sprayer for rear radiator

Topic: sprayer for rear radiator (Read 2174 times) previous topic - next topic

Re: sprayer for rear radiator

Reply #25 – June 13, 2016, 11:13:00 am

Mike, it is raining outside, but here is a pic I took awhile back while looking in the side door and down at the rad/fan.
Seems I have the same type electric fans on the back side of the engine radiator (2) and on the AC "radiator" up front (2).

Re: sprayer for rear radiator

Reply #26 – June 13, 2016, 11:19:52 am

Quote from: nitehawk – June 13, 2016, 08:48:32 am

I open the driver's side access door, look in & down and I see a "radiator" mounted horizontally, with a large electric fan on top, and hoses going to the Allison transmission. Was this standard? Or something ordered special or aftermarket addon?

My wild ass guess is that it's an add-on by a PO but you never know FOT tried a lot of different things over the years.

see ya
ken

Re: sprayer for rear radiator

Reply #27 – June 13, 2016, 11:27:23 am

Quote from: kenhat – June 13, 2016, 11:19:52 am

My wild ass guess is that it's an add-on by a PO but you never know FOT tried a lot of different things over the years.

What Ken said.

Re: sprayer for rear radiator

Reply #28 – June 13, 2016, 12:41:12 pm

These were very common in China, and other Asian countries on their overloaded trucks. They also water sprayed tires and brakes.

Re: sprayer for rear radiator

Reply #29 – June 13, 2016, 10:11:35 pm

Those small horizontal radiators near the rear wheels are desert coolers. I saw a Wanderlodge with those installed. They're very interesting and I seriously considered installing additional radiators. I opted for the sprayer ultimately and I'm glad I did. This is by far the best modification I've done to my coach. There's no need for additional radiators now.

Re: sprayer for rear radiator

Reply #30 – June 14, 2016, 01:28:42 am

RRadio I think someone modded the ATEC on you coach. No 600 series locked up in other than upper rpm third gear that I drove.

Would feel like a seven speed?

Re: sprayer for rear radiator

Reply #31 – June 14, 2016, 09:51:06 am

Quote from: RRadio – June 12, 2016, 04:20:40 pm

Much of the cooling problem is caused by the ATEC computer slipping the torque converter and making a huge amount of heat. I don't know if the 6 speed Allison does that but the 4 speed Allison does it all the time. If you don't have a sprayer you can keep your rig from overheating by paying close attention to your tachometer and never letting your torque converter slip. Learn to recognize the difference between the tachometer readings of a "real" shift and just splitting a shift by slipping the torque converter. Look at your transmission gauge to see if it's climbing, which it will be if the torque converter is slipping. Shift into a lower gear immediately if the torque converter starts to slip. Beware that it can slip in any gear, which may go against what you've read here on this forum. My 4 speed can lock up in any gear, it even splits 1st gear between slipping and locked up. I don't want to start an argument about that. If you don't believe me that's fine and I'm okay with that. I know one spot where it splits 1st gear every time I drive over it and I watch the tachometer as it splits first gear up and down while I've got it in 1st gear manually. This is really important when you're climbing very steep grades found in the rocky mountains. On super steep grades you can't upshift without the ATEC computer splitting the shift, so you're stuck in that gear all the way to the top of the grade if you're close to overheating, so basically you still need a sprayer to climb those grades any faster than a crawl, but it's very educational to try it without a sprayer just once.

My '81 with the Cummins splits the first 3 gears for sure, never paid attention to 4th. Climbing steep grades the position of the throttle determined the gear split. It worked like a passing gear and as you said shows up on the tach. The radiator is side mounted and the trans cooler is air cooled on it. Never could make either overheat even with over 100 deg. ambient climbing the Bishop grade.

Re: sprayer for rear radiator

Reply #32 – April 22, 2017, 11:46:17 pm

Scott,

Could post pics of your spray cooling system you built? Just

getting ready for summer.

