Hey All, I bought a generator- a 500KW Cat D398 that was converted to Natural Gas. Because of the absurdly low price, I bought it without knowing if it ran. It's now time to test it. I have two questions: 1: I need to figure out what batteries I need to turn this sucker over. I haven't been able to find any information on what voltage and cranking amps I need for this motor. It has two rather large starters, and i haven't found info plates on them. Anyone know the volts/amps I need? As best I can tell, it's a 48.3L twin turbo V12 with 10.0:1 compression. CAT/Holt was unable to find any info on the batteries for me. 2: The generator head has had all of the control circuitry removed. There are three large bars coming from the head (480V 3Phase head), connected to the windings, but nothing else. The voltage regulator was removed, and I'm wondering if it's safe to start in this condition? My concern is that it will arc or otherwise damage itself without the regulator. Anyone know if it's safe to start as is? Thanks, Dan
It's been almost 20 yrs since I've worked around one which was diesel. IIRC the starters are 24 volt but don't quote me on that. As for the gen controls they are quite complex and I'd start a search for a complete one. Ours had an electronic governor which received it's signals from the gen controls and it was quite sensitive to even small load changes. I'd check w/ Cat for the gen control panel first. If your's has the electronic governor I'm not sure what it will do on startup w/ no signal, so be ready to manually control the arm on the governor that goes to the rack. If it's hydraulic type that runs off engine oil pressure it should work fine. Ours had a relay setup so when you turned the switch to "crank" it activated an engine oil precharge pump and when oil pressure was sensed then it would start cranking. Remove the back panel on the gen and remove the field brushes from their holders. No field current= no output. Not much help but that's all I can tell you. I hope someone on here has an operation and repair manual for it that can make a copy for you. If not you can maybe find one somewhere on the web. Good luck, Mike
Where is this thing? I am in Grass Valley and I work on generators for a living. I might like to look at it complimentary to give you some ideas at least, if it is not too far in the boondocks.
Thanks Mike. I figured it was 24V, they usually step up to that to keep amps and heat down. Maybe I can look at the impedance to figure out the current requirements. As for the field brushes, that's what I was thinking I might have to do. I'll pop the back cover and see if that's feasible. That would be great. It's in town, I'll PM you my phone number, and we'll work out a time for you to take a look at it. I'll need someone to put it all together. I've called two local generator guys, but they both only knew what they were doing up to about 10KW and were apprehensive to the idea of something this big.
OK Birken Vogt, I can't PM you because I haven't posted enough I think, but I found your number on Google. I'll call you tomorrow. Thanks again.
At least a pair of 8D batteries, maybe a pair for each starter. I worked on a pair of D399's (V16) in a tug, but they were air start.
An engine that big is almost certainly going to be 24V electrics. As a guide our 3516 gen sets had 4 x 8D 1200AH batteries wired in 2 pairs to produce 24V and that was for a single electric starter, not two...... Maybe a good first step would be to get hold of an Operation & Maintenance Manual. Plug the Serial Number into https://servicemanualpro.com/ and see what comes up. It ought to be about $35 for a CD version.
I'll check Service manual Pro, thanks. I haven't found the plate for the serial number yet either. The 3516 is bigger than the D398. sounds like 4 4d's or similar should do the trick.
Don't skimp on battery power is something I learned a long time ago....... I would suggest that if you decide to go for a 4D frame size then go for 1400AH batteries.
Yep, I agree Nige. I learned that one the hard way with my pickup.
