Case 380/David Brown Engine problem

Bill Lee/Chandler, TX · Jul 4, 2014

My 380CK has been a wonderful tractor, but just last week the engine started really running funny. Best way to describe the symptoms is: it sounds like it's missing and/or back firing.

It's an old tractor, has been badly neglected, but just keeping it fueled and oiled and it ran perfectly. But I let the fuel level get down to 1/8th of a tank and was mowing when the engine started to act up.

Thinking perhaps dirt or water coupled with the low fuel level: cleaned the sediment bowl (it was BAAAD!), drained all of the remaining fuel out of the tank, new fuel filters, purged all the air according to the operator's manual procedure. No change in the way it is running, still popping and backfiring(or whatever it's doing).

Any suggestions for what tgo do next?

Thanks.

Bill Lee
East Texas.

RGMartin · Jul 4, 2014

If you get a miss in a 3 cylinder, it sounds like the world is going to end...

Possibilities...

Bent valve push rod

bad lift pump or lift pump push rod

Bad injector

Bad intake/exhaust valve

Timing gear crash, skipped some teeth

Can you isolate it to one cylinder by cracking the injector pressure lines one at a time, or does it involve all of them?

Bill Lee/Chandler, TX · Jul 4, 2014

I haven"t tried to isolate it to a single cylinder. Can try that tomorrow. But as I recall, it isn"t a steady mis-fire, more of an occasional one, occasional fire that is obviously putting a lot of unburned stuff into the muffler, black puffs of smokey exhaust, occasional sound like fuel burning in the exhaust (a backfire or something). I say "occasional" but with sufficient frequency to cause almost continuous sounds.

I"ll try cracking the injector feeds one at a time and see what happens.

Thanks for the ideas.

RGMartin · Jul 5, 2014

If it were mine, I would try to isolate it to one cylinder, then pull the rocker cover and look for a bent push rod.

Best money is on a bad injector, or a single exhaust valve/push rod issue.

Not likely huge money in any Case.

richardinnz · Jul 5, 2014

Check the position of the advance/retard cold start on the injector pump, I got myself a very cheap David Brown that was for sale because of a bad engine missfire because the John Deere dealer that had traded it did not know about the control! Dont forget to check your air cleaner before you go too far with the fuel system, also, if the tractor is so fitted, check the "Thermostart" cold start aid for leakage by blocking off the fuel supply to it.

Bill Lee/Chandler, TX · Jul 5, 2014

More analysis today. Did as you suggested and cracked the fuel lines at the three injectors. I made a video of this and it is on YouTube at

http://youtu.be/8S_8GeTCQ3g

If you have some time, please watch the video and see if you can see anything.

What I think:

1) cracking #3 and the engine obviously slows and the popping/misfire doesn"t change

2) Same for cylinder #1.

3) But cylinder #2 is different. The engine doesn"t seem to slow when it is cracked and the sound definitely changes.

My suspicions are that I have a problem in #2, and I suspect a clogged injector.

Any comments are sure welcome! Thanks in advance.
Poor running Case 380

Bill Lee/Chandler, TX · Jul 10, 2014

Has anybody looked at the Youtube video? Any comments?

I"m away from home for a couple of weeks so won"t be able to do any more testing, but would appreciate observations from the more experienced folks out there.

Regards,

Bill Lee

RGMartin · Jul 11, 2014

Just took a look at it. Have you had the rocker cover off yet? I really expect a bent push rod. The noise gets better but doesn't completely go away as it is still compressing air and blowing it back into the intake. There is a metallic rattle I am hearing too that is concerning, but it might just be a clutch or tin rattle that the camera is magnifying.

Is there a huge amount of blowby if you remove the oil cap when running? If so you may be looking at a piston/rings on #2.

It is a nice clean/straight tractor, well worth fixing even if it does turn out to be something much worse.

Bill Lee/Chandler, TX · Jul 11, 2014

Can you describe the "advance/retard cold start on the injector pump"?

The instructions I have for bleeding the air from the system when the filters are changed indicated a plug on the rear of the injector pump near the top. My pump didn"t look the same but had a fixture with a finger-operated twist valve or some-such. It was open when I started, i.e., turned couner-clockwise to its limit.

