Engine is now running too cool...

[ChrisMitchell45]

After changing out my manifold for a clean one the engine will not get past 110F without being under load now. Other than being clean the only difference between this manifold and the other is I'm not using the little pipe that connected the water outlet on the manifold to the hose that connects to the exhaust hose.

Do I need the decreased water flow with the little pipe to keep the water in long enough to heat up. In other words does the flow need to be restricted in how fast it goes through the block?

Thanks for the help!

Chris

[Dave Neptune]

?

Chris, just replied on another thread. For this are you using a thermostst? Is the engine raw water cooled?
If you are raw water cooled how cold is the water?

Dave Neptune

[ChrisMitchell45]

The water here is in the mid 50's and prior to the manifold replacement the engine would warm up. Yes the thermostat is in and working and I have the ball vale installed as well to manually control the by-pass hose. That's why I'm thinking the smaller exit pipe from the other manifold is the culprit. I've gone from about a 1/4" inner diameter to about a half inch.
Would less back pressure make a difference?


Chris

[hanleyclifford]

You have gone to some trouble to clear the manifold jacket it would seem. The increased flow is a good thing and will keep the jacket clear. IMO you should not restrict water flow but rather find another way to elevate water temperature.

[jpian0923]

I have the same issue. I'm considering removing the ball valve from the bypass hose (until needed). Although it's fully open, the check valve does create a back pressure of 2 to 3 psi...forcing water through the block.

At wide open throttle I get an engine temp of 110 degrees during winter and 140 during summer.

[hanleyclifford]

I have the same issue. I'm considering removing the ball valve from the bypass hose (until needed). Although it's fully open, the check valve does create a back pressure of 2 to 3 psi...forcing water through the block.

At wide open throttle I get an engine temp of 110 degrees during winter and 140 during summer.

Perhaps the check valve could be removed as a first shot. If that doesn't work you might have to cobble a three way valve to select between block and bypass. The late style head is more difficult to plumb for a really effective bypass.

[ChrisMitchell45]

I have the same issue. I'm considering removing the ball valve from the bypass hose (until needed). Although it's fully open, the check valve does create a back pressure of 2 to 3 psi...forcing water through the block.

At wide open throttle I get an engine temp of 110 degrees during winter and 140 during summer.

I actually removed the check valve before doing the manifold swap and it was warming up at that time.

The check valve did not line up with the water jacket T valve like in the pictures and made it a tough fit that was splitting hoses so I removed it.

I've been running it wide open all day and again the only way it heats up to recommended operating temp is if it is under load.

As always thank for the input!

Chris

[hanleyclifford]

It would seem that the preferential flow is thru the block and not the bypass. If you want to run without a thermostat the output from the water pump should be directed to a three way valve and split bewteen the block intake and the bypass. This will mean altering the T-fitting at the block intake.

[ChrisMitchell45]

You have gone to some trouble to clear the manifold jacket it would seem. The increased flow is a good thing and will keep the jacket clear. IMO you should not restrict water flow but rather find another way to elevate water temperature.

I totally agree! It gets damn hot here in Texas and having an engine that runs cool is better than having one hot. But other than putting it in gear I don't know of a way to to raise the temp without restricting the water flow through the block.

Chris

[ChrisMitchell45]

It would seem that the preferential flow is thru the block and not the bypass. If you want to run without a thermostat the output from the water pump should be directed to a three way valve and split bewteen the block intake and the bypass. This will mean altering the T-fitting at the block intake.

Any diagrams?? By the way, is that an Offshore 28 Cheoy Lee you have as your avatar? If so there is one here for free if you need some parts.

Chris

[hanleyclifford]

I totally agree! It gets damn hot here in Texas and having an engine that runs cool is better than having one hot. But other than putting it in gear I don't know of a way to to raise the temp without restricting the water flow through the block.

Chris

That's the idea. You must restrict flow thru the block but not reduce the total flow. The residual flow must go thru the bypass.

[ChrisMitchell45]

I'm going to run it up tomorrow and try again. If it still runs cool I'm going to buy a fitting like the one on the old manifold and see how that works.

Can't hurt...

However if that doesn't work I'll try the 3 way.

Chris

[Marian Claire]

Another option: You could try a recirculating loop. Where the water exits the manifold install a T. One branch goes to the wet/dry connection. The second branch returns to another T installed just before the water pump intake. This second branch has a ball valve. Valve open allows preheated water the be mixed with the raw water and pumped back thru the engine and she warms up. Valve closed and you are operating as normal. At all times you have 100% flow thru the block but the temp of the water entering is adjusted. You need to have easy access to the ball valve. This set up does reduce the amount of water going to the wet/dry, unless the ball valve is closed, but I ran a similar set up for many miles with no problems. FWIW. Dan S/V Marian Claire

[Dave Neptune]

Perhaps this or this!

Chris I run in water of about the same temp and do so also running cool however without a t'stat. I run at around 120+ in winter and 135 in the summer and that is with no t'stat.
Two things come to mind first is perhaps your t'stat is not sealling (closing) well when the temp is cold. There could be something stuck in the sealing area. It does not take much 50 degree water to cool an A-4 at idle and not much under load. Might be worth a check.
I would not offer up an additional restriction until I new what shoe was in my water pump. The best way to reduce the water flow is to reduce it~~ie change the shoe it is what determines how much the pump pumps. Just throwing in a restriction for a test is ok and if that is what you need to do do it right with a smaller shoe. It is not good to restrict this style of pump.

Dave neptune

[Ajax]

Have you considered upgrading to this: Indigo thermostat upgrade

I'm not sold on it, but I'm considering it. I'm trying to decide between a Holley thermostat, the Indigo setup, the MMI modern thermostat upgrade, and no thermostat with bypass valve.