KE70 engine low power?

[Ilikeurtractor]

I am at only 3800 feet elevation, my two cylinder TX1500F Iseki has lots of power and good low end torque. It has much more power than traction. I have no way of loading it except pushing the front end loader into a pile of dirt and it will spin all four wheels quit easily. Oh and it makes black smoke in abundance when it is accelerating the engine or pulling hard in high gear up a hill. It reminds me of the old diesel trucks of the 60s. Mine uses no oil. I do not know if this is any comparison for your tractor. I am really impressed with how had it pulls at low RPM it reminds me of the old 2 cylinder John Deers, they will lug down to nothing and still want to pull.

I certainly can't say the same for mine but it is the smaller of the two engines but I still think it should be a fair amount stronger than it is. In the higher gears (4th, 5th, 6th) when I get it rolling at lower rpm, opening the throttle wide only makes smoke and it takes a few seconds to get up to speed with virtually no feel of acceleration. Climbing a slight hill in any of these gears and I have to be careful of stalling out especially below 3/4 throttle.

I guess I'll be looking at a rebuild in the near future. Looks like engine kits are nice and expensive (I question whether it's worth it at this point). Anybody know of any "deals" for parts out there?

 

[Kernopelli]

Just a thought...One thing you can't rule out, at this point anyway is that you may have valve/head issues and not ring or cylinder wear issues. Probably wouldn't be a "major" expense in comparison if it's only a matter of having the head gone through.

 

[Ilikeurtractor]

Good point. Looks like I can get a head gasket relatively cheap all things considered. Would it be unusual if the cam was rounded off?

 

[Kernopelli]

Good point. Looks like I can get a head gasket relatively cheap all things considered. Would it be unusual if the cam was rounded off?

Hmmm, don't know. Always a possibility I guess. I have heard of this a number of times with gas engines but I would say not as likely as

1. Worn rings and/or cylinder wear

2.Head/valve issues

In the event that it is ring/cylinder wear...Your engine doesn't sound like it's gone too far south...just possibly needs to be freshened up. I'm just throwing this out there and someone more knowledgeable will have to comment on it. I have no idea if this can be done with a diesel but don't know why not. I had a 2 cyl gas engine that had low compression. The bore was a little egg shaped but still within spec for stock pistons, the rings were shot. I lightly used a Sunnen AN-112 hone to get the cylinder back round and flex hone to finish w/ fresh crosshatch. I bought 10 thousandth over rings and put them on the stock pistons and filed them down for correct end gap. Probably could have gotten away w/ stock rings but I was right at the outer limits of stock bore spec. Engine ran like a top for several years right up to the day I sold it.

Now I was lucky enough to have the hone set and my friend owns a Yamaha dealership and loaned me a flexhone to crosshatch the bore. You may not even have to go that far. If things aren't too bad and it's just a ring issue.... just put a fresh face on the cyl walls with a flex hone, some new rings and you're back in business? Who knows, I'm kind of thinking out loud and throwing ideas/possibilities out there. Bottom line is, it's still too early to tell exactly what you are looking at.

 

[Ilikeurtractor]

Yeah, I've been contemplating what the "minimum" I could get away with if it is only the rings. I don't have a lot of experience with re-ring jobs but I wonder what putting in a new cross-hatch would do with existing rings? I've even heard of people reusing head gaskets and it worked. I'm not sure I want to be that sloppy or take the chances associated with it but it seems like a set of rings alone are gonna set me back a few hundred bucks just in parts. Might be better off saving up for another used tractor now that I've gained some experience in what to look for engine-wise. Then again, I hate thinking about this one getting neglected. Everything else seems to be fine on it. Kind of a shame. I could just live with it, but come-on it's a tractor for crying out loud. It should be able to pull it's own weight with ease!

 

[Ilikeurtractor]

I rechecked the compression today. I just cranked the engine until the gauge wouldn't climb anymore. I also did it with the engine cold. The front cylinder gave 390 psig and the rear 340 psig. They took roughly a dozen cranks but I didn't specifically count them. I didn't squirt any oil in the cylinder because I wasn't sure how much and also I only had the glow plugs out and I'm not sure if it would work putting the oil through those holes.

I'm surprised to see the 390 reading - I wouldn't think that would even be possible at my elevation given the "new" value of 455 psig. Apparently the 3.5%/1000' of elevation power loss doesn't directly relate to compression although I would have thought it would. The pressure here is about 11.6 psia and so I would think it's like losing 3 psi of boost vs. sea level. For a 20:1 compression ratio, for example, the difference in pressure readings would be 294 psia vs. 232 psia from purely a compression standpoint which ignores the pressure gained due to the heat of compression. I haven't tried to go down the road of calculating the theoretical pressure value due to heat of compression + compression ratio at my elevation and even if I tried I'm not sure if it would be meaningful let alone correct. I don't know the compression ratio for the engine anyway.

For the next step I'm going to pop of the valve cover and redo the valve clearance just to be sure it's in spec. I'll also check the push rods and make sure they aren't bent. IMHO I'm still thinking the problem should be something obvious and major and not just general engine wear given the symptoms.

 

[Kernopelli]

The compression sounds better. I am not sure how altitude affects compression. I was always under the assumption that the "thin air", power loss issue was due do less concentrations of oxygen, not necessarily the amount of total "air" (gases) available? I would guess that barometric pressure could effect things also though....I don't know. I live in S. Illinois where the tallest points are the tops of the corn stalks in Sept. :thumbsup: The affects of altitude don't come up in conversation very often.

I suggest you give Bill Rogers at Valley Power a call. I think he knows as much as anyone about these engines and can give you some sound advice. I read a post he made stating that 350 psig could dramatically affect the KE70's performance. You are only averaging 15psig above that across the two cylinders so I have a feeling that is the issue but I am sure they can point you in the right direction and maybe save some time and effort.

 

[Ilikeurtractor]

Thanks, I'll keep that in mind.

 

[Ilikeurtractor]

The compression sounds better. I am not sure how altitude affects compression. I was always under the assumption that the "thin air", power loss issue was due do less concentrations of oxygen, not necessarily the amount of total "air" (gases) available?

My understanding is that at less ambient air pressure, less oxygen is available by weight for the same amount of volume (basically what you stated above). So with less oxygen available, then you have less available fuel that can be burned and henced lower available power. The actual compression pressure (ratio stays the same of course) is also affected as in my previous post but the major hit one takes is the lack of amount of oxygen. I've read were a turbocharger is desirable in high elevations because the turbo will actually spin faster in lower pressure environments under the same conditions, somewhat compensating better than a supercharger and raising the effective amount of air (oxygen) to the engine. A turbo would be a neat project, but I'd be happy just to get back to OEM performance

 

[Kernopelli]

Turbos are cool and there have been several TBN members that have retrofitted their tractors. If I remember correctly, one Yanmar owner did specifically because of altitude related performance.

I too think that you would probably be well pleased just to have the stock performance...to go from barely pulling itself to spinning tires would make a guy feel like he was in tall cotton. I think you have a solid tractor that is very well built...just needs a little freshening. I don't know what you have invested in it but I suspect that whatever it is, at this point an additional $300-$500 put into it wouldn't be a deal breaker on it.(?)