wet exhaust question

[Josh9685]

HI,<br />My engine is a 460 Ford.<br />It currently has exhaust logs that are water injected and through transom.<br /><br />I am replacing the transom becuase it rotted out.<br />I would hate to have to bore more holes through the transom for the exhaust logs.<br /><br />I am thinking of some over the transom headers.<br />Problem is, over the transom headers are about 600 bucks for a 460 ford.<br /><br />can I just get some full length automotive headers and put those on? I can get some for about a third of the cost of water injected marine headers.<br /><br />I realize I will have to somehow route the water out of the engine still, and I may just drill some holes in the exhaust and run it out there. <br /><br />I think the water pre-heats in the exaust logs before going into the engine???? is this so?<br /><br />how important is it for the water to pre-heat?<br /><br />if it helps the boat is an old jet boat.<br /><br />thanks<br /><br />Josh

 

[uaw9fan]

Re: wet exhaust question

Well for one I would think that the automotive headers are made to go down rather than up and out.Secondly if you run your exhaust dry it will get hot in a hurry, causing a possible fire.The water goes thru the engine first getting heated and then through the exhaust removing some heat before finally exiting the boat with the exhaust.

 

[Josh9685]

Re: wet exhaust question

HI,<br />thanks for the reply,<br /><br />on the current exhaust logs that are on it, the water comes in from the jet drive through a "T" fitting, where it splits and goes into the exhaust logs on each side. from there it comes out of the exhaust and goes into the engine(where the water pump would be on a ford,) after that it comes out of the thermostat housing through a hose that goes to the elbows on the exhaust logs.<br /><br />so, my question now is: why does it go into the exhaust before it goes into the engine?<br /><br />I think if I flip the headers upside down and switch the sides they will go on.<br /><br />wondering if its possible to drill a couple holes in the headers and weld up some fittings and run the water out of them also.

 

[mkast]

Re: wet exhaust question

I'd like to see your exhaust system. The water usually goes to the engine first, then to the exhaust. Can't think of any reason the cooling water would be preheated before entering the engine. I've seen alot of exhaust systems that use the water leaving the engine to cool the exhaust.

 

[rbezdon]

Re: wet exhaust question

something is not right as mkast is right, the water goes through the engine first, then the exhaust. you must have a modified system, not stock, and it isnt done correctly. Also, be careful with an auto exhaust. The heat is dangerous and as an aside, not USCG approved. If you get pulled over and they find it you'll be fined to say nothing of the insurance issues. For certain things (fuel system, ignition/electrical and exhaust) stick with marine, the issue is safety, your a$$ is on the line.

 

[Josh9685]

Re: wet exhaust question

why would someone run the water through the exhaust first??<br />there are 3 fittings on the exhaust logs, so it looks stock...<br /><br />I just bought the boat a little bit ago and we only had it out once, perhaps this is the reason the boat engine was overheating???

 

[Richard Petersen]

Re: wet exhaust question

BINGO, Josh. Get a mechanic to do it right.

 

[Reel Poor]

Re: wet exhaust question

Another thought...With the automotive headers installed upside down, the design of the header tube will allow water to enter the engine through the exhaust valves even with holes drilled in the bottom of the tubes. Marine over the transom headers have a drop/p-trap bent into them directly ajacent to the header flange. Automotive headers will only work with dry exhaust, and at about 300+ degrees your talking !!!DANGER- DANGER-DANGER!!! PLEEEASE DONT TRY THIS