Amphibious HEMTT

[ExWrench]

I would not describe the tires as marshmallows. Since they are designed for much more weight, (9000lbs. each) they are hard with only 25 psi.

Sorry, to clarify: I was referring to the shape, not the softness. With that big of diameter, at 60 mph they're not revolving super fast. What effective diameter are they?

 

[WaterH]

Sorry, to clarify: I was referring to the shape, not the softness. With that big of diameter, at 60 mph they're not revolving super fast. What effective diameter are they?

They are 46” tall.

 

[ExWrench]

They are 46” tall.

Yeah, they're big meats

So they spin about 438 revs/mile and at 60 mph they're turning ~438 RPM.
Nothing irritating about that unless the tread pattern gives off weird harmonics.

 

[WaterH]

Yeah, they're big meats

So they spin about 438 revs/mile and at 60 mph they're turning ~438 RPM.
Nothing irritating about that unless the tread pattern gives off weird harmonics.

i see what your saying. 438 seems slow for a tire. Maybe it’s too slow to make the roar that my 38’s make on my other Bronco. Also I drive that faster on the highway. (Not a lot faster, but 65-70)

I may need to balance these better too. I don’t have access to the helicopters balancer I had before. I wonder if a big rig tire place could do these.

 

[WaterH]

So I went to town the other day and of course it pour down rain. I hadn’t planned to take it in the rain for while, but whatever. The good news is it doesn’t seem to leak anywhere from the roof, windshield or the ring mount. I had some water on the floor by the doors. I think that came in the at the side windows and drains out of holes on the bottom of the door.

So I got to test the windshield wipers. The passenger side had too long of a arc and would jump into the center bar. This really pissed me off as I spent a lot of time making the wipers work. I couldn’t test that part because I didn’t have the windshield in at the time. To day I modified the mechanism so it had the right sweep. That wasn’t very hard, but getting to them was a complete PITA. I had to tear apart half the dash just to get one c-clip off. I’m going to have a stern talk with the engineer of this thing.

Other than that, I found a small leak in the fuel line. It was right at a fitting. It wasn’t very tight, so I hope that’s all it was. It couldn’t have leaked much because I’ve driven it about 150 miles in the last couple days and I can’t even see the gauge go down. I hope that means it gets good mileage.

 

[WaterH]

Well today my pax side windshield cracked in two places. I’m not sure what happened. It was the first time I used the heat/defrost. I parked it for maybe twenty minutes idling. It appears the most heat come out on the pax side defrost. (I don’t know why) When I got back in the truck, it was hot inside. Short time later I noticed the cracks. Then loud swearing could be heard coming from the truck.

Have any of you heard of glass cracking from the defrost heat? It might be the glass was too tight in the rubber. When I get new glass cut, it will be slightly smaller. I dread installing it again.

 

[aczlan]

Well today my pax side windshield cracked in two places. I’m not sure what happened. It was the first time I used the heat/defrost. I parked it for maybe twenty minutes idling. It appears the most heat come out on the pax side defrost. (I don’t know why) When I got back in the truck, it was hot inside. Short time later I noticed the cracks. Then loud swearing could be heard coming from the truck.

Have any of you heard of glass cracking from the defrost heat? It might be the glass was too tight in the rubber. When I get new glass cut, it will be slightly smaller. I dread installing it again.

Yes, how much do your defrost vents spread the heat out? If its just warming one spot it will crack, that's why cars have vents across the whole windshield.

Aaron Z

 

[ExWrench]

Got a pick of the cracks? Initiation points and direction may help diagnose the root cause. If it was too tight, it may have cracked by how it was constrained when it heated and expanded. If it wasn't overconstrained, differential heating could be a sole cause - could be time to make some diverters or spreaders for your defroster outlets.

 

[bdkw1]

A guy I worked for had a A pillar mounted spot light like a cop car on his truck. Dome light went out and he was using the spot for interior lighting. One cold night he ended up cracking the windshield with it.

 

[SLOWPOKE693]

Maybe the wiper jumping off that side in the rain the other day had something to do with your crack?

Btw...... The truck came out looking sick, you did a hell of a job building that thing!

 

[WaterH]

Yes, how much do your defrost vents spread the heat out? If its just warming one spot it will crack, that's why cars have vents across the whole windshield.

