Bertram 25 Repower 470 to 3.0???

[achris]

Re: Bertram 25 Repower 470 to 3.0???

...I had a 470 in an open bow runabout, and it ran great. But like so many of them, it blew. It wasn't half the engine the 4.3 engine that replaced it was.

Actually, it was 2/3rds... :rofl:

 

[mr 88]

Re: Bertram 25 Repower 470 to 3.0???

If it was my boat and used it for off shore fishing ,twins would be what I would put in it. Fuel usage will be the same and you have all the controls,gauges etc all set up for twins.I like the safety aspect and the acceleration along with keeping the boat not being cut and patched up from the dash to transom.One thing about rebuilding the 470's is you can update them to a point and if properly maintained are strong runners. It takes a couple hours to pull the motors then off to the Engine rebuilder or your garage.Everything is there,lines up and plugs in for the installation and zero outlay for drives, related parts and associated headaches. Not sure of the stringer set up and what it would entail to drop a big block in it.

 

[Benjaminlbarker]

Re: Bertram 25 Repower 470 to 3.0???

Mr. 88 you do have a point. I'm just afraid that by the time I spend all the time and money to get those 470's working I could have easily dropped in a good set of 10 year old 3.0's with drives. (Or that sexy 8.2) Checking the local craigslist there are several good looking packages for well under $2000. From what I understand the 470 is a sack of crap compared to a 3.0. Just easier and cheaper to get parts and despite raw water cooling they don't fair too badly in the way of manifold issues. Folks if I'm misguided here please straighten me out.

Another of my thoughts for going with lower power is the range and fuel burn. The 25 is by no means a modern go fast in big **** machine. From what I understand 30 is about as fast as you will ever want to go off shore barring a completely glassy day. Setup at a steady 25mph apparently they will slog through just about anything at very low burn numbers. The 3.0's could get near 3 mpg. That could take me from Boynton Beach to Marsh Harbor on a tank. With that 502 cube beast that would be a stretch I think.

 

[achris]

Re: Bertram 25 Repower 470 to 3.0???

Mr. 88 you do have a point. I'm just afraid that by the time I spend all the time and money to get those 470's working I could have easily dropped in a good set of 10 year old 3.0's with drives. (Or that sexy 8.2) Checking the local craigslist there are several good looking packages for well under $2000. From what I understand the 470 is a sack of crap compared to a 3.0. Just easier and cheaper to get parts and despite raw water cooling they don't fair too badly in the way of manifold issues. Folks if I'm misguided here please straighten me out.

Another of my thoughts for going with lower power is the range and fuel burn. The 25 is by no means a modern go fast in big **** machine. From what I understand 30 is about as fast as you will ever want to go off shore barring a completely glassy day. Setup at a steady 25mph apparently they will slog through just about anything at very low burn numbers. The 3.0's could get near 3 mpg. That could take me from Boynton Beach to Marsh Harbor on a tank. With that 502 cube beast that would be a stretch I think.

I will make a few comments...

I do agree that having 2 engines gives you redundancy and the ability to make your own way home should one turn up its toes... However, newer engines do seem to be much more reliable. And I have only ever had one engine, and I go WAY offshore, over 40 miles at times, fish FADs out at 30+ miles and run in some pretty remote locations. (BTW, my miles are nautical miles.)

As for fuel usage... Often a bigger engine will use LESS fuel for the same boat speed, as it will be running with less load (relative to what it can push)... so is running 'easier'... Example. The engine in my car was a 4.2l normally asp diesel. Replaced it with a 6.5 turbo diesel... The 6.5 is WAY better on fuel, especially when towing the boat.... So, that argument doesn't hold water... Until you push into the range above where the smaller engine could have gone...

The only thing negative about going to the 8.2 is the cost...
The only things negative about going to two 3 litre engines... Twice the maintenance and those engine will be working harder. And I think would use a little more fuel (compared to a new MPI large displacement engine).
The only thing negative about rebuilding the 470s... They're 470s :facepalm:

Chris........

 

[Benjaminlbarker]

Re: Bertram 25 Repower 470 to 3.0???

Thanks Chris. I tend to agree with you completely. I'm a huge fan of singles. If you are worried, mount a kicker. I guess laziness gets the better of me though because sticking with the dual setup just seems like an easier option. As previously mentioned in this thread, the controls, wiring, and drives are already there for the twin I/o. I suppose a detailed cost breakdown of all the options is necessary to really determine what's best not just immediately, but weighing fuel and maintenance costs for the expected life of the particular engine package.

 

[Scott Danforth]

Re: Bertram 25 Repower 470 to 3.0???

If you want to rebuild your 470, crank, rods and pistons, along with the head are "385" series ford (429 and 460). custom mercruiser crank and block.

best way to rebuild them is to buy a new Ford 460 head, and take to your local machine shop for machine work. if you pull it apart, the ford part number is even stamped on the con rods.


These engines make great light weight hot rod motors for that "vintage" hot rod look in old Model A track cars

I say rebuild them

 

[artificialreef]

Re: Bertram 25 Repower 470 to 3.0???

If you have shallow pockets why not try refreshing the heads and new head gaskets. Alot of labor but not much $. I have twin 470's that run a cool 150 degrees that are 30 years old. Though my compression is 145 to 150. Maybe yours will come up with the hgasket. I dig the old school points. You will have to buy an old school dwell meter on fleabay or cl. These motors are not as bad as everyone thinks they are. Great gas mileage and torque to weight ratio. They dont break down if you keep up the maintenance, be aware of your weep hole and keep an eye on your temp gauge.

 

[aerobat]

Re: Bertram 25 Repower 470 to 3.0???

Anybody had experience with used or older 3.0's? I haven't heard many bad things.

well, i have a volvo 3.0 with sx drive and can say its a reliable package. when it comes to power don,t worry. its especially on pushing a boat on plane more powerful than you would expect.