O/t Detroit diesel Starting

[theskytoucher]

Ok guys about a year ago my grandfather passed away, in the years before he died he bought a 54-55? gmc semi http://s103.photobucket.com/albums/m130 ... ucher/GMC/ that he was going to fix up and drive around town delivering gravel and whatnot. well his health went south before he got a chance to start on the truck!!! So i have decided to build this truck as a memorial to him because it was one of the few things any one of us in his existing family can remember him wanting to do!!
So my question is this wat steps do i need to take before trying to start this truck? It has sat for about 8 years but it ran when it was brought home!! I know i need to check the oil and the water levels, im going to drop the fuel tanks and clean them out and put fresh fuel in them (i know the caps have been taken off and left off for extended periods of time) is there anything i am missing? can i do anything with the injector pump to make the truck start faster or better?

Thanks for any help,

[MotorDog]

First of all, Detroit Diesels only have a "transfer pump" for fuel. That means that the fuel is just circulated through the passages and back to the tank. The injectors actually have a plunger on them and act like a hypodermic needle....push the plunger and the fuel squirts. Also, this is probably a two cycle engine. All this means that if this engine has not had fuel in it for a period of time, it may have "lost its prime." The fuel system must NOT have any air in it or it won't squirt and won't run. You have to "bleed" the air out of the fuel system to get it to run. If you haven't ever done it, you are in for a real job. This is not a job for the "faint of heart." If you put in new fuel and crank it over for a couple or so minutes and it doesn't run....consider calling someone who will come out a bleed it out. Try a Detroit Diesel mechanic shop FIRST! Just my 2 cents. Good Luck! By the way, That particular model truck is quite "rare" and would undoubtedly be quite a fine old truck if restored to running condition. That cab over really looks sharp....My Opinion!

[theskytoucher]

IS there any info you can give me on this truck i know very little about it because the title i have for it is the wrong title!!! abandoned title here i come oh joy

[fmartin_gila1]

From what I can see in those pics, it looks like a 53 or a 71 series 2 cycle Detroit Diesel. They used a "Unit Injector" type fuel system. If it has been just sitting for all this time, you should be able to give it a clean fuel supply and it should fire. Change both the Primary and the Secondary Fuel filters(make sure you fill the fuel filter cannisters with fresh fuel prior to fitting them to the filter head). Then plumb in a electric pump to the suction side of the Primary filter and pump fuel through until you get fuel without bubbles out of the (disconnected) fuel return line at the tank. This should ensure that you have 'prime'. Then hook up all disconnected hoses and it should fire. You may have to help it along with some starting fluid. When you first start it up, make sure you know where the emergency shutdown is and that ithe flapper works, as these engines have been known to "runaway" and keep gaining RPMs untill they self-destruct. If you are at all unsure of what I am referring to, please find someone who knows of this (usually old guys like me) before you attempt to start it.

Fred

[MotorDog]

Fred gave great advice on how to prime it and to get it started and running. Especially make sure you are able to shut it down. The "Damper" door, (air door that closes off the air and puts out the fire), should be checked and operable to prevent any "runaway." More than likely, the engine in this is a 4-53 Detroit. That means a 4 cylinder engine with 53 cubic inches in each cylinder. Pretty small for a diesel but the two cycle helps make a little more power by providing power on every stroke. These are "cute" little engines but also, because of the design of them, they are quite dirty. They have a couple vents in the airbox that dribble oil when they sit and idle. That is expected and normal. Also, this could have a 4-71 engine but that is highly unlikely. The difference would be a larger engine, 71 cubic inches per cylinder and 4 cylinders with more power. However, most of the GMC's from that era with the 4-53's. Let us know when you get it running.

[theskytoucher]

Thanks for the info!! Im 1105 positive this is a 6 cylinder motor now if it is a 53 series or a 71 series i have no clue!! Thanks for the info on the emergency shutdown! and ill see if i can find an electric pump to try to prime the system!!

[MotorDog]

Reviewing your pictures further, the Horsepower plate would indicate to me this is probably powered by a 6-71. Especially when you look at the weight rating of 69,000 lbs. The fact that it is rated at 2100 rpms also indicates a 71 series. The 53 series engines operated at 2400 rpms and didn't make 200 horsepower. The 6-71 with 6 cylinders, (426 cubic inches) have about 1/2 horsepower per cubic inch so this would be right for a 6-71. I would bet on that engine being in this truck.

[averagef250]

Never, ever get within 100 feet of any diesel engine with starting fluid! If you absolutely have to, use a rag soaked in gasoline close to the air intake.

Jimmy 2 strokes are fun engines. They are very efficient at turning diesel fuel into noise and leaving an oil path wherever they go. They are rediculously simple engines and easy to work on. Parts for the 71 series engines are still very common.

[fireguywtc]

Also I didn't see anyone mention the intake side of things. Is this engine turbocharged or supercharged? I would guess supercharged by the age of it. I would check to make sure everything is clean and no mice nest are in there, as well as everything is not siezed up. good luck I hope it starts right up.

[averagef250]

All two stroke Jimmies are supercharged. They don't have an intake stroke. Doesn't mean much though, they don't develop any significant manifold pressure without a turbo or two.

[theskytoucher]

I found another tag in the glove box of the truck and it said it is a 6-71!! I couldnt get batteries today so i couldnt try to start it btu i found out some interesting things on it!! Both fuel tanks were abotu a third full so i might try to start it using the old fuel (it doesnt egt below about 30 degrees here so the fuel shouldnt have geld! also the batteries have me confused both of the cables go to the starter any ideas, one goes to the soleniod one goes to the back of the starter housing?

[fireguywtc]

All two stroke Jimmies are supercharged. They don't have an intake stroke. Doesn't mean much though, they don't develop any significant manifold pressure without a turbo or two.

Every 6V 92 fire truck I have operated is a 2 stroke and all are turbocharged. I know that they are newer but they are still tubo.They are loud, smoke like a freight train, and come with a free oil leak from the factory Also drove an old GMC cab over from the 70s on the farm. It was a screamin deamon that was turbo and loud as hell.

[fomocoguy]

I found another tag in the glove box of the truck and it said it is a 6-71!! I couldnt get batteries today so i couldnt try to start it btu i found out some interesting things on it!! Both fuel tanks were abotu a third full so i might try to start it using the old fuel (it doesnt egt below about 30 degrees here so the fuel shouldnt have geld! also the batteries have me confused both of the cables go to the starter any ideas, one goes to the soleniod one goes to the back of the starter housing?

This is a neat thread! I can't wait to see if it starts. As for the old fuel, as far as I'm concerned 8 year old fuel should be changed without question, gelled or not. It's probably got a ton of moisture in it, and it may not even be flammable anymore. Now I'm basing this on my knowledge of regular gasoline; if diesel is different please somebody correct me. I just know that I've had two year old gas that wouldn't fire before, let alone 8 yr old. Just my ! Good luck!

[OldRedFord]

Having owned a diesel truck, I vote for getting rid of the fuel. My F250 had a 2nd tank that had been unused for some time, but full of fuel. Had alga growing in it.

[theskytoucher]

I think im gonna go ahead and drain the old fuel out just to be safe!!!