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| Tony's Tips |
ARTICLE DATE: 10/01/2005 |
| Installing shafts, logs,
struts & rudders with your favorite engine / transmission |
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| Now comes the fun part, and what I feel is the real
start of the job - WE ALWAYS start by lifting in the transmission first.
Inline or V-drive-makes no difference. We do this with 500 lb gears or 150
lb gears as this is the most accurate jig you can use. Easy to do, easy
to work around and, again, it is dead accurate and will allow you to position
everything, including engine mounts/brackets, rails, shaft log, strut, rudder,
etc. exactly where they need to be. In well over 200 repowers, I can only
think of twice that I have ever lifted in an engine during the install,
used it for measuring, and then removed it.. It can ALL be done with just
the gear 99% of the time and it is so much easier. |
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| Transmission
shimmed in place |
Set
in of transmission to get basic setup for clearances |
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| Once the gear is in the general location,
we used wood pieces and wedges to get it to a "close" location. Sometimes
we will use a small "A" frame to assist. Some more measuring now, using
our drawings and a digital level - Forgot to mention that if you want to
do this type of work, this is a must - ( about $150) certainly has made
my life easy and increased the quality of my work. Notice the "tube jig"
on the transmission input shaft - That's the ENGINE CRANKSHAFT and with
that, now we can really figure out how this engine/trans package is going
to fit. Yes, we use an accurately machined jig for this and have adapters
for gears up to ZF 320A's and others. But luckily, many of the gears share
the same input splines, so this makes it easier. With remote V-drive work,
we have made jigs to 8 ft long using this same technique - extremely accurate. |
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| Angles
for log cut |
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| Verifing
angles and clearances with crankshaft mock-up |
1st
log cut |
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| With the transmission now positioned
very close to what our drawing said, and we have now confirmed our engine
clearances, we recheck our angle(s) using our digital level. BTW, these
"angles" are always a "relative angle" to the boat bottom, and not to "earth
level". In this case (and most of these types of installs), we shoot for
a relative shaft angle of between 10 and 13 degrees-that's the angle formed
between the boat bottom and the propeller shaft. Most times we hope to have
the clearances needed for the right prop size and engine room clearance
staying at 12 degrees or less. But, it "is what it is", and if you need
21" of prop with 2.5" of tip clearance and you have "X" amount of space to
get that in, then the angle you end up with, "is what it is". |
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| Clearance-angle
verification |
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| Digital
level |
Transmission
fit mock-up |
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| Since we know that the engine/transmission is always
moved into final alignment to the shaft and we are now very sure that the
transmission is within about 1/16" from it final position, we now design
and build our rear supports/transmission brackets and get them installed.
Every installation is different and one must be "open minded" when designing
mounts and brackets to make the best fit/best design for each vessel. |
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| Starboard
transmission mount mock-up |
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| Port
transmission mount mock-up |
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| I just about NEVER want the isolators
to end up on top on the stringers. We like them inside, outside, on small
pedestals, or on some type of bracketing that allows thru bolting of the
isolator to a metal bracket. Since just about every stringer is not straight,
parallel to the finished centerline of the engine crankshaft, not even in
thickness, etc., we design our bracketing in such a way to allowing floating
them in place on a epoxy bed in perfect alignment before bolting in place.
Once we have designed and fabricated our transmission mounts (usually consisting
of 4 pieces) - port and starboard trans brackets and port and starboard
stringer brackets, we can install them. With that done, we can now remove
our temporary wedges, etc., and put that transmission on its own mounts
allowing very easy alignment for the rest of this project. |
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| Transmission
bracketing made to fit |
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| Designing
adaptation to old mounting pads |
Pre-fit
New fiberglass engine room pads |
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