Timing issue

[leonz]

What kubota or any other diesel engine have you seen the timing set to 0 tdc? The z1100 kubota engine was a small two cylinder engine and the timing spec on it is 24 degrees B.T.D.C ? Please explain.

Elmac Mine Boss buggies
were imported 2 wheel drive Kubota tractors and had the 2 cylinder water cooled diesels the engines them selves would be 41 years old now.

These tractors had full ROPS installed and rear cargo areas were added as well as 2 extra seats and full fenders on the front wheels.

 

[rdsaustintx]

Anything up to twenty five horsepower is in the EPA's Lawnmower class unfortunately.

EPA defines lawn-garden equipment as non-road, spark ignition (gasoline) equipment:

Lawn and Garden (Small Gasoline Equipment) | Nonroad Engines, Equipment and Vehicles | US EPA

 

[diesel466]

Elmac Mine Boss buggies
were imported 2 wheel drive Kubota tractors and had the 2 cylinder water cooled diesels the engines them selves would be 41 years old now.

These tractors had full ROPS installed and rear cargo areas were added as well as 2 extra seats and full fenders on the front wheels.

Thats nice about the rops and seats and fenders, But getting back to the engine, the z1100 was a two cyl. diesel of that era and its timing spec according the the factory manual was 24 degrees b.t.d.c. Show us a spec of 0 t.d.c.

 

[radioman]

I always read leonz dissassociative walls of text. No information about the tractor model or specific knowledge if his theory applies to the OP question. This don't mean we don't love ya leonz, just not on your astral plain yet...

These tiny, hi-revving, rubber-mounted, three-cylinder diesels shake like an Elvis pelvis. Both at low idle and at shut down. Just seems to be the nature of the beast. But they are purring beasts at WOT. My BX is (by far, hands down) the most reliable and abuse-tolerant engine I have ever owned.

I agree..:thumbsup:

 

[leonz]

I have some more information from the EPA and the tiers 1-2-3 engine data.


I have no quarrel with anyone but when they advance the injection pump timing 8 degrees after they assemble these newer tractors to get around the the EPA compliance emmisions issue...............

IF I knew how to quote and post another members comments on the shaking and how it stopped after they reset the injection pump timing I would post it here.

I do know that he traded in his B3200 for a larger model from what I remember.

 

[brain55]

Okay, I scanned through that EPA info. There was very little information on engines with less than 50 HP. I did learn some things about the engines with more than 50 HP. There are running the injection timing much later to help reduce NOx emissions. I decided to get out my Kubota M6040 (2006) manual and look at the injection timing (this is over 50 HP). and they have retarded the timing significantly from the old days. Timing is now 2.5 to 4.5 degrees BTDC.

I checked my B74, 7500 manual which is a little bit older (2000) but still post emissions (likely tier 1 or 2) and the injection timing is 17 to 19 degrees BTDC, still a long ways from 0 degrees.

I decided to look at my NH TC48, 55DA (> 50 HP) manual (2005) and it shows the injection timing to be 18 degrees BTDC, and my NH TC29, 33DA (< 50 HP) manual (2004) which shows the timing to be 21 degrees BTDC.

I also looked at my Kubota L30, 34, 37, 4310 (< 50 HP) manual (1998) and it is still showing 17-19 degrees BTDC.

Since I do not have a BX manual for any year I'm going to hold judgment for a little bit now. It guess it is possible for the timing in a post 2006 BX to be 0 degrees but I would still like to see it in writing.

Brian

 

[rdsaustintx]

I am a little confused here. The OP comment was about his tractor shaking at shut down. Shut down means no fuel is injected. How could injection timing have anything to do with how much a motor shakes *after* injection stops completely?

 

[Gordon Gould]

I am a little confused here. The OP comment was about his tractor shaking at shut down. Shut down means no fuel is injected. How could injection timing have anything to do with how much a motor shakes *after* injection stops completely?

It does't. His question just rekindled an old fire that was vaguely related.
This timing issue or question has been hanging for a long time. This is a good time and place to get it ironed out. IMO it needs to be done.
Keep going guys you are dragging out alot of good info in your research. Thanks.

 

[diesel466]

I was at kubota dealer today and looked at a bx1860 and a bx2660 and both said 21 degrees b.t.d.c. on engine id plate. Leonz saw where a guy had a b3200 that was running rough and had timing checked and it was found to be off 8 degrees and they advanced the timing back to specs and it helped. But what he does not seem to understand is that they did not set it to 0 tdc but advanced it. Again I have never seen any kubota that was set to t.d.c.

 

[638]

If you set a diesel engine to 0 degrees timing, the initial start of the flame propagation will be on the down stroke of the piston with a considerable loss of power. The only time I have ever heard of setting the timing at 0 degrees is on a hand cranked engine. After starting, the timing is then automatically or manually advanced. This is done to reduce broken thumbs from kickback of the hand crank.