Aaron Z

I have two defrost vents. (One on each window) They came from vintage air and are about 6” long. They have vanes to spread the flow. I might have them too close to the bottom of the window.

Got a pick of the cracks? Initiation points and direction may help diagnose the root cause. If it was too tight, it may have cracked by how it was constrained when it heated and expanded. If it wasn't overconstrained, differential heating could be a sole cause - could be time to make some diverters or spreaders for your defroster outlets.

I’ll take a pic today. The cracks are about 2” from each side of the defrost vent. They start at the edge of the glass under the rubber and go straight up the glass about 4”.

Edit, here’s the pic.

Maybe the wiper jumping off that side in the rain the other day had something to do with your crack?

Btw...... The truck came out looking sick, you did a hell of a job building that thing!

The wiper was jumping the center divider when it is vertical. The cracks are at the bottom. I only had the wiper on for two sweeps before shutting it down. I doubt it’s the issue. Thanks for the kind words.


I have four heat outlets. The two defrost and two vents that dump on your feet. I don’t have any valve, so the heat just gets divided to all. For some reason that defrost vent gets more air than the others. I might have to switch the ducts with one of the floor dumps. The funny thing is I had the heat on low fan. I still have two more speeds. At a high speed, would it heat the window more or defuse the heat more? I also have control of the flow of hot water. (I had it full open)

Edit, it wasn’t even very cold outside, maybe 50F

 

[subybaja]

Have any of you heard of glass cracking from the defrost heat?

Yes. Used car ads here refer to an "Alaskan windshield" when it looks like my Jeep. 50% of cars over 20yo have that horizontal crack where the defroster blows.

 

[WaterH]

I checked at the glass place and they said they maybe could cut one tomorrow. They were going to do some semi windshields. I asked the women if they wanted the whole job so I wouldn’t have to install it. She said no. She went on to ask if I wanted a job teaching her guys how to install them. Lol. She said all the experienced guys have retired and she can’t get anyone. She said she has watched someone do it many times but she has never. She will be teaching the guys tomorrow. Lol.

I have a giant crack in my Bronco windshield for over ten years. I wouldn’t have this fixed except the truck is brand new. I purposely am not taking it off road yet so I don’t scratch it before I take it to a couple car shows.

 

[WaterH]

Update time,

So the new winshield is in and I’ve been driving it quite a bit. When I originally built the full hydro steering, I did it kind of unconventional. I basically just hooked the hydro arm to the drag link as you can see here.

A lot of guys on the old site told me this won’t work and I’m really trying to get a bus load of nuns. On the contrary, it has work flawlessly. Of course, I’ve only driven it for about 400 miles in all this time and most of that is in the last month. In any case, I never liked it. Not because of any steering issue, but it still has the “low steer” tie rod going from knuckle to knuckle. The tie rod is the lowest thing on the truck. This thing was never intended to be a rock crawler, but it is going off road. I would hate to be cruising through tall grass/bush and hit a stump with that tie rod.

So to make everybody happy, I decide to go with a conventional full hydro setup. I designed a mount and welded it up here.

I did something here that really worked out good. If you look close above, you can see that I painted all but a 3/4” from where it welds to the axle. When I welded it on, I did short welds and let it cool in between. I did not hurt the paint and after it was all welded, I just hit it with a wire brush on the welds and painted. This allowed me to do a much better paint job then if I tried to do it all on the truck.

It is nice to jack the air bags up for this kind of work. I know dark pic.

Anyways, all back together. The steering is not really high steer, but it’s no longer the lowest thing on the truck. The mount is a good hard also. While doing this mod, I added another 1-2 degrees caster. The test drive to night seemed to be better at 60 mph.

Tonight I put $150 in diesel in the tank. (Still not full) Dam brandon.

 

[WaterH]

So I’ve been fighting high EGT’s and decide to install a intercooler. I knew this might be an issue, so I had already made some provisions for it. Here’s a pic of the intercooler and the intake tube it replaces.

I made a mount on the back of the motor.

Mounted.

