Rigging/plumbing things
02-08-2017, 06:47 PM
#1
Rigging/plumbing things
I noticed alot of guys are anti "header" on here. I will agree, that headers, especially when buying used, is a gamble.
I've had this conversation with buddys, but thought I'd bring it up here too for discussion. I can't tell you how many engines I see guys posting pictures of, with headers, whether it be CMI, Stellings, Lightnings, etc, that have too SMALL of line feeding them. There is nothing worse for double walled stainless headers with many welds, than getting them super hot, and then cold, then hot, then cold.
Most header manufactures, and Mercury Marine, recommend, or use, 1 inch, or 1 1/8, lines, to feed the headers with water. I see alot of guys feeding them, with -12 AN, or even sometimes, -10an. At idle speeds, there isn't a whole lot of pressure in the system. The sea pump can move alot of water, but it cannot make a lot of pressure, at low speeds. In order to get flow from small lines, you need lots of pressure. Just for comparisons sake, take a look at what a 1 inch line, can move, vs a -12 AN line.
-10 AN = 5.5 Gallons per minute
-12 AN = 9 Gallons per minute
1 inch = 24 Gallons per minute.
1 1/8 inch = 30 Gallons per minute
On top of this scenerio, you often see guys runnign a crossover setup, with Bypass's. When the thermostat is closed, very little water is moving past it, and most jumper hoses, are also very small. Now you are restricting flow to the headers even worse. Or those not running thermostats, will run "restrictors" in an attempt to build heat in the engine, and are really building heat in their exhaust .
I'm sure there is someone here with an engineering backround, that can chime in on this topic, that knows flow capacities better than me.
I've had this conversation with buddys, but thought I'd bring it up here too for discussion. I can't tell you how many engines I see guys posting pictures of, with headers, whether it be CMI, Stellings, Lightnings, etc, that have too SMALL of line feeding them. There is nothing worse for double walled stainless headers with many welds, than getting them super hot, and then cold, then hot, then cold.
Most header manufactures, and Mercury Marine, recommend, or use, 1 inch, or 1 1/8, lines, to feed the headers with water. I see alot of guys feeding them, with -12 AN, or even sometimes, -10an. At idle speeds, there isn't a whole lot of pressure in the system. The sea pump can move alot of water, but it cannot make a lot of pressure, at low speeds. In order to get flow from small lines, you need lots of pressure. Just for comparisons sake, take a look at what a 1 inch line, can move, vs a -12 AN line.
-10 AN = 5.5 Gallons per minute
-12 AN = 9 Gallons per minute
1 inch = 24 Gallons per minute.
1 1/8 inch = 30 Gallons per minute
On top of this scenerio, you often see guys runnign a crossover setup, with Bypass's. When the thermostat is closed, very little water is moving past it, and most jumper hoses, are also very small. Now you are restricting flow to the headers even worse. Or those not running thermostats, will run "restrictors" in an attempt to build heat in the engine, and are really building heat in their exhaust .
I'm sure there is someone here with an engineering backround, that can chime in on this topic, that knows flow capacities better than me.
02-08-2017, 06:56 PM
#2
Another complaint I often hear is
" I installed a crossover setup, and my water psi was too high, went back to a circulating pump, and its all good now".
The problem wasn't the lack of circulating pump, causing high water psi. The problem is, the setup wasn't plumbed properly more than likely, and the cooling system, simply couldn't get rid of the water fast enough, so psi builds up. I've seen it before, where a buddy had -10 lines feeding his exhaust. I suggested changing to 1" lines for his exhaust, or -16 AN as minimum. He didn't want to spend for the -16, and didn't want to use a hose with clamp setup, so he went to -12AN. His water psi did drop by doing so, and his exhaust manifolds were not as HOT , as before.
If you've ever hooked a sea pump hose directly to a 55 gallon drum, and simply idled the engine, you'll see how quickly it can empty that drum of water.
Water flow not only helps cool the exhaust, it makes the oil coolers, transmission coolers, and engine, simply run cooler. Oil coolers, are much more efficient with volume, as long as theres enough supply. With a raw water cooled setup, we have unlimited supply.
" I installed a crossover setup, and my water psi was too high, went back to a circulating pump, and its all good now".
The problem wasn't the lack of circulating pump, causing high water psi. The problem is, the setup wasn't plumbed properly more than likely, and the cooling system, simply couldn't get rid of the water fast enough, so psi builds up. I've seen it before, where a buddy had -10 lines feeding his exhaust. I suggested changing to 1" lines for his exhaust, or -16 AN as minimum. He didn't want to spend for the -16, and didn't want to use a hose with clamp setup, so he went to -12AN. His water psi did drop by doing so, and his exhaust manifolds were not as HOT , as before.
If you've ever hooked a sea pump hose directly to a 55 gallon drum, and simply idled the engine, you'll see how quickly it can empty that drum of water.
Water flow not only helps cool the exhaust, it makes the oil coolers, transmission coolers, and engine, simply run cooler. Oil coolers, are much more efficient with volume, as long as theres enough supply. With a raw water cooled setup, we have unlimited supply.
02-08-2017, 07:07 PM
#3
Platinum Member
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iTrader: (6)
I was talking to a guy at Teague a month or so ago and he told me they run -12 to all there header connections, nothing larger.
02-08-2017, 07:31 PM
#4
Registered
iTrader: (3)
Provided you are flowing enough water to fill the system, I dont see the benefit of pressure. Sure there will be some pressure as the system is full of water that is moving thru it, but excess pressure to me would mean either your trying to stuff too much in or you have a restriction and not letting enough out. Pressure is a byproduct of flow vs restriction is it not?
02-08-2017, 07:32 PM
#5
Provided you are flowing enough water to fill the system, I dont see the benefit of pressure. Sure there will be some pressure as the system is full of water that is moving thru it, but excess pressure to me would mean either your trying to stuff too much in or you have a restriction and not letting enough out. Pressure is a byproduct of flow vs restriction is it not?
02-08-2017, 07:35 PM
#6
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iTrader: (6)
These builds are the first for me not running a circ pump, going with a cross over with the whipple water pump delete kit, Im running CMI sweepers, it would be nice to know what the gap is between the primary and outer tube. if you put a large amount of water volume to the header manifold and it cant disperse it through the tubes you build pressure.
Last edited by F-2 Speedy; 02-08-2017 at 07:41 PM.
02-08-2017, 08:04 PM
#9
These builds are the first for me not running a circ pump, going with a cross over with the whipple water pump delete kit, Im running CMI sweepers, it would be nice to know what the gap is between the primary and outer tube. if you put a large amount of water volume to the header manifold and it cant disperse it through the tubes you build pressure.
My stellings headers, have four, 3/4" nipples, one for each tube.
