Function of water control valve?

[MarkHPCA]

What is the function of the water control valve on my 86 120 looper? The previous owner has re-routed the hose from the top-port side directly to the pee tube (added a tee) and blocked off where it went into the water valve.

 

[Joe Reeves]

Re: Function of water control valve?

Its purpose is to block off a added water exit at the lower rpms, but to open that extra water exit to allow more water to flow through the engine at the higher rpms for additional cooling.<br /><br />Apparently the previous owner, rather than correct properly whatever problem he encountered, took a short cut..... okay for a temporary fix but I wouldn't recommend leaving it that way. The engine would run too cool at the lower rpm ranges.

 

[MarkHPCA]

Re: Function of water control valve?

I did have to change the regulator when I got the motor as it was not working. I have read that some motors have a problem with bleeding off air from the top of the motors that could cause problems with cooling the regulators. Could it possibly why the modification was done and, if so, what could be causing the air entrapment.<br />The motor runs at about 150 deg when at low RPM and I can see the thermostat cycling on the gauge. At WOT it drops back to about 110 on the gauge, difficult to say as the gauge starts at 110. This is with a screw-in temp sensor in the threaded hole on the head, next to the overheat sensor.

 

[Dhadley]

Re: Function of water control valve?

Its hard to say why someone did that but I agree with joe -- it aint right. I'd put it back the way its supposed to be. <br /><br />However if you want to update the system you can go to the 93 and newer style cooling set up. That requires a different cap, spring and gasket. Then you can do away with the valve and all those hoses.<br /><br />Make sure you are not using the white vernatherm.<br /><br />As for venting the block, thats done on the block -- not the heads.<br /><br />As far as why the reg/rec went bad is anybodys guess. You may be on to something though. If, and its hard to say, the set up is allowing too much water discharge the block may not be getting full and causing a void of water around the reg/rec cooling fins.

 

[seahorse5]

Re: Function of water control valve?

If the powerhead was changed at one time to the later model one that used conventional thermostats, then the water control valve would be blocked off or removed.

 

[MarkHPCA]

Re: Function of water control valve?

The power head model # matches the tag on the clamp so I think it is original. <br /><br />I originaly put the plumbing back as it should be and replaced the regulator with an after-market. Worked fine for about 3 months then the regulator would shutdown after about 5 minutes of low speed. It would come back after about 20 sec of >3000 RPM. I figured this was due to thermal shutdown. The original OMC one had big fins on it but the replacement after-market did not. I just got a Bombardier replacement and it is the same as the after-market, no fins. Right now I am running with the valve by-passed and there seems to be no problem. <br /><br />I pulled the thermostats and checked them in a pan on the stove, seem to be opening at about 140 deg. I don't know what a white vernathem is but these are black thingys with a conical end and uses a spring between them and the cover to push them against a tapered seat in the head.<br /><br />Any ideas on where to start to see if there is a problem or should I just leave it as it is? The slow running temp seems OK I don't know about the WOT temp, should this be higher?

 

[Dhadley]

Re: Function of water control valve?

Youre running the black vernatherms, thats good. <br /><br />What kind of water pressure do you have? I'm still not convinced I'd run it with the control valve by-passed. Especially if youre still having reg/rec issues at low speed. <br /><br />If it were mine I'd use the updated 93 set-up.

 

[seahorse5]

Re: Function of water control valve?

Originally your motor used the expensive 35amp water cooled finned regulator. Since you have a smaller charging system, you only need the 12amp regulator that does not need cooling fins. The low speed charging system "cut off" was because the regulator got too hot, usually from an air pocket under it. That is the higest part of the block.

 

[evil grady]

Re: Function of water control valve?

Whats the udated system consist of and what parts do I need to buy and what parts do I need toget rid of?

 

[MarkHPCA]

Re: Function of water control valve?

Water pressure is about 10 PSI at idle and 28 PSI at 5500 RPM. How is the block bled of air pockets? Are the temperature I am getting on the gauge typical?

 

[MarkHPCA]

Re: Function of water control valve?

tt

 

[Dhadley]

Re: Function of water control valve?

However if you want to update the system you can go to the 93 and newer style cooling set up. That requires a different cap, spring and gasket. Then you can do away with the valve and all those hoses.

Yes the block will run warmer at idle than at WOT. The water pressure looks OK. At the risk of repeating myself, I still dont think I'd run the valve by-passed. I'd either use it as it was designed or go to the 93 style deal.

 

[rodbolt]

Re: Function of water control valve?

the pressure control valve on the stbd side of the block keeps pressure on the t-stat diaphrams to keep the cone on the seat. as the throttle opens it shuts the pressure off allowint the cone to raise off the seat allowing block pressure control. it needs to either be in place and working or the heads need to be updated,.<br /> good luck and keep posting

 

[evil grady]

Re: Function of water control valve?

Whats the udated system consist of and what parts do I need to buy and what parts do I need toget rid of?

 

[MarkHPCA]

Re: Function of water control valve?

Ok now I have a working regulator that seems stable I will re-connect the plumbing and see what happens. DH.. I will take your advice and upgrade to the 93 style do you (or someone else) have the part numbers of what I need for this upgrade?<br /><br />Thanks.

 

[evil grady]

Re: Function of water control valve?

Thats what I'm Looking for too!<br />Part numbers or diagram please

 

[MarkHPCA]

Re: Function of water control valve?

Am I correct in assuming the 93 upgrade changes the thermostat, spring, cover and gasket and ditches the water valve? I assume it will also need a change in the 'seat' in the head. What about the plumbing to the water valve? What do I do with this?

 

[Dhadley]

Re: Function of water control valve?

The thermostat assemblys (vernatherm) you have are fine. The new caps will have no fittings for hoses. You can then remove the water valve and all related hoses. Use a pipe plug to seal up the hole in the adaptor plate where that fitting is now. Or cap off the fitting.

 

[MarkHPCA]

Re: Function of water control valve?

What caps do you mean?

 

[Dhadley]

Re: Function of water control valve?

The caps over the vernatherms. Yours have fittings for hoses. The 93's do not require hoses.