Not finding the vent that the instructions specified, I removed the valve and pumped fuel with the fuel pump until it came out. But re installing the valve has been a mess: a lot of leakage that I cannot seem to stop.

I"m not home so I cannot take picture. Perhaps my description will help.

Thanks.

Bill Lee

RGMartin · Jul 11, 2014

The cold start mechanism is the "T" handled screw on the side of the pump.

I have never had reason to remove one to bleed a tractor. Shouldn't be anything more than a couple gaskets and O-rings to reseal it.

Bill Lee/Chandler, TX · Jul 14, 2014

Thanks for the comments and suggestions. I"ll be home in a couple of weeks and will try to take a look then.

Bill Lee/Chandler, TX · Nov 11, 2014

Resurrecting this thread....
I finally got a round tuit and did as suggested: pulled the valve cover and took a look.

Indeed, I have a broken valve spring, exhaust valve on the #2 cylinder. The valve moves easily, the pushrod is in its hole although obviously not riding on the cam follower.

Now the question: how do I fix it?

I hope I can do it without pulling the head. All suggestions and help greatly appreciated.

Regards,

Bill Lee

RGMartin · Nov 11, 2014

Now the question, I wonder what that valve looks like after being slapped a few 100,000 times by the piston?

I have used compressed air to hold valves in place while changing springs. They make a tool for the purpose for gas engines(screws into plug hole), would have to improvise for a diesel(make something that fits the injector hole).

A head gasket set is like $40 aftermarket, personally I would like to look at that valve.

Bill Lee/Chandler, TX · Nov 11, 2014

(quoted from post at 01:41:33 11/12/14) Now the question, I wonder what that valve looks like after being slapped a few 100,000 times by the piston?

I have used compressed air to hold valves in place while changing springs. They make a tool for the purpose for gas engines(screws into plug hole), would have to improvise for a diesel(make something that fits the injector hole).

A head gasket set is like $40 aftermarket, personally I would like to look at that valve.

While grasping at straws to keep from pulling the head .....

If the valve with the broken spring moves freely up and down and rotates freely over its full up/down excursion, would you venture a guess as to the state of the valve?

The valve is still constrained by the broken spring and the keepers. Will it contact the piston?

(I'm such a chicken about pulling the head! Never been into a tractor engine, closest was a recent replacement of head gasket on a Model A flat head 4 cylinder.)

RGMartin · Nov 12, 2014

Pulling the head is no big deal.

If you don't think it was hitting? How low does it seem that the valve was hanging?

Bill Lee/Chandler, TX · Nov 12, 2014

All of the spring is still there and the keeper is in place. I think the valve is down further than normal (obviously!), but no more than a fully compressed spring would allow.

I was thinking of taking the fuel injectors out so that turning the engine over won't be fighting compression (kind of like taking out the plugs on an A). Then pushing the valve all the way down on the broken spring, and then slowly turning the engine over a few times by hand while watching the valve. If it moves, it would be because the piston is hitting it. You could stop turning the motor at that point and move the valve up/down with your fingers and you should be able to feel it hitting. If the valve doesn't move, it means there is enough clearance to miss the piston.

(I'm just working up my courage to pull the head!

)

Bill Lee/Chandler, TX · Nov 13, 2014

Harbor Freight had a sale coupon: Cen-Tech 2.4" LCD digital inspection camera. $69.99. I bought one.

Took the exhaust manifold off the tractor and looked inside. The exhaust valve is not damaged.

However, I discovered another problem: the push rod for the INTAKE valve in that same cylinder is bent.

I can easily move the intake valve against the spring, force needed is what is needed. The valve is not stuck. I am guessing that the push rod was bent trying to open the intake valve against a cylinder full of burning fuel that SHOULD have gone out the exhaust valve but was trapped in the cylinder instead.

I intend to get a new spring and push rod and figure out how to replace the spring without removing the head. Will probably remove the injector and make an adapter for putting air pressure into the cylinder to hold the valve closed while I install a new spring.

Any comments?

Thanks.

