Cat 3208 electric priming pump

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Cat 3208 electric priming pump

December 07, 2015, 10:41:36 am

So I got my 1991 Grandvilla home but it took 2 days and lots of work and worry. I will need to do some major work on the injection pump as it leaked the whole way home. I will be adding an electric priming pump as there is no manual pump on this 3208. I want to put it in the area of the fuel tank and am wondering if owners have pictures of their electric priming /pusher pumps ? I am trying to avoid failures or pitfalls that others have experienced. I have yet to settle on a particular pump but one of the issues mentioned frequently in the Wanderlodge forum is if one has a pump failure will the fuel continue to flow thru it. another issue would be is how to wire it so it shuts off when the motor quits running.
Thoughts ideas and pictures are appreciated !
JOHN

Re: Cat 3208 electric priming pump

Reply #1 – December 07, 2015, 11:13:30 am

I am not an expert on the 3208 but having owned one, I don.t think a pusher pump would do a lot of good. The cat engines I have owned do not have return lines so the pump would be pushing against a closed circuit. I have bought all my fuel injection pumps and parts for them from Oregon Fuel Injection. A call to them might help you out. They have talked me through some issues with leaks and other problems.

Re: Cat 3208 electric priming pump

Reply #2 – December 07, 2015, 11:17:57 am

This 3208 does have a return line and I am fairly certain they all do but am not positive. Thanks for reading and responding !

Re: Cat 3208 electric priming pump

Reply #3 – December 07, 2015, 11:33:02 am

A fuel return line helps purge the air from the diesel fuel system. Here is the fuel system schematic for a 3208 CAT: ENGINES AND MORE...: 3208 INDUSTRIAL & MARINE ENGINES - Fuel System

Pierce

Re: Cat 3208 electric priming pump

Reply #4 – December 07, 2015, 11:43:09 am

Quote from: madsen – December 07, 2015, 11:17:57 am

This 3208 does have a return line and I am fairly certain they all do but am not positive. Thanks for reading and responding !

Sorry for misleading you. All my Cat's were in the 70's and all but one were 3306's which did not have return lines. I never had an issue with the 3208 and assumed wrong it didn't have a return line. I do have some cat parts for the 3208 and will give them to you for shipping if they are any good to you. I will check my shop later and let you know what is there.

Re: Cat 3208 electric priming pump

Reply #5 – December 07, 2015, 12:23:53 pm

Craneman sounds good. Let me know what you have !

Re: Cat 3208 electric priming pump

Reply #6 – December 07, 2015, 12:43:07 pm

Craneman,

Your old 3306 should have had a fuel return line. Wonder if it was an incorrect installation? Here is the fuel schematic for the 3306 along with the fuel system description: ENGINES MARINE WORLD AND MORE: 3304B & 3306B INDUSTRIAL & MARINE ENGINES /... Several other forum posts indicate the fuel return line was fitted to the 3306

Pierce

Re: Cat 3208 electric priming pump

Reply #7 – December 07, 2015, 01:20:09 pm

Quote from: madsen – December 07, 2015, 10:41:36 am

...another issue would be is how to wire it so it shuts off when the motor quits running.

Can't help on choice of boost/priming pump - not necessary on our Cummins.

Wiring the pump would be simple: run power lead to pump from a "ON with ignition key on" terminal. Put a inline fuse close to the source for the power lead. Key ON - pump runs...Key OFF - pump shuts off.

In my racing days (another life) we always included a relay activated by a oil pressure switch when wiring auxiliary fuel pumps. That way, if you crashed and the engine quit running, but the ignition key was still ON, the fuel pump would shut down. It was a safety thing...

Re: Cat 3208 electric priming pump

Reply #8 – December 07, 2015, 01:22:10 pm

Are you sure you do not have a Caterpillar manual primer pump on the Caterpillar secondary fuel filter?

Re: Cat 3208 electric priming pump

Reply #9 – December 07, 2015, 01:29:46 pm

Have a G3306 cat parts manual on cd,this is the natural gas version not diesel but most of the parts are the same and the
drawings could be useful.

Will send it to anyone who could use it.

