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OPINIONS AND THOUGHTS
ARO 244 Engine Start
Complexity: Medium
Transition between Tractor and Car?
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Yes, it exists in fairly large numbers and various designs.
In 2020, the concept of the off-road vehicle means something completely different for the design engineers as in the 1970s at the Auto Romania automobile factory.
At that years the off-road expression did NOT mean only the 'feeling of life itself', but the average everyday tasks such as transporting half a ton of gravel or some pallets of timber materials.
So it’s not a standard delicate urban SUV that knows the fine mud only from the pictures, because today’s SUVs are advertised in a few aesthetic photos, illustrated on slightly muddy roads and that’s all their connection to the real terrain.
My very first impression was that this vehicle is something different, maybe a transition between tractor and passenger car. I'm sure, this vehicle was not so angry if its owner transported corn to home from the muddy fields or just wood from the snowy forests.
The older generation will surely still remember because many types of ARO were exported from Romania almost everywhere. I also remember this old school vehicle from my elementary school age. It was very loud and nicely smoked like any suction diesel vehicle at that time.
Ancient Technique in the Present
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This vehicle was a bit forgotten because it had been waiting in a garage for a decade and a half for its fate to turn for better direction.
It had all sorts of problems in the past and was partly shut down as a result of these.
The task was briefly to pull it out, then try to estimate its condition and start the engine if possible.
Real Heavyweight Champion
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This four-door 244 was manufactured by ARO Romania in Brasov.
Judging by the thicknesses of the materials it seems to me that this car is simply going through on terrain obstacles or breaking them completely down.
It doesn't have to be compared to anything because it was a completely independent brand with a huge production volume.
I would say the Russian UAZ as a possible co-brand which was made for similar purposes, but I prefer not to compare them because I don’t have too much experience with any of them.
By the way, the ARO started also from a Russian license base, but the ARO vehicles have been manufactured with engines of various types and brands, such as Peugeot, Ford, Toyota, etc.
This type of vehicle was certainly an excellent tool for its target customers if they paid enough attention to its maintenance. In the good old days, it was completely accepted that every driver was a mechanic as well. Larger maintenance tasks were performed even on the roadside, such as replacement of torn chain or belt, etc.
So there was no fashion to transport cars on trailers to the official brand customer service.
That was the time for custom and individual solutions and today we are only waiting for services with a smartphone in our hands. Maybe that’s why no one needs a car like that, apart from a few fans.
The robust off-road Machine
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Due to its robust appearance, I can't even estimate its consumption, but judging from its very loud and deep tonality after the first start this will not be the category below 10 liters per 100 km. I suppose its consumption can be between 15 and 20 liters / 100 km, but it also depends on the road quality and the driver.
Not just the small layer of mud on the exhaust muffler tells us that it’s a real off-road vehicle.
In addition to the large off-road wheels, it has a simple manual transmission with a half-gear switch lever and there is an extra manual all-wheel drive switch as well.
Moreover, it has quite large swingarms with very strong and long springs and each suspension is as thick as a beer can.
There are strong tapes under the rear bridge, so in case of breakage, the bridge can not fall into the mud. It is really a clever solution.
The owner has some documents for this vehicle, but these have not been found yet.
According to my estimation, its length is around 4 m, and its height is 1.9 m.
As far as we know the engine is 2500 cc simple suction diesel, which has a maximum torque of 170 Nm and a power of above 70 hp. So more likely that it will not set a newer speed record, but in return, it has enough big stomach for diesel consumption.
Well yes, the half-axles might not be happy with these wide off-road tires.
These belong to a much more serious machine.
The rear differential is respectable as well and the Cardan shaft is also quite thick.
Tremendous forces can be occurred in the powertrain. Especially if we even hook a trailer after it.
The needle roller bearing of the Cardan shaft can get a terrible load in off-road situations.
The amount of force and torque can hardly be imagined. When 100 Nm of torque rotates the Cardan shaft, it means that a mass of ten kilograms has a gravitational force of 100 N.
