water circulating pump vs. crossovers
03-27-2004, 02:55 PM
#11
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I plan on starting this season out with all new belts, raw water pumps, and I figured I'd put on new water pumps before they started to leak...they are 15 years old , have 420 hours on them, dont you think preventive
maintenance is better than corrective? So I was talking to a highly regarded and very respected marine engine builder( who runs a 42' lightning w/1300 sterlings) who suggested I get rid of the circulating pumps and go the crossover route. I have no argument with him regarding his expertise. He didnt mention anything about potential water pressure propblems. This is a fresh water boat, with GIL high performance exhaust and Formula Silent Thunder....wont that water go out the exhaust?
maintenance is better than corrective? So I was talking to a highly regarded and very respected marine engine builder( who runs a 42' lightning w/1300 sterlings) who suggested I get rid of the circulating pumps and go the crossover route. I have no argument with him regarding his expertise. He didnt mention anything about potential water pressure propblems. This is a fresh water boat, with GIL high performance exhaust and Formula Silent Thunder....wont that water go out the exhaust?
03-27-2004, 09:16 PM
#12
It will work just fine as long as you do some testing. You will want to verify water pressure and I would run thermostat with 3 hole around 3/32 or 1/8. All set ups are different so plan on doing some testing to save yourself trouble later.
Most I have seen do not regulate temperature as well at idle speeds. Tend to run a little cool. Good luck.
Most I have seen do not regulate temperature as well at idle speeds. Tend to run a little cool. Good luck.
03-28-2004, 12:14 AM
#13
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so should I just say @!#$% it and stay with the factory set up... just put on new belts, change the raw water pumps ,fluids, filters and plugs and run the hell out of it this year...after all it ran so f#$@!ing good last year and I'm not looking to change the tried and true... what do you think...
03-28-2004, 10:11 AM
#14
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The only reason I have a crossover on mine is because it was on there when I bought it. I wouldnt remove it unless it was giving you problems.
So could high water pressure cause more oil consumption and condensation in valve covers?
Also where is the best place to install a water pressure sender unit, side of block where the water drains out or up on the manifold?
So could high water pressure cause more oil consumption and condensation in valve covers?
Also where is the best place to install a water pressure sender unit, side of block where the water drains out or up on the manifold?
03-28-2004, 12:10 PM
#15
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well the general concensus is if it aint broke dont mess with it! I am sure that excess water pressure is no good...it will certainly compromise head gaskets , etc... remember in a cars closed cooling system the radiator cap only holds 16 lbs of pressure...after that it is too much, so likewise in a boat more than 16 psi can cause trouble....why take the risk....happy boating too all
03-28-2004, 12:14 PM
#16
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Why is your "highly-respected marine engine builder" giving you advice running Sterlings if he is a good engine builder himself?
You have to consider that his application is very different than yours (blowers). Crossovers are pretty standard on blower applications.
I tried crossovers on non-blower motors years ago and had problems mentioned above. You have nothing to gain but looks, and will loose $$$ and motors if you develop a steam pocket or overheating from pressure problems.
Save your money and your motors, avoid the headaches, and put new circulating pumps on.
You have to consider that his application is very different than yours (blowers). Crossovers are pretty standard on blower applications.
I tried crossovers on non-blower motors years ago and had problems mentioned above. You have nothing to gain but looks, and will loose $$$ and motors if you develop a steam pocket or overheating from pressure problems.
Save your money and your motors, avoid the headaches, and put new circulating pumps on.
03-28-2004, 01:12 PM
#17
Charter Member
I totally agree with keeping the stock pumps. On a high HP supercharged motor, but consider that Merc uses the circ. pumps on their SC motors. What does that tell ya? 
When I first bought my last boat, it had a crosover. 1st time out, I ran it for less than 5 min then checked oil.
FULL of water! this happened everytime for the 1st 6 outings. Ruined many weekends. Tore motor apart thinking it was cracked, nothing.
Turned out my WP was pegging 30# at cruise. (my 1st HP boat, so wasn't aware of the WP thing) The pressure was blowing water past the intake gaskets, right into the oil pan. I was running a stat with 3) 3/16" holes and a bypass hose. Ended up just running a restrictor and no bypass hose which got the press right on, but then temp never got over 110*. Spent the following 3 yrs trying to dial in both temp and press. Finally got it great for the summer, but spring and fall, no dice!
If anyone trys them, I highly recommend a WP, Oil temp and water temp gauge on 1st time out and watch them closely.
Never again will I mess with crossovers. Some have good luck, some don't. I got tired of working on the boat all the time, so my new boat is all stock.
Just my opinions.
When I first bought my last boat, it had a crosover. 1st time out, I ran it for less than 5 min then checked oil.
FULL of water! this happened everytime for the 1st 6 outings. Ruined many weekends. Tore motor apart thinking it was cracked, nothing.
Turned out my WP was pegging 30# at cruise. (my 1st HP boat, so wasn't aware of the WP thing) The pressure was blowing water past the intake gaskets, right into the oil pan. I was running a stat with 3) 3/16" holes and a bypass hose. Ended up just running a restrictor and no bypass hose which got the press right on, but then temp never got over 110*. Spent the following 3 yrs trying to dial in both temp and press. Finally got it great for the summer, but spring and fall, no dice!
If anyone trys them, I highly recommend a WP, Oil temp and water temp gauge on 1st time out and watch them closely.
Never again will I mess with crossovers. Some have good luck, some don't. I got tired of working on the boat all the time, so my new boat is all stock.
Just my opinions.
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03-28-2004, 02:57 PM
#18
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you guys are absolutley right!!!!I will NOT be putting any crossovers on MY boat. I'm glad I can go to this forum and get the opinions of many different people before I change anything. We dont want any trouble with these stock Mercury setups. My boating season is too short here in N.E. to run the risk of making it shorter with mechanical issues. Thanks for all your input !!!
03-29-2004, 01:08 AM
#19
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Just got back from lake. Had crossover last year when I bought the boat.Ran too cold, blew hoses off from to much pressure. Put stock setup back on and it warms up fast and temp is always steady. You could probably get a crossover to work with many lake trips and pressure valves.Mercruiser made it simple, no pressure probs, no temp probs, no headache. If they didnt think it was needed I dont think the would waste the money puttin it on there. Mine runs great now the way it was stock!