Re: Cat 3208 electric priming pump

Reply #10 – December 07, 2015, 01:44:44 pm

Quote from: Pierce & Gaylie Stewart – December 07, 2015, 12:43:07 pm

Craneman,

Your old 3306 should have had a fuel return line. Wonder if it was an incorrect installation? Here is the fuel schematic for the 3306 along with the fuel system description: ENGINES MARINE WORLD AND MORE: 3304B & 3306B INDUSTRIAL & MARINE ENGINES /... Several other forum posts indicate the fuel return line was fitted to the 3306

Pierce

I have to reply to the beginning of the post to show images of my fuel system, will do so now

Re: Cat 3208 electric priming pump

Reply #11 – December 07, 2015, 01:49:05 pm

my 3306's positively did not have return lines. It was a Bosch direct fuel injection system, and the only way to get air out was to loosen all the fuel lines at the injectors and use the prime pump to bleed out at the injector. I rebuilt these engines for years as a heavy equipment mechanic. here are some pics of what I am talking about.

Re: Cat 3208 electric priming pump

Reply #12 – December 07, 2015, 02:46:19 pm

Craneman,

I found the factory manual for your engine. There are two different fuel systems available for your engine. The first is a system with a syphon break (found on page 6) and the second, which is like your posted engine, is the system without a syphon break. In your system as found on page 8, the excess fuel is sent back into the supply line from the tank. The first system uses a more conventional dedicated fuel return line to the tank. I can see why you had to bleed the injectors.

Here is the complete manual: http://www.numeralkod.com/cross/archivemanuals/caterpillar/3304%20and%203306%20vehicle%20engine%20service%20manual%20reg01349-01/part%201.pdf

It looks like your engine may have used pre-combustion chambers with glow plugs. Correct? Good starting in cold weather?

Pierce

Re: Cat 3208 electric priming pump

Reply #13 – December 07, 2015, 02:52:43 pm

Quote from: Pierce & Gaylie Stewart – December 07, 2015, 02:46:19 pm

Craneman,

I found the factory manual for your engine. There are two different fuel systems available for your engine. The first is a system with a syphon break (found on page 6) and the second, which is like your posted engine, is the system without a syphon break. In your system as found on page 8, the excess fuel pressure sends fuel back into the supply line from the tank. The first system uses a more conventional fuel return line to the tank.

Here is the complete manual: http://www.numeralkod.com/cross/archivemanuals/caterpillar/3304%20and%203306%20vehicle%20engine%20service%20manual%20reg01349-01/part%201.pdf

It looks like your engine may have used pre-combustion chambers with glow plugs. Correct? Good starting in cold weather?

Pierce

That was the system, it started no matter how cold it was. Too bad the new stuff is so different. Sometimes to get the air out of the system I would take a rag dipped in gas, as either could blow the head off if the engine was warm when it ran out of fuel and hold it near the air cleaner to get it started when I was in a hurry.

Re: Cat 3208 electric priming pump

Reply #14 – December 07, 2015, 03:01:51 pm

Quote from: craneman – December 07, 2015, 02:52:43 pm

That was the system, it started no matter how cold it was. Too bad the new stuff is so different. Sometimes to get the air out of the system I would take a rag dipped in gas, as either could blow the head off if the engine was warm when it ran out of fuel and hold it near the air cleaner to get it started when I was in a hurry.

Quote from: craneman – December 07, 2015, 02:52:43 pm

That was the system, it started no matter how cold it was. Too bad the new stuff is so different. Sometimes to get the air out of the system I would take a rag dipped in gas, as either could blow the head off if the engine was warm when it ran out of fuel and hold it near the air cleaner to get it started when I was in a hurry.

Quote from: craneman – December 07, 2015, 02:52:43 pm

That was the system, it started no matter how cold it was. Too bad the new stuff is so different. Sometimes to get the air out of the system I would take a rag dipped in gas, as either could blow the head off if the engine was warm when it ran out of fuel and hold it near the air cleaner to get it started when I was in a hurry.

Mine was without the siphon break. I had all the shop manuals for the 3306 engines and gave them to the buyer of my equipment when I sold them. I still have a 1985 Ford crane with the 3208 sitting in a yard that I hardly ever go to as I changed to a International truck with a DT 466 and can only drive one truck in my business.

Re: Cat 3208 electric priming pump

Reply #15 – December 07, 2015, 05:06:51 pm

So how about the 3208 electric priming pump question

Madsen

Re: Cat 3208 electric priming pump

Reply #16 – December 07, 2015, 05:21:34 pm

Madsen,

Please post a picture of your Caterpillar secondary fuel filter-- it is possible that it is set up with a blockoff plate that makes it easy for you to add a standard Caterpillar manual primer pump.

Not saying you could not use an electric one, but also don't know that you need to "reinvent the wheel". And, you would have to make sure how you wired it-- could see a real issue if you developed a fuel leak that the electric pump just kept pumping!

Re: Cat 3208 electric priming pump

Reply #17 – December 07, 2015, 07:26:27 pm

I learned to fill the fuel filter itself with diesel fuel before screwing it on. Then pump the manual handle until it got hard and while it was turning over by an assistant.

