Another water pressure thread

[pcrussell50]

agree.. if it’s not working with tha "stock" stuff find tha problem as ta why... jmo.

This is why I stick with the stock stuff, no matter how tempting it is to try something else. I don’t even dream of out-engineering, the those original Merc V6 engineers… And I even have my degree in Mechanical Engineering.

-Peter

[tlwjkw]

looks "kool factor" does it all tha time...............

[Merc 2.5]

It started with installing a damn temp guage, and would try heat up on long idle zones, I was chasing the ghost. I wanted to see it run little cooler , and I got a chance to see the results of diffrent mods or changes made. Definitely not the cool factor , hell my motor is already cool �� haha. I got everything under control with letting poppet open little sooner. But since merc started installing diverters in promax after 96 or 97, wouldn't it be a good idea for me stick some on there? Thats only thing I haven't tried. Real long idle ill see 165 maybe 170 on guage (head temp) but now I can move to fast idle and poppet opens and controls that

[tlwjkw]

diverters are good for any of 'em.... hard ta say but any "stock" coolin' sytem should operate as is in any condition???.. but it is a merc sooooooooooooooooooooooooooooo.

[Greg G]

So what you are saying is you cut one coil off the poppet and now it is cooling fine?

If that is what you did, I would just stay with what you did and "goose it" a touch when you need to lower the temp for long no wake zones.

[pcrussell50]

So what you are saying is you cut one coil off the poppet and know it is cooling fine?

In sports cars, if you cut a coil, it stiffens the spring (lowers the ride height too). I would think if you want the poppet to open sooner, a softer spring, not a cut spring would be what you want. A little surprised that Merc doesn’t offer a variety of poppet springs of varying rates for different apps.

-Peter

[XstreamVking]

If a merc master tech with 20 or more years of wrenching says to mod something so simple for a fix why not? Do remember that merc builds and designs these engines to run in freezing water and ALMOST any other water temp. When water temp is in the 90 deg range the cooling system is not up to the task at fast idle speeds in some models. My opti's don't care at all. But my 2.5's always got hot at fast idle in our fla waters in the summer.

[pcrussell50]

If a merc master tech with 20 or more years of wrenching says to mod something so simple for a fix why not? Do remember that merc builds and designs these engines to run in freezing water and ALMOST any other water temp. When water temp is in the 90 deg range the cooling system is not up to the task at fast idle speeds in some models. My opti's don't care at all. But my 2.5's always got hot at fast idle in our fla waters in the summer.

good to know. Wasn’t trying to overstep. I was just speaking from book theory, when I was talking about how cutting out coils actually stiffens the spring rate. This is true for sure, (basic physics). However making the spring shorter might be what is providing the benefit of early poppet opening at lower rpm.

also I boat in warm water that gets above 90degF too at air temperatures above 100degF (Mojave Desert). I test my overheat buzzer frequently, and have not had it go off even in long slogs through the no-wake zone. The heads don’t get hot by the old finger tip touch test (highly calibrated lab instrument, lol).

***

This motor has been trouble free enough that hooking up the water pressure and cylinder head temp have been on the back burner. Maybe I’ll get to it this summer? It has the two chamber “dog bone” poppet with two vertical water tubes and a single tell tale.

-Peter

[Greg G]

Fresh water also helps a motor over time with better cooling but you are a much better man than I running no gauges at all. Back here I plumbed the other cylinder bank to run a second gauge

[pcrussell50]

Fresh water also helps a motor over time with better cooling but you are a much better man than I running no gauges at all. Back here I plumbed the other cylinder bank to run a second gauge

yeah, just grass rootsing it so far. I ca tell by looking when the poppet opens. I can tell by feeling the heads that they aren’t hot, and as I said I check often, the overheat sensor that it works.

After I get the stock cylinder head temp and water pressure gauges hooked back up, I’ve been thinking of plumbing up an actual water temp gauge myself.

-Peter

[pcrussell50]

Fresh water also helps a motor over time with better cooling but you are a much better man than I running no gauges at all. Back here I plumbed the other cylinder bank to run a second gauge

yeah, I’m just grass rootsing it so far. I can tell by looking when the poppet opens. I can tell by feeling the heads that they aren’t hot, and as I said I check often, the overheat sensor that it works.

After I get the stock cylinder head temp and water pressure gauges hooked back up, I’ve been thinking of plumbing up an actual water temp gauge myself. I’ll probably ask for guidance on which water tube to tap into.

-Peter

[Greg G]

Steel sleeve 2.5 ....... Any thoughts or am I missing the obvious here

So Merc 2.5 where did you ever end up on your cooling issue?