RWC & no thermostat guys

[Bingy]

I am currently running with no thermostat,ball valve at inlet to thermostat housing and set at 1/2 closed/open position.Gauge reading is 130 degs. at cruising RPM ( no Tack )and doing 6 knots.
Should I open valve more to increase temp or is this okay operating temp?
River water temp is 70 Degs. approximate. RWC

[edwardc]

If it were me, I'd open the valve a little until the temp was up to 140. A hotter engine will burn more efficiently, but above 140, salt will start to crystalize out all over the interior surfaces of the cooling jacket.

That having been said, many here run their A4s at temps under 140.

[Dave Neptune]

Get some numbers

Bingy, I too run in the same temp waters. What I found was that once I was at about halfway open to maintain my just under 130 degrees if I opened it much further the temp did not go up much and wide open it actually dropped a bit. However my shut down temp rise was far more after shut down and the engines sendor actually seemed to register a bit cooler , that is what started me on rerouting.
Go ahead and open it a bit and see if it does run a bit warmer and check the temp rise after doing so once warmed up. Get back with the numbers if you would please.
Just the rerouting of my hoses has taken me from almost closed to run 130 to now almost 3/4 open to run the same temps. If I open the valve all the way I get around 140~150 now, I could not get this warm of a reading before.

Dave Neptune

[Bingy]

Too all

I tried that and temp did rice to 140 but was concerned about not diverting enough through the block. Also noticed higher temp at front end of block near oil pan . With the temp sensor located just below thermo stat housing are we getting a fairly accurate reading of block temps. Engine head and manifold are just warm to touch, good water out exhaust and a little exhaust smoke if I push engine revs over my normal setting for cruising speed.

My boat is a Ranger 30, fin keel ,Martec 12-6 folding prop and boat displacement app.10000 lbs.Boat is raced MON.- Wed beer can fleet and weekends on Lakes Erie and St. Clair where motoring for 3 or 4 hours to get to other clubs is quite common.
Mech fuel pump, points/cond ignition, no PCV . Rotella 15 w 40 Diesel oil and starts great all the time.

Lucky guy with a Happy Motor

[Marian Claire]

Bingy. If you are concerned about the amount of flow thru the block a recirculating loop instead of a bypass may be the answer. Dan S/V Marian Claire

[Dave Neptune]

Colder waaters

Bingy, to add to what Dan said, a recirculating loop is an excellent way to increase temps especially if operating in colder waters. The reaso I try to keep mine under 130 when cruising is cabin comfort inspired only!!!

Dan, where do you inject the recirculated wared water back into the "flow"?

Dave Neptune

[Marian Claire]

In my old RWC setup the recirculation loop T'ed into the hose between the raw water filter and the raw water pump.
My FWC setup T's into the freshwater hose between the HX exit and the freshwater pump.
As a note on my FWC system. In warm water, 80+ deg F, I close the valve completely to stay in the 160 to 180 range when fully warm and running at cruising rpm or slightly higher. My temp sensor is located at the exit of the manifold. Dan S/V Marian Claire

[Bingy]

Thanks for the information

Is there Thread showing the recirculation set up for RWC ,no thermostat and ball valve control?

[Marian Claire]

This may help. http://www.moyermarine.com/forums/showthread.php?t=4267
Make note of the Dole T-stat/ball valve info. Dan S/V Marian Claire

[S1lverfox]

Diverter cap openings

Dave Neptune, What size is/are the hole or holes in your water Jacket diverter cap? And, please comment on the addition of the second straight in hole in addition to the single hole, down and aft at a 45 degree angle, configuration.
Also, Please advise the pros and cons of using a mechanical temp indicating gage instead of an electrical sender/gage. Thank You.

[RMark]

3 am random thoughts

Just a random thought, what if you just ran bypassed water thru transom above water line? It would give you instant indication of thru hull, strainer or impeller issues. Like a outboard engine "pee" hole.Down side might be higher exhaust temp?

[Dave Neptune]

Silverfox, when you say cap I asume the t'stat husing and those are 3/8" NPT. The plug on the top of mine is a pencil zinc I added as I don't have a t'stat in the housing.
A static temp gage is fine and the only down side is you can't see it unless your looking at it on the engine. It would not be a bad idea for a backup if desired. I do have a static OP gage, just not permanently mounted, I have a port ready incase my electric is questionable or goes bad.

Rmark, a bleed of for a pee tube like an OB is fine but they constatnly have critters get inside and build a nest, especially moths. Just a plain static preassure gage works as well. I have a static gage on my big OB motors and my son was using the boat over the weekend and I got a call~~Dad the water preassure is at 5 when idling and 8~10 when running. Time for a water pump is all I said. I also like all the water going through the exhaust too, not dumping and leaving a mess where it exits.

Dave Neptune

[S1lverfox]

Diverter cap

Dave Neptune, 1. I 'm referring to the diverter cap, on the inside of the water jacket side plate, that connects to the "T" fitting and diverts water flow down and aft inside the block. I thought that I read somewhere that originally that cap only had a single hole that diverted the flow down and aft and that some A4ers have added a second smaller hole to direct some water straight across the block between #2 & #3 cylinders.
2. On my Tartan 27, the forward wall of the cockpit is just aft and slightly above my A4 so I should be able to mount the mechanical Oil pressure and Engine Temp gages on the regular panel.
3. Your by-pass plumbing looks great and it sure must be nice know that your temp reading is accurate. Good on you!

[Dave Neptune]

Cool

silverfox, OK I get it. The diverter is not something I have played with. I bought a new one from MMI quite a few years ago and it did have just the aft facing port. I have seen the mod however I haven't seen anythig regardig any particular advantage.
In 26 years I have only had my engine heat up once so I slowed until I was out of the shipping lanes , shut her down and went to work figuring out the problem as it was rather sudden IE last trip the pryor week was fine. I found it to be a obstructed intake by removing my intake lione from the valve. It was early in the season, in 55 degree water and being alone I did not want to go over tha side and pondered by predicament. I came up with the idea of blowing the line clear with a fire extinguisher and no problems since. It did make a bit of a mess however it also blew the krap out. That was the start of last year.

Dave Neptune

[Dave Neptune]

Cool

silverfox, OK I get it. The diverter is not something I have played with. I bought a new one from MMI quite a few years ago and it did have just the aft facing port. I have seen the mod however I haven't seen anythig regardig any particular advantage.
In 26 years I have only had my engine heat up once so I slowed until I was out of the shipping lanes , shut her down and went to work figuring out the problem as it was rather sudden IE last trip the pryor week was fine. I found it to be a obstructed intake by removing my intake line from the valve. It was early in the season, in 55 degree water, no wetsuit and being alone I did not want to go over tha side and pondered by predicament. I came up with the idea of blowing the line clear with a fire extinguisher and no problems since. It did make a bit of a mess however and it did blow the krap out. That was the start of last year.

Dave Neptune