Rebuilt Cat 3204 motor will not start on own power.

JamesB1991

New User
I hope this isn't to long of a post but I need anyone's help on this one. The motor being worked on is a PC naturally asperated 3204 cat engine. I had recently pulled the motor out of our D3 dozer due to the motor having a large oil leak between the block and flywheel housing. The motor was on the tired side so we decided to have a reputable rebuild shop rebuild our motor. It was a long block rebuild, and since we rebuilt the motor we also had the injection pump rebuilt, new and tested injectors, as well as a rebuilt lift pump. The motor went back together like a dream until we tried to start it. As of now you can start the engine with ether, shut it off and you can start it right back up again on its own. wait more than five minutes you have to use ether again.
We have a book for this motor and followed the Cat timing instructions, as well as, using the correct timing plate for the accessory drive housing. The procedure the book states was to align the timing marks on the crank and cam, pin the motor on compression number one ( both valves being closed on number one/ having vale lash at number one), installing the timing plate into the accessory drive shaft, and then torqueing the accessory drive gear while the timing plate was installed. After all this one needs to only install the pump; due to the offset cutout of the pump shaft and accessory drive shaft the pump can only go in one way. After the motor was installed and no start persisted we verified the timing marks were correct by fishing a camera light down the front of the timing gear cover. and going over the process again....and again.....and again.
After verifying timing and doing it more than just once, we then moved onto compression. We used the glow plug port and had 425 on all 4 cylinders.
Maybe 180 degrees out on valve setting i was told. We checked and even tried to set it off 180 degrees but physically couldn't due to massive lash issues, as well as, pushrod to rocker clearance issues. So valve adjustment is good.
Lift pump fuel pressure is just above 40 psi. We sabotaged our fuel line from filter housing to injection pump by removing a section of it and installing a clear hose to see if we were inducing air into the system before the injection pump. No bubbles, and we started it on ether to run it a while to make sure it had no air bubbles in a running state.
Thought the pump was possibly rebuilt wrong and sent it back to the repair shop. Said it bench tested good. I trust the pump place as we have done a lot of business with them in the past.
No air restriction for intake on motor and the starter is cranking the motor fast enough.
Only thing we haven't done is re-tested the injectors. Which number 3 and 4 when twisted apart had fuel in them but 1 and 2 did not. Don't know if that means anything or not. Injectors were torqued to 55 ft-lbs per cat spec into the pre-cup chambers and cross over lines to 35 ft-lbs per cat spec. We removed injectors to verify possibly if we had mashed one by mistake and did not.
Glow plugs are working, and pulling good amps. We even removed them and grounded them to be sure how hot they were getting. Once it starts with ether the motor runs well. Took temp readings on exhaust and looked good. We did the recommended break in period for the motor and it didn't lack power as well as any hesitation It did however smoke a light blue haze the entire time of running. Was hoping it would clear up when warm.
While trying to crank the motor we do not get smoke initially. It takes about 5 seconds for the exhaust to begin to emit smoke and 15-20 seconds to get full fuel pressure. The color is a white smoke while trying to start. The motor will not sputter or cough at all while cranking. Once started with ether and moved to 3/4 throttle and above we did notice a cylinder cutting in and out. Didn't notice that before when running it. Haven't loosened lines yet to see which cylinder it is yet. While running we get a faint blueish smoke out the stack.
I am not making oil so no diesel is leaking into the oil. We ran this motor for 3 hours at 75% load for break in.
Put 2 new fuel filters on it, cleaned the metal screen on the fitting going into the lift pump. replaced all lines from tank to injection pump which that wasn't cheep.
This is as far as my knowledge goes. I've probably left a few things out but I think its mostly there. I have been doing this a little over 10 years now and haven't really come across something like this before. Seems like the motor just isn't getting fuel. Any ideas would be much appreciated and helpful. I thank you for your time if you have read this and look forward in fixing this motor with your help.
 
What do you get for fuel pressure when cranking the engine?
Those early 3204's had a built in orifice in the fuel return circuit. If that got omitted or changed cranking pressure suffers.
 
Tell me more about the Long Block Rebuild. Could the rebuilder have installed DI pistons rather than PC pistons?
 
