Keltik's cast iron squirty thing

[keltik]

The boat never had a thermostat housing and instead came with a plate with a 5/8 double hose outlet on it.  This flowed directly into the exhaust manifolds with no restriction.  I had blocked off one hose and tried running the other down to the lower radiator hose but that was no good since the water flowed backwards to my intention due to the pressure difference between the cold side and hot.  So off to pick a part!

Standard commodore thermostat housing cut down and tapped for 3/4 bsp.  The 90 degree bend puts the water hose nicely over the coil packs so it fits under the engine cover.  This then dumps overboard behind the driver seat just out of reach to avoid accidental burns.

Couldn't get a 60 degree thermostat so the plan is to run at 80 in fresh water with the thermostat regulating the temp, then in salt or nasty water I can just open the manual dump valve from the heater hose outlet which bypasses the thermostat to keep the engine temp below 60. Or if anyone knows where I can get a lower temp 44mm thermostat -let me know.

Was wondering what latches to use for the engine cover when a Ute came into work needing a new canopy door...

Also added a flushing port to the cooling system using a dishwasher tap and a valve to stop the flushing water just going back out the sand trap.  The valve handle is oriented so you cannot close the engine cover with the cooling system shut off.

Next mission is to mount the seats and bolt a couple new rollers to the trailer

[keltik]

Ran the boat up to temp on the trailer tonight much to my neighbours delight.

Water temp gets up to 95 before the thermostat opens.  Then it falls to 80, thermostat shuts and the cycle repeats.  

So yup, definitely need to find a colder thermostat.

Also noticed with the thermostat open and the relatively low flow from the garden hose - the port side exhaust water stopped flowing until the thermostat shut again.

I think this means I need to chuck a restrictor pill in the exhaust water feeds to reduce the amount of flow wasted out of the system.  Or maybe the jet unit produces such a vast amount of water flow it won't be an issue.

 More testing required before I sign off on the cooling system as finished.

[tortron]

Can get 160f 71c thermostats for turbo grand nationals

[keltik]

14 minutes ago, tortron said:

Can get 160f 71c thermostats for turbo grand nationals

They appear to be bigger on the gnx.  I believe the commy ones measure 44mm OD

[tortron]

Got most of an early VN engine here, with the thermostat at the back. Might be same as USA on those

[nzstato]

Have you looked into fabbing a mixing tank?  Its the best way to try to limit temperature surging in a raw water application

 

 

 

[keltik]

I did consider a mixing tank but was having trouble visualizing how the flow would work.  What restricts the outlet of the mixing tank to keep the feed water at a reasonable temp?  Perhaps a MS paint diagram of the current setup will help

All of the mixing happens in the water pump housing at the moment.  If I added an external tank, it would be after the thermostat so I'm not sure how I would control the flow out of it.

[nzstato]

If you line up the jet in/exhaust out flows like in the diagram you dont necessarily divert the flow as most will pass through with some minor turbulence for your engine cooling needs - need to match inlet and outlet pipe IDs.   The aim is to mix a the engine hot water outlet with a portion of the raw water to supply water inlet at your thermostat temp (I found a thread which suggests 83deg for holden v6).  

[keltik]

Made up some seat adaptors

Then put on some John Denver and headed out to the lake.

Engine temp was pretty easy to regulate, just setting the dump valve to bleed a bit off kept the gauge showing about 70 degrees.  If i slowed down, the temp crept up until the thermostat opened.  So i think if i can get a colder thermostat - we'll be onto a winner.  On the whole, everything went well.  No major leaks, no big faults, just a smooth half hour of boating in some bloody cold water.  Did have a small fire scare when the paint I'd used on the exhausts decided it didn't like being hot.

 

[HighLUX]

Man it makes sweeet moooooo noises at full song

 

[keltik]

Went out with @brotherd to test his new motor.  I made it half hour before the bad noises started.

I took some bits apart and think it might be this?

I guess I'll fix that and see if the noise goes away.  Happy it didn't fire a flex plate and driveshaft through the bottom of the boat.

[keltik]

Put some hours on the boat this summer.  On my last outing, was trying to catch some other boats so had the throttle wide open for 10 mins straight. 5200rpm full noise. After backing off, the oil pressure plummeted and the engine tried to have a little soft seize.  

Coolant temp never got silly and oil temp is the one gauge I never finished hooking up.  Hand on the sump told me it was fucking hot.

After cooling it off and going easy for the rest of the day, it was ok.

The next weekend, I went out again and had 100psi idle oil pressure rising to off the gauge at cruise speed. 

