Help with an obstinate 3-71 Detroit

llafro

Member
I have a 3-71 Detroit Diesel generator installed under a passenger railroad car. It has generally been a very reliable power plant, and we have put over 11,000 hours on it. It seems to be eating coolant at this point, and there are no water leaks to be seen. I'm guessing the head gasket has taken a turn for the worse.

The problem is that I'm in California, and the railcar is in Quebec right now. It's escorting a shipment of high-value equipment. The generator gave up in northern Ontario on Friday. We need to get it back up and running in about a week, come what may. Does anyone know of good Detroit Diesel specialists in Montreal?



Link to previous discussion on the car
 

Birken Vogt

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I don't remember, have you posted on Heavy Equipment Forums before? They have more contacts with current people in the trade especially Canada.
 

Birken Vogt

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It is a different web site entirely. There might be someone here who can help you but that site has a lot of people actively working in the business and who know Detroit diesel pretty good.

There are more retired folks and hobbyists on here, good for if you want to do it yourself and cheaply but not as good if you need it fixed right now.
 
If the water temp runs 165- 180 degs. and their is no water in the oil ( Check under the oil filler cap and look for water drops and rust) and you don`t have bubbles or soot in the cooling system the head and head gasket is probably okay. Get a automotive coolant pressure tester. With the engine shut off pump the system to 7 psi and watch the pressure gauge for a drop. While under pressure re check all the hoses water connections and radiator for leakage. On the narrow part of the water pump there is a drain there for when the pump seal fails. Look there for a leak or a rust stain on the block. Detroit Diesel Allison Canada 418-651-5371 AL.
 
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llafro

Member
If the water temp runs 165- 180 degs. and their is no water in the oil ( Check under the oil filler cap and look for water drops and rust) and you don`t have bubbles or soot in the cooling system the head and head gasket is probably okay. Get a automotive coolant pressure tester. With the engine shut off pump the system to 7 psi and watch the pressure gauge for a drop. While under pressure re check all the hoses water connections and radiator for leakage. On the narrow part of the water pump there is a drain there for when the pump seal fails. Look there for a leak or a rust stain on the block. Detroit Diesel Allison Canada 418-651-5371 AL.
We do have the telltale soot in the coolant. The engine overheats and lost a couple quarts in about an hour. There should have been a puddle inside the enclosure, but apparently nothing visible.
 
Does the overflow pipe from the top tank of the radiator empty into the enclosure or onto the ground? A blown head gasket or a cracked head can pressurize the cooling system and force the coolant past the radiator cap and out the overflow tube. With the pressure tester hooked up and the engine running and the gauge pressure increases that is not a good sign. You could also put a container at the end of the overflow pipe to see if that is where coolant is going. The last time the head gasket was blown did you notice if the head gasket was one piece or individual water and liner seals? Old style low block, current type high block. In any case improper cylinder liner height adjustment can blow a gasket. AL
 

llafro

Member
Does the overflow pipe from the top tank of the radiator empty into the enclosure or onto the ground? A blown head gasket or a cracked head can pressurize the cooling system and force the coolant past the radiator cap and out the overflow tube. With the pressure tester hooked up and the engine running and the gauge pressure increases that is not a good sign. You could also put a container at the end of the overflow pipe to see if that is where coolant is going. The last time the head gasket was blown did you notice if the head gasket was one piece or individual water and liner seals? Old style low block, current type high block. In any case improper cylinder liner height adjustment can blow a gasket. AL
It's the newer style "high" block. It's not that the existing setup didn't last - we put 9,000 hours on it over about 8 years. We are still waiting for the railroad to deliver it, so that we can get to work. There's nothing like being under a deadline, and then the railroad says "We aren't going to run that train tonight. Maybe tomorrow."
 
Does the engine overheat only when the coolant is low? I have had good results with using Alumaseal is stopping small leaks that are not apparent. At a more convenient time the problem could IMG_3463.jpgbe addressed. AL
 

llafro

Member
The car finally got to a location where they can work on it today. The refilled it with water and ran it for a short time. It was blowing coolant out of the reservoir and heated up soon after that. We should have a replacement head for it on Tuesday. The install isn't that hard to do. Can anyone chime in on major pitfalls to avoid? Tips and tricks?

1. Set valve lash (0.015 go and 0.017 no go) and injector timing (N65 injectors use 1.460 injector timing)???

2. Set the rack up right.

3. Make sure the emergency shutdown flapper is working before cranking it over! Have a block of wood big enough to block off the intake tract if not.

Suggestions appreciated!
 
The car finally got to a location where they can work on it today. The refilled it with water and ran it for a short time. It was blowing coolant out of the reservoir and heated up soon after that. We should have a replacement head for it on Tuesday. The install isn't that hard to do. Can anyone chime in on major pitfalls to avoid? Tips and tricks?

1. Set valve lash (0.015 go and 0.017 no go) and injector timing (N65 injectors use 1.460 injector timing)???

2. Set the rack up right.

3. Make sure the emergency shutdown flapper is working before cranking it over! Have a block of wood big enough to block off the intake tract if not.

Suggestions appreciated!
The valve lash and injector height are correct. When the head is off bar the engine over and make sure that all the pistons come to TDC. ( water can bend con rods.) Put vice grips on the rack on the first start up then you can override the governor in case of a runaway. AL
 

llafro

Member
We have the replacement head ready to go on. Is thread sealant required on the head bolts? The torque specs show 190 ft-lbs and to work up to that in increments of 50 or so in the usual circular pattern.
 
The car finally got to a location where they can work on it today. The refilled it with water and ran it for a short time. It was blowing coolant out of the reservoir and heated up soon after that. We should have a replacement head for it on Tuesday. The install isn't that hard to do. Can anyone chime in on major pitfalls to avoid? Tips and tricks?

1. Set valve lash (0.015 go and 0.017 no go) and injector timing (N65 injectors use 1.460 injector timing)???

2. Set the rack up right.

3. Make sure the emergency shutdown flapper is working before cranking it over! Have a block of wood big enough to block off the intake tract if not.

Suggestions appreciated!
Did you get the engine running? Were my "suggestions" helpful? I`m out of here for now! Aloha AL :shrug:
 

llafro

Member
We finally did get it running. We installed a rebuilt head, head gaskets, a new water pump, new injectors, a new fuel pump, and replaced all the flexible fuel lines.

The source of the problems was a batch of bad fuel, it seems. The cooling fan runs on 480 VAC from the main generator. If the engine isn't up to speed, there is no power to the blower motor, and no airflow over the radiator. It did shut down on overtemp automatically as it is supposed to at 205 F. I don't know if there may have already been some issue with the head gasket and this overheating was the proverbial straw that broke the camel's back.

It would probably be best to have a crankshaft-driven blower, but that's not really possible. The radiator sits at a 90 degree angle to the engine. It was built that way to have airflow from one side of the train car to the other.

They fought for several days with fuel contamination. It fouled a filter in about an hour the first time. Then, it ran for a few hours before the next set plugged up. They finally drained the tank and refilled it, along with replacing the flex lines and blowing out the metal lines (200 gallons down the drain, plus we have to pay for disposal!). That seems to have cured the problem.

Any ideas on bigger/better filters to use? It uses a Napa 3122/3123 combo. The fuel/water separator is before the fuel pump, and the primary filter is between the pump and injectors. The setup has been fine for 11,000 hours, but this load of sludge fuel killed four sets of the filters.
 
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