Being that you have glow plugs it is the early version of the 3204. I have had several of these. I am thoroughly embarrassed on behalf of Caterpillar for designing only one compression ring (plus one double ridge oil ring) to go each piston. I hope the rebuild shop used the upgraded piston design with more compression rings. When I overhauled one of these I had a terrible time getting it started (stayed with original pistons). It would have never started the first time without ether. I would highly recommend buying new glow plugs because it really seems to help. Even if they get hot when testing they may not be as hot as new ones. Does the starter turn over fast? If not you have to address that. After one good day's work it should start OK with new glow plugs. Your challenge does not at all surprise me if the engine isn't broken in yet. I've had four machines with the exact same 3204.
 
If the engine is running ok after you get it started that takes the timing out of the equation, when you crank the engine over are you getting smoke out the stack, you should be, no smoke no fuel, no start, with the fuel system serviced and you seem to trust the fuel people there are two tests I would do, first I would check the injectors for blow back, loosen the fuel lines at the injectors, with the stop control in stop crank the engine over watching the injectors for any blow back, if a nozzle sticks open it will allow compression to leak back into the pump causing an air lock, if that checks out ok stop the engine without using the stop control, stall it or, the reason is to see if it will start again from cold, if it does there is an issue with the pump rack.
Good luck
AJ
 
EB1953 that's exactly where we headed. Calling the rebuild shop they crossed the p/n from cat to theirs and are using the correct pc pistons. I was told by Garry Brown, the lead at the pump/engine department at Hillsboro Cat, said that I would be having an interference issue if the wrong pistons were used due to the extreme cut outs that pc pistons use verses the di pistons. I believe that was if pc pistons were used in di engines. If pc pistons were used in di engines they would turn over without an interference issue, but have hardly any compression. I have no idea if this is true, but what I was told that by a man who says he's done many of these engines. Which makes sense when he explained the machining of the pistons on a di and pc piston. I was also thinking if they didn't install the pistons in correctly, by having them backwards, but then again I would be having an interference issue due to the cutouts of the piston for the valves.
The rebuild shop rebuilt our original motor; the cam and crank are thee original cam and crank that were in the motor. They said they looked amazing and only needed polishing. The internal parts are not genuine Cat but American made by a company called Interstate McBee. I was told that these parts are cheap garbage by some and others swear by them. We personally as a company haven't had and any issues with these parts in the past. The rebuild shop doing the work is called Northwest Castings. They are located in Portland Or.
 
Nordic thank you for your replay. I as well am not a fan on using ether. A diesel motor that gets started with ether will soon always need ether to start. I used ether as a last resort, but yes, the starter turns the motor over fast and strong. I as well was thinking glow plugs and did buy some which unfortunately didn't help. I hate being a parts changer and have resorted a little to that mindset on this project; I hate to admit this and know it's not the correct mindset to have. The motor has been broken in and still has the same issue. New without break in we were running 425 psi cold on all four cylinders which is plenty of compression to fire. Thank you for your input.
 
AJ thank you. I do trust the fuel rebuild shop as we have done a lot of business with them in the past. On this project though I am starting to become a little frustrated with their work. The lift pump we found, which I did not state earlier, was inducing air into the fuel system but that is now fixed; and was verified by installing a section of see through line as stated in the original post. I did however pull the injectors before I read your post and had them tested which found 2 were bad. I didn't get into it at the pump shop and just said ok and thank you even though they were supposedly new and had been tested! Sorry going on a tangent. It seems to me a fuel issue and the pump is what I suspect. I will do both tests. Even though the injectors were just tested I will still do the blow back test. I will try and stall the motor. I am not an operator and know very little on how to operate a D3 other than operating it to work on it. How would you want me to stall the motor. Same as testing the torque slip but at low idle, and how does this tell me the governor has been miss adjusted if it starts right back up after stalled? Thank you for your help.
 
EB1953 I have been gone the last four days and just replying to posts so unfortunately still not running. I did however pull the injectors before leaving on vacation and stopped by the pump shop on my way to the coast. They tested them then and there and found 2 out of the 4 were bad. As I wrote to AJ the injectors were supposedly new and had been tested prior to this...... I guess not. Not very happy about that. Going to run some tests today and will let everyone know that's chimed in what's going on.
 