I don’t have a pic, but the brass fitting you see plumbs into my coolant system With a small electric water pump. The intercooler is not real big, and of course, using hot water to cool is not the best. There was a slight improvement. Previously, my EGT would be around 1000 when driving 55-60 mph. If I hit a slight hill, it would go up to around 1200 and higher. Now it cruises 60 mph around 950 and can take a fair sized hill at 1100. The boost will run around 10 to 15 psi.

I believe the aerodynamics of this thing is a problem. If I stay 60 or under, it’s ok, but if I try to even go 63, the it takes another 5 lbs. of boost (20) and my EGT goes to 1400 and more. (If I let it) I’m not sure if I will change it or just live with it. I could plumb the cooler to a dedicated radiator. Don’t really want the extra complication. If I want to drive faster than 60, it’s obvious I need the tires balanced better. It’s very smooth up till about 55. Then it gets a “lumbering” feel to it.

 

[ExWrench]

I believe the aerodynamics of this thing is a problem.

Totally with you on that one. Hell, just pushing those tires through the air is a chore

If I stay 60 or under, it’s ok, but if I try to even go 63, the it takes another 5 lbs. of boost (20) and my EGT goes to 1400 and more. (If I let it)

Sounds like 60 mph is your max. ground speed as-is.

I could plumb the cooler to a dedicated radiator. Don’t really want the extra complication.

Taking ~200* out of the fluid side of your air-to-fluid heat exchanger should pay off significantly. It's your time, but I say it's worth doing.

 

[arse_sidewards]

Taking ~200* out of the fluid side of your air-to-fluid heat exchanger should pay off significantly. It's your time, but I say it's worth doing.

You don't even have to use a different fluid. Just send the coolant through some sort of radiator before it hits the intercooler. That should easily knock 50deg out of it since it's not like it'll be going through the radiator all that fast.

 

[WaterH]

Taking ~200* out of the fluid side of your air-to-fluid heat exchanger should pay off significantly. It's your time, but I say it's worth doing.

One of my fans comes on at 140 and the second one comes on at 150. The second one almost never comes on and when it does, it shuts off a short time later. That tells me the water coming out of my radiator is 140 to 150. Obviously, I can’t get any lower than outside air temp which is about 75 right now. So that tells me a separate cooler can only take out 75 degrees. Come summertime, the difference is only 60.

That being said, it certainly will help.

Today I drove to Panama City to have lunch with my wife. It’s about 50 miles one way. I kept it at about 55-60 most of the way. The temps were fine. Even charging up a hill, the EGT didn’t get past 1100. I used a lazar gun on the tranny pan and it read 174. That seems amazingly low. The rear diff got to 154 which also seems low for breaking in gears. For comparison, my DD Bronco got to 200 in twenty miles when I regeared. I guess the one ton diffs need more load to get hot.

So the biggest problem I have now is out of balance tires. Along time ago I balanced them with a helicopter balancer. I was in a hurry and only balanced them at 40 mph. It made a big difference and they have been fine ever since. Now that I’m officially on the road, that doesn’t cut it. I stopped at two tire places and they say they can’t balance a tire that big. I need to get the helicopter balancer again. That company moved Out of state. I might get them to send it to me or I might buy one. I still play with helicopters now and then, so I might be able to make it pay.

Until than, I guess it’s just local area for the HEMTT. It was a total blast driving it around town.

 

[aczlan]

One of my fans comes on at 140 and the second one comes on at 150. The second one almost never comes on and when it does, it shuts off a short time later. That tells me the water coming out of my radiator is 140 to 150. Obviously, I can’t get any lower than outside air temp which is about 75 right now. So that tells me a separate cooler can only take out 75 degrees. Come summertime, the difference is only 60.

What are the coolant temps in and out of your intercooler? Where is it plumbed into the rest of the system?
You might try plumbing it in to the inlet and outlet hoses of the radiator (so it pulls from the cool side and dumps onto the hot side).
If you end up going with a separate system, or a 2nd radiator I would look at the $70-100 all aluminum Civic radiators they are around 18" x 14" x 5" with 1.25" ports and many of them come with a 12" electric fan.

Aaron Z

 

[WaterH]

Where is it plumbed into the rest of the system?
You might try plumbing it in to the inlet and outlet hoses of the radiator (so it pulls from the cool side and dumps onto the hot side).


Aaron Z

This is how it is plumbed. How else could I have done it?

