Engine Mount Brackets Take Two!
Well, fact is when we installed the brackets for the engine mounts when we first put the new motor in we just did not do a very good job. We made two mistakes maybe others can learn from.
1. When we did the Cummins Repower, we tried to do it all in one shot, lower it in with the crane, mark where we wanted the brackets to go, install the brackets, and lower the engine down onto the mounts. To much in one day.
2. Our plan was we left the old shaft and coupling in to give us a good guide on where the engine would sit, and where the brackets needed to be. Un be known to us in all the excitement, the engine must have bent the shaft down, and that caused us to line everything up way to low. Good news is we didn't ruin the new shaft, bad news is we installed the brackets to low.
We were able to allign the engine, and use the boat for the summer, but there was a slight vibration from around 1,100 RPM's to 1,700 RPM's that I just don't want.
First up we had to build something that could raise the engine. After screwing with this thing trying to allign it, I decided I wanted something that could really do the job.
Heres my trusty assistant. "Christopher!! get me a 1/2 inch wrench, the sawzall and a fresh beer, I'm not coming out from under this engine till the last brackets off!!"
I did a fair amount of carpentry work to spread the load out as much as possible. I did not want it directly on the floor.
I had to disconnect everything from the motor but that wasn't bad at all. Since everything was new, and the wiring is all through a single harness, one good day was all I needed.
Next up we installed the chain falls and started hoisting away.
Theres Christopher, manning the chains for the forward hoist. "Keep your chain in the box, don't let it get away"!
Up it came like a baby. This is as high as i'm going to go, at first I thought about getting the entire engine even with the deck, but despite how well everything worked, it just looked a little scary up much higher than this.
Here are a few of the offending brackets, you can see the spacers we had to add to the bottom, because we had to get the control higher. And because we had to raise the controls, we lost the ability to easily move the bracket for and aft in the slot holes for the bolts.
You can see in this one, how the control next to the bolt is blocking the slot. Also you can see a slight angle to the engine mount post. This is because we did not have the correct 6 degree angle on the installation of the bracket to match the incline of the engine to the shaft.
Here they all are, felt like a dentist pulling some bad teeth; I'm glad there out!
Next up, filling the old bolt holes and making new brackets.
Well we got the new brackets, and the first thing we did was put the brackets and the mounts on the engine. Were going to lower the whole thing down, match it up to the shaft, mark it, then raise it up, remove the brackets, then install them in the stringers.
We are going to be moving the shaft back and forth quite a bit. One thing I'm petrified of, is bending it during the raising and lowering of the engine, so I want to back it off as often as possible. I put a collar zinc on the shaft, so when I pulled it forward from inside, it would stop right where I wanted it to.
Here we go, we lowered it down.
We angled the engine the best we could to match it to the coupling, and shaft angle while it was just hanging. This was not easy, the engine does not want to sit even, side to side so we had to try many times with a rope tied from one of the chains to the turbo. The problem being every time we wanted to make an adjustment on the rope, we had to raise it way up so we could block it and relieve the pressure. Some sort of small come a long would have been a big help here.
Heres Uncle Bill, he actually brought some science to this part, and we did eventually get the engine level.
Looks good!
Once we had it where we wanted it, we marked the position of the brackets with a marker, then we raised the engine, blocked it up, then removed all the brackets and mounts.
Next, I got into the bilge, but that was just after I mumbled something that sounded like some sort of krishna chant that I thought might help clear all the bad thoughts in my mind about getting crushed by the engine and dying a horrible death in a boat bilge.
Here is the rear port one.
This is the rear starboard one.
Here is a forward one installed, now it has that nice angle aft we need to match the angle of the shaft. Thats one of the things we did a poor job on the first time.
One thing that has absolutely tortured us on this project is the fact that the mounts on the gear, are not symetrical. I have to be honest here and partly blame myself, and partly blame Cummins for this situation. They don't give you any help in areas such as this, and the discussion about the nature of these brackets was fairly brief. I don't know what other options I may have had, but one things for sure; there is absolutely, positively, no way to properly mount this engine with the way they made these brackets, and thats not right. In my mind, as the manufacturer they need to give you a fighting chance.
Here is a picture of the rear brackets, which come off the gear.
As you can see the right hand side is considerably longer than the left, and more importantly the brace is a much more gradual angle than the left.
Right hand side.
Left hand side, you can also see how the control is bigger than the bracket, thats because the bracket will touch the bracket on the gear if it was not reduced in width.
This is the rear left bracket, you can see its been reduced in width.
Right hand side lowered onto the bracket. You can see there is good room for it, the bracket on the gear is well away from the control mount.
On the right hand side, the control has enough room to sit on the bracket properly.
Here is the left, you can see its very tight to the gear bracket, and in fact we had to make the bracket on the stringer narrower on this side than the right, and in fact the width is less than the actual control mount. What particularly bothers me about this situation is if you just match up the control to the bracket on the gear, its too tight. It's wider than the opening in the bracket on the gear, and when properly installed with the control as high as possible, or the gear bracket as low as possible on the post, the control touches the gear bracket!
Here is a picture of just the bracket, we put a smaller peice under the control to gain a little more real estate it could sit on. This picture does not show it, but we even had to take a grinding wheel and grind off the corners of the peice we placed underneath the control.
Other than replacing the brackets on the gear, I just don't know what the answer is.
Here is another shot of it.
Once we had all the brackets mounted, and the controls attached, we left them just tight enough so we could move them with the tap of a hammer. Then we lowered the engine down, adjusted things a bit a few times, (well, more like 20 times!) then lowered it onto the posts.
Here we go, "Christopher, down on the forward chain!"
Easy does it.
Here it is, on the newly installed brackets. Next we played around with fine tuning the allignment and got it fairly close for amatuers.
Well, we better see if this improves the situation first, before we start patting ourselves on the back!
Chapter II
One thing I was concerned about was the position of the bolts in the forward brackets. We re-used the old brackets and I wanted them bolted on in a better fashion. Of course I came to this conclusion after everything was all put back together again. So, this meant drilling through the stringer and the bracket while they were in place. Needless to say this was not easy, especially the part with the 1/2 inch stainless steel. I was able to manage this, and am happy with the result.
One negative aspect to this though is that now we have lost the ability to move the bracket for and aft, unless we remove the added bolt. But, I think we are past needing that now, and there is some lee way with the shaft in and out if needed.
Here is the starboard bracket prior to the added bolt.
Here is the port one.
Here is the starboard one with the added bolt.
Here is the port one with the added bolt.
Here is a picture of the inside of the port bracket.
Chapter III
Well I have everything all put back together again.
And just to be on the safe side had a mechanic do the final engine alignment, and bolting of the shaft to the gear.
A few last lessons.
One minor element i'm disappointed in this time around is I still needed some shims on the starboard side. The reason this happened is the engine was not perfectly level left to right, when we remarked for the brackets. It only takes the slightest angle to cause a fairly significant misplacing of the bracket. If I were to do it again, I would use plum bobs at all four corners to better gauge the height of each, and subsequently if there was any tilt to it. Just eyeing it is not enough to detect a half inch of tilt over the span of the width of the engine.
Well soon we will go for a test ride and see if the vibration has diminished!
Well, I took it out for its first ride and overall the results are pretty good. I think I have everything hooked up properly, mechanically it all seemed fine. As far as the vibration goes, I am happy to report it's dramatically reduced; not entirely gone, but dramtically reduced.
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