Two Days in the bilge, two new motor mounts and alignments

[peterkvs]

Ever since I bought the 400 DA I have been unable to align the 3116and ZF HSW 800 VI to the prop shaft. At least any better than about 8-10 thousandths. The problem was that on both engines the previous owner(s) had let the water pump drip for a long time onto the motor mount below it and low and behold the motor mount was rusted solid in place. I tried all summer to use penetrating oil and heat, but to no avail, it would not budge. So the big winter project was to replace the motor mounts and get the engines aligned.

I started on the port engine because it is much easier to access. At first I thought I was going to have to saw the motor mounts in half to get them off the engine, but I soon realized that the motor mounts one the engine could be unbolted. To gain access to the bolts, the water pump had to be removed and to remove the water pump the fuel cooler had to be disconnected from the water pump and fuel lines. I shut off the water and the fuel and removed the fuel lines from the cooler and then pulled the cooler off of the water pump inlet and set it aside. Then I removed the hose from the water pump to the heat exchanger, and finally removed the water pump. I unbolted the mount from the engine and the stringer and got it out of there. Replacing it was the opposite. The Starboard engine was a bit more of a challenge because it is on the side of the engine away from the center of the bilge and the only way to get to it is to lay on top of the engine and reach down from about and work on it. I also had to remove the pipe from the heat exchanger to the transmission cooler. The starboard engine was a lot worse and required grinding, priming and painting the block and parts which added a lot of time to the project.

Here are some pictures of the project. it took me about 4 hours to change the mount on the port engine, 8 hours to change the mount on the starboard engine and 15 minutes to align each engine. I was able to get both engines aligned to within one-thousandth all the way around the flange!





Fun times, except for having to do like 100 pushups to get into position top of the starboard engine!

Pete

 

[Mike Blake]

So, how many gallons fo Crown Royal did this job take? LOL

 

[ttmott]

Nice job and thanks for the details! How did you block up the engine? And, where were you able to buy the new mounts?
i need to change a couple of mine also.....

one observation; there are no stud threads protruding through the nylock which negates the locking feature of the nut even though it is a jamb nut arrangement there should always be at least one complete thread through nuts. I wonder why the engine sits so high on the mount to gain the 6 thou in angular alignment? Did you consider lowering the forward mounts in concert with raising the rears? Regardless, if this is the right location you may consider increasing the shim thickness under the mount to allow the engine to sit deeper onto the mount...

 

[rondds]

Helluva job Peter. Nice work! I too was wondering how you supported the engine with one mount missing.

 

[mwph]

Great pictures & text, Pete.
Aside from the technical details, this is a great example of how something a simple as dripping water can create major problems.
Thanks for taking the time to post.

 

[ZZ13]

Great pictures & text, Pete.
Aside from the technical details, this is a great example of how something a simple as dripping water can create major problems.
Thanks for taking the time to post.

So true. The boat I just bought came with a brand new generator and port engine starter from long term seawater dripping from hoses in two different areas. I still have a road ahead of me to get the collateral cosmetic damage cleaned up to my liking. If previous owners had just taken 5 minutes to inspect engine room prior to each outing there would be no problem.

 

[Boat Guy]

Wow, great job Pete.

 

[peterkvs]

Thanks Guys! Regarding blocking up the engine, I didn't. Previously when working with adjusting the mounts I noticed that I could easily take the upper and lower nuts loose above and below the arm on the engine mount and that the other three mounts when tight completely supported the engine. It doesn't even sag enough to make it hard to get the bolts out from the block. Damn stiff mounts, but I guess for a diesel with all that vibration and torque they have to be stiff. Even with me laying on the engine it still didn't sag at all. So that made it easy, because I had no good solution for blocking or jacking up the engine. Regarding the nylock in the nut. The threads, about two are exposed past the nylock, it is just the angle of the picture that makes it look like there are no threads protruding. I only had to raise the new engine mount about one turn and change the opposite engine mount a 1/4 turn to get the vertical alignment right. On the port engine the horizontal alignment was spot on, but on the starboard engine I had to use a 4' prybar to nudge the stern most end of the engine to the port side to get it right. I got super lucky and nailed it on the first tug. Regarding the purchasing of the engine mounts... I first contacted Cat and they wanted $440 a piece for the mounts. Then I contacted Barry Controls and they did not have the exact part as it is only manufactured for Cat. They did have a "close" match, but I was leery about using something different. I did a bunch of surfing on the web and found a site called http://www.machinerytrader.com/ and when I put the Cat part number into the search engine on that site I found about 10 places that were supposed to have the mounts. You contact the vendors through the website and the vendors get back to you. In a day I had three responses. One of them called me directly, Off Road Equipment Parts http://www.offroadeq.com/ and had 8 of the mounts in stock for $160 each. So that was a no brainer and I bought them there. Apparently the deal in Surplus Caterpillar parts. Nice to know, and no I have no affiliation with either of the places. After seeing how nice the new ones were compared to the old sagging ones I wondered if I should have perhaps bought them all and replaced them all, but damn that would be a lot of work and I am not sure what I would gain from it.

