Cucv engine turns smoothly almost a full rotation by hand then comes to a complete st

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CUCV MANIAC M1028

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Hey guys, so I got my injector pump and such and so the m1028 has been sitting for 10 years and it ran perfectly even though the injector pump croaked. But me and my dad were getting ready to start installing the injector pump and we heard you had to time it by turning the crank with a bar and it was turning so smoothly and when it was half way throght a full rotation and it stopped like it was hitting a brick wall in the same spot it was in, we opened the ports where the glow plugs go and there was no water in the cylinders, what do you guys think it is? Rust on a little bit of the cylinder wall? Pitting? And have any of you had this happen and if you have, how did you fix it? Dad sprayed wd in the cylinders and it does the same thing.
Thanks
 

cucvrus

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Could be a valve stuck. Have you tried using the starter? May help get it past that point. May not but worth a try. WD 40 will only get on the intake valves if you put it down the intake. While you have the intake off spray oil down the EGR port in center of heads. Report back. Good Luck.
 

doghead

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Any chance you dropped a bolt when you removed the IP?
 

gringeltaube

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First try to determine the cause. Do not... force it, e.g. by using the starter!

Yes, it could well be a valve, stuck open - as mentioned above. I would remove the rocker arm covers and check if all 16 valves are able to move freely. Also check the pushrods, if all in place and straight.
 

Jbulach

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This ^ do NOT use the starter! A stuck open valve can usually be coxed back closed by very light taps on the rocker or valve stem with a rubber hammer, but make sure to rotate the piston back away from the valve first. Once it comes back closed, gently bar the engine over and repeat as necessary if it sticks again, until the engine rotates free without hanging the valves.
 

cucvrus

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So I understand it correctly. You have a truck that ran when parked. You have a replacement injection pump but have not installed it yet. You have looked in the cylinders thru the glow plug holes and poured WD 40 down the intake. Looking in the glow plug holes you will see nothing but the pre-chamber. I am not sure I would go thru the process of removing the valve covers and rocker arms to check if the engine has a valve stuck open. If you are going to change the injection pump anyway you will need to remove the intake manifold. Do that and check the intake valves. If you have a flywheel tool use that. The nice thing about a flywheel wrench/tool is you can rock the engine back and forth to get this loosened up. The 15/16" bolt on the front will tend to loosen or over tighten turning it with that bolt. The flywheel gives you better leverage. I suggested the starter as a method that has worked for me. If it is tight starter or not it will stay tight. Without seeing it only you can make the right decision on what to do. Flywheel turner wrench always worked for me and I had a few with water in the cylinders. I think you are on the right path. But get a flywheel turner tool/wrench and turn it by rocking both ways. Easier than taking the injection pump and rocker arms / covers off the engine. If it were me I would remove the heads and have it done properly. Sitting 10 years did NOT help preserve the head gasket material. I can almost guarantee they are rusted thru at coolant ports. I never seen any yet that were not. Even off good running engines. Good Luck. I am still into the starter method after you have determined no studs or bolts are lodged in the engine. I think it is a stuck valve. Good Luck. Have a Great Day and Be Safe.
 

Sharecropper

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I've been thinking about this and, the only thing it could be is a valve stuck open or a bent push rod preventing the cam from fully rotating. If that is indeed the case, my first action would be to remove the valve covers and inspect each valve and pushrod to find the culprit. A valve stuck open can be loosened by spraying penetrating oil on the guide and letting it soak for a bit, and then working the spring up and down with a tool. If it is a bent pushrod, that is easy to remedy by simply removing the bent one and replacing it with a straight one.

Hope this helps.
 

sandcobra164

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Just to understand where you are at, is the old injection pump still on the engine or are you halfway into installing the new one? I had a similar issue when installing the 3 bolts into the injection pump drive gear when installing my new injection pump. I had tightened the first two down just a hair too far and my engine seized when trying to bar over to get the third one started. I simply went backwards, loosened the first two until they just cleared the cover and then could get the third one in. Went back through them 2 more times during the tightening sequence and had no more issues.
 

CUCV MANIAC M1028

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Hey guys, didnt see any notifications that you guys commented (wierd) but the truck ran perfectly until the ip crapped out. But I agree about not using the starter to free something, the engine is free and it has no water which is good. But I can turn the motor with a breaker bar almost a full rotation before it feels like its hitting against something. Dad even said it sounds like a valve. But how can I tell if it's a valve that's stuck open or a vent pushrod? Thanks for all the tips, and advice from everyone
 

sandcobra164

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Since you are replacing the injection pump, now's a good time to remove the fuel injection lines, remove the valve covers and do some snooping around. A stuck valve will attempt to stay in the downward position even when the rocker arm does not have tension against it.
 

gringeltaube

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...... A stuck valve will attempt to stay in the downward position even when the rocker arm does not have tension against it.
That... and then the corresponding pushrod may have jumped out of position, already. If lucky enough it isn't bent.

Reason enough (for me at least) to remove the covers and take a look.
 

cwc

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Post #1 says the resistance to turning happens "halfway" through a rotation; post #9 says almost a full rotation. To the extent that the crankshaft rotates nearly through a full rotation, that points more to a stuck valve. If it is closer to half a rotation, that points to a cylinder with a rusty section of the cylinder bore.