Carter-

Re: sprayer for rear radiator

Reply #33 – April 23, 2017, 08:44:19 am

Here's a picture of how I did mine, it's pointed up for the pictures. I used 1/2 inch PVC and rubber coated clamps to secure. And I added a separate surflo water pump off my fresh water tank like Ken. Works very well on hot days climbing western hills.

Re: sprayer for rear radiator

Reply #34 – April 23, 2017, 09:14:00 am

Another version on a 1994 U300

Re: sprayer for rear radiator

Reply #35 – April 23, 2017, 11:51:37 am

With the later 746 transmissions as fitted to the U300s, the only torque converter slippage encountered is in first and part way through second gear. Once the transmission goes into lockup, there is zero slippage and the heat generated is the same as a manual transmission. This is easy to see with higher transmission temperatures in congested city driving but once lockup occurs, the tranny temp drops rapidly. Earlier models won't have this lockup feature and others may lock up in different gears and speeds.

Looks like a couple of good radiator coolers on the above posts. My only comment is that if you happen to have filled with water that has a lot of calcium in it, you can have a white radiator. I was thinking a calcium inhibitor filter might help minimize the deposits and keep the nozzles clear.

Home Depot at: Calcium Inhibitor Filter-10109W - The Home Depot

Pierce

Re: sprayer for rear radiator

Reply #36 – April 23, 2017, 02:14:27 pm

Had a customer I have mentioned before that ran a twin turbo 350 hp cat marine setup on his 250/643 Allison for 95k miles.

Only got on it in lockup fourth

Re: sprayer for rear radiator

Reply #37 – April 23, 2017, 03:07:22 pm

Before there was CLR and all the new and improved stuff

for calcium build up we used just plain old white vinegar.

Sure won't hurt the drinking water system.

Carter-

Re: sprayer for rear radiator

Reply #38 – April 24, 2017, 11:44:38 pm

My torque converter definitely can slip or lock up in any gear. I'm absolutely sure of it. I can reproduce it any time I want. I can show you the exact road where it always slips and then locks up even at walking speed when first gear is selected. It makes no difference whether the torque converter slips or is locked up if the air temperature is 120 degrees or higher. At that temperature it's gonna overheat even at 60 mph on level ground with the torque converter locked up. That's when I knew I had to install a sprayer on the radiator. Keeping the torque converter locked up at air temperatures below 120 degrees is sufficient to prevent overheating at 60 mph on level ground. About 120 degree air temperature appears to be the dividing line. If you drive your coach at highway speeds at 120 degrees you're gonna need a sprayer on your radiator. I spent a whole Arizona summer experimenting and this was the only solution that worked. I only spray a couple hundred gallons of water on my radiator per year, so we'll all be dead long before any significant calcium builds up on my radiator... Interestingly, the dash air conditioning works great at 120 degrees, which was a pleasant surprise. The condenser is 35 feet away from the radiator so it doesn't cause overheating. The entire coach appears to be well designed for hot climates with the one exception of the radiator needing a sprayer.

Re: sprayer for rear radiator

Reply #39 – April 25, 2017, 12:19:02 am

Normally a 91 u300 shifts four times. First two gears are never locked up. Period. Halfway through third the converter locks.

NEVER unlocks in fourth.

ATEC versus DDEC.

Re: sprayer for rear radiator

Reply #40 – April 25, 2017, 11:36:45 am

Quote from: Caflashbob – April 25, 2017, 12:19:02 am

Normally a 91 u300 shifts four times. First two gears are never locked up. Period. Halfway through third the converter locks.
NEVER unlocks in fourth.
ATEC versus DDEC.

Bob,
The 1992 and later U300s are 102" wide and have 746 Allisons vs the 748 in the 1991. They are both ATEC (Allison Transmission Electronic Control) and have nothing to do with the DDEC (Detroit Diesel Electronic Controls). Different model Allisons will have different lockup points or even none depending on the model. Ours is always locked in third and fourth (high gear). I have heard that the ATEC computer (mounted in the nose of the coach) can be flashed to lockup at different speeds and gears. Earlier models without the ATEC are out of luck for lockup. Note: the 747 Allison is a manual control non-ATEC for buses and does not have the forged piston for lockup. If your Allison has a "B" in the model number, it stands for BRAKE as in retarder. Only the later U300s went to the Jake instead of the retarder.