 

[leonz]

It does't. His question just rekindled an old fire that was vaguely related.
This timing issue or question has been hanging for a long time. This is a good time and place to get it ironed out. IMO it needs to be done.
Keep going guys you are dragging out alot of good info in your research. Thanks.

-----------------------------------------------------------------------------------------

The rubber isolators are problematic in this regard as the force transmitted
is actually slowing down and the forces transmitted by the engine are much more pronounced at the 2 isolators and beyond to the tractor.

Generally when the vibration becomes more pronounced its an excellent indication that the rubber is failing or failed as their ability to absorb the forces created by the act of internal combution being transmitted by the three cylinders of the engine.

These engines also have mounting feet in some applications and the mounting feet can have rubber hockey puck isolators with spacers that are compressed when the mounting bolts are tightened to anchor the engine in place.


Ideally air bag isolators like the Timbrens would be a be all, end all for the motor mounts on these engines as the rubber bladder isolators s cancel all vibration.




The hockey puck type rubber isolators with the spacer pressed in the bore would be perfect as well for these engines as they come in many sizes.


I wil find the link or picture for the puck isolators and the Timbrens air bags and post it here when I have time.

 

[sqidget]

My bx-24 shop manual states on page
1-S17 factory spec for injection pump timing is 17*-19* BTDC. The only time you would set a pump to 0* is if it has a timing advance unit and the factory spec states so. Setting a inj pump to 0* static timing may indeed cause it to be smoother and less noisy because the piston is already on the down stroke when injection begins and the event is less violent, HOWEVER It will cause hard starting, low power, smoke, not to mention washing the cylinder out ( the fuel washes oil off the wall of the cylinder causing cylinder and ring wear and low compression) and causing sludge in the precombustion chamber due to incomplete combustion.
Anyone remember the sludge and problems in GM 350 diesels due to incomplete combustion?
Any way these engines do shake when shut down. I believe due to low rotational mass, after fuel injection is stopped the inertia of the rotating parts
is slowing and rapidly reaches a point where it will not fully compress the air in the combustion chamber and it stops turning. My BX sounds like **** when at low idle or shutdown, but try it with the hood and cowl off. The engine still shakes but doesn't sound so bad.
Dave

 

[bikerdib]

Can someone fill me in? I think it was in another thread that someone stated one reason the 3 cyl runs smoother than the 4 cyl is that the 4 cyl basically runs like a twin with 2 cyls on the power stroke at the same time. I take that to mean it is BANG ~ BANG, 2 + 2. So what about the 3 cyl? Is it bang ~ bang ~ bang; only one cyl on the power stroke at a time or is it BANG ~ bang; 2 cyls on a power stroke together and then one cyl by itself?

 

[Chilly807]

An inline three cylinder four-stroke fires every 240* of crank rotation, the cylinders are 120* apart, and fire on every second stroke. An inline four cylinder fires every 180*, the two "companion cylinders" are 1 & 4, and 2 & 3. When #1 is firing, #4 is on the intake stroke, etc.

Theoretically a 4 cylinder should be smoother than a 3, but it doesn't always feel that way. A lot depends on inertia, how much flywheel effect the engine has. Some engines also have counterbalance shafts which helps a lot.

Very few engines fire two cylinders at the same time. We have a V-16 at work that does that, essentially a big V-8 as far as the firing order goes.

Sean

 

[ENTS]

... but try it with the hood and cowl off. The engine still shakes but doesn't sound so bad.
Dave

You have a good point there. My consternation at shut down may be from the rattling of the sheet metal. I think the easiest thing for me to do is wear heavier ear protection and look the other way when I shut it down :laughing:

 

[roma3112]

At least you have sheet metal that shakes when you shut down, on my bx24 everything is plastic!!! I have already had the headlamp module crack and the lower cowl has been replaced (all warranty). Now that the warranty is almost up i will just cross my fingers.

 

[bikerdib]

Chilly807, thanks for clarifying that for me. That is actually how I understood it worked but in another thread (possibly even another board about the same subject) I thought I read someone else write that they thought 2 cyls fired at the same time.

 

[TGReaper]

I have a BX2200 that likes to do the shake,rattle and roll,and I just assumed it was the nature of the little beast.
I have 4 other diesels 2 - 4cyl. 1 - 6-cyl. and 1 - 8 cly. Three are indirect injection and they all have strange start and stop caracteristics.
I have noticed the fewer the cylinders the more violent the shaking.
Shutting down and starting with a throttle opening a bit above idle helps.
Dan

 

[leonz]

If they little buggers had manual shut downs it would be much less of a problem for all of you as the manual decompression would allow quick starting and no banging at start up or shut down.