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Please explain the advantage of a "Water Crossover"

Old 10-13-2004, 10:21 AM
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Default Re: Please explain the advantage of a "Water Crossover"

if you have closed cooling theres no way for the coolant to circulate and cool off the engine if you get rid of the pump!
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Old 10-13-2004, 12:57 PM
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Default Re: Please explain the advantage of a "Water Crossover"

I installed an EMI crossover (with bypass) on my HP500 when I was redoing the top end of it. The seawater pump was leaking anyway.

First time on the water, the temps were about 40 degrees different between the port and starboard heads at the intake. Humm. Then a hose blew off.

When I put a water pressure gauge on there, it pegged it (>35 PSI) at 2,500 rpm!!! Oops!!

I pulled the thermostat out, and the pressure then dropped to 10PSI at WOT, but then no water temp...

I ended up putting a Whipple washer in there instead (FtmBob had one!). I have not been able to get back on the water with this....

So, yes, you can have problems, even if the temp shows OK with a crossover...

I would recommend that anyone using a crossover test their water pressure.

Kent
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Old 10-13-2004, 01:12 PM
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Default Re: Please explain the advantage of a "Water Crossover"

Originally Posted by Mudball
I installed an EMI crossover (with bypass) on my HP500 when I was redoing the top end of it. The seawater pump was leaking anyway.

First time on the water, the temps were about 40 degrees different between the port and starboard heads at the intake. Humm. Then a hose blew off.

When I put a water pressure gauge on there, it pegged it (>35 PSI) at 2,500 rpm!!! Oops!!

I pulled the thermostat out, and the pressure then dropped to 10PSI at WOT, but then no water temp...

I ended up putting a Whipple washer in there instead (FtmBob had one!). I have not been able to get back on the water with this....

So, yes, you can have problems, even if the temp shows OK with a crossover...

I would recommend that anyone using a crossover test their water pressure.

Kent
Kent,

i was wondering what type water pickup you are using. I had very water pressure when using a low water type pickup ( 5 holes on lower edge of nosecone)

Mark
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Old 10-13-2004, 01:13 PM
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Default Re: Please explain the advantage of a "Water Crossover"

that should have read "very high water pressure"

mark
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Old 10-13-2004, 01:16 PM
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Default Re: Please explain the advantage of a "Water Crossover"

Hi Mark:

I have the standard side water intake on the Bravo.

What did you do to fix your pressure?

Kent
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Old 10-13-2004, 01:16 PM
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Default Re: Please explain the advantage of a "Water Crossover"

In order to run a thermostat, you must have a bypass to cool the exhaust while the thermostat is closed. In addition, we recommend 3 5/32" hole in the crown of the thermostat, so that it is not flooded with cold water. All the thermostats that we use are automotive based, and generally require the same temperature on both ends.
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Old 10-13-2004, 01:24 PM
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Default Re: Please explain the advantage of a "Water Crossover"

Brownie:
The thermostat that we removed (Bob from FTM and I) was open. The temp gauge showed about 145 and never went above this. There is only one hole drilled in the thermostat. It came that way from EMI.

Are you saying that more holes drilled into the termostat would help the pressure problems?

It seems to me (not being a crossover guru!), that the thermostat just doesn't flow enough. Is there a different style that flows more?

Kent
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Old 10-13-2004, 02:37 PM
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Default Re: Please explain the advantage of a "Water Crossover"

I think they are all pretty much the same. You pressure can come from the exhaust, also. It surely can't hurt to add a couple of more holes. Try to get your pressure below 30 psi, or worry about intake and head gaskets.
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Old 10-13-2004, 09:20 PM
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Default Re: Please explain the advantage of a "Water Crossover"

You can try taking your pressure reading after the thermostat, Then you'll know if thats where the problem is. It could be too much water for the dumps you have. Without a bypass the water pump and crossover are about the same thing, Only one requires power to use. Try to take a reading after the block or intake manifold.
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Old 10-14-2004, 05:37 PM
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Default Re: Please explain the advantage of a "Water Crossover"

Thanks Brownie.
I will try the Whipple washer first, and if I have low temp problems, then I'll try drilling more holes in the thermostat.

I sure like having a thermostat. It tends to make things more 'equal' from day to day when running.

Kent
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