Well the D398 gensets we used to have were set up with 32 volt starting systems. It was a pain at times finding big enough 8 volt batteries to hook up to get that voltage. On the other hand we had a D399 genset that was set up as a 36 volt system. Hard to be sure but believe that one was connected to six 8D's. Two sets of three in series to get the 36 volts then paralleled for the cranking amps. Did some digging and find that they list spec's for three different 50MT starters for the D(G)398-399 engines. They are 24 volt, 32 volt and 64 volt. Surprised that they do not list the 36 volt I remember our D399 had, unless they just used the 32 volt starters and upper the output of the alternator to get the 36 volts. I doubt running a 32 volt starter on 36 volts would do any harm. Heck I've been running my old Farmall BN with a 6 volt starter on 12 volts for about 30 years! Okay, might have a way to tell the voltage of the starters. Need to check the pull-in winding OHMS on the solenoids. Here is the spec's from SIS: As for the size of batteries I find this from Delco: Over to the right it lists the max CCA for a 24 Volt 50 MT as 1800 CCA. They claim too many CCA's can hurt a starter. From my experience the same is true or more so for too little CCA's. One other question I have is if you have two 50MT starters would one need to double the total CCA's? Guess that might require a phone call to Customer Service, number at this page: http://www.delcoremy.com/Support
I had heard of 36 volt systems on the tugs, but not 64... hate to cross that with a wrench, be like the 4th of July!
I actually remembered something after I went to bed last night! The voltage is almost always marked on the solenoid between two of the mounting bolts along with the Delco part number.
Thanks for the info. I found a rebuild tag on one of the starters. it had been painted over, which is why I hadn't found it yet. I called the company that rebuilt it, and gave them the number, and they said it was a 24V "50 frame" starter, which seems to match what you're saying. They were fairly certain it only needed 300 amps to turn the engine over. That seems really low to me. Considering the amperage should simply be the voltage/resistance, I have a hard time believing that too much battery would be a problem. Birken came out and verified that I still have a voltage regulator, so next step is to start this beast. I'll post a video when I try. Thanks for everyone's help! Dan
I agree that is way low. In a no load test with the starter setting on the bench the spec's are for 90 to 120 amps at 20 volts. Cranking over that 12 cylinder Cat would seem to take many more amps than that! A Cat 769C with a comparatively tiny 3408 uses two 8D batteries. My opinion would be that you will need at minimum of four 8D batteries. Connected with good 4/0 cables one pair to each starter and keep cables as short as possible to reduce voltage drop. I'm not familiar with the Natural Gas engines, just guessing they may run a lower compression ratio so they might crank easier than a Diesel but just the mass of the moving parts on a 398 will take some power to get turning. Does this engine have a pre-lube pump of some kind? The ones we had used a hand powered pump that we would work till the pressure gauge started to move then we would crank the engine over maybe 1/2 a turn with the starters then pump the oil pressure up again before even trying to start all while using the glow plugs to warm up the pre-chambers!
See, it has 1/0 wires running to each starter, and they're well used, so I'm thinking they're a reasonable size for the job. gives a little credit to the idea that this won't be a extremely high amperage job. Yes, the three differences between the diesel and the natural gas versions are the fuel delivery (direct injected vs mixer on the manifold), ignition (compression vs spark), and the compression (17 something vs 10.0) I don't have the slightest clue on the pre-lube pump. this is definitely something I want to know about to protect my engine if it has one, though. Where are these typically found?
10:1, yeah that won't need much to spin her over.
Yair . . . I know nothing of this engine but with large units like this in a powerhouse it was a requirement to bar them over at least a full revolution before attempting a start. If there is no provision for baring It would be prudent I believe to at least bump it over on the starters with no fuel to ensure no hydraulicing . . . maybe not so important on gas but on diesel one of those big injectors gone bad could put a lot of fuel into a cylinder which I found on several occasions. Water in a cylinder from a cracked head or injector sleeve could be catastrophic. kshansen makes a very valid point about pre-lube. The English Electrics, Mirrlees and Blackstones had electric pumps to charge the galleries, turbo and rocker gear. Such pumps, hand or electric are typically plumbed into an oil gallery external to the engine and often positioned adjacent the engine control/start panel so the operator can monitor pressure as it builds. Cheers.
Well maybe I'm way off in left field thinking this would need big cables. Makes me wonder if it even need two 50mt starters? To my mind 1/0 cables would be borderline for stating a 855 Cummins on a cold morning, but then I'm thinking of an engine with real compression! Only chart I could find quick said a 1/0 cable would be good for 170 amps so if the total amp draw on the system was 300 amps and it was split between two starters there would be a little extra capacity.
