Are you sure the block is made of iron?

 

Yea, iron block for sure.

Water going through the hood vents dont cause any damage to the engine. Look at all the WRC rally cars, they all have hood vents, drive like crazy, go through big water puddles, in rain etc and the engine is still fine.

 

won't put the hood vent there if it would result to engine damage

 

I used to love driving my '95 jeep wrangler 4-cylinder through flooded streets in my area. when driving through a flooded area at 20mph+ the water would start streaming up into the engine bay from the bottom of my car. it would get in there enough to shoot out the a/c vents and soak my feet .

when i'd get home i would open the hood and let my DRENCHED engine steam for a bit. rain water was reasonably cold and engine pretty hot. never had a problem. i think you'd have to have a near overheating engine and ice cold water to crack an iron block. thats not to say other hot parts of the engine couldn't crack, but i'm just givin you my experience.

 

The only concern that I would have is if you're using an open-element air filter (like a K&N cone filter) you definately don't want that to get wet.

 

Now lets see here, the only time I would really be afraid of this happening is when you are washing the car right after a long drive.

When it comes to rain and little things, there wont be much water getting in the bay at all. Air would actually be travelling out of those vents for two reasons. First off, air would be rushing through the front of the car, into the grill, and would have to escape from the various vents. Secondly, the air passing over the car would have a higher velocity (speed) than that inside the bay (which is a bit more stagnant). Therefore, the air going faster, by nature, would have a lower pressure (same way how wings work). This would mean that the more pressurized air (inside the bay) would by nature, move to the area of lower pressure (outside) through those vents.

With most air being exhausted through the vent, it would make it a tad more difficult for water to get in.

 

I just put some plexiglass over the vents on my hood because I don't want water getting on my spark plugs or my intake. Looks good and keeps the water out.

 

exterior

 

you can see the water spots from the rain thats being kept out

 

why would you buy a vented hood and then cover the vents? Vented hoods are great at dealiing with heat soak, and like people have said b4 in this thread, you would need a ton of ice-cold water to damage your engine.

 

The hood came with the body kit I have. Besides I didn't plan on covering the vents when I got the hood. When it rained, I looked under the hood and their was water on the valve cover around the spark plugs and from what I have heard, it isn't a good idea to get those wet. It just seemed like a good idea for someone who doesn't want water on their engine. I am not worried at all about damaging my engine, I would just feal better if water wasn't all over it.

 

pretty much the only time water will do major internal engine damage is if you hydrolock the engine ( more likely to bend rods or break pistons ) or over heat the hell out of the engine with no coolent then fill it with cool water out of a hose while it is still hot. then youve got a cracked head. rain, wash water, snow wont hurt... that gets all over when you drive any ways, you just want to keep it away from the ignition coils control units and electrical sensors/conectors
P.S. Its not a good idea to pressure wash or steam clean the engine, water can be forced into electrical conectors and cause all kinds of havok. misfires and codes.
If you want to make a vent in the hood you can try to make a duct that will still draw hot air out from above the exaust manifold and behind the radiator that way when you wash it or it rains the water that gets into that part of the compartment wont hurt any thing since that gets wet when its raining and being driven anyways

 

a little water shouldn't damage the engine because the evo vii and viii come with a water sprayer inside the engine bay that sprays water under certain conditions.