mswkickdrum
2008-08-13 05:51:40
How about some engine size advice from the experienced?
I just got my "starter boat", it has a dead engine (ford lehman) in the hold. Have to
put a new engine in the boat. How much horsepower do I NEED and how much
is a good idea to HAVE. Hull is 40, 6.8 draft, 11.3 beam. 23 gross, 17 net tons.
built 1934 and in need of paint more then any other wood boat I've ever seen
floating. Anyways, I think in the past it had a 371 then the ford. I have a line
on a 471 (150hp) super affordable or a nissan 6cyl (90hp) not nearly as affordable.
In 1934 wouldn't 100hp have been a lot? No idea what original engine was. I figure
the hull is 8knots at max throttle, to do 1 more knot probably takes 50% of what it
takes to do 8. Would I need that power to push up a wave front bucking
a tide in reserve? or is a typical old displacement hull go it's hull speed full
of fish or empty?
Bill M
2008-08-13 20:37:24
I'm no guru but I do know that there are far fewer mechanics who work on the Nissan in S.E Alaska than Detroits/Cats. I looked into buying a boat that had a pair of seized Chrysler/Nissans and the rebuild was going to be more expensive than a 471 etc. because the parts are getting harder to find readily from what I gather. You also want to consider the cost in changing out your housing and gear reduction or if the motor you are purchasing will work with what's already there and functional.
mswkickdrum
2008-08-19 05:33:11
Well I have some updated info, the engine that died was a perkins 6 cyl. would that have
been a 108 or a 107? anyway, the head is on deck and the block in the hold. I have a
line on not a 471 but a 453, I guess the info was different once I tracked down the actual
guy with the engine to sell. There isn't room apparently for the heigth of a 471 in
the boat. This boat needs a ton of TLC but thankfully little structural type work.
Isn't a 453 nearly like a 471 except the head is shorter/smaller boar? Does the 53
series have a blower like the 71? Will this be a good engine for me by power as
well as service when it comes to reliability and getting it fixed?
thanks,
MSW
paavoc
2008-08-20 18:38:37
My two cents is, that the 53 series is not as reliable as the 71 series. However, I have heard a mechanic say the the 453 is unfairly maligned and that for their money it is still one of the best engines around as far as weight to horsepower ratio. However in a full displacement boat such as yours, that is not really an issue and were you to put one in, you would be basically negating it's strength. Also, if your boat once had a 371 in it than you should be able to get a 471 in it as the height is the same. The 471 is longer, not higher, from the extra "71" if you will. I just can't imagine why you couldn't cram a 471 in there and there are lots of them and their parts around, easy to work on, etc. Although there seem to be boats your size happily running around with 371's, I think the 4 would give you a power reserve should you need it that might come in very handy. What you may want to do is note your reduction gear ratio, screw size and pitch, measure the waterline, and go to a engine dealer. They can plug this data in to a formula and give you some ideas of what horsepower you need, since after all you might decide the best course is a new engine, right?
You could reduce the height of the machinery by swapping reduction gears too, since the old crash boxes have a larger off-set from engine to shaft than some of the newer gears. I have also seen engines, specifically a 471 that I put in my boat far smaller than yours, that had an unnecessarily tall oil pan, that you could switch to a marine oil pan that would fit better. I must say I don't think you can go wrong with a 471 if you can find one and make it work. Anyway, that would be my thoughts on the subject. Good luck!
mswkickdrum
2008-08-28 19:15:55
What parts do i need to Marine-ize a 471 that wasn't a marine engine?
heat exchanger?
water/raw water pump?
anything else?
MSW
Ocean Gold
2008-09-11 19:59:39
Save your money and put a new teir 2 engine in with the new loans and the fuel savings you will pay it off in no time. I changed out a 671 to a new teir 2 engine about 3 years ago and in the 3300 hours have paid for it the new gear and instalation, not to mention the amount of savings in oil changes are farthur apart and they dont use or drip oil. With the price of fuel now you would pay it off in a couple years no doubt. My back mounts were almost the same as the gimmy.