Jinma 284 engine knock

I would look at valve lash, then a compression test. Injector timing isn't going to throw just one cylinder off. When I bought my 2008 it was a crate unit. Before firing it up for the first time I checked the valve lash, and one cylinder had one valve way too tight. Hopefully it's nothing worse.

Sounds like youve got air in your system.  This is a common issue.  To fix it, while the tractor is running crack the injector lines one at a time and let diesel fuel come out for a few seconds before re-sealing.  You will hear the difference in the engine when you do this.  Make sure you do this to ALL of them, not just #1.  I can pretty much guarantee this will fix your problem.  Also, as to why #1 is running a little cooler, is because your coolant enters the engine block in the front and as it heads towards the back it heats up from engine heat.  Hopefully this helps!  If you have any more questions feel free to give me a call. 

Trevor Nystrom

Keno Tractors

Parts Department

541-850-8193

866-363-8193

That has no effect on exhaust gas temperature Trevor, it is a compression issue, but due to the presence of blue smoke I suspect broken piston rings.

A dribbling injector can cause knocking from over-fueling on one cylinder, but since that has been discounted by switching injectors, that is not the cause. Injector timing will not cause this.

Bear in mind that #1 cylinder is closest to the fan so that portion will run cooler on the surface. Try your thermo test again this time shielding the manifold from fan air.

You're doing good.

first make sure that your fuel cut off(engine stop) is fully engaged pull the valve cover. On a warm engine retorque the head. Then turn engine over with the trans. in neutral and look at the valves when both valve rockers will rattle on one cylinder check the lash adjust  as necessary go to next cylinder. Hopefully you will not have a cylinder that the valves are so tight that they will not rattle. But if you do you have found a problem. remember better a little loose than to tight.

sorry I did not address the pulling the rad. if you have a socket that will fit the crank pulley bolt with out hitting the rad. then no. most people like to change all fluids around 50 hr. so if you are close pulling the radiator and rinsing it out is not a bad idea these engines have some casting sand in them when new so washing it out will save the water pump .I think I changed coolant at 100 hours also and have not had any water pump issues 500 hrs. later

the compression release depending on how far north or south you live from the equator how useful it is I live in Tn. only 4 miles from Ga. the compression release does not do much for me except being able to top off the oil filter after a oil change without the engine compression load on the starter , there are tractors with shuttle shifts that this is left off.

The blue smoke would concern me also that the misfire stayed with the hole and didn't follow the injector if it were mine I would drain a small amount of oil out the drain plug its a little messy but if you do it with the engine cold its not too bad pull the plug collect about a 1/2 a cup put the plug back in so you don't lose all the oil then check the oil for small chunks of metal or metallic flakes if there is metal present then something going on with the mechanical part of your engine broken rings or piston or when the engine/tractor was assembled  some careless person left some debris on the intake side which got into the engine and caused some damage I hope not as this can be an expensive repair.

Yes, I agree. You can also get an oil analysis performed for about $25 and that will tell you a lot. Maybe more than you want to know.

The #1 cylinder being cooler because of the coolant pump is pure bunk. I've operated many diesels large and small with thermocouples, never had an issue like that. The temperature you were measuring was of the exhaust gasses after combustion. The only way those temps would be lower would be inadequate combustion, which could be caused by lower compression from incorrect valve lash. Whitish grey smoke is unburned fuel or coolant in the combustion chamber. Glad you're happy with the fix, but I suggest doing another quick shielded thermometer check to be sure.

And let the engine run with the fan shielded for at least three minutes before taking your reading, allowing the manifold temps to equalize.

Just as a curiosity I'll run the thermo check on my TY395 dozer engine too. I'll perform the test at 1,500 r/m no load speed at operating temp. We can compare notes.

Just bumping this thread. I took a video of my EGT's through the manifold wall and shielded the fan draft. I took two series of checks, one on the top of the manifold, and one on the side. I just got back to civilization so will process the video soon.

For your entertainment:

I'm done. Let the wives' tales, misinformation, and superstitions run amok.

Ive had quite a bit of experience with diesels…. not just tractors.  Ive got thermocoupler in my 12v cummins, and my temps in the back of the engine are always hotter then the front.. Ive talked to several people and done a bit of research. I believe its because of how the water circulates in the block.  Don't believe its complete “bunk” LOL.

Modern internal combustion engines, gasoline or diesel, are designed for a maximum Δ-T of 15°F. To have more would create thermal shock and premature failure of cylinder walls. I didn't make this up. Long ago there was much discussion in SAE white papers. Check it out for yourself. Coolant circulation is designed SPECIFICALLY to eliminate hot or cold spots

Here is a Cummins K38 (V-12). How is #1 cylinder always going to run cooler? Or the cylinders at the rear allowed to run hotter? That's very poor thermal efficiency.

I maintain that your claim of lower combustion temperatures due to the proximity of the coolant pump is without merit. Please name your credible sources of information.

The type of engines we are talking about is a straight 3 or 4 or 6.  Much different cooling circulation then a v12.  Do a bit of research on straight style motors running hotter temps in the back few cylinders then the front few.  Theres tons of people saying this is how their engines run.  Yes, you most likely are right. But real life experience is sometimes more informative then what is “suppose to happen”.  As you even saw on your Yuchai the front cyl were warmer then the back.. lol so you cant argue to much either way.  I believe that is why they run hotter. And it does make sense, coolant in straight style engines runs from the front to the back.  Getting hotter as it reaches the back of the engine.  Sounds pretty logical to me.  

Well then I will concede that I don't know anything about diesel engines, and will no longer provide misinformation as a contributor to this site. Since you cannot back up your claims with verifiable sources I still maintain your claims to be without merit. I have never encountered your claims on Caterpillar, Cummins, Allis Chalmers, Buda, and other inline diesel engines equipped with pyrometers.