Pierce

Re: sprayer for rear radiator

Reply #41 – April 25, 2017, 01:26:55 pm

Here's pictures of mine:
- Sprayers next to fan to so water gets sucked in and blown over radiator.
- I soldered couplings where I wanted sprayers so there was extra thickness. Drilled and tapped for backyard style sprayer nozzles. Too little water - did nothing.
- Removed upper nozzles and left 10-24 threaded holes. Pours a lot of water now. Does the job.
- I just have a 12 volt solenoid valve tapped into the "house" plumbing and a switch in the drivers area.
- Forgetting to turn it off has been an issue with me but fortunately I don't use it very much.
- I have seen some calcium build up but not much. I like Pieces' suggestion of a calcium remover (as long as it's not corrosive).

If I were to do it again I would drill holes in the fan shroud and insert nozzles there. Pusher fans have a tenancy to create a doughnut shaped jet blast of air immediately behind fan and leave the rest of the radiator in turbulence. This is especially true of our rear radiator motorhomes. Due to length issues the fan is way too close to the radiator to create even flow over the radiator area which will yield the most of amount of BTU/hr removed. By putting the nozzles in the fan flow the speed is so fast I'm afraid not all of the water is evaporated by the time it leaves the radiator.

Re: sprayer for rear radiator

Reply #42 – April 25, 2017, 08:03:39 pm

Rradio has a 91. Referring to him only.

DDEC is connected to ATEC by three plug connectors in the edge of the engine bay.

I absence of the ATEC signal the DDEC goes into limp mode=80% power as the engine thinks the trans is hurt.

No codes shows. Drove Kent Knaus nuts until I got lucky and found it was disconnected

If he's heating I assume the lockup is not programmed correctly?

91's had a MTB 648 ATEC and a retarder as far as I remember selling them.

As far as I remember the 700 series were only unlocked in first gear only.

2,3 and four were always locked

Same 300/820 torque as the 88-89-90's as far as remember

If I owned one I would inquire about the 277/840 that the 88's had.

Bigger smile driving them.

Re: sprayer for rear radiator

Reply #43 – April 26, 2017, 11:30:54 pm

I don't know why I even bother posting anything technical on this forum anymore. I'm always absolutely sure about everything I post. Every time I post something "experts" who don't own my coach and drive it all over the country will tell me that I'm wrong. For the last time MY transmission locks and unlocks its torque converter in ALL forward gears. I'm absolutely sure of it. It locked / unlocked when first gear was manually selected every time I left the campground at Lee's Ferry, where I lived for several months. I drove down that hill every time I went to the grocery store in Page AZ and paid very close attention to it. It was 120 degrees that summer. I was studying the overheating issue from every possible angle at that time. I'm absolutely sure of what I'm saying. I will NEVER write anything on this forum that I'm not absolutely sure of and that I haven't done myself personally many times. I have a bunch of other modifications I've done to my coach but I'm waiting at least a year before I write about them because I want to be sure I'm giving accurate information... For those of you who write to me every few months wondering why I don't bother coming on this forum anymore this explains why... I think I'll post strictly about the beautiful places I go from now on. No experts ever tell me I didn't really go there and everyone seems to agree that the places are beautiful. I can't post high resolution photos on this forum anymore so I presume something was changed with the server. If any of you want to see my photos please feel free to contact me and I'll friend you on my Facebook page. I have high resolution photos of my stay here in beautiful Zion national park this winter. Looks like I'll be going to Grand Tetons next!

