Diesel Running Backwards

[RickB]

Or a two stroke Detroit.

Posts 13 & 18 disagree.

The link has good info as well.

Detroit 92 series running backwards - Yesterday's Tractors

Saw the post from yesterday evening about the Detroit running backwards. I thought I'd start a new thread because I could tell from many of the reply

www.yesterdaystractors.com

 

[Complete Turf Care]

I did not read all posts in this thread. I had a New Holland TC45 run backwards for a few seconds.

I was pushing some trees with the front end loader and just as the engine was about to die, I mashed the clutch pedal, and the tree pushed me backwards. As I was moving backwards, I released the clutch and the engine restarted in reverse. All of this happened within maybe 3 seconds.

I knew something was wrong and turned the key off immediately and it shut down. Before restarting, I called my New Holland dealer and explained what happened and he told me it was running backwards. Anyway, there was no damage and I kept the tractor for many more years.

 

[finn1]

When I was a young Diesel Engine Development Engineer, back in the mid 1970s, one of my first projects was to develop a Bosch in-line fuel system to replace the old Ambac Model 100 rotary distributor pump on our mid range Diesel engine family.

Part of the qualification process was to spin the engine backwards to make sure it wouldn’t run backwards.

Apparently our competitors had issues when their engines would run backwards, and several people were injured over the years. Lawsuits inevitably followed.

The requirements that all new products net run backwards was still in effect when I retired thirty five years later.

 

[pmsmechanic]

Posts 13 & 18 disagree.

The link has good info as well.

Detroit 92 series running backwards - Yesterday's Tractors

Saw the post from yesterday evening about the Detroit running backwards. I thought I'd start a new thread because I could tell from many of the reply

www.yesterdaystractors.com

I'm not following your thoughts.

The time I ran a 6-71 backwards the intake was smoking exhaust. Grumpycats post says the the air still goes in the intake and out the exhaust when the engine runs in either direction. Well it doesn't.

 

[RickB]

I'm not following your thoughts.

The time I ran a 6-71 backwards the intake was smoking exhaust. Grumpycats post says the the air still goes in the intake and out the exhaust when the engine runs in either direction. Well it doesn't.

It’s not that complicated. He’s wrong.

 

[Marinemammal]

To save money I’ll let my tractor engine run backwards for 8 hours as it pulls CO2 out of the air through the exhaust stack and refills the tank with diesel by the end of the day! It can’t be bad for the tractor cause the hour meter says it’s getting newer and newer!
….say, anybody want to buy a bridge?

Actually, the one time it happened to me, the tractor was spitting diesel out the exhaust...

 

[ranchito]

So I discovered something I was unaware of and just wondered if this was common knowledge. When using my logging winch, and bogging it down to the point of almost stalling, the engine would start running very oddly. After shutting it down I noticed the cable was unwound and tangled inside the winch. This happened twice before I discovered why. Apparently the engine under stalling conditions can start to run backwards, taking air in from from the exhaust and exhausting through the air intake, not a good condition for the engine. And in the process running my winch backwards and tangling up the cable. Anyway, now I'm more careful about how I run it with the winch. So is this common knowledge that I somehow previously just missed?

I have heard of this happening on a Detroit diesel 2 stroke, but not on a 4 stroke. The only way to stop the DD running backwards is to shut off the air or fuel. Smoke billowing out of the air cleaner is very disturbing.

 

[Fuddy1952]

Some years ago my friend and neighbor started building racing go cart motors using Briggs and Stratton 5 hp motors, they're 4 stroke flathead motors. I did some experiments here out of interest. One thing I did was grind the intake lobe off a camshaft, then tried different springs on intake valve. With a light spring motor ran seemingly well, the valve opened on piston down stroke (suction) and shut on up stroke like normal. I believe it opened wider higher rpm.

 

[Massey convert]

I want to add my 2 cents. About 50 years ago the neighborhood was out on a snomobile ride, we had about ten different brands, (when there were about 80 or 90 manufacturers). I was running a Scorpion with a 268CC (I think) Sachs 2 stroke engine. It was a warm day and to keep up I was usually at full throttle. We had stopped for a short break and when I pulled the recoil, it snapped back in, but the engine started. What shocked me was when I hit the throttle, the sled went backwards. The single cylinder Sachs recoil housings had a rubber plug oppsite of where the recoil cable came out. I beleive they were designed to be set up to run in either clockwise or counterclockwise rotation. If my cousin had not witnessed the event, I doubt anyone would have beleived me.

 

[Jstpssng]

I've heard of 2 stroke motorcycles running backwards, but never saw it. I hope my tractors never do.

That's how many newer snowsleds have reverse; upon pushing a button the spark is retarded enough so that the engine reverses direction. My new Cat is like that, and I need to move the button before my dog hits it while riding on the seat in front of me. I also had similar experiences to the OP's when I had my L275 Kubota. I don't know the exact results as I was too busy getting it shut down, but do remember that the dash would light up like a Christmas tree, and it sure did smell nasty for the few seconds the engine was running that way.