Unlimited jd

iTrader: (5)

I must've been thinking of something else. I swore the last 502 I had apart had open holes. I'll have to look at the shop Monday.

sutphen 30

gen 6 502's are blind,gen 6 454's aren't and 502 bow tie blocks aren't.

mike tkach

iTrader: (3)

the early bowtie blocks had some open holes,the later ones have blind holes,at least the ones i have seen.

Fordtrucks

Water crossovers are fine. I run one because im procharged and want a cold block plus its less cluttery on the front of the engine. Im setting up my new 540 with -16 line coming from the raw sea pump through the coolers to a Y fitting then in to the block via block inlet fittings. Ive got a T right off the outlet of my sea pump to feed the intercooler and since I don't run a T stat I simply have to -10 lines coming out of the T stat housing running to the Exhaust manifolds. I will also have a water pressure regulator plumbed in and ran to an overboard fitting just in case pressure gets out of hand. If you run a T stat then youll need a kit that has a bypass that runs from the water inlet on the block up to the top of your T stat housing which will feed water to your exhaust while the stat is closed. Also run a pressure relief valve in case you need it. A water pressure gauge is also a very good idea.

I also run the stainless lifetime rebuildable sea pump and think its a great piece.

MILD THUNDER

iTrader: (3)

IMO, and from what I've seen, a #10 line, is too small to feed the exhaust manifolds.

Excessive water pressure, can arise from a variety of things. But one sure way to increase water pressure in the block, is to restrict what is leaving the block, by using too small of lines.

Most exhaust systems, utilize 1'' ID hoses feeding the exhaust. A #10 line, is 5/8 at best. Actually closer to 1/2'', when you factor in the flare orifice diameter.

I had a buddy with a procharger setup. His exhaust was getting hot, and his water psi was high. I noticed he had plumbed his imco manifolds with -10 lines. I recommended he either go with 1'' id rubber hose, or -16an. He instead went to -12, and it did help lower his pressure a little, but still not right imo. They put 3/4 NPT fittings in most manifolds for a reason. Next time your by your exhaust, put a #10 fitting up next to a 3/4 NPT hole, and take a look.

Fordtrucks

I understand what your saying but heres the numbers that lead me to my decision. I have dash 16 coming in to the block. That's 0.880" ID. Right out of my sea pump theres a dash 16 T that has a reducer on the T down to dash 10 that runs off to my intercooler. So, we have 0.880" ID hose going in and dual dash 10s going out to the exhaust. Dash 10 is 0.563" ID so my theory is that since the volume of the dash 10 hose X2 is 1.126" and ive only got 0.880 coming in, There wont be any restriction. In fact, the water should flow easier through the 2 dash 10 lines then it will the single 16 coming in. Going to a larger hose will only slow the water down as it will have less velocity, which shouldn't matter anyways. Now if im wrong, please let me know. These are just my thoughts.

Fordtrucks

Well now that does make sense. With that said, Do you think dash 10 lines will keep the exhaust cool? I think theres a lot of variables there to decide that.. In my case im also feeding my intercooler from that dash 16 so what water is left will make its way out through the 10s, The guys running a T stat will only flow so much water through there also.

mike tkach

iTrader: (3)

one -16 hose will flow more than two -10 hoses will.the smaller hose has more resistance.it is not the same as air moving in a port.the raw water pump produces the flow,the hoses create the resistance.pressure is caused from resistance to flow.

MILD THUNDER

iTrader: (3)

Mercury spent a lot of time on these cooling systems . typically , water line feeding the engines , is 1.25" ID. Then , either two 1" or 1.125 id lines feeding the exhaust.

This is just my opinion, but -16 is small for feeding the engine, especially when you will be teeing off them to feed the intercooler as well.

To properly cool everything, which includes the oil cooler, engine block, intercooler, exhaust manifolds, you need lots of water moving thru the system, especially when the HP goes up. My preference is to bleed excess water off after the system being cooled, rather than before the system.

My particular system, consists of 1.25 hoses feeding the strainers from the pickup. 1.25 feeding the sea pump from the strainer. 1.25 feeding the bell housing coolers, 1.25 feeding the crossover. I have 1" lines feeding my stellings headers.

My engine blocks stay cold, my headers stay cool, my oil temp stays at 210 * even when the throttles are held on the dash for several minutes at a time. Water psi at wide open is 18-20psi, and no relief valves bleeding pressure off.

One of the reasons I think guys have psi issues with crossovers is when they run thermostats with them. Most of the bypass diameters are simply to small, and with stat closed, there simply trying to bypass all that water coming from the 1.25 lines, and feed it thru a small -10 single bypass feeding the exhaust. Mercs crossover system, even with stat closed, is still able to freely flow water to the exhaust .

Your setup may work for you. Just not the way I would rig it , based on my experiences.

MILD THUNDER

iTrader: (3)

Diameter is critical to volume.