Repower 5.0 liter to 5.7 383 stroker

Based on this thread I did some additional research on fresh water cooling. There are what appears to be informative articles on the subject located in the lower right hand corner of this webpage in the area titled "Fresh Water Cooling Tech Articles" http://www.perfprotech.com/mercruiser-fresh-water-cooling-systems/category/1287

The water flow diagrams would seem to indicate that risers and manifolds would still require regular maintenance.
 
Phlorida said:
.............The water flow diagrams would seem to indicate that risers and manifolds would still require regular maintenance.
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Yes they do, you'll just get a lot longer life out of them with a "full" system. I just replaced mine this last spring after the 12 years the boat had the originals. I elected to go with the "dry-joint" style manifolds, risers and elbows.
 
It looked to me like just as much raw water was passing through the manifolds, it just isn't being routed through the block. Have I interpreted the diagram incorrectly? If you could eliminate or significantly reduce manifold and riser maintenance the full FWC is a no brainer.

fwc-full-flow.jpg
 
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I did get a call back from Brad at San Juan Engineering today. They do not have a complete closed system for my engine. Half system is available. Reasoning from what Brad told me is how Merc is remanufacturing lots of new/reman engines using pieces parts from some older models that may or may not be consistent, so making a standard package could be impractical.

I was asked to send some images of my new engine so they could look at the configuration to see if they could make something work. Pics are on the way.

We will see what comes of this.

Jim
 
I should be doing a sea trial tomorrow (Monday). For now the engine is not getting a FWC system. I will post some photos and performance info when it happens.

Jim
 
jimandsue60 said:
I should be doing a sea trial tomorrow (Monday). For now the engine is not getting a FWC system. I will post some photos and performance info when it happens.

Jim
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Good luck. If you can maybe run it on a lake to eliminate Salt Water. Otherwise rinse with Salt Away after each use until you do get FWC.
 
Yes the repower went well, I put @ 3 hours on it the first day and the weather has been fairly crappy since. Everything did what is was supposed to do. I can not really tell any major performance increases yet as I am limited to 3750 RPM'S till the 20 hour break in period is over. I did notice @ 4mph more difference at 3500 rpm than the old engine. We are starting a trip today that will cross the state of Florida, leaving Ft Myers and heading east on the Okeechobee Waterway over to Stuart, Florida. Since I have not gone to WOT I don't know if we will have to reprop it yet. I am probably going to have limited internet during our trip and will post when I am able to. We have no time limit and are not sure where we will wind up!! My course shows about 158 miles to the St Lucie River near Stuart, Florida. Most of the trip will be in fresh/brakish water :)

Jim
 
Miles looks about right for your trip. I just did it last month from Hobe Sound to Tarpon Springs. If you get a chance stop at Rialto. They are very friendly and helpfull. www.rialtoharbor.com
 
We made it over to Stuart,Fl, and are staying at Loggerhead Yacht club and Marina. They have very nice amenities. We spent last night at Roland Martins in Clewiston on Lake Okeechobee. Eight dollars and 50 cents for the overnight slip. There was a band and the Ahi Tuna was great. Tomorrow we are gonna play on the ICW and look for another marina to stay at.

The engine ran great, it now has 13 hours on it. It has not used any oil yet ( I was told it would). Engine temp is a consistent 161. It appears I am getting @ 2.5 miles per gallon by the amount of fuel I have added since we left Ft Myers.

Jim
 
I have 25 hours on the engine now. The max rpm goes up to just over 5200 and does not hit the rev limiter at 45 mph. I purchased a used set of 24P props which should bring the max rpm down to @ 4900/5000. I am not sure what the speed will increase to yet. The props should be installed Wednesday or Thursday.

Jim
 
Jim - isn't the WOT spec for that engine 4800-5200? I'm not real familiar with it, so I only did a quick search on Merc's site. If it was me, I'd say it's perfect just like it is. Even though increasing 2" of pitch should still keep you in your proper range, I've always felt it's better to be at the top range - mainly since you'll probably be adding more weight/people most of the time?

Regardless, I'm glad it's working out for you. I'll be curious to see what type of speed change you get. My guess is very little - but I'm still curious!
 
Lazy Daze said:
Jim - isn't the WOT spec for that engine 4800-5200? I'm not real familiar with it, so I only did a quick search on Merc's site. If it was me, I'd say it's perfect just like it is. Even though increasing 2" of pitch should still keep you in your proper range, I've always felt it's better to be at the top range - mainly since you'll probably be adding more weight/people most of the time?

Regardless, I'm glad it's working out for you. I'll be curious to see what type of speed change you get. My guess is very little - but I'm still curious!
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You are correct with the 4800-5200 wot range. My boat was still full of gear and fuel when I tested. I am guessing I might have hit the rev limiter if I was a bit lighter. I am not so interested in the top end speed, I am trying to get a little more speed at cruise power with a little less throttle. I wanted a spare set of props to keep on the boat so if the 24P doesn't work that great I can always go back to the 22P and still have a spare prop set. I don't mind being near the top of the range but at or going over the max bothers me.

I am expecting to see just below 50 mph with the 24P, I will keep you posted.

Jim
 
Gotcha. Good - looking forward to updates!

I can't find the exact spec, but I believe the limiter would probably be somewhere around 5400-5500. I'm basing that only off of memory for my engine, though. I think mine is at 5150 (WOT of 4800).
 
I had the 24 P props installed yesterday and took the first ride today. I noticed that the bow did not come up as high and we got on plane quicker. My WOT was just under 49 mph @ 5175 RPM. I never could get above 44 with the old set up. That was nice ! What did impress me was that I was at my 30 mph cruise that is very comfy on this boat but was 350 RPM less than what it was with the 22P prop. It is to early to tell what difference (if any) I will see in fuel fuel consumption. Not that it really makes a difference in the big scheme of things :)
 
jimandsue60 said:
I had the 24 P props installed yesterday and took the first ride today. I noticed that the bow did not come up as high and we got on plane quicker. My WOT was just under 49 mph @ 5175 RPM. I never could get above 44 with the old set up. That was nice ! What did impress me was that I was at my 30 mph cruise that is very comfy on this boat but was 350 RPM less than what it was with the 22P prop. It is to early to tell what difference (if any) I will see in fuel fuel consumption. Not that it really makes a difference in the big scheme of things :)
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It sounds like you found a good set up.
 
I wouldn't mind having a 383 in my 230. However, i am afraid it would tear up my Alpha Drive rather quickly.
 
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