Anyone done the 600hr front axle pivot or 800 hr engine valve clearance adjustment?

[IslandTractor]

Reviewing my DK40se maintenance schedule chart I see that my tractor hours are coming close to a few adjustment items I haven't done before. Has anyone done the front axle pivot adjustment or the engine valve clearance adjustment? I do all maintenance services myself (tractor is on an island) so am trying to figure out how involved these are. Anything needed other than feeler gauges and wrenches?

 

[ritcheyvs]

I have done valves on other Diesel engines. I expect access is the main issue with a tractor. Off topic, but the hoods on my W123 and W126 Mercedes cars can lock in a 90 degree vertical position - very nice for engine work.

Make a diagram (or copy from manual?) to keep track of before and after measurements, which valves have been adjusted already, and which are intake vs exhaust.

The gap changes when you tighten the lock nut so there is an art in guessing how much to turn the screw before re-tightening the nut. Typically I need to adjust the first few valves several times to get it right until I get the hang of it; after that it only takes one or two tries to get it right. When it's right, the next larger feeler gauge won't slide in.

Of course you need to turn the crank (only in the direction of normal rotation) to position the camshaft, which may be a challenge unless you have a helper to watch the valve position while you slowly turn the crank. You need to go slow or compression will mess up the cam position, requiring another two turns.

 

[oldpilgrim]

so tell me why diesels need valve adjustments while no other gas vehicles with solid lifters do.

 

[ritcheyvs]

so tell me why diesels need valve adjustments while no other gas vehicles with solid lifters do.

First. your premise is wrong. Most or all gas (and propane) engines with overhead valves push-rods, and solid lifters have provisions and specified intervals for valve adjustment. That would include my 22 hp B&S riding mower, my Generac standby generator, and my BMW motorcycle, just as examples. I don't think there have been production US cars with push-rods and old-style solid lifters since the 60s. Many newer cars have overhead cams use a mechanical "bucket and shim" lifter directly between the valve stem and the cam (no rocker arm).

Second, Diesels are more sensitive to valve timing. They will have a cold starting problem if the valves aren't right. The heat for combustion requires compressing a volume of air, like 20:1. If some of that air escapes because of valve timing (or poor compression) the compressed air mass may not be hot enough to initiate combustion.

Third, Our Kioti engines (like many smaller engines) have the cam in the block and use push-rods between the tappet (which rides on the cam) the rocker arm. So there are many potential wear points between the cam and the valve stem. This is a rugged, proven design but occasional valve adjustment may be needed to compensate doe wear

 

[DK35vince]

so tell me why diesels need valve adjustments while no other gas vehicles with solid lifters do.

My motorcycle, ATV, side by side, zero turn, Etc. all call for valve adjustment checks at certain miles/hours

 

[DieselBound]

If you can pull glow plugs out that will make it a lot easier to rotate the engine as you adjust the valves.

Haven't adjusted valves since my hotrod youth days! I think I'm still a ways off from having to do this on my B7800 (2,000 hrs or 3,00 hrs, can't recall).

 

[tcreeley]

It is down the road on my tractor. I don't look forward to it. Had a MGB once and it was easy to get at the valves, easy to adjust. I hate fiddling with a wrench, trying to apply pressure at an odd angle with a feeler gauge in the other hand.

 

[IslandTractor]

Thanks for the comments guys. I have a related question: richeyvs implies that maladjusted valves would lead to cold start problems. If my engine starts easily can I put it off indefinitely or is there a risk to the engine?

Also, DieselBound suggests that his Kubota doesn't call for valve adjustment until ?2000hrs. As Kioti and Kubota engines are quite similar technology, is Kioti being overly aggressive by suggesting valve adjustment at 800hrs?

I want to take care of the engine properly but I'm not necessarily a "by the book" type if there is a good rationale and experience for doing it otherwise. I'm well aware that engine companies tend to exaggerate.

 

[ritcheyvs]

... If my engine starts easily can I put it off indefinitely or is there a risk to the engine? ...

I don't know enough about the thermal expansion properties of Kioti engines to answer.

In my old (617) Mercedes Diesel engine (overhead cam) the valves get looser as the engine warms to operating temperature. So if that engine starts it will be OK. But the Kioti valves have an entirely different setup; possibly they get tighter with temp?. If so, valves that start too tight could be a problem.

 

[tjkubota93]

so tell me why diesels need valve adjustments while no other gas vehicles with solid lifters do.

Any engine with a solid lift cam requires adjustment. Gas or diesel.