L1 22DT engine trouble

ozyclint · May 25, 2020

hi guys, just joined the forum. i'm in Australia and have what i believe is a gray market L1 22DT refurbished by SOTA tractors.

i was using it the other day when the engine suddenly began missing upon acceleration. i blows black smoke when trying to accelerate, misses then picks ups revs. lacks power.

i have checked the fuel system as far as supply to the injector pump which seems ok. with engine running there is fuel at each injector.

by chance i put my hand over the air intake and noticed pressure coming out like as if the compression stroke of one of the cylinders was pushing back into the intake. i took the air cleaner out and it was loud and clearly there was something pushing air out into the intake.

i thought perhaps that maybe there was a broken valve spring allowing this to happen, (which would explain the sudden onset of the issue) so i pulled the rocker cover to find that all the springs are fine.

thinking about it more, is it possible that the head gasket has blown in between cylinders allowing cross feed of compression between cylinders and into the intake? this would also explain the sudden onset of the issue.

if i take the head of to inspect it is it mandatory to use new head bolts and gasket even if the old one is intact?

i was thinking of testing this theory by taking the the rocker assembly off then applying compressed air to the cylinder via the injector port. i can then manually depress the intake valves to check if it is bypassing between cylinders. being careful not to cause valve/piston contact of course. but i guess i don't have to have the rocker assembly off to do this if i just crank the engine by hand to close the valves in each cylinder before testing.

can anyone give me the head bolt torque specs and sequence? also the rocker assembly torques and valve clearances?

am i on the right track or is there some thing else to check? the back pressure through the air intake was a huge red flag to me that's all.

thanks. clint

GeoHorn · May 25, 2020

ozyclint said:
by chance i put my hand over the air intake and noticed pressure coming out like as if the compression stroke of one of the cylinders was pushing back into the intake. i took the air cleaner out and it was loud and clearly there was something pushing air out into the intake.

i thought perhaps that maybe there was a broken valve spring allowing this to happen, (which would explain the sudden onset of the issue) so i pulled the rocker cover to find that all the springs are fine.

thinking about it more, is it possible that the head gasket has blown in between cylinders allowing cross feed of compression between cylinders and into the intake? this would also explain the sudden onset of the issue.

if i take the head of to inspect it is it mandatory to use new head bolts and gasket even if the old one is intact?

i was thinking of testing this theory by taking the the rocker assembly off then applying compressed air to the cylinder via the injector port. i can then manually depress the intake valves to check if it is bypassing between cylinders. being careful not to cause valve/piston contact of course. but i guess i don't have to have the rocker assembly off to do this if i just crank the engine by hand to close the valves in each cylinder before testing.

can anyone give me the head bolt torque specs and sequence? also the rocker assembly torques and valve clearances?

am i on the right track or is there some thing else to check? the back pressure through the air intake was a huge red flag to me that's all.

thanks. clint

Lots of diesels momentarily puff air backwards, especially at low speeds. This facilitates the centrifugal-air-cleaner action. Before disassembling anything I think I’d do a compression-test first, if you suspect valve problems.

Dave_eng · May 25, 2020

Unfortunately your tractor was never sold in North America and info on it is very limited such as the engine is a D1462 1.5 litre 86mm bore 81 mm stroke.

You are observant to note the pressure in the air intake. Clearly something is not right.

To test cylinder leakage using compressed air, just rotate the engine until both valves on one cylinder are closed. No need to remove the rocker arm.

Head bolts can be reused but never the head gasket.

Searching for info on the D1462 may be more productive than searching for the tractor

Dave

North Idaho Wolfman · May 25, 2020

ozyclint said:
hi guys, just joined the forum. i'm in Australia and have what i believe is a gray market L1 22DT refurbished by SOTA tractors.

i was using it the other day when the engine suddenly began missing upon acceleration. i blows black smoke when trying to accelerate, misses then picks ups revs. lacks power.

i have checked the fuel system as far as supply to the injector pump which seems ok. with engine running there is fuel at each injector.

by chance i put my hand over the air intake and noticed pressure coming out like as if the compression stroke of one of the cylinders was pushing back into the intake. i took the air cleaner out and it was loud and clearly there was something pushing air out into the intake.

