wrote:
On Oct 19, 10:42 pm, jim wrote:
wrote:
On Oct 19, 10:16 pm, jim wrote:
wrote:
On Oct 19, 6:33 pm, "mmc" wrote:
wrote in message
...
Years ago when I installed this diesel in my sailboat, I read about
aligning the engine output shaft with the prop shaft by using a valve
clearance guage to check all round the round pieces that bolt the two
together. One would tighten or loosen the engine mounts to make it
the same all round. I can no longer find these directions and am
having problems getting it just right. One side is off by .008" and
all I can think of is slightly rotating the engine (about a vertical
axis) by pushing against the engine mounts but this doesnt sound
right. Thoughts?
DB,
You're doing it right. I couldn't remember the tolerance so did a google on
aligning sailboat engine and found this on a site (http://www.alberg30.org/maintenance/...n/Diesel/Insta...)
about swapping an Atomic 4 for a diesel:
The most critical part of an engine replacement is the new engine alignment
with the prop shaft. The tolerance on this is .004" maximum. This
measurement is taken between the engine flange and the shaft flange. It is
in two planes, vertical and horizontal.
If you can't get that close you probably need shims.
mmc, thanks. I was considering living with my .008" diff but I'll
give it another try.
However, I think the height and horizontal adjustment are dead on.
Unfortunatly, the plane of the engine output flange is misaligned by
roughly .3 degrees (three tenths of a degree). I got this number by
taking the size of the gap between the two flanges (.008) divided by
the radius of the flange and taking the arc tan. I really think I
should use the diameter of the flange which would give me .15 degree.
Is this close enough?
The bolts slide in very easily indicating good alignment.
Take your time and do it right. I wouldn't settle for more than .002
difference top to bottom or left to right. Also you want to rotate the
engine and prop shaft 90 degrees and check again after you think you
have it right. You will be rewarded with a lot less noise and vibration.
I will do so. This necessitates taking apart part of the bulkhead
around the engine compartment but it is intended to be taken apart.
Then, I get a large crowbar and brace it against the engine mount
whilst I pound on it to slowly shift the front of the engine. At
least its no longer 100 degrees down below.
Gentlemen do not pound on engines. Can't you get at the mounts to loosen
them you can adjust them or move the motor?

Mounts are each held to the mahoganey stringers with 2 lag bolts. The
mounts have elongated holes. In theory, you could loosen the lag
bolts and somehow lever the engine sideways. In reality, the easiest
way considering the lack of room is to place the end of the crowbar
against the base of the mount and tap the other end of the crowbar to
nudge the engine over. Considering the length of the engine and
diameter of the flange and the gap of .008 at the side of the flange,
I figure i need to move the forward end of the engine toward port by .
1".

That's easy enough to work out. The coupler diameter is what? what is
the distance between the mating face of the coupler transmission end to
the centerline between the front engine mounts?