turbo owners: caution in transport

[DraftHorse]

I was at my dealer the other day and talked with service staff about this issue. It seems that Kubota had issued a service advisory on this very topic. From what they said, there have been several failures related to this issue, and not only with Kubota. They are a big Ag dealer and handle a lot of big equipment and they all are prone to this type of failure.

According to them, the units with the upright stacks with clappers have more failures than the low slung units because when transported, the wind force forces the clappers open which allows moisture and dirt particles into the turbo.

They also told me it is not uncommon for the farmers that transport equipment between locations or to the shop, tend to leave them running (non HST units).

So it seems that there is validity in this issue and not only with Kubotas.

Looks like I will be making an easy-clamp cover for my 5740 c/w cap reminder.

Peter

 

[Smokin Diesel]

Normal diesel have no overlap in their valve timing, there dead ending the tube.

Not true. Overlap is a 4-cycle piston engine thing. Fuel type is irrelevant.
Diesel Cycle

 

[SPYDERLK]

I think its a crock.
Not THAT MUCH suction across the top of an exhaust, certainly not THAT MUCH air able to enter via......
Well, lets see; an open inlet AND exhaust valve (on the same cylinder) the air filter.
Enough to spin up a turbo ?
and Oh BTW, [[[the other end of that turbo shaft has to push the compressor around ?]]]

[[[Iv been thinking about that.]]] I think the air coming in the intake and feeding thru a cylinder and out the exhaust tends to power the rotor on BOTH sides. The compressor side is not a load in this scenario. However I, like near everybody, cant believe the air forced thru the very restricted path of the system, at the very small pressure available to push it, would amount to enuf to overcome a static rotor. Still, I wish I knew this when my tractor was trucked. Id do the cheap insurance.
larry

 

[ray66v]

Upon further consideration, no matter how much air blows into the exhost pipe, the turbo will not be turned by it. Because, the fins are curved in the opposite direction. The fan does turn freely in either direction. But, air is only going to turn it the way the fins are curved. This was confirmed by static testing with a turbo & a leaf blower.

 

[SPYDERLK]

Upon further consideration, no matter how much air blows into the exhost pipe, the turbo will not be turned by it. Because, the fins are curved in the opposite direction. The fan does turn freely in either direction. But, air is only going to turn it the way the fins are curved. This was confirmed by static testing with a turbo & a leaf blower.

it doesnt blow into the exhaust. The air goes thru the whole breathing track in the normal direction.
larry

 

[ray66v]

it doesnt blow into the exhaust. The air goes thru the whole breathing track in the normal direction.
larry

You should tell the brain trust at TORO that.
http://www.toro.com/customercare/commercial/bulletins/general/pdf/03-03.pdf
(It's not going to turn very much, if at all, the other way either)

 

[SPYDERLK]

You should tell the brain trust at TORO that.
http://www.toro.com/customercare/commercial/bulletins/general/pdf/03-03.pdf
(It's not going to turn very much, if at all, the other way either)

You hit it with 'brain trust'. I think they are simplifying a more complex situation in order to fit within the attention span of TCMITS. The frontward pipe would favor backflow - air, debris, water. Rather ineffective at spinning, but cover it up and you solve everything with the scattergun approach without learning any non fiction. It cant be argued that covering is a bad idea.

(I agree, and said that a few posts back.)
larry

 

[Dargo]

Hot dog! I put my leaf blower on my exhaust and blew all the dust out of my air filter!

Just kidding on that. My turbo tractor is not a Kubota, but I did get out the manual and look up the trailering section. It did not say anything about covering the forward facing exhaust outlet. I bought this tractor as it was being repo'd and trailered it nearly 800 miles home on interstates running between 65 and 100 mph. That was a couple of years ago. I've not had any issue.

By no means do I know if this is phenomenon is fact or fiction. However, I actually did use a small (and basically worthless) electric leaf blower to blow air into the exhaust outlet. From all indications, other than discovering a loose exhaust clamp that was allowing air to leak out, it appears as if air does not flow into the exhaust. Your mileage may vary and this proves nothing other than it appears as if this idea does not seem to hold true on my tractor.

 

[2Botas]

Normal diesel have no overlap in their valve timing, there dead ending the tube.

Are you kidding??? Valve overlap is crucial to the efficiency of any 4 cycle engine, no matter what fuel they use. I realize your whole post has alot of information about trying to move air in a system with one end closed, and all of what you said is correct for that situation. but i am sorry to say, that does not apply here. If one cylinder happens to be in the appropriate position in its cycle, both valves could be open, thus the tube is not dead ended.

 

[slowzuki]

Ok full explanation, 2 stroke supercharged diesels and turbo diesels have useful valve overlap, the two stroke for scavenging and the turbo for exhaust valve cooling and scavenging. But look at a diesel exhaust manifold, there is no tuning. This goes extra for the turbo diesel, the turbo destroys any exhaust harmonics.

Average normally aspirated diesels don't have a real lot of functional overlap. What I mean by functional overlap is the valve lift is small during overlap. This is because under full load there is residual pressure in the cylinder and it would blow back out the intake if it was open very much.

Ken

Are you kidding??? Valve overlap is crucial to the efficiency of any 4 cycle engine, no matter what fuel they use. I realize your whole post has alot of information about trying to move air in a system with one end closed, and all of what you said is correct for that situation. but i am sorry to say, that does not apply here. If one cylinder happens to be in the appropriate position in its cycle, both valves could be open, thus the tube is not dead ended.