rebuilt 5.7 Mercruiser water not flowing

[dan2744]

So I was on here a while back because I bought a 1985 Tiara with a 5.7 Mercruiser. Block ended up being cracked so I bought a block that came out of a 1975 Chevy Camaro. I switched all of the Mercruiser stuff over and installed all new gaskets, I got it to fire up than timed it. When I finally hooked up water to it i have this weird problem where water is not circulating in the block (Its on a pallet in my garage). I even put in a new water pump and it just will not circulate. Its like I have blocked a water passage or something. Could I have installed a intake gasket wrong or a head gasket? If I try to flush the motor from the thermostat housing it fills the crank case and oil pan with water but does not let in water when running. I am completely stumped.

 

[Bondo]

If I try to flush the motor from the thermostat housing it fills the crank case and oil pan with water but does not let in water when running. I am completely stumped.

Ayuh,..... If ya put the garden hose in the inlet port of the t-stat housin', runnin' or not, 'n this happens,.....

Ya, ya went terribly wrong, hopefully with a gasket durin' the swap,....

How "Dressed" is the motor,..??
exhaust manifolds, 'n All,..??

 

[alldodge]

My first guess is you had a Right Hand rotation motor, and you installed a LH motor. If it has an Alpha drive then the impeller is operating in reverse

1975 Chevy Camaro

Side note, this motor does not have the correct cam, need one from a truck

 

[dan2744]

Its rotating the right way and the motor is completely dressed, with manifolds rises and all. Its on a pallet stabilized, it runs great, has good compression but its not cooling. I thought it had a blockage at first but now its looking like I blocked a water passage or something. Maybe a hose is hooked up wrong, the gaskets really only go on one way so I cant imagine I could have messed it up but its possible. Im pretty confident that the blocks are identical, I even shot air and water in the cooiling holes where the water pump mounts and it shoots back out at me. I have no idea, thanks for the replies guys.

 

[Bondo]

Yer runnin' it with water in the oil pan,..??

 

[dan2744]

No, Ive changed the oil about 3 times now, its getting kind of pricy.

 

[Bt Doctur]

water simply cannot enter the block or pan from the T housing, If you introduce water into the intake manifold it will fill to the top and stay there. If you cant do that you have a intake gasket problem

 

[Bt Doctur]

 

[Bt Doctur]

 

[Scott Danforth]

did you change the cam to a truck cam or a boat cam? because the stock camaro cam will have a ton of reversion at idle and suck water into the exhaust ports which will then run past the piston rings and into your oil pan.

 

[alldodge]

Being a 1985 it should have this cooling system

 

[dan2744]

I used the old cam from the previous boat, water gets pumped into the block but never comes out anywhere, I must have really messed up installing a gasket or gaskets somewhere

 

[Bondo]

Ayuh,..... Did ya reuse the frozen intake manifold,..??

 

[dan2744]

I did, I just popped off the thermostat housing, and poured water into there with the hose, whatever it is, its real big. From the looks of the diagram it goes from pump into block which then comes into thermostat housing? Its definitely not getting up to the thermostat. Im gonna pull intake off tomorrow and see if anything jumps out, but I thought the intake gasket install was pretty straight forward, but Ive been wrong before and this is my first SBC. I really appreciate the replies guys. Is there a way a head gasket can be installed wrong or backwards and block coolant flow?

 

[Bt Doctur]

I did, I just popped off the thermostat housing, and poured water into there with the hose, whatever it is, its real big.
the intake manifold cavity is only a 1 1/2 deep and if your not hold level there you have a problem

 

[Bt Doctur]

 

[Bt Doctur]

If you notice the manifold only the front of it has water ports, the rear ports are blocked off.So only the front of the heads will pass water up into the therm housing . You cannot reverse a head gasket to block coolant flow , you can put it on upside down though but will not close off any water holes.

 

[dan2744]

Gotcha, thanks, hopefully it's just my intake gasket, when I fill the block from thermostat port, the water level drains off fairly quick, so when I take off the intake, I should see the problem right away, thanks.

 

[Bondo]

I should see the problem right away,

Ayuh,..... I suspect you'll see a big crack in the bottom of the intake manifold,.....

 

[dan2744]

I really hope so, that wouldn't be so bad, I can't imagine a head gasket leaking like this. I hope that it's leaking and getting into the lifter area and getting in the motor like that.