Cross over kit
 

Hi
Im going to take my water pump off , who makes the best crossover kit with a thermostat
Thanks

I like this one http://teaguecustommarine.com/em0011...th-bypass.html, except that I'd order it with the thermostat housing to have AN fitting outlets.

JMPH,may i ask why you are removing the circulating pump?

I was looking and this one it catches my eye it's made by Diamond performance # 16634 with thermostat , does anybody use the Teague or Diamond Performance crossovers ?

If going with a thermostat outlet with AN fittings, make sure the fittings are big enough. Most mercury and aftermarket manifolds are fed with a minimum of 1 inch ID hoses. A -12an is substantially smaller, and may cause high water psi, or inadequate cooling of the exhaust/engine due to less flow. A -16 is still smaller than what mercury used

my thermostat housing is the old style and I need a new circulation pump so I thought that I like the look of these , I have been reading a lot of people like it and a lot of people don't ( hot spots in colder heads etc ) but I had it on my old boat and didn't have a problem , what do you think?

I not going with AN fittings , I going with the stock hoses but thanks

what engine do you have?

I've been contemplating doing this also but am concerned about hot spots in the back of the heads. Has anyone tapped into the rear of the heads to run a line back to the front?

You will need to run some lines from the front of the intake manifold (water jacket) to the rear water jacket on the manifold.

Thanks...that's what I thought, just haven't been able to find any pictures of it done. I've got Merlin intakes on my motors so there should be enough material to tap into.

Or you can dump water off the rear of the intakes overboard. You can adjust diameter of these lines, to help dial in water pressure as well.

i don,t understand how removing the circ pump will cause hot spot in rear of head,can someone explain that to me?

Cool...thanks for the input. Doubt I'll have much pressure issues as I'll be lucky to see 70 mph out of my boat.
OP...didn't mean to hijack your thread bit seems it's all useful info for running crossovers.

I'm not sure either....had just read it so was curious if anyone had any input either way.

lot of experts with no experiance giving advice lately.the circulating pump slows down the water flow through the engine.removing it in no way will cause the back of the head to have hot spots.if you remove the circ pump you will increase water pressure due to MORE water entering the block.merc uses the circ pump to help the engine maintain constant water temp and to reduce water pressure.

If removing the circ pump resulted in lower water pressure steam pockets would form at a lower temp.

no,it does not lower pressure enough to do that,if it di merc woild not use the circ pump.edit in,i was watching the bears win and not thinking,removing the circ pump will increase water pressure,not lower it.

I think the main reason mercury used a circulating pump, was so when thermostat was closed, water would keep "circulating" thru the engine, via the byass hose. Water never stood still in the block while thermostat was closed, it simply went in the front of block, thru heads, back out intake into circulating pump, and back thru front of block again. The extra raw water coming in during that period, simply went out the exhaust. The system works well, and imo, if running a thermostat, its a better way to go, having a circulating pump.

The OP said he likes the look without the ugly merc t-stat, I believe. If looks are your goal Diamond also offers a few nice polished stainless replacements for that ugly t-stat housing and keeping the circulating pump.

502 , 60 over

I would keep the Circulator , get you a replacement Polished Cast Stainless Housing and roll on. Moderate speed , moderate HP applications the water temp is too cool and all over the place with a crossover. Unless you are making lots of HP and running hard , the only advantage is less baggage and better looks .
Just my.02c

That does not tell what you have for a motor. Mike was asking What motor you have as in 502 EFI or carb etc.... This is important because if you have an efi, and you run a cross over and you run the motor at a different temp then the computer is programed for it will run rich, thinking it is cold. Merc and others run circulation pumps to keep the block a more even temp from front to back. The circ pump stat system will mix cold & hot water together and bypass to exhaust as needed. The system works great for lower HP motors. The problem with cross overs is... block temps from front to back will vary. With cross overs you can run with or without a stat. With out a stat you just run cold water through the motor without a constant stable motor temp. With a stat in the cross over system you bypass water till the stat opens and then it lets cold water in when the stat opens. This can shock the front of the motor a bit............... There is a little more to it then I just explained, but without going on for pages you should get the idea.

When you use a circulation pump you can be pretty sure the water is circulating through the engine because the water is being forced in one side so it has to come out the other, correct? Now when your replace the circulating pump with a crossover and bypass how can you be sure water is actually circulating through the engine? If the water coming into the crossover is flows equally towards both sides of the block and to the t- stat housing how do you know that the water doesn't just choose the path of least resistance through the bypass and stay sort of stagnant in the block because pressure is being applied equally to both sides of the block from the crossover?

bck, you bring up a good point. Water will always take the path of least resistance (unless forced to do otherwise). That is how both systems work. First you must understand a circ pump has fins that direct water, it does not pressurize. Now your sea pump will pressurize, they pump around 7 to 11 gpm at idle and up to 35 to 40 gpm at & above 3500 rpm. The cross over system works in the way of ... it is easier to go through the block then the bypass. The paypass has a smaller more restrictive passage then the block. Now when you have a bad pump both systems will suffer, more so the cross over. There is where the problem with steam pockets in the back of the block/heads can arise. That is why guys will tap into the intake on both sides in the back by the distributor, and either dump or redirect to the front by the stat housing. Once a steam pocket starts water will not go near it.. it is forced away.. again path of least resistance. bad buzz. It can be a problem with unpressurized systems. Now I said CAN BE, it does not always happen, usually only with a very weak sea pump, But thats not the fault of the system, thats maintenance problem.

I have actually been playing around with a cross over with stat design that incorporates a 4 pound check valve in the bypass. It works great.

502 60 over naturally asperated 600 hp 5750 max rpm

the steam pocket is more a problem with the 502 vs a 454 because the cylinders are siamezed .i like to add a -3 line off the back holes of the intake to stop airlock that causes steam pockets.

Yes you are correct Mike, Guys also use different size lines to adjust for too much block pressure if thats ever a problem. But with the lines off the back, you will help regulate block temp differential, and never have to worry about air/steam pockets. And JMPH, whatever system you decide to go with........... Its all about the way you rig it.

i think a lot of times water pressure is high because the hoses from the t-stat outlet to the exhaust is to small.

Yes .. Also sometimes the dumps in the tails are to small, where someone modified them or they were just made that way. Its all about radius times pie squared... What goes in must be able to go out easier

I read all your post thank you, I don't really understand when using crossover with a bypass thermostatically controlled like CP 620-300100 with a big bypass hose how it's it different than a circulating pump.
When it idles your creating 3or4 psi and then when it revs you have more psi , as long if you don't get to much psi I think you good?
I know that merc doesn't make circulating pumps for nothing , I still not convinced before I buy one.
Can anyone share there experience before I buy one

If you want call me (920-475-0852) I can explain both ways in better detail. I have done several motors with both circ pumps and cross overs. There is advantages, and disadvantages to both ways. Its hard without going into pages of writing to explain.

Whats the block water pressure ?