Update on the motor. Injectors have no blow back, but the pump still delivers some fuel when the governor is in the no fuel position, which is interesting. Also I never pulled a compression check after it was hot. 425 psi cold seems plenty of compression, but just for kicks I checked it after starting the motor and having it reach operating temp. The motor was still at 425 psi. After starting the motor and getting it to fire on ether we ran it until it reached operating temp again. We then proceeded to check fuel pressure/temp verses engine shut down time. We cranked it up and it fired after one minute, two minutes, three minutes, five minutes, ten minutes, twenty minutes, and forty minutes with no problem on engine restart. Before it wouldn't start after five minutes of sitting so maybe it was the 2 bad injectors!!!. It did however crank slightly longer the longer it sat. Psi on the filter housing was dropping a little but would jump right back up when cranking. So fingers crossed we let it sit for one hour and tried to start it. After one hour and engine still very warm it would not start. Tested again after firing it on ether letting it warm up to operating temp and shutting it down for one hour; no start. One hour is the magic number. After one hour of of shutdown after the motor being at operating temp it will not start on its own power. The motor is definitely plenty warm, even hot I would say. Give it a sniff of ether after sitting for an hour and off she goes running great. We found after one hour fuel pressure at the filter test port drops from 40 psi to 15psi; it builds pressure right back to 40 when cranking. It's not temp related, or timing we believe, but fuel related.
At this time we are going to remove the fuel pump and send it to a different pump repair shop and see if something is miss adjusted in the governor assembly. I was told these pumps are very straight forward to rebuild and almost impossible to miss- adjust but at this point I'm hoping something is miss-adjusted in the governor.
I will let you know what happens.
 
Very interesting results with your testing. When you try restarting after one hour, are you using the glow plugs? If so, how many seconds? I will just say this because it happened to me with the very first 3204 I had... after just buying it and having this difficult starting and only depending on ether for results I got suspicious of the fuel in the machine, put in by the previous owner. The smell of the fuel was not quite the normal diesel smell. After emptying the tank and putting in good quality fuel it all changed, like a different machine all of a sudden. I assume you know the quality of your fuel, just be sure it's the best, to eliminate all doubt. If you put in one or two quarts of Automatic Transmission Fluid in your fuel tank you will be amazed at improved starting especially in lower temperatures.
 
The throttle control on all injector pumps does not have a direct connection to the rack, the stop usually pushes the rack to the stop position, the rack is pulled back through the governor by a spring to the run and speed position, if the rack sticks in the stop position all that will happen when you pull the throttle to run is the spring will expand and no fuel would be injected, next time you stop the engine put the throttle on full after stopping and see how that will fare on the next cold start, I think by what you say that the engine rebuild is good, was the machine starting before the rebuild without ether, that engine needs heat to start from cold, Nordic made a very valid point about the diesel is it ok, the engine needs four basic things to start from cold, heat,fuel,air and compression, if it belches out smoke while turning over what is happening then is the fuel is not igniting, why, glow plugs, not enough pressure to atomize the fuel, lack of air or poor compression, we know the compression is ok, air is ok or you would have black smoke, Hmm if you posted saying just about it not starting from cold and not mentioning the rebuild bet everyone would be saying glow plugs, you are sure that they are working, I know how depressing it must be after the effort you have made and I would say you done everything right, it seems it is down to the heat or the fuel, what does the ammeter say when you apply heat?, come back about the smoke and the ammeter.
AJ
 
