How To Engine Alignment

[Delancey]

I confess that as someone who prides myself on my sailing prowess, I am pretty ignorant when it comes to drive systems beyond general concepts and rudimentary maintenance.

I have done some searching and found a variety of slightly different approaches to performing engine alignment that leave me with even more questions.

As someone currently repowering my sailboat the first time by myself I am hoping you would share your own experiences on this subject.

So far I pulled the engine on the dock using the boom before hauling to save time out of the water and once on the hard I did most of my demo with a sawzall and a grinder rather than wrenches including cutting the old shaft and stuffing box.

I've since done my prep on the strut and engine stringers and will be dropping the new engine starting and performing the initial alignment on the hard before towing back to the slip before finishing the job over the next couple weeks.

Despite my ignorance I get it that engine alignment is critical to performance.

I also understand that beyond the initial alignment, a follow-up alignment after the break in period should be performed but wonder if this is common knowledge amounts new boat owners?

And further that poor engine alignment is often overlooked as a culprit when people have problem with vibration or other issues?

Seems like something anybody who wants to could learn and would be good to know. XYZ axis, why the mystique? It ain't like rocket surgery of brain science is it?

[Delancey]

Here's a photo of the old engine on a dolly on the dock. It was a Universal 44hp that weighs about 500lbs. I had to take the transmission off to get it out of the hatch and while I was at it I sort off striped as much off of it as I could to make it lighter.

This was which pretty fun since I didn't have to worry about putting it back together and I learned a bunch of stuff in the process about what the engine looks like on the inside and how the different components work together.

In the photo I wrapped it in a moving blanket to protect the companionway. I started out nervous but in the end it was easy so don't be afraid, you can do it too. I'll post some more photos as I go.

[robert sailor]

Everyone here probably has different opinions but if you are changing to a different type of engine from the original you can bet that the engine mounts will not be at the right height so the beds often have to be modified. Once you have the beds all good to go then its not a bad idea to make a jig for the mounting of the new engine and where it meets the drive shaft. This can be made from plywood. If you have been really accurate with the jig you can pre drill/thread the engine mount holes in the bed. After that its not much more than dropping it in place and installing the bolts that secure the mounts and using the adjustment on the mounts for that last bit of adjustment. Feeler gauge for the flange and you'll be good to go. Also a good time to add a flexible mount on the drive shaft. Another thought if your fuel tank is right behind the engine and needs to have the engine removed to get it out now would be the time to do any repairs or replacements. Have fun

[model 10]

From what I have heard, some boats (fin keel) can flex enough from the support stands to being in the water, to need another alignment.

[Delancey]

The boat had a life raft locker beneath the cockpit sole. About 10 minutes to lay out and 5 minutes to cut out with the sawzall and say goodbye to 40 pounds of dead load we never used except to store trash during passages. Has made access for the whole project a lot easier. No regrets with that decision.

You can see in the photo the fuel tank which I pulled when we got the boat. I cut and installed inspection ports and cleaned the thing out, found a leak on a corner weld which I had welded up.

Three years later it has a new pinhole leak in a different location. Add that to the list of things to fix on my thirty year old boat. Painting the hull white in the engine room helped make spotting that one easier.

[robert sailor]

Originally Posted by Delancey

The boat had a life raft locker beneath the cockpit sole. About 10 minutes to lay out and 5 minutes to cut out with the sawzall and say goodbye to 40 pounds of dead load we never used except to store trash during passages. Has made access for the whole project a lot easier. No regrets with that decision.

You can see in the photo the fuel tank which I pulled when we got the boat. I cut and installed inspection ports and cleaned the thing out, found a leak on a corner weld which I had welded up. Three years later it has a new pinhole leak in a different location. Add that to the list of things to fix. Painting the hull in the engine room helped make spotting that one easier.

Is that one of the earlier Firsts?

[Delancey]

Jeaneau Sun Fizz designed by Phillip Briand and built under license in USA by O'Day when they were owned by Bangor Punta. When I was younger I swore I would never buy an IOR hull or a boat built with a liner. Funny how life works out. I really like it though, drives super nice with the tiller.

[Delancey]

The new engine is a red one, also based on a Kubtoa block same as the Universal so only differs in dimension in length. The guy who sold it to me assured he was giving me the right engine mounts so that it would drop right in.

I thought about making a jig to locate the new one based on the old one but decided that wouldn't be as much fun as figuring out the location from scratch.

We'll see how dumb that decision was down the road. I am adding a new shaft and folding propeller in the the mix so can address length as required.

I have read it is important to have the shaft cut and faced to match the coupling, but again, the guy who sold it to me said I could cut it to length myself. I've cut a lot of stuff before, hope I don't mess this one up!

[nicholson31]

Great idea, wish I could cut out my cockpit floor like that for much needed access, my fuel tank is there unfortunately. I spent two days leaned over from the front to change a cracked flex coupling on my drive shaft. By the way are you including one of these with your new shaft, they do give you some latitude for a small bit of misalignment and most importantly abrupt stoppage, hence why i was changing mine?

[Roy M]

Here's the jig I built for establishing my engine mounts. All the measurements are on your engine specs drawing. I used a one inch dowel to replicate the shaft axis. I spaced the feet according to the drawing, and adjusted their height above the ideal engine bed to see what I needed to do with the existing engine bed logs. To retain the middle ground of adjustment on the engine mounts I had to chop about three-quarters of an inch from the existing bed (from an older Volvo MD2B to a Yanmar 3GM30F). When all was complete, the engine fit perfectly with only minor adjustments to achieve the 0.004 inch alignment requirement. It's like a sewing machine now. Click on the individual pics to get a closer look.

[robert sailor]

Originally Posted by Delancey

Jeaneau Sun Fizz designed by Phillip Briand and built under license in USA by O'Day when they were owned by Bangor Punta. When I was younger I swore I would never buy an IOR hull or a boat built with a liner. Funny how life works out. I really like it though, drives super nice with the tiller.

Depending on what year it was built I think some of those early ones were constructed quite well. Personally I have no problem with many of the IOR designs as they were decent sailors. I'm not talking about the extreme ones that were primarily for racing. Looks like a fun project.

[Cap Erict3]

Angularity and offset are normally checked with dial indicators and tolerance limits are decided by the type coupling used.

Millwright stuff.


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Looking for another pretty place to work on the boat.

[captain58sailin]

We have done quite a few with feeler gauges.

[boeing1]

from what I have read, adjustment should be made with the boat in the water, that is how I check mine...

[Cheechako]

Originally Posted by Delancey

The new engine is a red one, also based on a Kubtoa block same as the Universal so only differs in dimension in length. The guy who sold it to me assured he was giving me the right engine mounts so that it would drop right in.

I thought about making a jig to locate the new one based on the old one but decided that wouldn't be as much fun as figuring out the location from scratch.

We'll see how dumb that decision was down the road. I am adding a new shaft and folding propeller in the the mix so can address length as required.

I have read it is important to have the shaft cut and faced to match the coupling, but again, the guy who sold it to me said I could cut it to length myself. I've cut a lot of stuff before, hope I don't mess this one up!

Uh OH...Red engine.... I think only the blue ones are ok for Blue Water!

You can cut the shaft your self, but someone will have to put a keyway in it anyway.