If this 10 kilograms weight is at the end of the 1 m force arm, then there is exactly 100 Nm of torque at the end of the force arm.
Always think one step ahead
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After the first sight, this engine start seemed like a bit far goal and a very bold thought, because several conditions were missed for a successful engine start.
Anyway, the engine oil level was satisfactory, the cooling system was not damaged, and it contained enough water.
However, the acid came out of the old batteries and left some dry powder behind on the surface.
This issue was quickly solved because a proper 170Ah battery was built-in instead of the old ones.
The old diesel must be replaced from the tank, but at first, we thought that perhaps there is no need to drain the diesel from the engine. On the one hand, the old fuels are much more stable on the other hand, with this step, the engine would be full of air bubbles. Anyway, it is quite sure, that some air bubbles have already entered the fuel supply system during the long years of parking because this is the most likely scenario, but we still wondered if we were lucky in this case. After the raw and fine filters of the fuel, a third transparent filter showed that the diesel was in good condition. It was a pleasant surprise and that is what we based all our hopes on.
Set the priority of problems
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The fuel pump can also be driven manually.
In the case of manual pumping, the pump arm must be harder after a while.
Unfortunately, it did not work at the first attempt, but later it just started to pump some diesel oil.
Perhaps the membrane may be partially broken due to its age. It was pumped up as much as it needed for a short engine run. So that was not the most important thing right then.
Now the supposedly damaged fuel pump cannot be disassembled because the entire fuel system would be airy and the engine would start much harder and would stop immediately after a short spin up.
So the goal was not to fix everything in this vehicle within a few hours but we had a couple of free hours when we could deal with it and then everyone went about their business.
So at first we only estimated up the whole situation and the more complex part of the work followed later.
Does the glowing system work?
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The preheating is essential for a more comfortable start of the diesel engine.
The glow plugs are heated by the electrical power of the battery.
After a little adjustment and a short check, this component was able to work almost properly.
Just to be sure brake cleaner was also used for the cold start, but let’s not go that far yet.
By the way, the glow plugs can consume a huge amount of electricity, and after the preheating comes the approximately 3 kW starter motor, which can put a really high load on the battery if the engine won't start. Therefore, we have also prepared with an especially powerful battery charger and start to assist which can provide plus 180 A.
I think the estimated starting current can be 250 A and the first peak current may be higher than 600 A. I can measure the cold starting current up to 2000 A and I have already measured the starting current for other vehicles but I did not measure this.
Does something get stuck?
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I quickly noticed during the first ignition cycle that the current consumption was huge, because the 170Ah battery with a cold start current of 1000 A just turned the crankshaft very slowly.
The diesel engine must be spin up quickly to start. Unfortunately, there was no decompressor either.
The engine was last started more than 10 years ago so all oil was at the bottom of the crankcase.
I thought the pistons slide dry on the oxidized cylinder wall and that is the main reason.
The situation did not improve even after several rotations.
At this time we had to take into consideration that bearings that may be jammed somewhere make the engine start especially difficult.
The belts were loosened and the parts were checked one by one, but all the pulleys ran well.
Meanwhile, I noticed that the generator was very hot and slightly smoked.
Thus the generator was disconnected from the power line, but the situation did not improve, the crankshaft turned only very slowly.
The small result is more than nothing
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After a lot of brainstorming, we realized that if the air filter tube is clamped down, then without intake air, all pistons move under vacuum.
This condition means something similar to a simulated decompression state.
This allows the starter motor to rotate faster during ignition with a significantly reduced load.
With this method and some brake cleaner, the engine was started for a few seconds.
Only the brake cleaner burned mostly in the combustion chamber which was sprayed into the air filter tube. I would say that this little result was more than nothing on the very first try.
The long-forgotten sound of this raw suction diesel was finally enjoyable for a few seconds.
Faulty component
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Finally, only the starter motor itself was the last possible option of the difficult engine start.
