Replaced 5.7 Alpha with 7.4 Bravo

[aazeng]

Hi Guys,
After 4 months throught the winter here in Australia have finally finished this project.
Major works which involved in strenghting the stringers, relocating the Fuel tank forward by 6" to allow for exxtra length in motor.Extra hatches to access the pumps, batteries etc. Built New 120L S.S tank and Installed as a sub tank which now has 400l Fuel Capacity just incase.
Looking forward in taking her out for a run tomorrow HP differance from 260 to 400HP

 

[Sundancer]

Tell us what kind of boat you did this too! That's quite a jump in horsepower!

 

[aazeng]

I fitted it into a 23 weekender, Offshore with the 5.7 was lacking hp and tourch.

 

[sprink56]

This is outstanding....we need more info and pics. You just don't float some "teaser" like this to us without follow up info and pics.:huh: You are being cruel.:thumbsup:

Where in Australia are you? We might have our resident "expert Aussie reporter" Chris have a look at this if you guys are near each other.

 

[Tail Chaser 661]

Very Nice.:thumbsup:
What year is your boat?

 

[aazeng]

Hi Guys, Its good to have some laughs.
The boat is a 23 weekender 1985.
I do a little cruising with the family and stay out on the boat. The reason for the upgrade is the offshore fishing that I do often for Marlin,Tuna and Shark approx 35 miles offshore.
For its class, one of the best boats in dirty water. Makes the local boat look sub standard.
These boat are not very popular here. The Aussies dont know what the missing when it comes down to comfort in rough sea due to the Hull specs and weight.
Unfortunately parts here in Australia both from Searay and Mercruiser are very expensive.
Most parts that I purchase come from the US.
Happy to chat further email also listed below.
anthony@aazeng.com.au

Cheers
Anthony

 

[Larry]

Nice job!!

That came out great!

Only one question why didn't you run the bilge blower intakes down lower as any gas fumes are heavier then air and will be at the bottem? (hey, I had to find something wrong...)

 

[Tail Chaser 661]

Most fishermen don't acknoledge the Sea Ray as a fishing boat. If theres no Pilothouse or maybe a Walkaround they have nothing to say usually. They return from fishing in 1 day. I return in 3 days. I'll take the comfortable boat.

Couple of things. Is your Racor the type with the clear plastic bowl? If so, There's one with a steel bowl for inboard use.
Going with FWC might be a good option also. When I was researching engines, One person mentioned the 7.4ci can have valve problems.

The reason being... In raw water cooling. The heads are always heating and cooling at lot. Expansion and contraction. After a while the valve guides may become loose causing the engine to suck a valve.

In a FWC engine, The temps stay more consistent cutting back on those frequent expansion rates eliminating the potential for the guides getting loose.
Once again, Nice ride you put together there :thumbsup:

 

[aazeng]

Hi All,
In aspect to the blowers.I prefered them higher due to the heat despersement which will rise, But having said that I also could put some flex to drop them lower if required.
I prefered the The Racor with the Clear bowl as I can visally see if there is in water which that I can drain. I also have the original mercruiser seperator fitted to the engine.
Inaspect to the cooling side the New S.S Manifolds dont run as hot as the castings,and provide better water flow out which supposed to run a more consist water temp.
At present the water temp is sitting at 170 deg .
The engine test last wekend was good but looking at changing prop.
At 3800rpm it was doing 45mph.
The Prop that I was using was a bravo 15.5 X 22P 4 blade
I need to change the prop to achieve better rpm.
Looking at enertia 14.75 X 21P which should give me at WOT 4600 rpm
at 56mph.

 

[WWCephas]

I have an '88 454 Magnum 230 Weekender. I have been thinking about switching over to a Bravo Drive, how hard a conversion was it? The Alpha has been working well for me though, I just need to be smooth when bringing power up, but then again my 454 is not putting out 400 HP like yours. I also see you have the stainless exhaust, very nice! I am very tempted to get them although they are very expensive (Doing an engine overhaul now). Any idea how much weight that saved you? (which probably more than compensated for the extra weight of the Bravo drive) Which model of Bravo did you use?

I also had a question about the fuel tank, I was about to go poking around in mine to give it a good inspection. Was it sealed in with foam, how hard was it to access?

Anyway, your mod looks great, I love my old 230! It is great for blue water fishing and crabbing/shrimping when you clear out the seats from the back end, comfortable up front, and fast as hell. Mine was doing 45 at 4600 RPM on a tired engine before I yanked it, and that was with a 15 hp 4 stroke kicker hanging off the back. I have shed that now since my engine will be zero timed again along with at least another hundred pounds of other gear, so I can't wait to try it out when I am done.

