Operating Temperature with 160 Thermostat

[Hiker_00]

Well now I'm completely confused. 1/2 Ball valve brought the temp down to about 165-170. Great says me. So what happens when the valve goes completely closed to route all water through the side plate ..... wait for it.... Nothing.

Temps did not move.

The WG Side Plate side is clean , the oval passages in the block (manifold side) are clean. I've done a pressure wash and acid bath. Ample water is batching out the exhaust. It seems like a fine amount. The manifold was pressure tested and hosed out.

I now have a laser temp gun. It seems the next step is to pull the thermostat out and see where this lands.

Also but different I have an oil pressure problem. 3 qt of 10 -30 went in right before launch. Over winter there was a MMO rich batch in there. It may be the 10 -30 has mixed with the MMO left over and made the viscosity too thin. It's hard to tell what's on the dip stick. More telling is the pressure. Idle, no load, pressure reaches 40 PSI. Increasing rpm, the pressure goes to 60. Under load and running hard (testing temps) the pressure went past 60 and stopped around 70. This is all bad, right? The BOOK says it should level off back down at 40. That's no where near what I"M seeing. The accessory drive sounds loud to me. I'm having a perspective problem. I only know my engine and have lost reference.

The Pressure Sending unit is new. The gauge is new to match the sender. I have never adjusted the Oil Pressure in this motor. I guess I need to learn that part.

Plan to change the oil. Thinking 15-40

I just want this to go back to simple. It's not been simple since I back flooded the engine in a very, very rough sailing trip.

Thank you to all involved.

Tim

[hanleyclifford]

If this is a late engine it has the ball and spring oil pressure relief valve. These are subject to sticking and the the fact that you mixed in some MMO and let it sit in the engine all winter suggests a dissolving and resticking event. Try adjusting the valve. Sometimes just jogging it will free the ball.

[Mo]

Tim,

Not a major.

15w40 is not a bad idea but that likely will not fix the problem. I think Hanley is bang on the money re: malfunctioning oil sending unit. The sending unit for the earlier engine works very well. I have installed a couple of early sending units in late version engines that were experiencing oil pressure irregularities and fluctuations...sorted it out as the sensor was the problem. MMI has them.

If you have the MMI manual have a look. Adjustment is easy IF the unit is not full of paint. I used my bench grinder brush to clean them up in a few seconds...then adjustment is easy.

[Hiker_00]

So several issues swirling to settle yet they all seem related.
New oil to quite the rumbles. Temp measurements to understand more. Likely a new Pressure Regulator kit.

just jogging it will free the ball.

How far does this go? Does jogging mean screwing in and back out to its original spot? Is it troublesome to remove the Rod, spring and ball? How do you know when it's time to purchase the replacement kit?

I looked at these parts last night and see more rusty untouched than paint stuffed. They probably have not been turned in 20+ years.

Tim

[hanleyclifford]

Just loosen the lock nut, and then back the screw out 1 turn and observe the pressure. If no change occurs, try tapping lightly in the area with a small ball peen. If still no change, more drastic measures will be required. However, I would confirm present pressure with another, preferably direct reading, gauge.

[hanleyclifford]

The $.02 +++rant

Since this thread is about operating temperature I'm going to give you my disertation on A4 cooling. Cooling the A4 is all about flow. Thermostats represent a major, major, major, restriction in any system, RWC or FWC. The bypass valve is far to be preferred for regulating temperature and I mean a full bypass. The late thermostat housing is a lousy valve seat. I'll save the FWC/RWC blurb for another rant. FWIW.

[JOHN COOKSON]

More Free Advice

I now have a laser temp gun. It seems the next step is to pull the thermostat out and see where this lands.
Thank you to all involved.Tim

Warm the engine up and shoot the temp with the laser gun. Note the temp gauge reading.
Remove the thermostat and repeat the above.
Is the temp difference with and without the thermostat the same for the gauge as the laser gun?
Confirm that the thermostat is working by heating it in a pan of water. It might not be opening all the way. (my current bet)

TRUE GRIT

Edit: Are you sure you have the right thermostat housing? I don't know much about this;It's just a thought.....

[Hiker_00]

I have the following.
Block
gasket
thermostat
gasket
spacer
gasket
Thermostat Housing

Having a gaskete between the spacer and thermostat is a problem but it seems needed. There's an indentation in the spacer for the lip of the thermostat to sit in. It gets lost with the gasket. This was not an easy configuration.