So this weekend, decided to have a look at the relief valve.  Oil was pretty grot.

The relief valve lives behind the oil filter housing in the middle circular bore.

While I had it apart, tapped a home for my temp sender.

And because it's a 3.8, the gasket was $8 and available easily.

The relief valve had some minor scoring on it and some schmoo particles, I'm not convinced that was the problem but polished it up and reassembled.  Ran it up to temp, I'll reserve judgement until it's been out on the water again but seems alright for now.

I think a little modine style oil cooler would be a good idea.

Kinda keen to build a new boat.  I think this one has taught me enough to know exactly what I want and how I want it.

But I also like not spending money.

[keltik]

On 30/04/2022 at 16:40, keltik said:

I think a little modine style oil cooler would be a good idea.

Yeah.  Today's cruising oil temp was 110 rising to 135 under load.  That seems a little spicy

[keltik]

Got a small oil cooler off a Subaru and all the gaskets to fit it. Should be able to put that together tomorrow.

Tonight's job was to verify my oil pressure issue.  The last couple trips I've been seeing 100+psi cold and 80 hot.... Which seems excessive, especially with my high oil temps.  Oil temp bottom left, water temp bottom right and pressure top right:

Grabbed a pressure gauge from work, replaced the factory pressure switch and took some readings:

Meanwhile the dash gauge was showing 85.  So I put another mechanical gauge in the same port the oil pressure sender was in:

That seems rather conclusive.  Gave it some big revs but still only saw a max of 75psi on the mechanical gauges.

So hopefully tomorrow night I can install the oil cooler then see what difference it makes on Sundays river run.

[keltik]

Had everything set for my oil cooler. A long ass M18 bolt with the hex parted off. A 12mm hole bored down the center and a nut lathed down to half width, Subaru oil cooler with a new seal.

Began assembly and hit the first snag...I never measured the diameter of the sealing surface on the block side of the Subaru oil cooler housing.  I just assumed it would be the same as the filter side... It isn't.

So the inner recess is where the seal should sit and the outer protruding bit is the diameter of the oil filter housing sealing surface on the Holden block.

Couldn't think of a better solution than to cut a new gasket to fit over the raised section and see if it will work.

Bit of sealer on the jointing paper, fingers crossed and bolt it together eyeballing everything concentric.

Fired it up, no leaks so far and about a 10psi drop across the cooler with thick cold oil.  Im no fluid dynamicist but my intuition says this pressure drop will reduce with thinner hot oil?  But then the flow rate would be increased through the bearings so I really don't know.

Going to take it for a blast and see what happens.  I would've been happier if the cooler fitted properly... But I'm also going to be happier if the oil temperaturev needle stays on the gauge.

[keltik]

Test run this morning gave some good data. At 3600rpm cruise, oil temp rose to a steady 120c.  I originally placed the cooler on the manual temp control line so it only saw a medium amount of water flow at whatever temperature the engine block was at.  This wasn't ideal.

I did another run with the manual temp control valve wide open so the oil cooler would see max water flow with a lower water inlet temp.  The engine chilled down to 30c and the oil temp settled at 95c.  So its clear I would need the oil cooler getting its water from somewhere else.

Moved the cooler in line with one of the exhaust manifold cooling feeds.  So now it gets feed water straight from the jet pump and sends its outlet into the drivers side exhaust manifold which has enough flow it shouldn't mind being fed warmer water.

Final test will be a JBNZ run up the Tarawera river tomorrow.

I did also find a new water leak from where the battery box plywood base rubs against the hull - its worn through the steel.  The bottom is also looking very second hand so there's only 2 years left before it falls to bits I reckon.

[keltik]

Today's run up the Tarawera river was rather boring. Lots of reeds, floating debris, overhanging trees full of spiders and one big angry weir that was a bit too grunty for me to attempt.

Managed to block the grate, lose steering going downstream and slam the back of the boat sideways into a stump.

The steering cable pulleys mount right behind that dent so for the rest of the trip - the boat handled like a fucked old tractor as the cables went loose.

Dunked the boat in at Matahina on the way home to wash the mud and salt out of it.  Showed the misses the lovely waterfall that's appeared.

Oil temps got up to 120 with a thrashing but would cool off much quicker than before.  Good enough.  That will do.  I'm not changing it.  I'm also not fixing that dent.

[keltik]

Anyone want a boat?  Hawkes bay peeps perhaps?

Up for sale on the tard and bookface munterplace.

Uncle keltik needs the money for jag parts.