Logo
FULL SITE MENU

Engine Alignment

S

settimo velo

Contributing Member
I bought myself an alignment tool on eBay http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=370503133199&ssPageName=STRK:MEWNX:IT which I've been using to fit twin V6s in my Settimo Velo. This is not an OEM tool but I hope it is fit for purpose as they have good feedback ...

I've fitted and had a go at aligning one engine and have just put the second engine in today. A couple of things are bothering me:

1. I cannot achieve a level of alignment so that the tool slides in freely with 2 fingers i.e. as per the Mercruiser Installation Manual. I can only achieve a firm sliding fit, which seems to be due to the weight of the tool and the close fit of the tool in the gimbal bearing.

2. The alignment instructions from the manufacturer of the tool call for the engine to be rotated through 90 degree increments to recheck alignment once initial alignment has been achieved. However, the Mercruiser Installation Manual does not call for this.

Also, I believe that the hull must have flexed a little when I put the second engine in as the alignment tightened up and will need to be adjusted, again. It occurs to me that things could shift again when the boat is lifted and, as it is wood, I guess there will be some take up and movement when it is in the water.

I do not yet have any drive units, so I am unable to compare tolerances with the alignment tool, to get a better idea of the quality of alignment I need to be looking for.

I'm not sure where this leaves me so would welcome any shared experiences and advice ...
 
Get it as close as you can. Obviously, the boat will flex again when it is in the water. As long as you have it so that the grease is displaced evenly all the way around then that's about all you can hope for.
 
too late now, but always try the tool in the coupler before installing in the hull.
I fought with alignment on my Bayliner for hours - finally lifted the engine back out and discovered the new aftermarket coupler was simply tight on the tool. duh

One trick I have.... I have a steel yardstick- probably about 12 or 14 ga. steel- just the width and thickness of the splines- So, I can slide the yardstick into the coupler nice and snug and it sits inside the gimbal and shows me which way I need to go...
once I get the yardstick eyeballed to center of the gimbal bearing (about a half inch either side or whatever it is), then I start with the alignment tool
 
I tried the tool in the coupler before I put the engines in, so there's no problem with that. The tool does seem to be much tighter in the gimbal bearing, but then it needs to be to set up the alignment. I have a dimension for the gimbal bearing so I'm going to check the tool against that today, before I go any further. I'll let you know what I find ...
 
I checked my alignment tool and the shaft is about 9 thou under the dimension I have for the gimbal bearing, so no problem there. The second engine went in fine and the alignment tool fit in this one with the least resistance. I then reset the alignment on the first engine, which I adjusted to be a little tighter than the second - the best I could get it! - but acceptable, I think. I also rotated the crank on each engine through 90 degree increments and turned the alignment tool in the gimbal bearing to make sure it remained free to rotate. As mentioned above, the 90 degree check is not in the Merc installation instructions but I think it makes sense to do this to look out for any runout on the coupler.
 
If you can push and pull with one hand and not much effort vs the two finger "rule". You are good to go.... Not all are perfect....

Also I would wait a few days and recheck after evrything settles abit due to a all wood structure.

One other note is, make sure the rear mounts are tight and retry adjusting the stiff one again after a few days. Be patiant and try adjusting one side more or less than the other. Maybe one is a bit more uneven based on any number of reasons.
 
I checked the alignment on both engines again this morning. The port engine had not changed but the starboard engine had shifted slightly and tightened up again. So, yes, I will have to leave it to settle for a few days as just a small amount of movement seems to alter the alignment.

The starboard engine has one new engine mount on it. Maybe it is holding up better on the new mount and compressing slightly more on the old, so I will try raising the engine on the old mount to start with, to see if that does it. I think the stringers are sound (I did a lot of reinforcing work on them) but they haven't felt the weight of an engine on them for over 10 years, so I guess some movement is to be expected from 2 x 700 lb engines!
 
Spent quite a lot of time adjusting the starboard engine today, now that things have settled. I eventually got the idea of reading the grease on the end of the alignment tool, to see where it was rubbing. I then worked out that I needed to raise the engine to prevent it rubbing on the bottom and vice versa, which was a bit counter intuitive (because the engine pivots on the back mounts). I got the height set right this way and then found out that it was rubbing more down the right hand side than the other, so I then had to release the back mounts and pivot the engine a touch to get better horizontal alignment .... So, TIP OF THE DAY from Settimo Velo is READ THE GREASE!
 
yea baby grease it before putting it in.

Bond-o says any grease is better then no grease.

Congrats you took your time and learned.
 
settimo velo, I sort of did the same as you but only one engine and drive system. I also had a hard time getting alignment being it my first time. I was afraid of smoking the engine coupler if not aligned properly. I did all of the procedures as you have stated above and found that a sharp blow hammer after alignment tool was fully inserted and bottomed out into coupler worked well. However, just getting to that point was a pain in the ass. lol Anyway, I took the sharp blow hammer and gave the outer end of the tool a good shot in a 12,3,6,9 oclock orientation. I think what it does is align the gimble bearing to the coupler. I believe the gimble bearing swivels or for a better word pivots a bit and may need a little persuasion (carefully, of course). This seemed to get my engine aligned perfectly and have not had any issues so far.
jmho. Maybe you have already done so but figured before you try and run her you might want to check it out. Note that the alignment has to be real close before you attempt this and you may have to tweak adjusters on engine as well. After doing all of this, I was able to slide tool in and out with two fingers as suggested. I had to walk away from it several times because I got a little discouraged at first and had no one to help me. I strongly suggest that you get a second person to do fine adjustments inside the boat and maybe you could work the actual tool as you have been doing. Just so you know, I started from scratch and rebuilt engine mounting block, stringers, transom etc. so nothing stays the same and you basically have to be close with all the new installations. Oh, one more thing: Before I bolted engine down at front engine block, I loosened rear transom engine mounts, carefully moved front of engine to port and starboard until tool went in nicely. However, this takes time to get this far. To be honest, I think all in all it took about 8-10 hours (most of it was on my own) until I got the thing where I felt satisfied.jmho all the best, Tom
 
Last edited:
Back
Top