Amphibious HEMTT

[WaterH]

The relay is not protected against that, as I just showed you.

But you do you.

I'm just pointing out (one of) the issues with the way things are wired in your car.
If you added an ignition switch to control the power to all relay triggers, you wouldn't have this problem.

Again, there is a reason why nobody does it like that.

The link that you posted said that most if not all relays are protected from this.

What problem?

Again, there is a reason why aircraft manufacturers DO do it like this.

 

[Bebop]

Re-read what I posted and try to understand it.

Relays with a diode are protecting their own fly back from the coil. Not from the one coming from the load downstream.



I'm done doing this. Point have been made on each side, I showed you where you system could be improved IMO, and you don't think I'm right. I can't change your mind.

I'll go back to wiring cars for happy customers and you go back to asking questions on the board about why you're frying relays and thermostat switches.

 

[WaterH]

Re-read what I posted and try to understand it.

Relays with a diode are protecting their own fly back from the coil. Not from the one coming from the load downstream.



I'm done doing this. Point have been made on each side, I showed you where you system could be improved IMO, and you don't think I'm right. I can't change your mind.

I'll go back to wiring cars for happy customers and you go back to asking questions on the board about why you're frying relays and thermostat switches.

I completely understand flyback. How do you know what the diode on a relay protects from?

Are you suggesting that the sticking contacts are from flyback? I posted a reference that states that running too small of a rating causes stuck contacts. Some others said that 75 amps is not enough overkill to handle 50 amps of fans starting up. I changed it to a higher rating and it seems to be fixed. I have no relay problems on the radiator side and they have been wired that way since day one.

The thermostats is still yet to be determined. I have new information on that. Today I ran the truck till I saw 230 on the temp gauge. I immediately pulled over and noted that one fan was not running. I pointed a temp gun at the pipe where the thermostat is and it read 145. That thermostat should trigger that fan at 160. (The other comes on at 140) If I ground the thermostat, the fan comes on. So maybe there’s nothing wrong with the thermostat set up and it’s just a dash gauge problem. If I determine the thermostats are frying from flyback, I will be the first to admit it.

Bebop, I’m not suggesting you’re stupid. Don’t suggest that I am. As you said, there are points on both sides. I hope we can agree to disagree.

 

[WaterH]

So today I wired a switch that turns on the intercooler pump and radiator fan number one. I figure this switch will stay on unless I want to listen to music with the truck not running. (To save battery and not hear the fan) I put fan number two on the 140 degree thermostat. I’m hoping that the rad will run cooler that way. I don’t need it for the engine because it doesn’t seem to overheat with just one fan running. But the intercooler should work better.

 

[Bebop]

Bebop, I’m not suggesting you’re stupid. Don’t suggest that I am..

You're not stupid, far from it.
You're just stubborn and want to do things your way.

Thus it's not worth my time to keep on beating this dead horse, despite showing you some of the shortcomings of the current system.

 

[WaterH]

You're just stubborn and want to do things your way.

Completely agree with you.

But I will change it (and admit it’s fubar) if it gives me trouble.

 

[Bebop]

Completely agree with you.

But I will change it (and admit it’s fubar) if it gives me trouble.

It already gave you trouble, that's why we're having this discussion...

 

[WaterH]

It already gave you trouble, that's why we're having this discussion...

I’m afraid your being stubborn now. I have not had any “flyback“ issues at all. The AC relay that failed was always off when I cut the main power. The two relays (radiator) that weren’t always off when cutting the power are still fine.

If your talking about the thermostat switches, the 140 degree switch is always on when I cut the power and it’s still working fine. The 160 degree thermostat switch might be bad, but I have not confirmed that. That switch is hardly ever on when I cut the power, so flyback would be much more likely to fail the other one.

Basicly, the only circuit that would suffer the flyback issue you mention is the 140 degree thermostat switch hooked to the relay and fan number one. Now I have changed the wiring so I switch the first fan off and on, so the only circuit that could have the issue will be the second fan. (Now on the 140 switch) If I leave the first fan on, it will have possible flyback issue. That’s what I plan to do as an experiment. Care to estimate how long it lasts?