 

[Chris Dauth]

This is outstanding....we need more info and pics. You just don't float some "teaser" like this to us without follow up info and pics.:huh: You are being cruel.:thumbsup:

Where in Australia are you? We might have our resident "expert Aussie reporter" Chris have a look at this if you guys are near each other.

Where abouts are you ????

I should have my "up grade" completed next week. 5.7L to 383 stroker. I did contemplate going 454 but there was too much work to get a 454 into the engine room. plus the extra 250 kilos in weight. Seemed to me the way to go for me was to keep the SBC block and get the same output as the 454.

Anyway, I'm in Hervey Bay, about 200 meters from the Great Sandy Straits Marina.

 

[aazeng]

Hi Chris,
Sorry Chris for not getting back to you sooner as I was up in Cairns on the P&O Cruise.
I was orginally going to stoke the engine to a 383 which would have given me the extra HP. I was looking at also achieving more torque. The engine does not work as hard now and Im finding only over a couple of trips the fuel wise no worse off.
I'm located in Melbourne and happy to chat further.
The engine weight wise is on approx 40 or so kilos in weight as I have saved on weight due to the SS manifolds. According to the specs, the 454 bravo to the 350 Alpha was .approx 140 kg differance. The weight differance to the SS manifolds is approx 60kg.
email me at anthony@aazeng.com.au to discuss further and exchange details

 

[aazeng]

The bravo leg has the same ratio as the alpha.
but only rated at 300hp. The bravo is rated to 600hp
The engine was orginally rated at 330hp with minor work and the ss header now generates 400hp. I payed approx $3300 AU for the pair.
Weight wise engine and leg due to the ss manifolds, about 40kg worse off.
happy to help out further
soory for not getting back to you sooner as I was away on vacation
the tank is easy to remove, just undo the straps around the tank. personnally I have not modified the tank but have added a sub tank of approx 100l.

 

[Chris Dauth]

Great about the cruise. :thumbsup:

We had the 383 0n the dyno Thursday afternoon. Just been going throught the break in program. The last run she made 380HP with 390 ft/lbs torque, and the ignition hasn't been set yet. They make the preliminary runs with the spark retarded so as to prevent any detonation while running in.

You should follow the " Official pre-Clinton" under "Sport Cruisers "

http://clubsearay.com/forum/showthread.php?t=13874

It's where the old guys with old boats hang out. Lots of great information there.

Also, duck over to my profile and have a look at the picture albums. http://clubsearay.com/forum/album.php?u=6372

We think my 270 Weekender is the only one in Australia. She came from North Palm Beach in Florida. Special import, even found US money in her when I stripped her down.

Have a great weekend !!

.

 

[aazeng]

Hi Chris,
Pictures of rebuild look great. Just some quick advise, The reason why I upgraded was due to the mercruiser headers with the heat generated finished cracking the header and as a result I had water enter the bore in one of the blocks.
I have heard there are some companys around in Australia that can ceramic dip the manifolds which will give you better water flow and longer life on the headers. Mercruiser are aware the the life span on there headers isnt great and require regular maintenance.

 

[Chris Dauth]

G-Day Tony(?),
Thanks for the tip.
The Exhaust system was new when I put the FWC system on, and the manifolds, elbows and risers are still like new. I changed the cooling system a little, in as much as I put the separator gasket between the riser and the elbow. The risers are now FWC, and only the elbows see salt water.
Also I take the cooling water up thru the hull, 1 1/2" line to the raw water pump, this gives a much greater flow thru the exchanger and the elbows.
Even after long runs up the coast (5 hours), you can hold your hand on the elbows, only just warm.
That lousy little line up from the leg on both Alphas and Bravos just can't deliver enough water and those fittings that go thru the transom plate have always been a source of trouble. Corrosion gets in behind the fitting and crushes them down until you get no water flow.

If you haven't done it, get your cooling water off the bottom of the boat and don't forget to cut the line in the gimbal housing next to the U-Joint bellows.

If you need genuine Merc workshop manuals, PM me.

 

[aazeng]

Thanks Chris,
Because my boat is a trailer boat it would be easier to wack the muffs on the legs for flushing. Water flow through these headers has very little restictions and there are no dead legs where the water can hold up. I will keep your idea in mind for future applications