I've got a 2001 310 with dual merc 5.7's that were raw water cooled. i'm re-powering with fresh water and the mechanic is recommending fresh water manifolds for an additional $3000!! I changed the risers/manifolds about 5 years ago and I was wondering if anyone had any thoughts on this configuration?
Repower VDries
- Thread starter Murf
- Start date
kap2
Active Member
If the manifolds are 5 years old in salt water they may need to be replace now or in the next year or two anyway. If you include the manifolds in the closed system you'll never have to replace them again.
I would replace them and convert to the full closed system. $3K sounds high for manifolds and risers... Maybe shop around for the parts and supply them to the mechanic.
I would replace them and convert to the full closed system. $3K sounds high for manifolds and risers... Maybe shop around for the parts and supply them to the mechanic.
sub'ed with interest. I would love to know the total cost of converting from raw to fresh (using existing MPIs)
hottoddie
Well-Known Member
- Jan 11, 2012
- 2,230
- Boat Info
- 1986 Sea Ray 390 EC
Garmin 4212 Chartplotter
Garmin 24 HD Radar
Garmin 546s Plotter
- Engines
- 454 Crusaders
I believe the main difference between 1/2 FWC and Full FWC is a larger heat exchanger and block off gaskets between the manifolds and risers. The cost difference should be fairly small. 1500 per engine sounds like added profit to me.
Were your originals Horizons, or did you have to add all the fresh water cooling bits from scratch?
KevinC
Well-Known Member
If you are repowering and considering moving 5 year old raw water cooled manifolds over you are likely asking for problems and you will need to do them very soon if not already.
If the $3000 is for full parts and labor for both engines then it is just a little high. If the labor was already factored in for moving the old manifolds then there should be only minor additional time to hook up the fresh water cooled manifolds - if it was not then that explains the difference. Standard dry-joint manifolds, risers, spaces and gaskets for a 5.0/5.7 are typically a little over $1K (per engine) purchased online if they are OEM Mercruiser.
-Kevin
Thanks. Looking forward to any details you may share regarding the parts needed to do this conversion.
- Mar 28, 2016
- 499
- Boat Info
- 1999 Sea Ray 290 Sundancer
2005 Sea Ray 320 Sundancer
2005 Sea Ray 340 Sundancer
- Engines
- Twins V-Drives
8.1 Mercruiser
I just repowered my 320,, With 2 new long blocks and put on brand new Standard dry-joint manifolds and risers.. Raw water cooled (salt water) for around 3k in parts... They last about 5 to 7 years depending on how you flush them... So you say how long u keeping the boat for. Even if you change them again in 5 years time.. Then you know what you have. I also recommend changing your shaft seals while your motors are out... Prob the cheapest price your gonna get to do them now... And of course new sea water pumps
scoflaw
Well-Known Member
- Aug 10, 2011
- 6,395
- Boat Info
- 1999 Powerquest legend 260 sx 502 mag
2005 Baja 242 islander 496
- Engines
- 502 mpi Bravo 1
496 mag B1
If he converts to dry joint full cooled system he'll need a set of hoses as well, which isn't cheap.
Manifolds on full system should last the lifetime of the engines, risers will be the wear item
Manifolds on full system should last the lifetime of the engines, risers will be the wear item