor into place (they can only be used once). I carefully re-installed the transmission by sliding the shaft through the tunnel and getting it bolted on.
Before I reinstalled the coupler to fully line the shaft up with the transmission flange I took a look underneath and saw that the rotor was still pretty close to the bottom of the transmission. I had hoped that by compressing the rotor on the bellows, it would push it far enough aft to clear the bottom of the transmission. Nope, still just touching...
I pulled the transmission again and removed the grub screws from the rotor and compressed the bellows ~1" and sacrificed the last 2 grub screws to lock the rotor in place. Once again I re-installed the transmission (I'm getting very good at this) and took a look to check rotor clearance. It looked better, but I decided to install the split coupler to see if it would clear. The rotor now did have clearance, but only about 1/8" which seems way too close for comfort.
I'm not sure if that is ok, but my gut feel is that it's not. All it would take is one shock load (like wrapping a lobster pot or even shifting hard into reverse from forward) to introduce enough flex into the system to cause the rotor to hit the bottom of the transmission. That would not be good. So time to rethink what I can do to fix this. Raise the engine more, probably not. Maybe find a new dripless seal that's is shorter/smaller. I've seen a lot of boats with lip seals (volvo, vetus) that are clearly shorter than the PSS.
The thing that had me stumped was that I believe the boat had a PSS on it when the previous owner bought it, there was even a photo of it, but not very clear. I went to my shop and started digging in the old parts bin and low and behold, I found the old dripless seal. It looked like a PSS but it was about 1.5" shorter than the new one that I have and the bellows did not seem to be nitrile. I thought maybe they changed the design, but after some research I found that it is probably either a Michigan Shaft Seal (I don't think they are made anymore), Nakashima, or a Maucour.
So I have to do some research and see what my options are. I know that other Niagara 35 owners have the same engine/transmission combo and are happily using the same PSS I have. One is also a 1986 like mine, so I would think that the layup and general tolerances would be pretty close within the same model year, but the engine beds could be different or maybe replaced at some point. All I am sure of is that I don't want to go back to the old style flax packed stuffing box. No matter how good I get at removing the transmission, I don't want to have to remove it every time I adjust the stuffing box. Despite this setback, I'm still pretty happy that I was able to get the engine aligned without too much fuss.
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