Im happy you brought this up because I learned something. I believe the reason I never heard of flyback is because it’s such a rare problem. I don’t know why you believe that the diodes in relays don’t protect them from flyback when that is their purpose. I also don’t understand how you believe the aviation engineers are designing aircraft to have problems.

In any case, it is a dead horse. I’ll bring it back up if my switchable fan relay fails. Maybe I’ll be eating crow.

 

[WaterH]

So I did some more testing today. I wanted to determine if I had any air pockets in the cooling system. I pulled The cap and it was right full. But that doesn’t really tell me if there might be some trapped somewhere. Then I got the idea of parking on a sidehill to make the rad the highest point in the system.

I was looking at my shooting backstop when I realized, I don’t need no stinking side hill, I have air bags.

After getting it slanted, I noticed the front fender was close to the tire. I reached up in there and confirmed that there was about a 1/2” from the corner lug to the fender.

That was with no air in the left side bags, so it should never get that low while driving.

Anyways I started the truck and idled it until the thermostat opened. I was checking to many things with a temp gun while it warmed up. One thing I noticed was the head and the sensor measured about 10 degrees less than what the gauge says. Would you think the water jacket is 10 degrees hotter than the metal right there? The other weird thing was when the head was 170 and the gauge was 180, the top (hot) rad pipe never got over a 130. That’s a thin SS pipe. I’m sure it’s the same temp as the water inside it.

 

[ScottRS]

Is the thin SS pipe polished? Or just semi shiny silver? Paint it black if you want a decent temp gun read on it, temp guns don't like to read off shiny very well. Usually read dramatically low in my experience.

As for the "could they be 10deg off" bit, yeah, they could. I'd recheck temp gun vs gauge when both are steady state (not actively rising temp) and "calibrate" the two to each other.

 

[ExWrench]

Is the thin SS pipe polished? Or just semi shiny silver? Paint it black if you want a decent temp gun read on it, temp guns don't like to read off shiny very well. Usually read dramatically low in my experience.

That^ Most IR temp. guns are set for a surface with emissivity of 0.90 or 0.95 (black paint or even electrical tape will get you there). Emissivity of stainless is between 0.3 and 0.6, so your IR thermometer reads lower than actual.

 

[WaterH]

Is the thin SS pipe polished? Or just semi shiny silver? Paint it black if you want a decent temp gun read on it, temp guns don't like to read off shiny very well. Usually read dramatically low in my experience.

As for the "could they be 10deg off" bit, yeah, they could. I'd recheck temp gun vs gauge when both are steady state (not actively rising temp) and "calibrate" the two to each other.

That^ Most IR temp. guns are set for a surface with emissivity of 0.90 or 0.95 (black paint or even electrical tape will get you there). Emissivity of stainless is between 0.3 and 0.6, so your IR thermometer reads lower than actual.

Ive never heard this before. I wouldn’t say it was polished, but it is pretty shiny. That would explain why I couldn’t keep my hand on the pipe. I’ve always heard that you can’t keep your hand on something that is higher than 140 degrees.

I haven’t heard of “emissivity”. Would my blue engine paint be somewhere in between black and shiny stainless? I checked my turbo and exhaust manifold. Both were about 250. Since it was only idling, I assume that they would be the same. But the manifold is dull black and the turbo is dull silver. (Both ceramic coated) I guess I need to look up emissivity.

 

[ExWrench]

I guess I need to look up emissivity.

