reversion aftermarket exhaust ?
03-15-2003, 07:25 AM
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reversion aftermarket exhaust ?
I'm getting water in #3 cylinder 94 502 EFI. I've pressure tested both the manifold and cylinder can't find the problem. the next step will be to pull the head. Is it worth it to change to after market exhaust as a preventive for more problems down the road ? I know I won't see any real H.P. gains the motors are stock and probably won't do much if any thing in future but this could always change. one motor has been flawless the other several problems with vst and raw gas thru exhaust never seems to idle the same always some little something, now water in cylinder. Are the merc exhausts a future problem ? i know ++'s looks,weight & sound - - 's $$$ what about the the new dana flows
03-15-2003, 09:05 AM
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I am not following you when you say " I've pressure tested both the manifold and cylinder can't find the problem. " Are you referring to the exhaust manifold? If so, did you pressure test it with the riser in place? One way to check for water entering the motor from the exhaust is to pull the risers and look down into the manifold for signs of rust or water marks.
I am sure that everyone on this board will agree that stock Merc. exhaust manifolds suck. Not so much that they suck because they can't flow enough with a stock motor, but they tend to leak from the riser gaskets. This is their biggest drawback. I would definetly recommend putting on a set of Gils' or a comparable aftermarket exhaust. As you said, you wont see much of an improvment as far as power goes, but it will save your motor from water damage.
I am sure that everyone on this board will agree that stock Merc. exhaust manifolds suck. Not so much that they suck because they can't flow enough with a stock motor, but they tend to leak from the riser gaskets. This is their biggest drawback. I would definetly recommend putting on a set of Gils' or a comparable aftermarket exhaust. As you said, you wont see much of an improvment as far as power goes, but it will save your motor from water damage.
03-15-2003, 10:06 AM
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What exactly is this water reversion? I always thought it was when I stopped my boat, the water that could run back up my exhaust into the heads? yes or no? what is it ?
03-15-2003, 05:23 PM
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Briefly put, reversion is mainly caused from cam overlap. This means that at some point during the engines cycle, the intake valve and the exhaust valve are open at the same time. This causes a reverse pulse in the exhaust which can suck water back into the cylinders. The more radical the cam, the more reversion will be encountered. This is why modified motors MUST have aftermarket or performance exhaust systems. These exhausts allow the water to mix with the exhaust gases farther away from the exhaust valve, thereby either eliminating or greatly reducing reversion. Some systems are even totally dry. The gases and water don't mix at all.