Sorry everyone this is a long post. AJ and Nordic thank you for staying with me on this one. I have some bad news on this one unfortunately. After pulling the pump I noticed a metallic glaze to the motor oil....... I did not notice this on the dipstick after the initial brake in period. So pulled the filter and yes, massive amount of metallic. So we pulled the motor yesterday and it's not good. Massive play in the main bearings. After calling the rebuild shop and explaining to them what we were observing they gave us otherization to tear it down. Yes, we could of just sent it off, but I wanted to see what was going on. I have wasted serious time on this project and now know it's not looking like it had anything to do with the pump. After pulling the head we found we could move the pistons 40 thousandths inside the bore. Note we were not rocking the piston in the bore but moving the piston inline with the piston rod and crank. The rods and mains were hammered. The back side of the rod bearings all looked like they were spinning inside the rod eyes; but the tab on the bearings were not shaved off so they weren't spinning. Very weird with the measurements we came up with later. Back side of mains were fine. We checked bearing clearances for crank journals and rods and found them on the very outer limits on the tolerances. Needless to say due to the bearings being hammered. We checked the block main bearing ids and they were right on. Removed crank and checked the od on crank mains and rods journals and found them to be in spec. Thank God the crank doesn't appear to be damaged. Checked the cylinder bores of the motor and found them to be in spec and not out of round. Checked the id of the rod eyes and they are in spec. Measured the piston skirts as well as measuring them above and below the compression ring. Even with a lot of wear on the skirts they measured out. I don't know where the 40 thousandths is coming from...........Didn't know what the piston protrusion was suppose to be, but they weren't touching the valves. Lost the the camshaft. The lobs are gone on the outer base as well as all the followers. Rings were installed correctly and ring gap is good. All in all the motor checks out with the measurement side of things. Luckily the company I work for brought in the big guns and brought a machinist to help me take the measurements and readings on this thing. Either we are both really incompetent or we are seriously missing something here.
Our thought before dismantling the bottom end was that we were obtaining a good "static" compression reading, but while during a combustion cycle we were having a massive blow-bye effect due to the excessive play in piston to bore clearance. Just a guess though that we can't back up due to the measurements. I thought we would find a machined crank with standard bearings, or oversized pistons in a standard bore, or something of that nature....... I am at a loss on this one as well as the others on this project. I will inform you of what the rebuild shop says. Funny thing is now we get to send the pump off to have it cleaned and inspected again like we wanted!!!!! Got to laugh at something.
 
425 psi compression is not sufficient for combustion. I would expect 550-600 psi cranking and 620-660 psi run. Anything below 445 psi is hard starting. Seems this engine has several issues going on and some of the logic is faulty.
Fuel pressure should not drop from 40 to 15 psi when running.
 
Well I have to admit you had me fooled into believing you had done the right thing by having the engine rebuilt by a professional engine rebuilding shop, what went wrong, did ye run it without oil, did they use the wrong size pistons, I think if I remember there were three different size pistons, standard and two oversize, what is stamped on the piston, when those engines were overhauled at my place the procedure was machine in, powered washed, engine out, stripped, examined, block to the machine shop to be re-bored, pistons would be supplied by the machine shop, same with the crank, if it was reground they would supply the bearings, when the parts came back to us into the hot tank, rinsed off every port and orifice rodded out, blown out with air and finally purged with oil then assembled, engine back in the machine and hooked up, all fluids in, the engine primed with oil till the gauge pegs out, all new filters bleed and start, run it up for a few hours, check for leaks, covers/guards back on return the machine to the customer, that is a simple engine to put together, it is not the best Cat made but they do a fair lot of hours between overhauls, we had some come in that had been re-bore twice and had to sleeve them, is there a hitching pole outside your engine rebuild shop there is some cowboys somewhere, great learning curve for you.
AJ
 
40 thou, was standard pistons put into an oversize bore ?, that would be some rebuild shop, with those small diesels the best thing to do is have a remanufactured unit from Cat rather than trying to do them yourself, every second post on here is I rebuilt my engine, it will not start, it has no power, it's smoking it's heating, i rebuilt my shuttle the tractor wont move now, I replaced my brakes the wheels are locked etc etc that is the DIY syndrome, then coming on here like its a big big technical mystery when all it is is incompetence by whoever done the work, another thing is all those specifications and measurements, that is a sure sign of lack of experience and is only used by armchair engineers like a policeman using statue numbers to fool one about the law.
ED
 
That's a great comparison, it reminds me way back in the sixties when I got stopped by a motor cycle cop and when I asked him why he was quoting this number and that number of the road traffic act and me been who I am said to him you seem to be very good at numbers and it was a pity he wasn't as good the day he was doing the shelf stacking test at the super market and did not get the job and had to go to the free clothing association for a job when he could get a job no where else, that's life.
AJ
 
Old Magnet that was my thought as far as the compression being at 425 and not being enough to start the engine without some help. Cat doesn't have a spec. for compression on these motors, rather they have a leak down test which I did not perform. Was told by several Mechanics that anything above 300psi is enough. 300 being the absolute minimum as well as a hard start symptom in low ambient conditions. It had 40 psi while running and cranking but fell to 15 when off and sitting.
 
