JMPH

iTrader: (1)

502 , 60 over

dunnitagain

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

Bawana

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.

bck

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?

Bawana

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.

Bawana

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.

JMPH

iTrader: (1)

502 60 over naturally asperated 600 hp 5750 max rpm

mike tkach

iTrader: (3)

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.

Bawana

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.

mike tkach

iTrader: (3)

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