i thought perhaps that maybe there was a broken valve spring allowing this to happen, (which would explain the sudden onset of the issue) so i pulled the rocker cover to find that all the springs are fine.

thinking about it more, is it possible that the head gasket has blown in between cylinders allowing cross feed of compression between cylinders and into the intake? this would also explain the sudden onset of the issue.

if i take the head of to inspect it is it mandatory to use new head bolts and gasket even if the old one is intact?

i was thinking of testing this theory by taking the the rocker assembly off then applying compressed air to the cylinder via the injector port. i can then manually depress the intake valves to check if it is bypassing between cylinders. being careful not to cause valve/piston contact of course. but i guess i don't have to have the rocker assembly off to do this if i just crank the engine by hand to close the valves in each cylinder before testing.

can anyone give me the head bolt torque specs and sequence? also the rocker assembly torques and valve clearances?

am i on the right track or is there some thing else to check? the back pressure through the air intake was a huge red flag to me that's all.

thanks. clint

Same head bolts
Always a new gasket and O-ring (oil transfer tube).

Compression test would tell you more than anything.

Bolt sequence is from inner to outer, I can give you the exact sequence and torque valves if you end up pulling the head.

ozyclint · May 25, 2020

thanks guys. looks like i have to fabricate some sort of attachment for a slide hammer to remove the pencil type injectors it has in order to do a compression test with compressed air.
will report back after i get that done.

thanks heaps!

ozyclint · May 25, 2020

well i decided do the compression test through the glow plug ports rather than try to get the pencil injectors out because the glow plugs screw out. just have to take the inlet manifold off to get to them.

after taking the inlet manifold off it was immediately evident that the number 3 port is oily black. the others are squeaky clean. to me that indicates either number 3 intake valve problem (not what i suspect) or a blown head gasket between number 3 and number 2 cylinders. as number 2 is trying to compress it is leaking pressure into number 3 at a stage in its cycle where the intake valve is open.

thoughts?

GeoHorn · May 25, 2020

What are the actual compression readings on each cylinder?

Often a head gasket leaking between two cyls will result in those two cyls having similar or identical compression readings.... both of them on the low side.

ozyclint · May 25, 2020

Sorry I mislead you there. I decided to go through the glow plug port but actually haven't done the test yet.

North Idaho Wolfman · May 25, 2020

I'll bet you could have a head gasket issue, sounds right for your symptoms.

ozyclint · May 26, 2020

didn't bother with compression testing as there is something clearly wrong and the head has to come of anyway.

the gasket has blown between cylinders 2 and 3 causing back flow through into cylinder 3 from cylinder 2. glad it wasn't a burnt valve.

nice simple job now.

anyone know the head bolt/nut torques and valve clearances?
also are the clearances different between the intake and exhaust?
which valve is which? one is bigger than the other.

ozyclint · Sep 27, 2020

I got the head back on a couple of months ago and it seemed to run fine for a while. Just lately I noticed that the coolant overflow bottle was over filling and the radiator level would be down. So I would drain the excess from the bottle and top up the radiator but after use the next time I checked it it would have done it again.
Yesterday I was using it and it was sitting idling for a while when I noticed a puddle of coolant under the bottle. The temp gauge was showing it was hot. After that I checked the radiator level and it was way down. I topped it up and started it with the cap off and it was bubbling. Damn! I think the head gasket must be gone again.
So I pulled the head today. Gasket is intact. What I did notice was that a few of the head bolts seems loose. As in, I think they should have been way harder to loosen. Maybe they yielded too much upon torquing when I replaced the head gasket previously? I will get new head bolts this time as well as a new gasket. The head and block seem flat as far as I can tell with steel ruler and .0015" feeler gauge.

When I look in the right light it does seems as though there is evidence of compression getting past the gasket into 2 small blind holes in the water jacket. These ports are only about 2mm from the bore. Looks like number 3 piston is the culprit.

So basically the only thing I can think of is that the head bolts didn't tension properly. The gasket certainly doesn't appear to have failed and the block and head seem flat.
It only did 16 hours since I did the head gasket from it's previous failure.
Any thoughts??

Thanks

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L1 22DT engine trouble

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