Did they mean 300 amps for each starter? Mike
Just remembered that 398 we had finally went in for overhaul at 20k hours. Still running good, just leaking oil and burning some. There's good things to say for an engine running at 1200 RPM's. Mike
Mike- Yes, they were talking about 300 Amps per starter. With only a few feet of cable, a 1/0 might last awhile at pretty high amperage. I would be very very interested in hearing what they pay to have it overhauled. I've got the fuel side of things together, and I have 2000CCA's of 24V ready to try to kick her over. I don't have a starter panel- I'm still very interested in hearing if anyone knows where I might find a pre-lube pump on the machine, or if it has one. I could figure something out to bar it over a turn or two if that's deemed necessary to pre-lube it. Or I could bump it with the starter and no fuel, if that's acceptable.
It's been 15 yrs so IIRC it's low on the right side of the engine. I could be wrong because I've slept since then, LOL!! You could crank it over w/ no fuel for maybe 15-20 seconds. I wouldn't crank much longer than that. Mike
Here's a photo of the prelube pump, but according to SIS, it was only installed on the 16 cylinder engines.
Ah yes, I have been intimate with a couple of those prelube pumps on the 399's, worked sweet after being reassembled correctly. As somebody mentioned though I remember seeing somewhere some manually operated prelube pumps, don't remember where.
I've come across engines with a manual diaphragm pump for emptying the sump. Maybe that's what you're thinking of.
You may well be right, I haven't done any actual work for at least thirty years so I'm told, so my memory is a bit hazy on some things...
lantraxco, ever change oil in a 399? 110 gallons and IIRC 6 filters!! Mike
We had twins, yes indeed, six elements in two stacks of three? I thought it was a drum of oil for each and a total of 110 gallons per service, but like I say it was long ago. On the boat we had suction for the drain oil tank, and filled off a clean oil tank with a pump, way too easy. When we were busy they ran around the clock so it wasn't long between services. They were old even then and not in their prime power wise, but I loved those big beasts... the pair would burn 2,500 gallons of #2 in 24 hours, towing at a hair over six knots in good seas and fair weather. They turned 8 foot wheels in Kort nozzles. Good memories.
Maybe the marine version had a smaller sump. Ours was for powering a portable crushing plant. Mike
Our D399 was used for various things last I was involved with was a continuous mix asphalt plant. The D398's were used to run "small" crushing plants and related screening plants. The 399 did have the electric pre-lube system like the one Cmark posted the 398's had a hand operated pump. It was not a diaphragm pump but sort of a vane type pump. It had a wing shaped thing on the shaft with check valves. Hold on I'll see if SIS still shows them, yep here it is: and here is the outside view: Note that the ones in the above pictures are shown as being "fuel priming pumps" which our's had and the "pre-lube pumps were identical, just plumbed in to the oil system. As I recall when pumping the oil you had to hesitate at the end of each stroke to let the pump fill with oil. You could feel a "thump" in the pump handle when the check valves closed. If you tried to pump too fast you would have lots of wasted movement in the handle. We would just pump both pumps full time till we got oil pressure showing on the gauges then just bump the starter to crank the engine about half a turn and go back to pumping. Of course a "gas" engine would not need the fuel pump. The D399 with the electric pre-lube pump had the glow plugs wired in so all the time you were pre-lubing the engine you were also heating the glow plugs. The D398 with the two hand powered pumps did create a problem with pumping two pumps and holding the heat start switch to "Heat" at the same time so we had a wire we could use to hold that switch on while pumping like crazy to get things ready to start.
Doubtful, it's more likely my memory is faulty. Considering we stood that boat on it's beam ends in storms, with the bows pointing at the sky one minute, and the wheels out of the water the next without losing oil pressure they must have had deep sumps.
Just an update, I heard this albatross is still gathering dust there, and the yard owner would like it gone....
Somebody should add it to their collection.....
If you want to ship it here I might find a home for it! Just let me know when it's on the way so I can be sure wife isn't around! Wonder what it would take to convert it to diesel, don't have natural gas lines clos to here!
12 pistons, 6 cylinder heads, maybe new camshafts, 12 injectors, the injection pump, all fuel lines, etc. just for starters, oh dear!