We didn't have to search too much because its starter is big enough, but it was especially difficult to unscrew and take out.
We don’t have a repair and maintenance hole, we had to lie under the vehicle in the grass.
So it was demounted with great difficulty and tested without load.
Well yes, there was a serious problem with the starter motor because, with tremendous huge current consumption, the shaft was just moved without load very slowly.
It is more than likely that the coils are burnt down and therefore there is not enough power in it.
It needs to be disassembled and completely renovated.
Summarizing the Story
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This car was parked in the garage for 10 or 15 years and it is likely that there could be air bubbles in the fuel system too, due to the lack of engine start.
So with a proper starter motor and fuel pump system, the elimination of air bubbles will be the next step in the coming days and weeks.
To get the best results out of this vehicle the mentioned repairs were carried out under the guidance of an experienced mechanic and I was just an observer and assistant in this story. That is why this topic is under the ‘Opinions and Thoughts’ section.
Let me tell You that I consider myself such a person who is a bit familiar with the subject of vehicles.
In my opinion, this off-road car is a great opportunity and an extremely valuable renovation fund from a technical point of view. We cannot meet every day such a story where an ancient technique was quite accidentally hibernated for the present.
I think it is quite an authentic and especially unique piece because it seems to me that it has an original Romanian suction diesel engine with a beautifully raw tonality under its hood.
Of course, there can certainly be more challenges in this vehicle and I’m not saying it’s an absolutely failure-free piece but I hope it is clear that this old school vehicle has an enormous value even for non-experts too because for preserving something in a beautiful state from the past is a very noble thing.
The results a few weeks later
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As I wrote it above in the first few hours only those mentioned guesses were made from our sid, but the professional mechanic who was there to help us was fortunately very experienced in the field of diesel engine. Thus, we were able to deal with all problems and difficulties in a very targeted and effective manner.
The old diesel oil was drained into a 20-liter can and the engine get completely fresh fuel and the old diesel filters had also been replaced at the same time, because the entire system was full of air bubbles everywhere and the mentioned diesel feed pump had to be checked and repaired as well.
Fortunately we were able to find another original ARO startermotor.
After that both have been taken to a vehicle electrics workshop for a professional inspection and maintenance, where the complete rotor component was replaced to the mentioned another ARO rotor which had a much more healthier windings.
The diagnosis was that the original starter windings were burnt a little and because of this reason they didn’t want to work too efficiently. So the result of this was that the original starter motor has been completely rebuilt in a very professional way. It has been already put back into the engine and since then it has been working perfectly and doing its job as it should.
Thus, this problem has also been solved in a very short way.
Of course, the generator was also sent to the same vehicle electronics workshop where it was inspected and repaired. I had a good guess that only the voltage regulator diodes were faulty.
So they have been professionally replaced and as a result we have a healthy charge again.
Only after these steps could the systematic deaeration of engine components began which processes were performed by our specialist alone who is a very experienced master in the science of repairing diesel engines.
Finally the well-designed and executed work has borne its fruit because it managed to start this old legendary machine. I immediately remembered that I had heard this sound many times about 20-30 years earlier and the characteristic diesel smell was also very familiar too.
Let us stop here for a moment.
I was expecting an especially big soot smoke from the exhaust pipe but it didn't come.
For me, this means that its engine could be in a very good condition. It is more than likely that the combustion should be perfect and could not eat so much engine oil. I didn’t try it under load, but I just played with the accelerator a bit and I would like to emphasize that this was my first impression. Therefore, I do not want to draw far-reaching conclusions from this.
In my closing thoughts let me say that I really hope that this vehicle will find its new owner very soon who will carry on this respectable legacy to the future, because I suppose that after correcting its smaller or larger issues it will be in the market soon.
Last but not least we could only fulfill this project with the powerful help of our mechanic what we thank him very much again.
ARO 244 2.5 D 4x4
ARO 244 2.5 D 4x4
ARO 244 2.5 D 4x4
ARO 244 2.5 D 4x4
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