Here's a random internet table of emissivity:

Infrared Emissivity Table

Emissivity Table​

Material	Emissivity Value
Aluminium: anodised	0.77
Aluminium: polished	0.05
Asbestos: board	0.96
Asbestos: fabric	0.78
Asbestos: paper	0.93
Asbestos: slate	0.96
Brass: highly polished	0.03
Brass: oxidized	0.61
Brick: common	0.81 - 0.86
Brick: common, red	0.93
Brick: facing, red	0.92
Brick: fireclay	0.75
Brick: masonry	0.94
Brick: red	0.90
Carbon: candle soot	0.95
Carbon: graphite, filed surface	0.98
Carbon: purified	0.80
Cement:	0.54
Charcoal: powder	0.96
Chipboard: untreated	0.90
Chromium: polished	0.10
Clay: fired	0.91
Concrete	0.92
Concrete: dry	0.95
Concrete: rough	0.92 - 0.97
Copper: polished	0.05
Copper: oxidized	0.65
Enamel: lacquer	0.90
Fabric: Hessian, green	0.88
Fabric: Hessian, uncoloured	0.87
Fibreglass	0.75
Fibre board: porous, untreated	0.85
Fibre board: hard, untreated	0.85
Filler: white	0.88
Firebrick	0.68
Food & Organic Materials	0.95 - 0.97
Formica	0.94
Galvanized Pipe	0.46
Glass	0.92
Glass: chemical ware (partly transparent)	0.97
Glass: frosted	0.96
Glass: frosted	0.70
Glass: polished plate	0.94
Granite: natural surface	0.96
Graphite: powder	0.97
Gravel	0.28
Gypsum	0.85
Hardwood: across grain	0.82
Hardwood: along grain	0.68 - 0.73
Ice	0.97
Iron: heavily rusted	0.91 - 0.96
Lacquer: bakelite	0.93
Lacquer: dull black	0.97
Lampblack	0.96
Limestone: natural surface	0.96
Mortar	0.87
Mortar: dry	0.94
P.V.C.	0.91 - 0.93
Paint: 3M, black velvet coating 9560 series optical black	@1.00
Paint: aluminium	0.45
Paint, oil: average of 16 colours	0.94
Paint: oil, black, flat	0.94
Paint: oil, black, gloss	0.92
Paint: oil, grey, flat	0.97
Paint: oil, grey, gloss	0.94
Paint: oil, various colours	0.94
Paint: plastic, black	0.95
Paint: plastic, white	0.84
Paper: black	0.90
Paper: black, dull	0.94
Paper: black, shiny	0.90
Paper: cardboard box	0.81
Paper: green	0.85
Paper: red	0.76
Paper: white	0.68
Paper: white bond	0.93
Paper: yellow	0.72
Paper: tar	0.92
Pipes: glazed	0.83
Plaster	0.86 - 0.90
Plaster: rough coat	0.91
Plasterboard: untreated	0.90
Plastic: acrylic, clear	0.94
Plastic: black	0.95
Plastic: white	0.84
Plastic paper: red	0.94
Plastic paper: white	0.84
Plexiglass: Perspex	0.86
Plywood	0.83 - 0.98
Plywood: commercial, smooth finish, dry	0.82
Plywood: untreated	0.83
Polypropylene	0.97
Porcelain: glazed	0.92
Quartz	0.93
Redwood: wrought, untreated	0.83
Redwood: unwrought, untreated	0.84
Rubber	0.95
Rubber: stopper, black	0.97
Sand	0.90
Skin, human	0.95 - 0.98
Snow	0.80
Soil: dry	0.92
Soil: frozen	0.93
Soil: saturated with water	0.95
Stainless Steel	0.59
Stainless Plate	0.34
Steel: galvanized	0.28
Steel: rolled freshly	0.24
Styrofoam: insulation	0.60
Tape: electrical, insulating, black	0.97
Tape: masking	0.92
Tile: floor, asbestos	0.94
Tile: glazed	0.94
Tin: burnished	0.05
Tin: commercial tin-plated sheet iron	0.06
Varnish: flat	0.93
Wallpaper: slight pattern, light grey	0.85
Wallpaper: slight pattern, red	0.90
Water:	0.95
Water: distilled	0.95
Water: ice, smooth	0.96
Water: frost crystals	0.98
Water: snow	0.85
Wood: planed	0.90
Wood: panelling, light finish	0.87
Wood: spruce, polished, dry	0.86

 

[WaterH]

It would appear that the main things that give you really bad readings are polished metals.

