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Model 01 with Cummins L10 overheating issue

This is a public forum to discuss Eagle related technical issues. If you are having a problem with your Eagle, this is the place to find help.

I was talking to Bill Klein (Billbuss) in the chat room and he was asking about possible ways to remedy his L10 overheating. He's already talked to all the most knowledgable people I know when he was down at Breaux Bridge but none of the ideas they tossed at him made any difference. I thought maybe we could brainstorm a little here and see if we can help him out.

He has a 1968 Model 01. He has been through two 8V71s and always had trouble with them heating up. He made the big leap to 4-stroke with the Cummins L10 and thought that would be the end of it but it is not. He has a brand new radiator. He is not running the stock Eagle mitre box and fan but he had to leave the chat before I found out what he is running. He is a full-timer who travels so you can imagine how frustrating this is for him.

I'm sure he will jump on here and fill in the blanks that I didn't know. And some of you guys that talked to him at Breaux Bridge who have actually seen his setup might be more help too.

Dale Houston
1993 Eagle 15-45
Nashville, TN
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I did get to talk to him, but sad to say didn't take the time to look his repower over. I hope he can fix the problem, as he changed the engine over in a parking lot at an RV park in a few days. What a task he accomplished. Great to meet him and his wife.

Becky & Paul Lawry
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I did not check out Bill's repower. ( To many Crawfish to eat :lol: ) I will throw out a couple of ideas. Make sure the shroud is set close to the fan and about 1/2 as deep as the fan, also make sure that no air can get around the shroud. These fans suck a lot of air and if there is a hole it will suck there and not through the radiator. Chek that the belts are tight. Sometimes a more efficient fan is the answer.

Good Luck Wayne
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Wayne, I think he is trying to use electric fans for cooling and Mark is the only one I know of that has been to make electric fans work so far.Mark can you help Bill out here. If it was me and it is not I would go with the Prevost set up with Boston Gear 90 degree at the fan with a 2 speed fan clutch and belt drive from the engine it's a nice setup I am going to it to rid my self of the power hungry mitre box. good luck
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Thanks Clifford, I do not know anything about electric fans. I have been told it is very hard to get big enough electric fans to cool an engine that big. But I understand Mark has done it.

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Biggest problem with electric fans is that there are so many to choose from.
1. Is it a 24v or 12v set up?
2. Electric fans don't like air resistance is there any outlet resistance?

Engine L10
has the pressure been bumped up on the rail?
Does the engine feel like it has normal power?

Just some items to answer (check) to help try and pin point the problem(cause)
Once the point of cause is determined then maybe we can come up with a solution.

YCMV c=cooling

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I'll add my 2 cents worth on the inadequacy of electric fans.

Electroc fans SOUND great for a bus, becuase they sort of work ok on many non hotrodded, factory standard cars. They are used there because the auto companies have fuel mielage corporate average mandates to meet, and an electric fan does divert far less power from an engine and can be more easily disconnected when not needed for actual cooling - just break the electrical connection.

However, the physics of an electric fan are bad, AND a bus engine requires MUCH more cooling than a typical car or pickup truck engine.

To give you an idea how much power is needed, Caterpillar in its excellent booklet on coach/ RV performance nots that its SMALLEST, least powerful engine requires well over 40 hp under load. This is their smallest remember.

The conversion between horsepower and watts of electricity is pretty simple. IF you could find a "perfect" electric motor, that converts ALL electricity fed to it into mechanical power (which you can't find), you would need 40 hp x 750 watts/hp = 30,000 watts or 30 KW of power. At 12 volts, that's 30,000/12 = 2500 AMPS!

At 24 volts, it's STILL 1250 amps!

ACTUAL electric engine cooling fans of course draw far less than that, as you cannot get wiring large enough to handle 1250 or 2500 amps, even if you could find the necessary 12 volt or 24 volt alternator to keep the fan supplied!

I have no data on how powerful an electric BUS cooling fan might actually be available, but on car and trucks, the LARGEST electric fans draw only 30 amps (and require fusing for much more for startup loads!). 30 amps x 12 volts is only 360 watts, or less than half a horsepower. Pathetic.

There's the reason that good cooling fans are mechanical versus electric.
Jim Gnitecki
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Hey Guys

I looked at Bill's installation and his shroud did
not cover the entire radiator. It has 2 electric
fans mounted in a shroud and this is mounted
to the inside of the radiator. It had big gaps
in the top and bottom, I suggested he build a
new shroud that would cover the entire radiator.
If I remember correctly, it has 2- 24 volt fans.
They were moving lots of air, but it was only
thru the middle section of the radiator.

Good Luck!
Sonnie Gray
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For your information:

Following is the URL of an electric fan drive manufacturer with an impressive line of products. EMP's 'miniHybrid' is probably the most successful electric thermal management system for bus applications available today.

Good luck, Chris
Christian Berlit
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The electric fan package Chris refers to is a group of 8 fans in a 31"x51" design. It draws 400 amps, 24 volts. It would probably require a custom radiator and structural modifications to fit the bus. Even then, it may not be enough cooling to handle a high hp, heavy conversion in hot weather.
The tried and true belt and fan system can always be made to work when installed properly.There's a reason the OE's didn't use electric motors....
Good luck,Hal
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