Dieseling Backwards

3RRL · Feb 14, 2006

This weekend I had a couple of things go wrong.

First, while trying to clear a culvert, pulling a chain through it, I blew up the Blazer (I thought) Actually, pulling in reverse caused the front "U" joint to knick the oil filter and oil was flying all over. Luckily several months back I brought an oil filter that fits my Harley Davidson, thinking it might fit the tractor (it didn't) but it did fit the Blazer and I had extra oil so I wasn't stranded. Got over that pretty easily.

Then this happened right after that.

While boxblading our homesite circle I got the tractor stuck on a huge rock and nearly stalled it. I shoved the clutch in just in time to hear it "chug" back to life. But suddenly all kinds of dust and smoke was blowing from under the hood. I thought I'd blown an oil line of some kind so I left the tractor running and took a look under the hood to see if I could spot where the leak would be. To my surprise, no leaks of any kind...that's odd. Then why all the dust and smoke?

I thought to pull her onto the road to have a better look at it. I tried to lift the 3pt but it did not respond! What the heck is going on? So I decided to try and drag it forward a bit to a clearing to look at it. I shoved the tranny into 1st and then forward gear and let the clutch out. The tractor started to move BACKWARDS! I thought I had really screwed it up this time, maybe blew the transmission up completely? So I put it in reverse, let the clutch out and she started going FORWARD! Man, I couldn't believe it!

Well, by this time I figured out what happened and shut the tractor off. By almost stalling the engine, I must have stopped the normal rotation of the motor. And when it started to chug up again, it must have fired just before top dead center and started rotating the engine backwards. That explained the dust (not oil smoke) blowing out of the radiator. The fan was turning backwards.

This happened to me a long, long time ago when trying to kick start a 2 stroke motorcycle and the compression resistance started it and it ran in reverse. (What luck for me...huh?) Jumped on and it it shot out backwards from underneath me. Man, was I ever surprised.

Anyway, the tractor did not run good in "reverse mode" probably because the timing was now retarded instead of advance slightly. So after letting cool off a little (and me too) I started it back up again. Now whe was running fine and all the hydaulics worked again. I wondered what could have gone wrong by it running backwards? I used it for about 10 more hours the rest of the weekend and it ran fine. I couldn't find anything wrong with it.

Anybody ever have that happen before?

MMM · Feb 14, 2006

Not common, but it happens. A lot of the bigger dsls can be set up to run either CW or CCW.

JerryG · Feb 15, 2006

Likely you didn't hurt anything. You do need to check your air filter. It may need to be replaced. Always remember if it does it again to stop it as quickly as possible.

Soundguy · Feb 15, 2006

I guess OP would be the only thing to worry about.. for the short term.. etc..

Soundguy

3RRL · Feb 15, 2006

Jerry,
Now that I know the syptoms, I'll shut it down right away. I did not know it was running backwards at first and thought to look for a blown hose so I could spot it.
Thanks.

Soundguy...OP??? ... Operator Problem??? /forums/images/graemlins/confused.gif Is that what you mean?? /forums/images/graemlins/grin.gif

RalphVa · Feb 15, 2006

Strange. Only ever heard of this happening with ether for starting.

The valve train sometimes can get damaged because the chain is running counter to the way the tensioner is supposed to operate. However, I overhauled an Alfa Romeo engine once and found that its chain tension wasn't working at all! I had to fabricate a little piece to get it working again.

Think the Benz manuals tell you in turning the engine by hand while adjusting the valves to not turn it backwards. Think I did on my 1973 Benz engine though.

Ralph

Soundguy · Feb 15, 2006

</font><font color="blue" class="small">( Soundguy...OP??? ... Operator Problem??? Is that what you mean?? )</font>

Oil pressure... look at the diagram of your oil pump, pickup, and galley exits.. pasageways.. etc.... filters with check valves? etc..

Soundguy

Joe1 · Feb 16, 2006

I concur with soundguy. A few years back, I drove a school bus; a 1979 Crown with a crashbox manual transmission and a Detroit 2 cycle 671 diesel. While running the engine in reverse never happened to me, it did to several others not familiar with manual transmissions. When starting out, particularly on a hill, they would let the clutch out too fast and the bus would want to stall. The drive would depress the clutch at the last second and catch the engine at a point where it would run inrevers. With port valves instead of poppet valves, it did not harm the engine. (The driving instructors called it "spinning the filter"). Obviously the filter didn't spin, but whenever this did happen the mechanics would drive out to where the bus was located and would always replace the oil filter before restarting the engine. This was because of the checkvalve in the filter.

It would probably be a good idea to replace the oil filter.
You can buy a heck of a lot of oil filters for the price of a diesel engine.

JerryG · Feb 16, 2006

It's kind of scary the first time. Makes you think that it is really messed up. We all live and learn. /forums/images/graemlins/laugh.gif

3RRL · Feb 16, 2006

Hmmm...good point. I didn't know that.

I will check the oil system and filters this weekend.
Although in running for the remainder of last weekend, I did check that the oil pressure guage showed normal pressure. And as I said, it ran fine....but I'll check again.
Thanks for the tips.