 

[ExWrench]

It would appear that the main things that give you really bad readings are polished metals.

Temporarily putting a strip or 2 of black electrical tape will give you reasonable results from an IR temp. gun.

 

[WaterH]

Temporarily putting a strip or 2 of black electrical tape will give you reasonable results from an IR temp. gun.

Not sure if electrical tape will hold up to 180 degrees. Probably turn into a slimy mess. Maybe masking tape?

 

[ExWrench]

Not sure if electrical tape will hold up to 180 degrees. Probably turn into a slimy mess. Maybe masking tape?

Or just spritz a small dot of satin black spray paint. Scotch Brite or polish it off afterwards, or leave it for future diagnostic work.

 

[ScottRS]

I spritzed my radiator tanks black for this purpose. Electrical tape will hold up for a little while, brake clean will easily remove the left behind goo when it departs. Masking or duct tape will also work but will be harder to clean off after cooking.

 

[WaterH]

So I got a turbo blanket from Thermal Zero.

Its supposed to reduce under hood temps. The motor mount on the turbo side was getting some cracks in the rubber. (The other side looks new)

Got to get some wrap for the exhaust pipe next.

 

[WaterH]

Today I got a woody!

The yoke in the pic is to convert the T-case front out put to 1350. (The driveshaft is 1350 at both ends) I’ve always been nervous about the old driveshaft because I made it and it was never balanced. Of course it was a small U-joint at the T-case. I allready had a 1350 driveshaft made by TW in the rear.

In other news, if you’ve not followed my “transmission snake oil” thread, I found out today I need a better trans cooler than the “in radiator” one.

 

[CDA 455 II]

Today I got a woody!

The yoke in the pic is to convert the T-case front out put to 1350. (The driveshaft is 1350 at both ends) I’ve always been nervous about the old driveshaft because I made it and it was never balanced. Of course it was a small U-joint at the T-case. I allready had a 1350 driveshaft made by TW in the rear.

In other news, if you’ve not followed my “transmission snake oil” thread, I found out today I need a better trans cooler than the “in radiator” one.

Is that drive shaft going to have the prop mounted on it?

 

[WaterH]

Is that drive shaft going to have the prop mounted on it?

Not in the plans, but you never know.

 

[CDA 455 II]

Not in the plans, but you never know.

Will the tires be the propulsion then?
Or do you have a dedicated propulsion system?

 

[WaterH]

Will the tires be the propulsion then?
Or do you have a dedicated propulsion system?

I allready have a prop for the rear DS. It’s been installed and tested. (Slow)

 

[WaterH]

So I wanted to get some fresh air to my radiator. I got aircraft ducting and built a flange to hold it to get some “ram air”.

Fits under the front.

I took it on a 300 mile trip. Every thing seems to be OK. The water temp will go to about 220 if I keep it over 60.

Expensive, ”cheap hotel” in Cedar Key.

 

[vetteboy79]

That's just plain cool. Glad to see you stacking up some miles on it

edit: do you have any plans for the rear cargo area? Build out a camper or any specific utility uses?

 

[WaterH]

That's just plain cool. Glad to see you stacking up some miles on it

edit: do you have any plans for the rear cargo area? Build out a camper or any specific utility uses?

I want to rebuild the canvas and hoops. That part really bugs me. When I do, I want a rear cover and window. RIght now when I drive down a dirt road, the back fills with dust/dirt. Then I could camp in it like a tent.

 

[Penetrode Offroad]

Slick as hell man. Looks cool.

 

[subybaja]

With your skills, seems that you could whip out a removable hardtop for the back in a weekend. That would make camping a whole lot comfier!

Maybe with a step-up for headroom?

 

[WaterH]

With your skills, seems that you could whip out a removable hardtop for the back in a weekend. That would make camping a whole lot comfier!

Maybe with a step-up for headroom?

Ive thought about the hard top, but you must be joking about the weekend.

Edit update, the duct air didn’t seem to make any difference in temps on the long trip. My brother suggested I run the duct to a mini rad for the intercooler. Than I don’t need another dedicated fan.