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Discussion Starter #1
I have a KIOTI tractor with a Daedong 3 cyl diesel. It quit right in the middle of hurricane Sally cleanup. It was just sitting and idling, made a funny sound, popped once, belch of black smoke and quit. Removed vale cover and all 6 push rods are bent. I assume jumped timing and pistons hitting valves. BUT: I bought the repair manual for the engine and it indicates a timing gear not belt or chain. Are timing gears prone to timing problems like belts and chains? I can't think of any other scenario that would bend all 6 push rods. The valves seem OK and I can depress them with my thumb. Any chance that if it is timing that the pistons are OK? Thanks in advance to anyone that has any thoughts on this. Bob Ritter, Pensacola, FL. USA
 

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Thanks. Any idea how much work to fix it? From the pics in the manual it looks like it might not be to bad.
 

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Discussion Starter #4
Any idea of the chances the pistons and valves are OK. Like I said the valves are free and seem OK. Thanks.
 

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Probably need to pull the head to inspect the valves and pistons and go from there. Then figure out exactly what broke that caused it. As wally2q said, hopefully just a sheared key on one of the timing gears. I'm not familiar with that engine, but there's usually a gear on the crank shaft, one on the cam shaft and another that sits between them, so it could have been the key for any one of the three.
 

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i am guessing valves may be bent... if the pushrods are bent... .the valve stem can be out-of-true by .001-.004 and it will get hung up once the engine warms up.

will need to take the head off anyway to inspect pistons....
 

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Unfortunately you'll probably have to pull off the cylinder head and inspect for any signs of a collision between the valves and pistons...usually a diesel engine is an "interference" engine that will bend valves if it jumps time, due to the fact they have to be so close to get the required compression ratio ..

Hope your engine isn't set up like a straight six for the timing gears..


I've had two Chevy straight six engines ,a 1956 235 and a 1975 250, both had a fiber timing gear on the camshaft, made of a substance like masonite, that ended up shedding some teeth in one spot..

This happened on the highway going 60+ mph both times..engines were high mileage but well cared for.
These engines are not "interference engines" so no valves kissed the pistons, but after replacing a cam gear on them, I would probably swap in a V8 if it ever happened again !..

I was able to locate an aluminum cam gear for the 250 six, but the 235 never had one as an option so I had to use a stock fiber one.
It was a real bummer to install--had to remove the grille, radiator, timing cover ,fuel pump, valve cover, distributor, side cover; remove all the valve lifters and push rods--and jack up the engine off its mounts in both trucks to get the camshaft out--in the end pulling the engine would have been faster and easier!..

The gear has to be pressed on the camshaft at a machine shop--the place I took the cam from the 235 too, broke the retaining plate ,I was very lucky a Chevy dealer still had one dusty one on the shelf, this was around 1980..
To this day I still wonder why GM didn't just use 3 bolts to hold the cam gear on,like on a small block V8...

Hopefully your push rods bent before the valves got bent.. those are a lot cheaper and less work to replace...
 

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Discussion Starter #8
If it's a sheared key and I can replace it easily how about doing that and putting it back together. If the pistons are toast or valves bent it won't work and I can then go all the way into the pistons. If I'm really lucky it will be OK.
 

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If it's a sheared key and I can replace it easily how about doing that and putting it back together. If the pistons are toast or valves bent it won't work and I can then go all the way into the pistons. If I'm really lucky it will be OK.
The problem with that is, if something inside is hung up you risk causing even more damage spinning it over again with a new/new keys installed. /luck

Pulling the head may sound like a pain but it's a lot less pain than replacing the engine.

Take it apart and see.
 

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If it's a sheared key and I can replace it easily how about doing that and putting it back together. If the pistons are toast or valves bent it won't work and I can then go all the way into the pistons. If I'm really lucky it will be OK.

do you want to gamble a >$1000 engine problem on "luck"?... i wouldn't.

having push-rods bent is not a "whoops" kind of a problem... it's a major "engine guts are not happy" kind of a problem... it's not a question of "if the pistons are toast it wont work"... it's a question of dealing with a $250 valve job that turns into a $1500 engine rebuild job... or a $3500 new-engine job...

Why would the key fall out or shear in the 1st place (if that's what it is)?....get to the root cause....

Do the right thing and take the head off, inspect and fix it the right way....

cheers!
 

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Discussion Starter #11
Ronin/Wally - Of course you are right. I'll let you''ll know what I do. Right now with hurricane Sally clean up facing me I would really like a quick fix even though I know I should go for the full "RIGHT" fix. Thanks again.
 

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Discussion Starter #12
Update: Got back to working in the tractor. Need to remove the cover on the front of engine to get at the timing gear. Have removed water pump, alternator, RPM sender. Hit roadblock. 3 bolts hold on the fly wheel pulley but removing them doesn't seem to enable removing pulley. No room for a puller and I assumed the pulley would just come off. It may just be stuck but seems very solid. The pulley also has the spline gear for the front PTO (not installed). The front cover has bolts under the pulley so it has to come off. Hopefully it doesn't mean pulling the engine to get a puller on the pulley. Any one know if this pulley need puller? If so does engine need to come out? Thanks all in advance. Bob
 

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Discussion Starter #13
UPDATED UPDATE: Spline gear bolts on front of crank pulley and pops right off with a little encouragement. Couldn't tell it was separate from the pulley due to the nice paint job on the engine. Popped it off and exposes the big nut that holds the pulley to the crank. Unfortunately I don't have a deep well socket big enough. Anyone know what size that nut is? Bigger than 1". Probably goo to Harbor Freight this afternoon and buy a set of large sockets. Thanks again, Bob
 

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Discussion Starter #15
Harbor Freight has a 12 piece 1/2" impact set for $24. Had a 20% off coupon so it only cost me $20. The nut is 30mm. Got it off OK but the pulley is pressed on and needs a puller. Had to cut away a bit of the frame to get the puller on but my set only has 2 bolts and it needs 3 for this pulley. Going to hardware store in the AM. One step at a time. Hope to get that cover off tomorrow to see what happened with the timing gear. Thanks for reply, Bob
 

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Discussion Starter #17
Right front side of engine looking forward is a small solenoid. The plastic piece that connects to a cable is broken. Was about to remove the last of the things needed to remove that front cover when I found it. Can't image it has anything to do with my bent push rods but I thought I'd ask before I continue. And can't image they would engineer it so a little piece of plastic like this would kill the engine. NOTE: Just checked again and the cable going to this thing is the KILL switch so probable nothing to do with my bent push rods. Anyone ever taken off that front cover to expose the timing gears? I've just about removed everything external in the way but a little worried about what will fall/spring out when I remove the cover. Any thoughts? Thanks again for the help, Bob Ritter
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Discussion Starter #18
$&^J$&T^F^&**() Got the front cover off to discover possibly the worst case scenario. Crank shaft gear is totally trashed. It doesn't look as though the gear can be pulled, anyone know? Starting to look like pull engine for total rebuild or engine replacement. Bummer!! Any thoughts? Bob
 

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Can you post some pics?
I'm not familiar with this engine, but on the diesel I used to work on, both the crank gear and cam gear were pressed on, the keys were only for location. On this engine, the fit on each gear was tight enough to need a hydraulic press to remove the gears. The cam could be pressed on, the crank had to be heated up and dropped on. Once on, they didn't move.
 

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Discussion Starter #20
As you can see, I hope, the gear on the crank shaft is totally destroyed. I was hoping that the cam gear had slipped but no such luck. I'll be looking for a mechanic or engine Monday I guess. Very disheartening cause I really loved my little tractor. Thanks for your response. Bob
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