An interesting observation and thought came to me after looking at the difference in height of the old and new mount. The new mount is about a 1/4' taller than the old mount because the old mount has taken a set due to being under compression for 15 years. If the engine was installed and aligned to the theoretical centerline of the shaft (I think they do that with a laser through the strut) first, and then aligned to the coupler second (I presume by adjusting the mounts furthest from the coupler as to not introduce mismatch between the propshafts theoretical centerline and the centerline of the vdrive), then if the engine has settled over the years the centerline of the vdrive coupler might now be a 1/4" lower than the theoretical centerline of the shaft, which I imagine would not be good and introduce shaft whipping and vibration. So MAYBE my engines are sitting too low in the boat, but they only way I can figure out how to check that would be to remove the prop shafts and shoot a laser through the strut and see. But that sounds like it would be a few boat bucks.

Pete

 

[ttmott]

Thanks For the sources and insight into the project. If the cutlass has any play at all I would think the centerline through the transmission would be hard to determine except through the flange angularity. I guess you had to keep one bolt loosely in the flange ( bottom or top) so they remained concentric in order to get the gap measurements?
Tom

in retrospect, with the coupler unbolted (boat in water) and shaft moved forward a fraction, one could see if the coupler could be manually moved up and down and side to side to kind of tell if it's centered and happy (I would think this would be a prerequisite to the angularity measurements).. The more play in the cutlass the more challenging to find the happy spot. Also sag in the shaft due to its weight may be a factor but it's a pretty healthy piece of metal....
From what I have read you always want to do the final alignment with the boat in the water as the respective positions of the equipment can change.

 

[peterkvs]

Tom,

The flanges stay concentric because there is a boss on the prop shaft flange that goes into the transmission flange about 1/4". I pulled the coupler completely apart and the shaft droops down about a half inch. It is impossible to use the vertical shaft motion to determine the concentricity of the centerlines because the shaft is cantilevered so far from the strut and as you said it is a healthy piece of metal which causes it to droop signufucantly. Left to Right looked fine and the sides of the flange lined up, so no worries there. Interestingly, before I replaced the motor mounts on the stern end of the engine I tried lowering the vdrive end, and I could get the engine in alignment doing that, but after I bolted the flanges together the shaft was in a bind and I could no longer turn it by hand. To this day I don't understand what made it bind, but I figured that wasn't a good thing.

I had the cutless bearings replaced a couple of months ago. They were original, squealing, swollen and tight as hell. It took all my strength to turn the shaft holding the ends of the prop blades with both hands. After replacement I was able to turn the prop shaft by the shaft with two fingers (The cutless bearing was lubed up with soap). That alone tells me the shaft has to be in pretty good alignment. And, yes the boat should be in the water at least three days before you do an alignment, mines been in for a few months.

Pete

 

[ttmott]

Thanks Pete, Really appreciate your experience here. Mine is coming out for bottom paint and propscan in March(I'm going to take an inch out of the props). While out the shafts will be pulled for Sure Seal replacements and inspection of the cutlass; so this would be a very good time to change the two motor mounts that are corroded. Naturally, after all that shaft alignment will be verified.

 

[JC3]

Pete, Great job, good pictures and description. Well done! JC

 

[peterkvs]

Tom, if you have the boat out and the shafts out I'd replace the cutless bearings. They are cheap, like $60 each. The OEM for my struts and cutless bearings was algonac cast products. http://www.algonaccast.com They somewhat reluctantly sold me the cutless bearings much cheaper than anyone else. They are all named after fish, and mine were Grouper. Your probably are too. But all you need to know is the shaft diameter and the length. Or get the part number/name from searay.

I am also,interested as to why you want to take an inch out of the props. Are you really that over propped? I turn 2850 WOT with hytorq 22x23 l-cup props.

 

[peterkvs]

Just wanted to update the final results of the motor mount replacement and alignment. I have owned the boat since Dec 2012 and have always been annoyed by the vibrations while underway. They were severe enough to cause the seatback of the seat next to the captains chair to visibly shake back and forth. Also, the railing on the bow of the boat would visibly vibrate at certain speeds. Over the course of the last year I had the props tuned and balanced, and the cutless bearings in the struts replaced. I also made some crude measurements of the runout of the prop and the shaft while it was out of the water and really could not see much. When I bought the boat I checked the alignment and it was out about .010" and I was able to get it closer to about 0.008" adjusting the three free mounts on each engine. Now that I have replaced the frozen mount on each engine I was able to dial in the alignment to less than 0.001". By that I mean I put a 0.014" feeler gauge between the coupler halves and was able to insert another 0.014" gauge all around the coupler, but NOT insert a 0.015" feeler gauge anywhere. I took the boat out for a long ride yesterday and was amazed that 90% of the vibration is now gone. I really would not have believed that the alignment would be so profound on the vibration. The seatback and railing have no visible motion at any speed nor can you feel any vibration with your hand. I went down into the bilge while the admiral drove at 2200 rpm to check things out. The engines and transmissions did not appear to have any signs of prop shaft speeds vibration and the only real vibration I could feel was in my feet on the hull of the boat which I imagine is the propeller blade drumming on the bottom of the boat each time if goes by the hull.

Pete

 

[Boat Guy]

Peter, do you know the part number for the mounts?