I am not sure I would go thru the process of removing the valve covers and rocker arms to check if the engine has a valve stuck open. If you are going to change the injection pump anyway you will need to remove the intake manifold. Do that and check the intake valves .
This is a good point - since the intake needs to come off anyway, look at the intake valves and see if one is stuck open. The valves should move as you rotate the engine, you should even be able to follow them in order according to the firing order, You can also remove the exhaust manifolds and look at the exhaust valves to spot one that stays in the open position all the time. I have a 6.5 from one of the M1045A2s from Albany that got water in the motor, just happens to be in the shop with manifolds off now; here are some pictures looking into the ports:

Exhaust.jpgIntake.jpg

The valves could be stuck because of rust on the exposed part of the valve stem; if you see rust there you could probably get a small wire brush into the port and clean it up, also hit it with some lube. Forcing a rusty valve stem into the valve guide could damage the guide.

A valve can also stick because of gunk/varnish in the guide. I have gotten those to free up by spraying some carb cleaner on the stem through the valvespring area. The valvesprings are not all that strong - you can work the valve up and down in the guide just by pushing on it. Of course this means removing the valve cover, which can be a real pain if they are siliconed in place.
If it were mine, I would not hit the starter on an engine that will not turn over by hand. It could bend a valve or damage the valve guide. If the problem is rust in a cylinder, the force could distort the ring lands on the piston.

Be careful of hydro-locking the motor by pouring lube into the cylinders. When you get it turning over freely, you might want to crank it real good with the glowplugs out.
 

royalflush55

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Has this engine ran any since sitting ten years and if so how much? Or did it quit running 10 years ago and then set? What were all the symptoms when it quit running?
 

richingalveston

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if it were mine, i would pull the heads and have them rebuilt. the valves are probably all rusty and it will not take long for the rust to eat up the valve guides. This gives you a chance to hone any rust on the cyliners and new head gaskets. cost is approx. $600 for rebuilding heads with new gaskets and new head bolts depending on where and who does the head rebuild. mine cost about $350 to have done.

once you do this, the engine should last a long time as long as the bottome end is good. If you have the IP and rocker covers off then the heads are the next to come off. very easy if you are already this far into the top of the motor.
 

Sharecropper

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if it were mine, i would pull the heads and have them rebuilt. the valves are probably all rusty and it will not take long for the rust to eat up the valve guides. This gives you a chance to hone any rust on the cyliners and new head gaskets. cost is approx. $600 for rebuilding heads with new gaskets and new head bolts depending on where and who does the head rebuild. mine cost about $350 to have done.

once you do this, the engine should last a long time as long as the bottome end is good. If you have the IP and rocker covers off then the heads are the next to come off. very easy if you are already this far into the top of the motor.
Ditto on what Rich said.
 

CUCV MANIAC M1028

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Hey thanks for the signs Sandcobra164. We are 99 percent sure it's a stuck valve, going to try and remove the valve covers this Saturday to make sure that it's actually a valve issue(almost positive).I heard I can use a brass hammer to tap on the valve gently, do I need to remove the rocket arms to do this? And if yes, do I need a valve spring tool ? Thank you for all the help from everybody and sorry for responding a day later, I closed last night and got home at 11:30 since I work in a restaurant that is my first job
 

cucvrus

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You will need to remove the fuel injection lines or bend them up out of the way. And do you know which side ( R or L head) is hanging up? If so I would just remove the entire fuel injection system. That is injection pump with lines still attached. At that point you will need to break the seals on the valve rocker covers and take a look see. If you are going that far you had just as well pull the heads and have them checked. If the valve is stuck that hard that you are tapping / beating on it, it will surely need further attention. Pull the heads and have them refurbished at a competent automotive machine shop. Have the pre-chamber cups changed and all the valve seat and guides gone over as previously outlined. That is if the vehicle is worthy of that. You still have an un running vehicle that has a driveline that has aged and sat still for a decade. I have done this several times. The transmission does not care how many miles are on it. Time weathers everything. It seems to accelerate with down time. Good Luck. I would get it running and evaluate from there. A $1000. investment can turn into a $5000. money pit real quick. Been there done it and still get other peoples vehicles that are in need of many repairs and people keep getting in deeper even after being advised of it. In the long run to each his/her own. What is the condition of the rest of the vehicle. Is that what you want to drive and spend money on. That is a decision only you can make. And be realistic. Guys tell you they are worth this much. And many times I see them for sale for less. Don't bury yourself in one. Do a total vehicle assessment. Have a Great 4th of July weekend and enjoy.
 

cucvrus

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DSCF6052.jpgDSCF6053.jpgDSCF6019.jpgDSCF6020.jpgDSCF6080.jpgDSCF6083.jpgI can't say never. They can be bent. Is it a PITA? Yes. I bought trucks that had the lines bent out of the way at some time. I re-bent them and got them back in the brackets again. But yes if you can avoid it don't. But I will never remove an intake manifold on a customers truck to change a leaking valve cover. The labor and liability associated with that would far out weigh the extra effort. Picture 5 of 6 is the reassembled after bending. 6 of 6 is a stock never been bent engine. 1 of 6 shows the safe bent lines after reassembly. It can be done. It is tedious work. Most engines do not have the line clips anymore. Have a Happy 4th. Be Safe.
 
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