Merc 454 water by-pass kit?
 

Gentlemen,

A friend of mine has a stock twin 454 29 Fountain with bravo 1's. Here is a "cooling" question: he asked me about a cooling by pass kit that eliminates the belt driven water pump. I have never heard of this and would like some input...does such a thing exist...if so--pro's and cons. He said that it apparently adds power as there is one less belt and pulley. Thanks. Pigpen

I use bypass crossover with thermostat and like it better. Does the engine have cerpentine or Vbelts? If it has Vbelts EMI has a bypass crossover with thermostat. If it has cerpentine that is more expensive, I saw a product in CP performance catalog that would work.

it has v belts

That is easier. Several company's make them you get the crossover, thermostat housing and bypass hose. I use all AN fittings.

I like using the by-pass kits, you just have to watch what size by-pass hose you use, insuring that you flow enough water to the headers when the therm. is closed. I have used anything from a #8an -#12an.

Just so I understand this right, and I was just on the Eddie Marine site looking at the crossovers, you get rid of the belt driven water pump completely? I think I understand the drawings. The thermostat housing just bolts into where the existing thermostat is? What kinds of differences did you see from going with this setup?

Any suggestions on what to use on his setup? With all do respect...that #8an-#12an doesn't mean anything to me. Is that the different size crossovers?

I was told to just punch out the inner part of your stock thermostat. If you need to build more heat you could maybe valve down a bit to get the desired oil temps.

AN fittings use threaded fittings and stainless braided hose instead of rubber hoses and clamp. They typically range in size from 4 AN to 16 AN. I use the 8 AN for my bypass hose. 12 AN for hose from housing to exhaust. 16 AN for main water inlets. 6 AN for fuel line. 12 AN for oil lines. Somewere there is a conversion chart that give the actual measurement of each.

Its simple, remove the water pump and thermostat housing. Then replace it with this.
Here is the crossover I use.
http://www.eddiemarine.com/store/car...l&p=11552&c=40
Here is the thermostat kit.
http://www.eddiemarine.com/store/car...l&p=11564&c=52

hey you should be putting your engine back together so you can post your results. thumpody thump....

Thanks for all the input...The wealth of info is great.

I just can't seem to get all the parts in. I am still waiting on springs and timing chain. I am expecting them today. I am keeping things updated on my post.

IMO it is not worth the effort. Just get a new water pump if you need one. They last a long time. Some times you can have water preasure issues after you make the swap over as well. You will not see any notable performance gains. They do clean up the front of the motor a bit...

Jon

If he is just running stock 454's, it is not worth the cost and effort to change it over, if it needs waterpumps, just put on new pumps.

Im installing a blower and dont have the room for the stock mercruiser thermostat housing. This looks like it may be the best alternative for me.