Raw water pump question

[f_inscreenname]

I have this raw water pump that I in the process of building a bracket for and installing on the front my new motor.

The pump always fit better one way (with the inlet and outlet on the outside of the pump) on my old motor and in my motor compartment (with the hoses coming off of it also) so thats why I installed it the way I did originally.
Now I am installing it on the 454 on the opposite side of the motor from where it was before. The question is do I have to keep the same inlet/outlet end up or can I flip the whole thing over and it will still work the same?

 

[Don S]

Re: Raw water pump question

Yes, you need the same inlet and outlet. Unless you also change direction of rotation.
Why don't you just use the Merc pump that came with that engine? It would also have a higher volume output for the bigger engine than this pump would have

 

[rodbolt]

Re: Raw water pump question

as Dons suggests about volume, you may wish to contact the pump manufacturer as most big block pumps have different pump cams than small block or 4 cylinder applications.

 

[f_inscreenname]

Re: Raw water pump question

Ya I did look up the pump and the Sherwood is listed for BB's and the 454 specifically. As for the original Merc pump it was taken off before I bought the motor (I knew it would be). So I have to make my stuff fit right. Didn't want to start off with the pump up side down. Thanks Don.
The picture is how it looked when I got everything to fit proper. The whole top end of the motor is being held together with only a couple bolts so it will be easy to take apart to make everything look pretty again before the final build.

 

[Don S]

Re: Raw water pump question

That hose hookup doesn't look right to me. You can't go from the raw water pump outlet to the Tstat housing and tee to the bottom of the water pump. You will never cool your manifolds and risers that way.
There is supposed to be a hose going into the Tstat hsg and and another passage on the Tstat hsg for the hose going to the bottom of the water pump, but inside the hosing is only a small bypass passage.
The way you have it there, I don't think the block would cool at all because you have equal volume and pressure on both the inlet and outlet of the block cooling.

 

[f_inscreenname]

Re: Raw water pump question

Let me see if I can explain it if I can.
The red line, water comes in from the bottom of the boat and is sucked up through the raw water pump. It then reaches a "T" and can go two ways. The way of gravity wants the water to go down to the motors water pump inlet. If that has excess water pressure the water then flows up the second hose from the "T" (the blue lines). It goes to the top of the thermostat housing (the motors thermostat is below the inlet) that is a clear passage to the manifolds outlets (also above thermostat). Now the over flow inlet to the thermostat housing does have a smaller diameter inlet then the hose I am using. From what I read it about the same size as a Mercruisr "bypass".
The yellow lines are as it flows through the motor. The water then reaches the thermostat. If closed it stops there but if its open it allows the water from the block to flow to the top of the thermostat housing and out of the exhaust manifolds outlets along with the “by passed” water.
When I first re built the boat many years ago I first took pictures of everything to make sure it went back together the same way. Well the old owner didn’t run a thermostat and I thought it was because the motor was shot and ran hot or something. I was wrong. I put the new motor in and hooked it all back up the way it was (with a thermostat) and proceeded to blow freeze plug after freeze plug out. One was under the bell housing.
The last time this happens I am sitting at this whole in the ground marina waiting for the wife to come pick me up. With time to kill I am wandering around and what do I come across? The same motor as mine with the original cooling system like I was supposed to have. I couldn’t use it being it was all rotted but I could build a new one just like it. So I did and it has worked great for years.
If it doesn’t work on the 454 I will change what needs to be to make it work but in theory it should like it is. Just much simpler version of a Merc. Sometimes Chrysler is not all that bad.

This is the motor I found and what I did for my 360ci.

 

[rodbolt]

Re: Raw water pump question

maybe DonS can post a cooling system flow diagram for a seawater cooled 454.
I dont think your drawing is going to keep the 454 cool enough.
it may, but a quick comparison may find any fatal flaws first.
best I remember the water bypass hose going from the t-stat housing to the circulating water pump is not used on raw water cooling but sometimes memory is fuzzy.

 

[f_inscreenname]

Re: Raw water pump question

Here you go. I end up doing the same thing as the Merc thermostat housing does but with different pieces along the way and use a single hose to each manifold. The exhaust I plan on using sooner or later only has a single inlet.

 

[Don S]

Re: Raw water pump question

In your manual just uner the drawing, does it show the thermostat housing? It should. Look at the flow and sizes of the openings in it compared to what you have with your fittings. Also note that in the drawing there is water being put into the exhaust manifolds AND the risers. That is because of all the extra heat the BB engine puts out compared to the SB engines.
The water flow goes thru the top of the stat housing (#12) when the stat is open, but you only get water flow into the risers all the time. That bypass hose keeps things circulating "somewhat" in the engine at all times.

 

[Don S]

Re: Raw water pump question

Here is how Volvo does it on carbed engines. This pic is from a small block, but the Tstat housing is the same as is the flow diagram. Volvo doesn't have a carbed BB anymore and the picture is really confusing going thru the EFI system. NOTE also that there is no bypass hose on the Volvo system.

 

[f_inscreenname]

Re: Raw water pump question

Mine is basically the same thing but the "T", bypass hose and thermostat inlet acts like the front part of that thermostat housing but wicked over sized. Got to remember that this set up comes from the early 70's and from Chrysler. No need for fancy thermostat housings. Just make up a couple new hoses.
I guess it uses the heater core bypass hose to recirculate the warm water when the thermostat is closed. I will be honest I am not sure why it works but it does. I have never had a cooling problem and always a steady motor temp. Ya if I ran WOT for a couple miles and came to quick stop it would jump up a couple degrees (5 to 10) but would settle right back down. So I am not worried about the set up just more concerned about getting the pump on right.
Thanks for the help guys.