[Public-list] Motor alignment

[C.B. Currier]

That works great but ... I usually do my repowers from the dock and find
that that is easier than hauling the boat. If  I use your method Don I
must dive frequently and find tape that will stick underwater. Correct?

I have found that with the many repowers I have done ... feeler gauges
work very well and is the recommended method in most of the old engine
installation manuals... including the Atomic 4.

My major problem with your method is that once bolted to the engine you
are assuming that all is well and little torque is on that shaft. WIth a
measurement of the end of the shaft outside you are not accounting for a
new or intact/good shape cutlass bearing.

Having found that the best thing is to position the engine perfectly
opposite the propshaft before tightening assures most minimum of torque on
the shaft.

It is a more physical way of alignment but can easily be done if you can
get your hands behind the engine... you need to get them there any way to
adjust the rear pitch of the engine.

Just my $0.02


-- 
C.B. Currier
Infinity #57
Daybreak #458

Don Campbell wrote:
> The question of engine alignment is always one that those of us who do
> not do it every day might find daunting, particularly when we do know
> that if the shaft is not aligned, cutlass bearings will wear and perhaps
> other stuff that we did not expect will also wear. Both are probably
> correct.
>    I have written my method of alignment up for Towney for the upgrade
> of the manual that he is putting together, but that does not help for
> now. This is cheap and easy and with a much greater accuracy than the
> method CB Currier has suggested because it uses the length of the shaft
> to advantage for the measuring. I have copied this from a note I did
> write to one who was about to remove his A4 from an Alberg. This system
> works for any engine and any time.
>    I have had confirmation that the system works well by one Canadian
> owner who used a laser alignment system as well as the coat hanger
> needle and his comment was that the chap who owned the laser could not
> believe how accurate the coat hanger system was.
>    Perhaps the greatest problem is to know how many shims and rubber
> pieces are between the motor mounts and the beds. Trial and error are
> the guides here.
> Don # 528
>
>    The tricky part is to align the motor once it is to go back in and I
> have a set method for that which I find quite easy. I assume you know
> what, if any, washers need to go under the weight bearing brackets that
> hold the motor to the beds. Connect the drive shaft when you have the
> alignment close. Tighten those bolts up well on the coupler. Make a
> pointer out of coat hanger wire or equivalent and sharpen a fine point
> on the end of that wire. Bend it in such a way that the point of the
> wire can be set to just about touching (0.002") at the edge of the aft
> end of the  drive shaft and there are several bends now in the wire so
> that you can tape the wire to the rudder and the point will be secure
> and just about touch the end of the shaft at 12, or 9 or 6 or 3 o'clock
> places if there were a clock face on the after end.  Now using the prop
> if you are alone, or preferably with help from inside the boat, turn the
> shaft. If the point is in a constant alignment with the shaft, it is
> straight and the motor is set. If not adjust accordingly and continue
> until the point is fixed in relation to both a 12 and 6 set up and a 9
> and 3 set up. You need to do both so that the up and down and right and
> left alignment is adjusted. It helps to have a second person so that
> they can turn things and you can adjust from inside. You will find that
> even tightening the motor mount bolts bolts will change the alignment.
>    As an example if you set the wire point to 6 o'clock and turn the
> crank and the shaft rises above the wire, then the front of the motor
> needs to come up so add shims or tighten the back down. If you set the
> wire to 9 o'clock and the point moves into the shaft as it is turned,
> then the front of the motor needs to move to port. Just a bar or a small
> hydraulic jack with a big wooden block as backing on the firewall is all
> you need. Once you think you have things really close, then put the wire
> point on the centre of the shaft and turn it again. It should stay in
> the centre. Recheck things once in the water, and I usually get a pro in
> for that. I have never been more than 0.003 " out though. This takes a
> bit of getting used to the first time but is cheap and easy to do.
> Because it uses the leverage of the shaft to check on the deviation at
> the coupler there is at least  a 15: 1 leverage advantage so it is
> accurate too. Shaft is about 27" and the coupler is about 3" across, so
> 1.5 " radius. Use the mechanical advantage to help you as best you can.
>
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