Durango318
Seaman
- Joined
- Jun 12, 2010
- Messages
- 68
http://www.youtube.com/watch?v=TpOYqRvoERY
http://www.youtube.com/watch?v=XSG-eQXLRQU
Well it seemed a good idea at the start but....you know how one thing leads to another and another and......?
I got the wild hare idea about the first of the year. The boat had two working engines and tranny but the more I serviced them the more signs of age told me they were on their way out. Everything had been rebuilt at least once already and the marine parts were calico colors by the mix of new and old. A new boat was out of the question and another used boat would still have questions of reliability so I opted for new engines and new transmissions.The re-power labor was supplied by myself and my son, Eric. He expertly guided the engine off and on the stringers. The old engines were 5 liter/ 305 cidMerCruisers mated to 71C Borg Warner 2:1 V drives, starboard was standard rotation and port was reverse rotation. I decided to replace with a pair of Marine Power, Vortec 5.7L fuel injected, fresh water cooled and the stronger 72C V drives. Both engines are standard rotation however the port transmission is a chain and the starboard is a gear reduction which gives me the rotation needed. Externally the transmissions are identical. By doing this both engines are kept Identical and easier to maintain.
The boat was hauled at Delta Marine Sales in Stockton Ca. The owner, Tony and the yard foreman, Bob are very helpful and frendly for the do it yourself-er. The bottom issues were addressed and painted by them, thanks guys! Once the engines were out, the bilge was cleaned and inspected. It was good to confirm the stringers had been replaced in the past and they are in great shape but the firewall had dry rot from the top. The source of the water intrusion on deck was sealed and effected wood replaced, beveled, epoxied, glassed and lot of sweat later better than new. Finding the new engine and transmissions brackets too short to reach the stringers the old brackets were re-utilized with new mounts. The new transmissions are 7/8" longer from the mounting point to the engine, so the old engine mount holes in the stringers were plugged/epoxied and new ones were drilled after a test fit. The prop shafts were both beyond hope and the new ones were manufactured by the experts at Stanley Adams Machine in Stockton Ca. New shaft couplings, prop nuts and GTU Gore packing were also used. A note here about this packing. You may find it difficult, if not impossible to get this stuff to have the required drip while running. I even removed the packing nut with water coming in, mashed it around the shaft to loosen a bit, re-installed and still it wont drip. So I gave up since it dosen't get warm, leaves no marks on the shaft, so no harm and dripless... a winner! Once you splash the boat, make sure you burp the trapped air in the shaft log by temporarily backing out the packing nut (a bit) so there is water at the packing. When seating the packing, turn in till you just feel the packing contact, then lock the jam nut. Check again under way for dripping and heat.
The props were reworked at Delta Propeller in Lodi Ca. The Dyna Quad props had to be cut down due to damage from 18X17 to 17X17. The consensus was to give them a try and see what the new engines want, the old engines could only turn them to 3500. The engine room was painted where I couldn't get at it once the engines were in place but not were I would smear it from standing and working, this could be done later. The engines came with the high performance aluminum exhaust manifolds that have 4" outlets vs 3" of the old engines. So this necessitated new thru hull and flappers. The fore and aft spark plugs may be harder to remove with a socket, none of mine would clear the manifold, hummm? Before installing, go over the entire engine, check connections (a loose one!), hose clamps, routing, rubbing. Look at things like; once installed can I get at the hose clamp the way it's installed? can I just rotate it?
The shaft to transmission alignment.
This is a lot of work and must be done correctly. The new isolation mounts can be set to the same height as the old ones but this only gets you into the ballpark. If the engine is properly located, all axises can be adjusted to get the less than .003" flange clearance while keeping the shaft centered in the shaft log. This can take an entire day the first time around depending on your knees and gout. You will need to do again once floated and later after the mounts have settled (much easier). I could write a book on it but I prefer to forget.
The wiring harness comes with a standard 10 pin MerCruiser or so called "universal" connector, tho if you count the pins there's only 9 pins....why, because it's always been that way. My boat is of the old style 10 pin with amp gauges so the number 4 pin is fat (boat side) and carries the charging current all the way to the front thru both helms and back. Just a little bit of voltage loss/problems, can't imagine why they went away from it? Well the new #4 pin hole (engine side) is smaller and is for the "check engine light"...or at least it should according to Marine Powers diagram. It would have, if it were connected in the harness and if the computer had this function enabled at the factory. I found this out after I carefully Dremeled the pin diameter smaller, moved it slightly and shortened to make things clean looking. (I don't recommend this method, cut/twist out the pin, use a jump around wire, it's a lot easier.) I removed the amp gauges, installed volt meters new hour meters and made other appropriate wiring changes under the helm. Even if the "check engine light" or alarm were enabled, they wouldn't become active till about 220* F , so I have elected to install a sender at the water pump that goes to ground at 180*F to give me more of a "heads up" if an impeller goes or a water hyacinth blocks an intake. If the computor detects something wrong with the engine, it may go into a "reduced power mode" or shutdown to save itself.
Looking at the factory test run, noticed a low water temperature on one engine. Well, when the factory upgraded the engine, they forgot to change the thermostat from 143 to 160*F.
Let there be life! Time to light em up! The engines fired up within three turns, must have been fuel in the system.
When I ordered the engine/tranny package from Michigan Motorz, I also ordered a PC based diagnostic system, which was a good thing. I started one engine and watched for the oil pressure up on the gauge, but nada! I glanced at the PC and it said over 50 psi, but still I shut it down. I checked connections, all good. Ok, I'll get back to it later, move to the other engine. Started it and the same thing. I pondered this for a few minutes. Well it's either my old gauges or the new senders. That's when I found out there's such a thing as dual helm senders. Swapped in my old senders and bingo! Interestingly, the water senders are dead on and not swapped.
Sea Trials
Dang these things sound healthy!
With everything as it should be, my son at the helm and me between the engines looking everywhere, we idled out of harbor. We reach the turning basin and we shut down so I could work on the packings. A while later I got to the helm fired them up again, noted they were at temperature. I looked at my son, I didn't need to say a thing. he knew we were headed for Wide Open Throttle. A few minutes later we were in the clear and he push the throttles forward to half, I ran back to jump down between the engines for another look around, still all good. Got back to the bridge and the engines went to full. The boat felt like it was flying! The tachs both read 5,000 and when the GPS toped out at 26 mph we throttled back to low speed cruse for the engine's sake. Perfect prop load. Not bad for a 22,000 lb houseboat with two small blocks.
I noticed the port engine water temperature started having some excursions to 190* and back to 160*F. I went back to the engine and noted the coolant over flow tank was high and bubbling. Not good. First I'm thinking low water flow but looking at the exhaust it appears identical to the other engine. Than the bad thoughts like blown head gasket, cracked head and pulling the engine. Shake it off and think. What cause water to boil? Heat, combustion gas or...low system pressure. Back at the harbor and with a cool engine I removed the filler cap. The cap looked fine but the seat in the housing i could feel a very small depression across it. Could it really something this small? I removed the housing from the engine and with a bladed screwdriver I scraped the high points down to either side of the depression to blend. I reinstalled it and went out for another run and got another surprise, this time the temperature was low and stable at 145*F What the? As it turns out this engine had a cold thermostat too, but the small pressure leak masked it. Marine Power expedited another new 160* thermostat and now everything is perfect. 10hr oil change complete, tighten bolts and hoses clamp and now with over 20 hrs the engines will go just over 5K and 27mph. Could it be with the wind or tide?
Thanks Guys