dongfeng tractor with y385t wont start help

[Ross71]

OK now I'm wondering why two pistons should break down so quickly. Oil starvation?

I would check that the oil pump is all as it should be, and that the oilways in the crankshaft and con rods are clear and unobstructed before reassembling the motor.

An hour prodding around with a bit of wire and pipe cleaner and the air compressor could save a lot of heartache. Even if you find nothing wrong it'll give you some peace of mind. It would be better to find and solve the root cause of the problem Rather than just fix the symptoms, only to have it happen again.

Ross

 

[Bob Rooks]

As for casting sand, that is common to find in a piece of new equipment. That's why I always drain the initial lubricants out after one or two hours use and replace them. Cheap insurance.
That's a very good practice, even if you're purchasing used equipment.

Virtually every manufacturer leaves some residue in castings and, the bigger and more complex the item, the more you're likely to find.
That's why the interior of gear cases, and some engines, are paint seal coated - to keep any loose casting sand from sluffing off.

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[Ross71]

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Virtually every manufacturer leaves some residue in castings and, the bigger and more complex the item, the more you're likely to find.
That's why the interior of gear cases, and some engines, are paint seal coated - to keep any loose casting sand from sluffing off.

This is news to me, but I'm sure you are correct. Even on a Volkswagen though?

 

[Bob Rooks]

OK now I'm wondering why two pistons should break down so quickly. Oil starvation?

That explains why it suddenly quit - overheated and siezed. Previous owner should be jailed.

 

[Rich Waugh]

That would be my guess, Bob. Operator failed to keep the radiator fins unobstructed or didn't check the coolant level and cooked the poor little critter. With only 60+ hours on it, the clearances would have still been tight and so it seized a couple of pistons, breaking the lands between grooves and the rings and tweaked the head, all the parts that heat up the quickest. Probably didn't even run hot long enough to hurt the bearings, if he's lucky. Never good to seize one up, but this does sound like about the most minimal seizure scenario possible.

I doubt it was oil starvation, Ross. He said the bearings he looked at seemed pretty clean and no oil wouldn't leave the bearings that way. I'm inclined toward a coolant issue, something that came on quickly and caused rapid rise in temps in the combustion chambers/cylinders seizing the rings in the bores.

 

[Bob Rooks]

Even on a Volkswagen though?

I believe Volkswagens are all investment cast aluminum. Doesn't apply there. Also, usually only applies to cast iron, but even our EMD 710 engines which are welded fabricated steel with only a few cast iron components, are still seal coated.

 

[sd455dan]

OK now I'm wondering why two pistons should break down so quickly. Oil starvation?

I would check that the oil pump is all as it should be, and that the oilways in the crankshaft and con rods are clear and unobstructed before reassembling the motor.

An hour prodding around with a bit of wire and pipe cleaner and the air compressor could save a lot of heartache. Even if you find nothing wrong it'll give you some peace of mind. It would be better to find and solve the root cause of the problem Rather than just fix the symptoms, only to have it happen again.

Ross

I disagree as to the oil pump being the culprit here - most pistons and cylinder walls are lubed by splash from the crankshaft throws (although some engines do utilize pressureised oil thru spurt holes in the rods and some do use oil thrown off from the rod journals) ... If the oil pump had failed it would be much more likely IMO to have siezed or spun crank or rod bearings especially on a new engine .

I think Rich is on the right track that heat- as in running a brand new engine hard right off the get go and then on a hot day running a high RPM implement like a rotary brush cutter at full speed and load- clearances tightened up friction increased and rings broke...If there are compression rings that are still in one piece I would insert one down its bore and check the end gap.. just to see if the gap is enough that the ends are at a minimum of around .014" wouldn't be the first time an engine suffered from being assembled a little tight... or not being broken in as per manufacturer ( and some chinese tractor engine manufacturers break in is a little brutal ...)

as for sealing the interior castings - all of the insides of the sumps of chinese manufactured tractors i have seen on TBN and my own have been sealed at the factory- and IIRC my American tractor was not...

 

[reelnative]

I'm curious, Who actually assembled the tractor in the first place? Dealer or customer. On a self build, is the engine a fully built component?

My dealer built 254 has never had any problem in 4 years that wasn't due entirely to my inexperience/stupidity.

I have heard of a build-it-yourself Jimna where the customer decided to take a look inside the assembled gearbox, and found that under all the cogs was a load of casting sand that hadn't been cleaned out!

hahahah ross dealers or customers dont assemble these tractors, some asain dude with a bowel of roman noodles in one hand and a jug of soi souce in the other assembled it, then they are crated up and sent state side and the dealers pull them out of a crate and put some parts on them, tires, seat, rops, ect test run them and make sure its all adjusted right and then out the door they go, thats why they are called chinese tractors hahaha if they were assembled here they would be called american tractors,

 

[reelnative]

yea I think the old man that owned it before me was out in a field mowing just like he told me but he prob let the rad get full of that fine grass that all of us have washed or blown out of our rads that ya get when your mowing, and didnt stop to clean it out and didnt look at the temp gauge and ran that poor motor till it just locked up, or started to lock up and she broke some rings and the piston, the rod ber all look good one had some marks on it but nothing you could feel when you scrape your finger over it, and no bluish color to it, and to the poster that said I should ck all the passages, it prob isnt needed but seeing that i have it open im gonna crawel up in there and will know every inch of that eng, seeing that im thinking it over heated i also will have a close eye on the water pump when it gets restarted

 

[reelnative]

I really want to thank Tommy at AFFORDABLE TRACTOR, hes the man, he got all my parts out to me today and he is a really strait shooter, the world would be a better place with more men like him in it, Thanks Tommy