Re: sprayer for rear radiator

Reply #44 – April 26, 2017, 11:41:29 pm

Quote from: RRadio – April 26, 2017, 11:30:54 pm

I don't know why I even bother posting anything technical on this forum anymore. I'm always absolutely sure about everything I post. Every time I post something "experts" who don't own my coach and drive it all over the country will tell me that I'm wrong. For the last time MY transmission locks and unlocks its torque converter in ALL forward gears. I'm absolutely sure of it. It locked / unlocked when first gear was manually selected every time I left the campground at Lee's Ferry, where I lived for several months. I drove down that hill every time I went to the grocery store in Page AZ and paid very close attention to it. It was 120 degrees that summer. I was studying the overheating issue from every possible angle at that time. I'm absolutely sure of what I'm saying. I will NEVER write anything on this forum that I'm not absolutely sure of and that I haven't done myself personally many times. I have a bunch of other modifications I've done to my coach but I'm waiting at least a year before I write about them because I want to be sure I'm giving accurate information... For those of you who write to me every few months wondering why I don't bother coming on this forum anymore this explains why... I think I'll post strictly about the beautiful places I go from now on. No experts ever tell me I didn't really go there and everyone seems to agree that the places are beautiful. I can't post high resolution photos on this forum anymore so I presume something was changed with the server. If any of you want to see my photos please feel free to contact me and I'll friend you on my Facebook page. I have high resolution photos of my stay here in beautiful Zion national park this winter. Looks like I'll be going to Grand Tetons next!

Im no expert but....are you sure?

Just kidding.. I like the technical stuff as it helps me to understand .. Yours might not be mine or Visa Versa but all in all it is very helpful to the community. I dont have Facebook but can you post the pics anyway?

Just messing!!

Re: sprayer for rear radiator

Reply #45 – April 27, 2017, 10:28:53 am

Scott,

Your ATEC Allison computer may have been flashed to lockup in every gear. They don't come stock that way but the computer controls what gear and what RPM and can be changed. The only thing certain is that it can't be locked up in first when you are at a stop sign.

Many diesel pushers overheat in hot weather. Ours is one of them. From 5.9 Cummins on up. The design is marginal, very marginal.

When someone rains on your back, just let it run off like a duck. I do and survive nicely.

Pierce

Re: sprayer for rear radiator

Reply #46 – April 27, 2017, 01:36:11 pm

Quote from: Kemahjohn – June 12, 2016, 04:36:29 pm

why yes I've got the same thing with our 1989 unihome 3208T never gets really hot 190,200 so far....but I plan on the sprayer system. With the trucks we've had I use a similar system and it works fantastic.
Maybe Foretravel slightly undersized the radiators for the Detriots. I seem to see a great many post about heating problems on these 92 series engines. My 1990 Unihome with 3208T Cat mechanically injected engine (no engine computer) and 4 speed Allison trans with Atlas radiator never gets over 160 degrees no mater how hard you run it or how steep the climb. It is a rear radiator set up. Just curious, any other folks with the 3208T set up experience any heating problems, or use a water spray system?

Re: sprayer for rear radiator

Reply #47 – April 27, 2017, 05:34:00 pm

Will,

Have never seen my 3208 overheat but adding the cooling sprayer is like having a horn.

It's there and unused until you need it. I remember seeing pictures of the logging trucks

in the Pacific Northwest. They rigged water sprayers on the truck and trailer brake drums.

Cooling the Allison is as, if not more important, to me, than any of it.

Carter-

Re: sprayer for rear radiator

Reply #48 – April 27, 2017, 11:55:17 pm

Quote from: uniWill – April 27, 2017, 01:36:11 pm

Maybe Foretravel slightly undersized the radiators for the Detriots.

Foretravel didn't undersize the radiators they put in the biggest ones that would fit. It just so happeneds that in hot weather it is still undersized.

The owner add-on water sprayers are a viable solution. If you are overheating with the water sprayer you are doing something wrong.

My favorite solution is to head north.

see ya
ken

Re: sprayer for rear radiator

Reply #49 – April 28, 2017, 12:11:34 am

Funny enough the rear radiator on the first unihomes was pretty well capacitied for the Detroit..

Overcooled the 3208 250hp. Caused engine damage from running too cool.

Foretravel ended up blocking part of the radiator

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