ham_r_down01

iTrader: (1)

I'm putting a set of lightnings on my boat. Actually they are already on. I'm wondering on how to plumb the water out of the t-stat housing out of the boat. I have a few ideas, I was thinking of getting some 1" ss through hull fittings and making a drive shower out of this water. It's a fresh water boat. So no closed cooling.

I have the standard merc t-stat housing, inlet, cross to engine water pump, two spring loaded checks for exhaust cooling, and two outlets above the stat for engine cooling out.

Any ideas? Or am I on the right track?

Budman II

iTrader: (1)

I think you are referring to the old style t-stat housing that had four outlets to the manifolds and risers instead of just two. When I ran that setup with my Lightnings I made a set of T-fittings out of copper pipe and fed them both to the headers. You have to be careful which ones you route to the headers or you could end up not sending any water when the t-stat is closed.

A friend of mine is running Lightnings with a crossover and a water pressure bypass valve to regulate block pressure. He is doing exactly what you are talking about - dumping the excess right over top of the drive.

Tinkerer

I did what you are proposing. I installed 1/2 PVC pipes bent to spray the water on the sides of the drive. I ran the hoses that would normally go to the top elboes to these dumps. To solve the lack of cooling water to the headers until the thermostat opens I figured out how to drill the housing to allow water to bypass from the water inlet to each of the two dump hoses. I drilled one 1/4 inch hole for each dump.
don't drill the thermostat or the engine will run way too cold at low throttle settings. If you pull the housing apart there is a way to get water to bypass from the water inlet to the dumps .

ham_r_down01

iTrader: (1)

The part of the t-stat housing with the spring loaded checks comes right from the sea pump(for lower exhaust)...?? After it goes through the oil cooler and p.s. cooler. The other two are the ones that Im questioning. They are post thermostat. Headers would get no water until the stat opens if I hooked them there. Those 2 are the ones that Im thinking of dumping on the drive. I dont care if the water is 140*-150*, its better than no water. I was going to raid the auto parts store to try and find some hard rubber turns, or make them out of copper pipe. Im not a fan of the copper, but as of right now, Im not sure I can get ahold of the stainless fittings Im after.
This is the housing I have, Im pretty sure. There are the 4 in front. The 2 rear by the t-stat are the ones I plan on dumping.

These are the through hulls I was looking at unless someone has a better source/supplier/
http://www.attwoodmarine.com/store/p...u-Hulls-Barbed


Oh fwiw, I have holes drilled in the t-stat because I have no bypass hose. Single plane that is on it has no provision for one. That way there is some flow until the engine gets to operating temp.

Tinkerer

You want cold water on that drive. I ran the after thermostat hoses to the exhaust.

Budman II

iTrader: (1)

Yep, and it's also better to have the water that is heated by the engine to your exhaust - cuts down on condensation.

Budman II

iTrader: (1)

My buddy that I mentioned before just went to Home Depot and plumbed a shower head pipe pointed down at his drive. No kidding - painted it black, and it looks like a big donkey d!ck pizzing on his drive. Not exactly pretty, but effective! I have always kidded him that I am going to hollow out a big black dildo and put it over that thing.

There was no need to drill your t-stat because the Merc t-stat housings allow the water to circulate in the block even with the stat closed. In other words, the bypass hose is redundant even if your manifold has provisions for one. There is another thread on this forum that addressed this. If you look closely at the passages in the housing, you can see how this works.

Budman II

iTrader: (1)

Ham_r, are you doing this to limit the water going to the headers, or simply as a solution on what to do with the extra two hoses? Make sure you have enough water going through the headers to keep them cool.

Tinkerer

Once the thermostat is open you will have plenty of coolant water. The problem is until it opens. That is why I drilled the two bypass holes. Never a problem now.