Re: Cat 3208 electric priming pump

Reply #18 – December 07, 2015, 10:33:59 pm

My 91 GV has a 3208T which has a manual priming pump on the fuel filter. Works great when needed. It has only been necessary to prime the engine if it sits for over about a month. Have a great day ---- Fritz

Re: Cat 3208 electric priming pump

Reply #19 – December 08, 2015, 12:51:40 am

Quote from: craneman – December 07, 2015, 02:52:43 pm

That was the system, it started no matter how cold it was. Too bad the new stuff is so different. Sometimes to get the air out of the system I would take a rag dipped in gas, as either could blow the head off if the engine was warm when it ran out of fuel and hold it near the air cleaner to get it started when I was in a hurry.

Craneman's comment about the ether is right on. While ether can aid a cold engine starting, it can just as easily blow up a warm engine. Truckers and other professional drivers get training on cold starting but RV drivers may change filters on a warm engine, not be able to start it because of air in the system and then squirt some ether into the intake.

While diesel needs about 500 degrees for auto-ignition, ether only requires about 425 before it explodes. Unlike diesel that is sprayed in at an exact moment, ether arrives along with the air and when compressed to the 425 degrees, it's only part way up on the compression stroke in a warm engine. This can break piston rings, blow off the head, pull studs or bend connecting rods.

Pierce

Re: Cat 3208 electric priming pump

Reply #20 – December 08, 2015, 10:18:38 am

Fritz
You say you have a 1991 Grandvilla with a priming pump on a 3208 T could you tell me where the pump is
better yet post a picture ?
Wolfe
Sorry but I do not have a Secondary Cat filter or priming pump on my 3208 t ! ( That I can see or find ) I am beginning to think that someone removed that Cat priming pump and secondary filter.

Yes I am aware that I need to plan for a situation where motor quits and the pump keeps pumping
Probably wire the pump to an oil pressure where oil pressure allows pump to work . No oil pressure no pump.
My ideas about this modification have come from the Bluebird and school bus forums where people describe the best fix as putting in the primer pump to eliminate the air sucking leak issues associated with the Car 3208 motor.
Would also install a momentary button where I could use the pump to push fuel to prime and bleed with out attempting to start the motor. Likely do that on the front wall of engine compartment under the bed.

Re: Cat 3208 electric priming pump

Reply #21 – December 08, 2015, 10:51:36 am

The Cat engines I had used an oil pressure switch to start the hour meter. I am sure it would work for the pump you are planning. In my opinion I would wait until you have eliminated the idea of putting the Cat filter and priming pump on before using the work around.

Re: Cat 3208 electric priming pump

Reply #22 – December 08, 2015, 11:11:52 am

Craneman
Using an electric pusher pump eliminates one of the few bad features associated with the Cat 3208 motor especially as used in these motor home, school bus, Wanderlodge configurations. That being that the injection mounted lift pump sucking air and having the motor quit. With the pusher pump installed you know when you have a problem and where the problem is because instead of leaking air being pulled into the fuel delivery system which gives you no warning, you have diesel fuel being pushed out of the fuel system which if you are paying attention lets you know you have a problem before your dead on the side of the road.
John

Re: Cat 3208 electric priming pump

Reply #23 – December 08, 2015, 11:27:34 am

I was not aware of the issues that you mention. Oil pressure switch and momentary switch to start is what I used on my race car to shut the engine off when no oil pressure was present. I was watching the tach not my gauges. You would get the same benefit.

Re: Cat 3208 electric priming pump

Reply #24 – December 08, 2015, 12:54:58 pm

Quote from: Pierce & Gaylie Stewart – December 08, 2015, 12:51:40 am

Craneman's comment about the ether is right on. While ether can aid a cold engine starting, it can just as easily blow up a warm engine. Truckers and other professional drivers get training on cold starting but RV drivers may change filters on a warm engine, not be able to start it because of air in the system and then squirt some ether into the intake.

While diesel needs about 500 degrees for auto-ignition, ether only requires about 425 before it explodes. Unlike diesel that is sprayed in at an exact moment, ether arrives along with the air and when compressed to the 425 degrees, it's only part way up on the compression stroke in a warm engine. This can break piston rings, blow off the head, pull studs or bend connecting rods.

Pierce

All Foretravel installed ether systems are thermostatically controlled and do not function over 50 degrees F.

Measured shot of ether. Perfect results with lots of ORED and unihome customers long ago.

My m11 has the system and I would not hesitate to use it if conditions required its use. Backup for the block heater and aqua hot motor preheater.

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