Lister Engine Forum

How to / DIY => Engines => Topic started by: Willw on July 02, 2018, 02:08:24 AM

Title: Now I've seen it all....
Post by: Willw on July 02, 2018, 02:08:24 AM
Hi guys, just wondering if anyone has ever seen this happen.
I just finished repairs on a Yanmar L100 air-cooled diesel. On Thursday  evening she fired right up on my first start attempt; feeling quite proud of myself I did a short video and sent it off so the customer could see the progress.
On Friday I mounted the engine to it's cement mixer and wound up the rope to start her. I yanked the rope and she started right up with quite a bit of smoke and rough running, and that's when I heard my son say "Dad, why is she exhausting through the intake?" Sure enough, that's what she was doing and I put my hand over the muffler and I could feel the vacuum as she inhaled.
Puzzled, I shut her down thinking it might be a fluke, and started her again with the same result. Quite boggled now, I thought maybe she is left-hand rotation, so I wound the rope in the opposite direction and gave her a strong pull. Exact same result except now the engine was running in the opposite direction. I shut her down and left her alone until this morning, all the while trying to figure out if I was actually seeing what I thought I was seeing.
By this morning I had prepared myself for some malady with the camshaft timing, but first of all I turned the engine by hand and felt as it came against something solid. I turned it in the opposite direction and eventually I felt the same hard bump. By observation of the flywheel I concluded that the bump happened every other revolution of the crankshaft which led me to conclude that it was either a problem with the IP, something was caught in the cam gear, or the timing was off.
Choosing easiest first, I removed the Injection Pump, and sure enough the "solid bump" was gone. It was a brand new IP but nevertheless I took it apart and examined it but found nothing wrong.
I then started wondering if the injector could somehow cause these issues, and after a battle I managed to removed it from the engine. At this time I used a piece of wire coat hanger through the injector hole, removed the valve cover, and by observing the valves at overlap with the piston at TDC I was able to determine that the cam timing was correct.
I took the injector apart, removed the needle and sprayed some Carb Cleaner into the nozzle and let it sit for a few minutes while I arranged my Injector Tester.  Not having the correct fitting to hook up the entire injector to the tester, I put the nozzle into an injector that could attach to the tester. At the first few strokes I could tell that the nozzle was not working properly, but I persisted and after a few more attempts I got a satisfactory Pop and Spray Pattern.
I moved on to the body of the injector and discovered that a previous "Diesel Mechanic" had not aligned one of the two alignment pins correctly, and instead of it entering its respective alignment hole, it had caught up on the body of the injector next to the hole and he had tightened the nozzle holder so tight that the pin had actually penetrated the injector body and mushroomed it's head as well! What a mess!
I happened to have a good injector body that was near enough that I could used the "Valve and Seat" from it to replace the damaged seat. I then used my grinder and "sharpened away" the damaged threads in the area where the pin had swelled them.
I then reassembled the injector and reattached it and the IP to the engine, checked that the IP was Popping the injector, and had my son give her a couple of good pulls and off she went.
Has anyone had similar experiences with engines acting this way?
Title: Re: Now I've seen it all....
Post by: cobbadog on July 03, 2018, 07:34:14 AM
Not me but it sounds as if you had some fun.
Good problem solving.
Title: Re: Now I've seen it all....
Post by: snowman18 on October 29, 2019, 02:43:45 AM
Lug an old Mack engine down then just before she stalls engage the clutch, gravel truck had an oil bath air cleaner. Running backwards the oil covered the windshield.

The mack engines are know to run in reverse, just shut the engine down and restart.
Title: Re: Now I've seen it all....
Post by: glort on October 29, 2019, 12:13:41 PM

I have..... umm..... a load of the Chinese copy Yanmars and have seen them run backwards numerous times.  They didn't run backwards every time but if they fired on a certain part of compression where they didn't quite pull through but then bounced back, they will go backwards.
When stopped Decompressed and re started with the de comp dropping at the correct time they run like Normal.

I did have one do a Runaway once in reverse which was easy to stop with the decomp lever but Blew the air filter foam and paper to flaming confetti.
When re started it ran is it should.  Oil was not high, don't know what caused it and it hasn't done it ever again.
Title: Re: Now I've seen it all....
Post by: Willw on November 02, 2019, 01:42:54 PM
Good stories, guys ;D
As I mentioned this was a Yanmar L100, and since that time I have noticed that the L100/186F engines, having larger displacement, seem to require a stronger pull to start than the L70/178F engines, especially when attached to a sizable cement mixer.

I've thought about this engine some, and I started to wonder if maybe my Arnold Schwarzenegger-like physique just ain't cutting it any longer :( :laugh:

I found this online and what is the first main cause they mention?  It says right there in black and white "Will, you're just a weak brother" :(

https://www.manualslib.com/manual/907108/Yanmar-L40ae.html?page=112#manual (https://www.manualslib.com/manual/907108/Yanmar-L40ae.html?page=112#manual)

Since reading that, I've adjusted my starting procedure somewhat and it goes something like this:
Turn the throttle to max fuel
Turn the flywheel to compression
Wind the starter rope around the starter cup
Depress decomp lever
Grasp starter rope with both hands while leaning slightly forward on my left foot, with my right foot back
Repeat these words in a barely audible voice (in my best Slingblade voice) "I'm here to kill you"
With every fiber of my being and in one fluid motion, I pull with everything I've got, while throwing my entire 135 LB weight back onto my right foot, while thinking to myself that either:
I'm going to rip my own hand off
I'm going to rip the engine off the mixer
I'm going to pull the entire mixer over onto myself and be crushed to death
The rope is going to break
The engine is going to start