 

[aczlan]

This is how it is plumbed. How else could I have done it?

I wasn't sure how it was plumbed (off of the cabin heat ports, or off of the radiator), that is how I would do it.

If you want to get fancy, for $25 this would let you watch radiator in/out, intercooler air in and out and intercooler water in and out (tape the probes to the hoses and possibly put a piece of foam over the outside), reads 32-482℉: https://www.amazon.com/AKSESROYAL-Wireless-Thermometer-Grilling-Bluetooth/dp/B083RDCL46

Aaron Z

 

[subybaja]

I need to get the helicopter balancer again.

Whachoo talkin about, Willis?

Surely not a HF bubble balancer?

 

[aczlan]

On the balancer, have you tried a heavy truck repair shop?

Aaron Z

 

[WaterH]

Whachoo talkin about, Willis?

Surely not a HF bubble balancer?

No, the one I used was the Vibrex 2000. I know it cost about 5K when the company bought it. I figured all these years later it would have gone down.I just got a quote on a new one. $23,000 Why doesn’t HB make one?

On the balancer, have you tried a heavy truck repair shop?

Aaron Z

I tried every tire place in my town and 3 places in Panama City.

 

[subybaja]

I'm leery of Googling "Vibrex 2000"!

Have you looked into dynamic balancing at all? Dynabeads, Airsoft, golf balls?

 

[aczlan]

I'm leery of Googling "Vibrex 2000"!

Have you looked into dynamic balancing at all? Dynabeads, Airsoft, golf balls?

Or RV antifreeze...

Aaron Z

 

[WaterH]

I'm leery of Googling "Vibrex 2000"!

Have you looked into dynamic balancing at all? Dynabeads, Airsoft, golf balls?

I be had mixed results with air soft BBs in my Bronco. These tires turn so slow, I’m doubtful.

Or RV antifreeze...

Aaron Z

Never heard of this, but again, I think they need to turn fast for that principal to work.

 

[aczlan]

Another idea from the old site:

Ive been fighting the balance on my 47 or years now. I still cant find a tire shop in this county that can fit a 47" tire on their machine and properly balance my tires. After years of discussion about what to do with 40+ tires a ship builder gave me this method, it turned out to be amazingly precise. and pretty quick. Now all I have to do is dismount the tires and glue the balance pads on the inside. I made the balance jig so that the pivot point of the tool was in the exact location of the center of gravity of the tire thus the wheel offset did not effect the balancing. the best tire took 1 oz and the worst took 20 oz. that would have been 60 oz on the rim due to the difference in rim radius vs tire tread radius. So by putting the weight at the exact opposite of the heavy side, far much less wight is required, and you don't have wheel weights coming off in the rocks.
Here is the same tire hanging in balance with the balance pads thumbtacked into position. I used a paint marker to outline the position of each one so it can be glude inside the rim. what amazed me through this whole process is that just moving a pad a 1/4" makes a huge difference in balance.

This is one of those deals where having a lathe and a welder means never having to say you are sorry.
I did some math to determined that with my 12" wheels I had to be 2 1/2" from the back side to get to the center of gravity. So I welded a 2" long piece of 1"dia. Al to some scrap 3/4" plate. then I chucked it in the lathe on the 1" piece and took light cuts till I had the correct id, .005" under the wheel ID at 1/2" wide, leaving a 1/4" shoulder. then I drilled it 1/8" through the center for an 1/8" cable to go through.( note:ignore the flat on the shoulder, as the piece of scrap I used was not big enough to get full round so I split the difference and there is a matching flat on the back side of the picture you cant see, but by making it symmetrical It does not effect the balance.) I used a piece of 3/4" plate aluminum, roughly 5" x 4" and then sawed it round as I could prior to the lathe work. I'm sure you could make one out of steel as well. as long as everything is turned symmetrically it would not effect the balance.

Aaron Z

 

[WaterH]

That’s interesting. One of the guys on Steel Solders gave me a similar idea. It looks a bit easier to make.

 

[MattS]

I use these in my bro dozer on 40's. They have almost eliminated all the issues. I need to buy another packet and put more weight in one tire that is worse than the others.

https://www.amazon.com/gp/product/B00Z65ZL1M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1