Bill Lee

Bill Lee/Chandler, TX · Nov 21, 2014

I was able to buy a new valve spring and pushrod at the local Case dealer. Was surprised since it was not expensive at all! I took my Parts Catalog for the tractor with me, they were able to look up the parts based on the part number and had it to me from Dallas the next day. Couldn't ask for better service!

I pulled the injector on the #2 cylinder and will make an adapter on the lathe to allow me to attach an air hose. Had to go buy a drill and tap of that (cost more than the new valve parts.)

Now I just need another round tuit to get it done.

Bill Lee/Chandler, TX · Apr 17, 2015

Resurrecting this thread once again.....

Finally got around to making the adapter to plug into the injector hole on #2 cylinder. Plugged in the air and pulled up on the valve. Bang! Held tightly shut! A sharp rap on the valve keeper and it came loose. Was able to get the keepers off and the broken spring removed. (The spring was broken in about 4 pieces!) Wrapped a piece of wire around the valve in the keeper slots so that it couldn't escape and fall into the cylinder.

Put the new spring in place but was faced with somehow trying to compress it to put the keeper back on. Borrowed the strong back of a friend and was able to compress the spring, remove the wire and put the keepers in place.

Put it all back together and fired it up. What a joy to hear that nice David Brown engine running smoothly again!

Thanks to all here for the conversation/advice/suggestions/etc.

Regards,

Bill Lee

Bhunt · Apr 17, 2015

(quoted from post at 18:42:51 04/17/15)
Resurrecting this thread once again.....

Finally got around to making the adapter to plug into the injector hole on #2 cylinder. Plugged in the air and pulled up on the valve. Bang! Held tightly shut! A sharp rap on the valve keeper and it came loose. Was able to get the keepers off and the broken spring removed. (The spring was broken in about 4 pieces!) Wrapped a piece of wire around the valve in the keeper slots so that it couldn't escape and fall into the cylinder.

Put the new spring in place but was faced with somehow trying to compress it to put the keeper back on. Borrowed the strong back of a friend and was able to compress the spring, remove the wire and put the keepers in place.

Put it all back together and fired it up. What a joy to hear that nice David Brown engine running smoothly again!

Thanks to all here for the conversation/advice/suggestions/etc.

Regards,

Bill Lee

Glad to hear you got it fixed I had a broken spring on a case sc I ran some small rope in through the spark plug hole and compressed it against the valve this allowed me to remove and reinstall the new spring .Sorry I never saw your post in time but hey you got a great looking tractor and you got it fixed. Im just posting this for anyone who might come up against this in the future.

Bill Lee/Chandler, TX · Nov 28, 2018

I am resurrecting this thread because I just had MORE broken spring problems!

I was doing my yearly mowing when, once again, the engine started to run badly. Since it was quite similar to the first time a few years ago, I immediately pulled the valve cover. I found the exhaust valve spring on #1 cylinder broken. Fortunately it had captured the valve and kept it from dropping into the cylinder even though the keepers were all laying loose on the top of the head. Darned lucky!

Started to plan another replacement and discovered that the spring on the intake valve of #1 was also broken, a loop or two broken off but the spring and keepers all in place.

I have dodged the bullet twice now and decided to go ahead and replace ALL of the springs other than the one from a few years ago. Here's what I found:

Of the five remaining springs, three were broken! The exhaust and intake on #1 and the intake on #3.

Using the adapter I made in 2015

I pressurized each cylinder in turn. I made a simple valve spring compressor tool

I was able to easily remove the keepers and the old springs and then install the new. All seems to be working now, the engine is running nicely, I only need to figure out how to stop a small fuel leak at the injection pump (a question for a different thread).

RGMartin · Nov 28, 2018

I have never seen a broken valve spring on a DB. Ever. seems very odd. Has the engine been rebuilt before? Someone maybe put the wrong springs in?

Bill Lee/Chandler, TX · Nov 28, 2018

(quoted from post at 22:53:07 11/28/18) I have never seen a broken valve spring on a DB. Ever. seems very odd. Has the engine been rebuilt before? Someone maybe put the wrong springs in?

I have no idea if the engine has been rebuilt. I have owned it since 1992 and it has not in that time. Before? No idea.

Case 380/David Brown Engine problem

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