Official Caterpillar3116/3126 Thread

ttmott said:
It's not that bad. First get things close. Then get the shaft centered in the shaft log; use the mounts at the coupler for that. If things were close you should not have to touch the mounts at the coupler again. Then align the coupler faces by moving engine on the mounts furthest from the coupler up, down, left, right. That is really it.
A couple of things -
The engine should be close to the same height from the top of the mounts left to right.
Coupling faces must be clean and rust free.
Mount a dial indicator and verify the gear coupler is flat; TIR should be less than 0.001" outside of the bolt circle.
Face to Face any gap between the coupler halves needs to be less than 0.006" but I strive for half that. You can hold the coupler halves temporarily together with a pair of vice grips lightly clamped. Verify that coupler gap measurement both by rotating one half in 90 degree increments and by rotating the entire assembly in 90 degree increments.
Finally, after all that is done and the coupler bolts are installed and torqued, put the dial indicator on the shaft at the shaft log and run out the shaft; it should have a TIR of less that 0.006".
Click to expand...

Follow up question on the engine alignment. How does one move the engine laterally in the mounts or the mounts themselves?
I'm assuming the rough lateral alignment would be the first step.
 
SCFoster said:
Follow up question on the engine alignment. How does one move the engine laterally in the mounts or the mounts themselves?
I'm assuming the rough lateral alignment would be the first step.
Click to expand...
The engine bracket that sits over the mount is slotted. My mechanic used a Porta Power with a jaw type of thing to move the engine side to side.
 
ttmott said:
The engine bracket that sits over the mount is slotted. My mechanic used a Porta Power with a jaw type of thing to move the engine side to side.
Click to expand...
Thanks.
You mean something like this?
Hydraulic spreader.png

Want to be careful about side loads.
 
ttmott said:
We first centered the shaft in the shaft log then moved the engine to align to that and coupling. This is a bushing I made to do that centering -
Click to expand...

Have to take a step back and get the cutless bearing in the P-bracket aligned to the center of the stern tube you show in the picture.
Going to go a similar route to have a slip in plastic plug that goes into the cutless bearing. It will have a small hole in the center in my favorite rifle caliber. Use a bore sighting laser placed in the hole to sight to the center of the stern tube.
Then I can use a similar plug you show to align the shaft.
Thoughts?

boresight.jpg
 
SCFoster said:
Have to take a step back and get the cutless bearing in the P-bracket aligned to the center of the stern tube you show in the picture.
Going to go a similar route to have a slip in plastic plug that goes into the cutless bearing. It will have a small hole in the center in my favorite rifle caliber. Use a bore sighting laser placed in the hole to sight to the center of the stern tube.
Then I can use a similar plug you show to align the shaft.
Thoughts?

View attachment 141836
Click to expand...
Well, unless your struts are suspect of being bent, like mine were, I don't see the need for the bore-sight. As long as the shaft is straight and can smoothly slide and rotate in the shaft log bushing you will be good to go. We had to drop the struts and get them straightened so I had quite the alignment setup going to reinstall the struts. Search my posts in the 500DB thread, start at post 1734 - I put a lot of pictures and narrative there.
If that shaft isn't centered in the log your dripless seal will rapidly wear out.
 
ttmott said:
Well, unless your struts are suspect of being bent, like mine were, I don't see the need for the bore-sight. As long as the shaft is straight and can smoothly slide and rotate in the shaft log bushing you will be good to go. We had to drop the struts and get them straightened so I had quite the alignment setup going to reinstall the struts. Search my posts in the 500DB thread - I put a lot of pictures and narrative there.
If that shaft isn't centered in the log your dripless seal will rapidly wear out.
Click to expand...

Had both shafts checked at Kastel Brothers in St. Michaels MD. Port side was fine but the starboard shaft had some wear and was bent. Decided to have them refurbish it as a spare, while having them make a new one.
Now that you mention it, perhaps I should drop off the P-brackets and have them check them as well.
I'll give them a call.

**update** called them and they agreed with your approach.
I'll get the stern tube plugs made, to align the shaft to the center of the stern tube. Then I'll install the shaft struts (P-brackets), tightening the bolts with the shaft in place. Will check to make sure it rotates freely.
 
I also went the route of aligning the shaft in the tube first then moved the engine to match. My strut was also bent; so it was a big process.

moving the engine was a combo of that tool shown above and a big pry bar wedged against the inside stringer where I could. I had to come to terms with the engine “looking” crooked in the bilge but perfectly aligned to the coupler. It still looks weird to me, but I had zero clearance 360* around the coupler and I’ve checked it multiple times so I trust the measurement.

I found final alignment to be very frustrating but we got there
 
Strecker25 said:
I also went the route of aligning the shaft in the tube first then moved the engine to match. My strut was also bent; so it was a big process.

moving the engine was a combo of that tool shown above and a big pry bar wedged against the inside stringer where I could.
Click to expand...

Did a quick check of the struts with both of them upside down on a workbench, with a string from the cutless bearing and a weight at the end. Thankfully straight.
 
SCFoster said:
Did a quick check of the struts with both of them upside down on a workbench, with a string from the cutless bearing and a weight at the end. Thankfully straight.
Click to expand...

that’s good, the rebedding was a little bit of a pain too but not bad. Lots of 4200 squeeze out which is a good thing
 
Strecker25 said:
that’s good, the rebedding was a little bit of a pain too but not bad. Lots of 4200 squeeze out which is a good thing
Click to expand...
I found the strut when sitting in just the hull's strut pocket wasn't even close to alignment with the boat either to the hull centerline nor angular - the shaft through the strut wasn't even close to the shaft log let alone in it's center. I first set the strut up with hangers and jacking screws and located it then locked down the jacking screws. Then formed an epoxy shim between the strut pocket and strut then after that cured dropped the strut and fully coated and sealed it with 4200. I detailed that process in the 500DB thread.
 
ttmott said:
I found the strut when sitting in just the hull's strut pocket wasn't even close to alignment with the boat either to the hull centerline nor angular - the shaft through the strut wasn't even close to the shaft log let alone in it's center. I first set the strut up with hangers and jacking screws and located it then locked down the jacking screws. Then formed an epoxy shim between the strut pocket and strut then after that cured dropped the strut and fully coated and sealed it with 4200. I detailed that process in the 500DB thread.
Click to expand...

that’s a great write up, I referenced it many times during our repair. I was lucky enough the strut was well aligned in its bed from the factory. Once the strut was straightened, measuring the center keel and outside of the hull sides confirmed both props are equidistant from each other and properly in the tunnel.

my only gripe is after sitting for a day the prop shaft takes a little effort to ‘break loose’ so I can then rotate it with one hand easily. No abnormal wear on the cutlass that I can see so i left it alone

alignment is an art!
 
I am trying to find one gallon of the ELC antifreeze. I called my local CAT shop, they said the part # is 2388648. When I went to the site that doesn't appear to be a gallon though, it's the premix concentrate. If I purchase the premix concentrate what do I mix it with? My preference is to purchase one gallon already mixed though.
 
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