This is from the kit on this site with the single action thermostat and longer studs.

Tim

[Hiker_00]

http://www.moyermarine.com/forums/showthread.php?t=6557

another case "Yet another cooling thread" from last year.

Seems to have the same characters: Bypass valves, 160 Thermosats, No thermostats, oil pressure issues, temperature concerns.

While I may have 2 or more issues going on. The heart of this case is why adding a brand spanking new single action 160 deg thermostat to an engine with long history of cool runing would act this way in a clean engine with good water flow, healthy impeller vanes, cleaned manifold and recently (3yr) old rebuilt exhaust. So far my action plan is to verify my gauges are reasonably correct and to yank the thermostat. If this does not solve it, I'll open the pump, check for missing parts and put up the sails.

Major aside
Hopefully the open communication on this case brings others some confidence they are making progess on their own issue. I often feel this wide spread information should be edited into a crowd sourced wiki. Start with 5 project case histories in various systems, EI, Overhaul, FWC.... State it from the DIY approach and clear problem to resolution case history, with costs and pictures.

Regards,
Tim

[bigoledave]

No bypass valve..no thermostat.. 24 years no problems

I keep reading about the horrible things that will happen if I continue to run without a thermostat or bypass valve..but in 24 years I have not had any problems severe enough to cause me to change.....BUT...I am buying some cool new 270 sweep gauges and finally DO want to add a bypass valve and be able to set my RWC temp.

So....dumb question..is the correct plumbing layout to add a valve set up such that I divert the water coming out of the aft end of my manifold to either flow straight through or to flow back to the output port on my water pump?? ...or???

Thanks...

Dave
Moonduster
Columbia 29
Puget Sound

[Mo]

Dave,

Here's what I have going on and it works for me and many others.

-by valve open 1/2 and I just leave it there.
-no thermostat.
-spark plugs NGK XR4; these keep the top end a tad warmer and no buildup of carbon occurs in the combustion chamber.
-my back up temp test is that IF I cannot hold my fingers on the head I need to be looking at why. Head stays just hot enough that I don't have to pull my fingers off.
-I burn 5 gallons of fuel for 6 hrs of running time at about 5 kts. I have heard of some that do better mileage. My thinking is I'll run a little cooler and sacrifice a little mileage ... the engine temp has room to climb rather than going to borderline high temp while cruising.

[romantic comedy]

I have FWC, and run at a consistent 180, with a thermostat. I cant hold my fingers on the head, ouch.

I leave the by pass valve open. Once in a while, it goes to 190, and I close the by pass valve a teeny bit, to get back to 180. Usually the temp goes way down.

I spent 25 on a infra red thermometer. The thing sure is strange, i get all sorts of readings

[Hiker_00]

Dave

The Cooling Parts on this site has the following brass ball valve and check valve that restricts flow from the pump to the bypass loop. The flow is then directed in the cylinder chamber via the tee in the side plate. Full flow into the chamber should cool the engine down. It's also the proper path for anitfreeze and acid during those procedures.

Here's a view

http://www.moyermarine.com/images/cool48.jpg

Tim

[Hiker_00]

Temp Report

Well now it seems a different story.

Ran the engine around the harbor at a good clip for 30 minutes. Operating temp never passed 160. This is completely different from previous trials where the temp went up to 180. The t-stat is still installed.

The only thing that changed was 'jogging' the pressure regulating valve. I ended up taking the rod out to free the rod and nut rusted together. Putting it all back together was a guess. Now initial pressure jumps to 50psi and stays there for the duration. No up, down, growing, settling nothing. It seems a manual, secondary pressure gauge to directly read the pressure (as suggested) is really needed.

Running the laser temp gun (by myself for this so had to grab my mooring to keep control of the boat).
Engine temp 130
Front of Head 116-120
Block 86
Gauge itself sticking out of the head - 104
Top of head 99
Coil Top 130 at the band et Bottom 260

So I really don't know what is happening. This last run was clearly different the all the previous reports. It really does not feel bad and more operating time is needed to understand better. The t-stat is toast if I get a whiff of high temps.

Now time to remind myself that this is a SAILBOAT! The rig needs adjustment and engine turned off.
Regards
Tim

[hanleyclifford]

Sounds like progress. I still don't like that 50 psi reading - seems suspect, especially since it is so steady. 40 psi at cruise rpm is the ideal but at idle it can be much lower, 10 - 15 psi. On a cold start it's ok to see 50 or 60 but it should decline as the engine warms up.