Works like a charm :laugh:
As I used to tell my sons when I was teaching them to hand-start diesels "You have to show it who's the boss"
Title: Re: Now I've seen it all....
Post by: Willw on November 02, 2019, 01:49:18 PM
Never had one run in reverse since
Title: Re: Now I've seen it all....
Post by: glort on November 02, 2019, 10:20:02 PM

They are bit of a lump to be sure but I haven't found them to Require and " Every fibre of being " type effort.
I have several engines that are much worse and definitely need that very serious do or die Commitment. Mainly my Italians, The Ruggerini and the Lombardini  do not accept half efforts in any way,

I get a lot of people "mention" My hand shake and often commenting I give knuckle crushers ( was always taught a good Firm handshake is a sign of respect) and my hands are pretty big and strong but having a pull cord ripped through your fingers when an engine back fires is something one doesen't forget and tries at all cost to avoid.  Funny enough, the little 2 Stroke engines I used to hot up and put silly compression with loads of timing advance into were the worst for that.  I remember times I couldn't write with a pen because my hand was so sore and swollen. I then grew an extra brain cell and Modified a car starter motor to take a socket to put on the crank nut and some wide handles for Torque like I got the idea from Top Fuel engine starters.
I have wound the Chine Diesels the same way with a Socket in a power drill and Hold the Decomp till the thing gets up some speed.

I find on the China Diesels getting the thing wound right back to the point of compression and making sure the decomp lever is full and properly activated is the key to these things.  Sometimes they can be a bit touchy and drop prematurely . Get that wrong and you know it.

The worst of all is my Kubota singles. They are a wind up style and so far, I haven't had the grunt to even get them to spin through compression after dropping the de comp let alone start.  Lister is no trouble at all but the little Kubota..... No battery ( and a good battery) no start on those things!
Title: Re: Now I've seen it all....
Post by: Willw on November 04, 2019, 01:24:32 PM
I was kinda poking fun at myself with that post.

One observation I've made though is that the clones that are taken off gensets seem to have a heavier flywheel.

i have a couple of these and I have already cut a keyway for a sprocket on one of them so that I can try it on a cement mixer.

My plan is to limit the maximum RPM using the adjustment screw, and retard the timing a couple of degrees with shims under the pump. My objective is to find out if the engine will still be strong enough to mix cement at the lower RPM, and also whether I can get it to not rattle so much at that speed.

The lightest flywheel I have ever come across could literally be picked up with one finger.
Title: Re: Now I've seen it all....
Post by: glort on November 04, 2019, 10:08:40 PM

My plan is to limit the maximum RPM using the adjustment screw, and retard the timing a couple of degrees with shims under the pump.

The first clone of these engines I got was so advanced I thought it was going to knock itself to death. Being the first one I didn't really know what they sounded like but a bit of running had me convinced it shouldn't sound like that!

Not knowing what I was doing but pulling it apart anyway and looking how things worked I ascertained that the only way the timing could be adjusted was with those shims.  I took one off, cleaned it up and scanned it on my computer. I then put the heaviest single layer cardboard I could get hold of and luckily having a special straight path printer, laid out a bunch of templates on said cardboard. I cut them all out and then packed the Pump with them.
Thing sounded much better after that.  Dunno where the timing was but it's still there to this day. Thing runs fine, doesen't make an unholy racket and sounds like the other 6 similar engines I have since got.

Always wondered what the hell fuel they set that thing up on as even when I ran veg oil through that engine it was still way too advanced.

Quote
The lightest flywheel I have ever come across could literally be picked up with one finger.

Flywheels are NOT all about weight.
Circumference actually has more effect than weight does.  I used to play around with 2 stroke engines and remember a guy that had a Home Built Dyno.
The flywheel was a Piece of 1/4 round plate But it was about 1M across. He had it geared to half speed as circumference also makes for higher tip speed... IE, propensity to explode when spun.

The larger Diameter gives more " Leverage" of the mass there is.  I surmise heavy flywheels are largely for Compactness and packaging of the engine.
If you say melted a heavy Flywheel down and made it say 1/2" thickness, you'd have metal for a really large diamater piece but with the outside edge being so far away from the crank which would make the engine pretty easy to turn through the leverage, you could probably end up with a lighter flywheel that did the same job.  Just wouldn't be in most applications a very practical way of going about it.

Combine weight and Diameter with something like a Lister flywheel and you have the best of both worlds.
Title: Re: Now I've seen it all....
Post by: dax021 on November 05, 2019, 07:00:48 AM

Since reading that, I've adjusted my starting procedure somewhat and it goes something like this:
Turn the throttle to max fuel
Turn the flywheel to compression
Wind the starter rope around the starter cup
Depress decomp lever
Grasp starter rope with both hands while leaning slightly forward on my left foot, with my right foot back
Repeat these words in a barely audible voice (in my best Slingblade voice) "I'm here to kill you"
With every fiber of my being and in one fluid motion, I pull with everything I've got, while throwing my entire 135 LB weight back onto my right foot, while thinking to myself that either:
I'm going to rip my own hand off
I'm going to rip the engine off the mixer
I'm going to pull the entire mixer over onto myself and be crushed to death
The rope is going to break
The engine is going to start

Works like a charm :laugh:
As I used to tell my sons when I was teaching them to hand-start diesels "You have to show it who's the boss"

Sounds very similar to starting my old XT500, just substituting ankle for hand.