View Full Version : General Repower Inquiry

09-06-2006, 09:17 PM
"I am interested in finding out what my options are in repowering for a 50 ft wooden power cruiser. The existing engines, twin 300HP Trojans, are shot, and rather than remanufactruing these, I would like to consider something smaller if possible. Let me preface these questions by saying that I know next to nothing about engines, and very little about boats in general.

First, my intention with this boat is to simply take it a few miles off shore at most. I don't have any need for high speed cruising. Functionally, I just want to be able to get in and out of the harbor and I don't really care how fast I do it. That being said, what sort of repower would be most beneficial for a vessel this size? I'd like to be as fuel efficient as possible, but I'm also a bit hesitant to consider diesel given how I plan on using the boat. Can I go with a single engine? What sort of costs are incurred on the labor portion of a repower? What sort of fuel efficiency can I expect out of certain engine configurations?"

09-06-2006, 09:40 PM
"The natural choice would be a pair of midsized diesels, but unless you're willing to "invest" $80,000.00+ (Which you will never recover)this may not be the best option. I'm assuming your boat is 35+ years old. A single would possibly make more sensce, but you're talking about a major reworking of the running gear and bilge. This option will probably run 50K or so. Keep in mind a boat this size with single power will be very difficult to maneuver.

Twin gas will be the most economical financially at around 40K, but will cost more to operate.

Take a good look at the market and do your homework before comitting to such a project. You might luck into a good pair of take-outs which would make a lot more sense.

Good luck

09-07-2006, 01:53 PM
Thanks Rick

What I'm gathering is that finding a pair of used gas engines which would be more compatible with the existing configuration of the boat would be much more economical? Do you have any idea how much the labor costs are in terms of removing an old engine and replacing it with a working compatible engine?

09-07-2006, 10:59 PM
"That's really tough to estimate without knowing the configuration of the boat and power packages.

For what it's worth, here's what Mercruiser lists as flatrate:

Complete engine R&R, Sedan cruiser and aft cabin - 16.5 hrs., open or sportfish - 7.0 hrs.

Considering the age of your boat, there is going to be a lot more going on than just R&R."

09-08-2006, 01:23 AM
Stupid question: What is R&R?

09-09-2006, 12:03 AM
"R&R is "remove and replace". But, standard R&R is replacing an engine with a like engine. If you are changing brands, size, vintage,etc. modifications will add to that base time."

09-09-2006, 05:46 PM

Here are a couple of websites you can browse to get an idea of new and re-manufactured marine engine prices (not labor).
http://marineengineparts.com/shopsite_sc/store/html/page39.html ("]http://www.1800runsnew.com/[/url]

Last year, I re-powered my single engine 1975 Trojan F26 with a remanufactured long block purchased from the first website (a long block is the engine block with crankshaft & cylinder heads factory assembled.) This doesn't necessarily require *rebuilding* your engine, if you can find the same engine already rebuilt. The re-man block is not dressed meaning it has no oil pan, timing cover, flywheel, intake or exhaust manifolds, carburetor or distributor, water pumps, etc. If most of these components are in usable condition from your old engine, you can save a lot by taking this route. If you switch to a different make or model and don't have a source of parts, its probably not worth doing because by the time you buy the parts needed to dress out the engine, you could buy a new fully dressed engine. Re-manufactured blocks are available for common engines, Chrysler, Crusader, Mercruiser, etc. (I never heard of a Trojan engine.)

I took delivery of the re-man long block in my garage at home, the boat was stored in my yard for the off season. I hired a crane to pull the old engine out of the boat, and put it back when it was done. With the re-man block and the original engine in my garage, I transferred parts, the oil pan, timing cover, manifold, carburetor, distributor, etc. from the old engine to dress out the new block.

I'm no mechanic, but I'm pretty handy and I learned a lot through the process, and saved quite a bit of money, but it took a lot of sweat equity, and once I got it in the water, it took quite a while to work out all the kinks. I don't think I would have had the stamina to do two engines in one season. I also hired a mechanic friend for some of the key steps, assembling (sealing) the water pump, oil pan, timing cover & the intake manifold, and test firing the *new* engine on the stand before putting it back in the boat.

Here is a rough run down of my costs:

$1,990 re-manufactured long block Chrysler LM318
$ 950 New transmission velvet drive 1:1
$ 700 Exhaust manifolds risers & exhaust elbows
$ 120 New water pump
$ 150 hoses
$ 350 Carburetor & distributor rebuild
$ 200 replaced starter
$ 110 replaced alternator
$ 750 mechanic help
$ 200 crane service in & out
$ 200 new engine mounts
$ 300 misc. hoses, wires, fittings, sealants, gaskets, other hardware
$6,000 total ( approximate)

Sweat equity ~200+ hours includes finding parts & figuring out what to do next.

By the way, I also bought an engine hoist $120, and engine stand $100 that came in very handy during the project but I donít have much use for them now.

Unless you are in the business, I would say this is close to the rock bottom estimate for a novice do-it yourself direct replacement of 1 engine.
Good Luck,

09-10-2006, 01:24 AM
"Great information, thanks to both of you."