AJ as far as the motor goes the rebuild shop machined the block and pressed back in standard inserts. Everything in the motor is standard. The crank and cam were only polished and had all standard bearings installed. Number six rod journal had a massive scratch inline with the oil journal in the crank. As I said before a machinist came by and measured everything in the motor and said the measurements looked good. Other than that it honestly looks like the bearings, and all other damage, was due to a lack of lube condition or a massive contamination issue.
After installation I put oil in it, cut the fuel and cranked until it created oil pressure, then turned on the fuel to start after checking oil level. It was either a lack of lube or possibly shavings left in a journal somewhere after the machining prosses is what we're thinking. Don't know if they put enough assembly lube in it on assembly or not.
 
Penn you are right on the Cat reman. We should've spent the extra money on purchasing one from Cat, because now we're paying for it. Also, changing subjects a little, Penn that's what doesn't make sense about the piston/bore clearance. We measured the bores and all 4 are right on target. The pistons are standard with a standard bore. The book doesn't give a skirt diameter, but from the readings we obtained on the piston skirts there's not a 40 thousandths gap anywhere. With pistons in we have a 40 thousandths play. We're not getting this confused with the piston articulation either. I'm missing something obviously.
I tore into it just so I would have some ammo on my end when it goes back to the rebuild shop, but couldn't find anything wrong on their end as far as wrong parts being installed. It looks like it was a lack of lube issue or massive contamination in the motor that caused this thing to die. Which in that case I know the rebuild shop is going to fight this telling me it was my fault for this condition. Looking back we should have done the rebuild ourselves. Due to time that's why we shopped this one out, but now it hasn't saved us any time rather it's taking all of it.
 
Update on the motor. Sent the motor off to the rebuild center and they are going to put all new components in it and send it back. They did sate that there was no significant damage to the motor, so still doesn't explain why the motor wouldn't start. Sending the pump off to another supposedly reputable shop to see what the deal is with it. I'll keep you posted.
 
After a long and frustrating project the new motor is back, assembled, and installed. The fuel pump that we sent off to another shop is being finished up today and we had some good news for a change. The fuel pump had problems!! When the pump was undergoing it's initial rebuild the assembler sheared off pieces of aluminum from the aluminum tappets; these pieces then became trapped under the timing spacers. This is not uncommon I was told if one is not carful installing the tappets due to the ridge they acquire during their travel in the pump. The aluminum shavings that came off the tappets then became trapped under the timing shims. Fuel is then able to bypass through the gap they create and won't allow the pump to come up to pressure. This effect masks itself with rpm change. Hints why it would only start on ether. When rpms were gained from the shot of ether the pump was able to create enough fuel pressure to run, or get itself cycling fast enough to compensate the fuel loss internally. The higher the rpm the more the problem would become masked. They also found the governor spring guide damages which was causing the spring to hang up. Also on the pump which they found was that the low idle was set at 900rpm and high idle was set at 2800rpm!! We had this changed to 750rpm and 2100rpm.
Look forward to putting this pump in and firing it up.
 
Glad to hear about the progress. It sounds like the current shop is far more qualified to work on injector pumps! I wonder if the first injector shop would own up to any of their mistakes? Looking forward to your start up report.
 
I have only just seen this , to read everything will
take some time !!! My first comment is what oil are
you using in engine?
 
Post the serial number so I can determine what injector pump you have with aluminium tappets, aluminium would be way to soft to be used for anything like a tappet, the housing of the injector pump may be aluminium but all the parts inside are usually the hardest of steel, but greed can change things.
AJ
 
Well it went together very nicely, primed the oil system, and off she went. Motor runs very well and it's out of the shop. The serial number for the machine 79U878.

This post was edited by JamesB1991 on 06/24/2021 at 08:02 am.
 
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Glad if everything is working like it should... It has been a learning experience for most of us including the shops that did work for you. You have truly had your share of trouble and spending of money. Let's hope for many trouble free years!
 

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