Hi, I need some new brains working on this. I got this backhoe and it was only running on 3 cylinders and I paid accordingly. I took the valve cover off to find that the pushrod was stuck beside the #3 intake rocker. I thought easy fix. I placed unbent pushrod correctly, adjusted the clearance in accordance with the book. It was then that I started noticing the backfireing out of #3 intake. Local wisdom directed me to have the head rebuilt, still backfired, took the head off found a bent valve. :Banghead Bought new set of intakes from Case, replaced head still backfires. Checked all new valves from Case and found all to be slightly bent:Banghead. Took head back to rebuilder had them recheck their work, They tested with a vacuum and it drew a vacuum, how much I couldn't tell, so then I had that guy's work checked out by another head repair shop. Head looks okay, wasn't Magnafluxed, I thought original high priced, formerly well respected head repair facility in Denver had performed that, but no. Camshaft moving all rockers almost identical. Will check to see if camshaft is opening #3 intake valve too early next. Also had injection pump rebuild and installed all new injectors. Injection pump is timed correctly, even starts easily on 3 cylinders. Although reading about other Case's starting woes, maybe this is an indication of something really bad. Have had suggested: cracked rings #3?, camshaft worn, but all rockers moving almost identical, crack on intake side of head (magnaflux?) Anything I am missing? Anyone had this much fun with a Case? Thanks in advance, Boots
Boots, Melben and Elast are two that have have experience in this. I'm not sure about other mechanics on this forum as I have only been on here a short time. Until they come on board here are a few questions that come up in my mind. The bent valve problem seems hard to believe as well as the service you have from the machine shop. Check the compression with a gauge. See if you can borrow one. Using an old injector and a check valve, these are not hard to make. Did your head gasket look good? No signs of blow by between cylinders? Have you ever removed #3 injector, turned it upside down, tightened it back up to the injector line and cranked her over? Look for that nice fine spray.Loosen the other injector lines off so it won't start. I'm assuming you're sure #3 is the problem cylinder. A "general" cam timing check I use is to put a piston to the top on it's "dead stroke" and check that the intake and exhaust valves are overlapping exactly at T.D.C. Remove and injector and use something to feel the piston rising. Turn the engine back and forth by hand slowly while that piston is at T.D.C Does this 207 have a turbo? A friend of mine bought a new replacement 207 exhaust manifold that had a port plugged. I just added that to confuse you... Phil
Hi, I have the head off for the 3rd or 4th time currently, with a new head gasket each time. I can see no evidence of blow through between the cylinders. I have been checking T.D.C. by looking at the top of the piston. I had the injection pump rebuilt because it was leaking and I replaced the injectors because I think it is wise to do when you rebuild the pump. I can't see how the injection pump could affect the backfiring because you can physically see the backfire out of the #3 intake port, even when the injector isn't connected I saved a couple of the old injectors to make a compresion gauge before i pulled the head the first time, maybe you can tell me how this will help now? My only thought will be by seeing if we are getting compresion from a neighboring cylinder? I know it has compression, it just seems to be opening at the wrong time. Don't get me wrong, I'm open to suggestions. As far as a cam problem which has been suggested, if the cam lobes were worn, it seems that the valve wouldn't open at all early, which is what it seems to be doing. I thought that it might be the exhaust lobe that was worn and not letting all of the exhaust gasses out before the intake opened, but the exhaust is opening the same distance as the other exhaust valves. I have asked many times about the timing gears being off a tooth, but the general concensus is that it would make it run very rough or not at all on the other 3 cylinders and that isn't a problem. As far as the valve problems, I took the valves to a machinist friend and he chucked them all in a lathe and they all wobbled. When I finally found the good head rebuilding shop, he checked them with a dye check and they were sealing. He did find a lot of carbon buildup in the exhaust guide, but he didn't think that the head was the problem??? Thanks for your interest
Reading through your last thread , I still think I would do a compression test. Use your old head gasket just for the test, if you want. For that matter I think I would keep reusing the old head gasket until you find the problem. If that cylinder is missing I would find out why . It needs at least 350 psi. Check all the cylinders while your at it. Applying air pressure to the cylinder, if it has a low reading, will tell you where the leak is. Before you put the cylinder head back on, turn the engine over and look down at cylinder #3 cam followers. Put a push rod in each and make sure they are not binding, while going up and down. While the exhaust manifold is off, make sure the ports are clear. I think odds of the cam or it's timing, being the problem, are very slim. Check the rocker arms on that cylinder for galling or binding. Check that #3 piston comes up to exactly the same height at T.D.C as the others. You should be able to feel that all 4 liners are above the block a few thousands of an inch. If compression checks out, do that injector check I mentioned and make sure the valves on #3 overlap just as the piston reaches T.D.C. on the dead stroke.Leave the rocker cover off when you start it up and watch them move at low idle. I don't think there is a problem with your cylinder head but I haven't had a lot of experience in this area. Tip the head on it's side and pour gas into the port if you are suspicious. 188 and 207 heads are usually very forgiving. As for the intake valves wobbling, I'd be checking your friends chuck for accuracy first. So until we get more help here, that is what I would do. Normally I don't stick my neck out, but this is a pretty good forum and a good bunch of guys. Phil
Take the exhaust manifold off and start the engine. You will be able to see which cylinder is misfiring. Then do the compression / bleed down on that cylinder. Listen where you add engine oil you will hear the air bleeding by at a good rate if there is something wrong. If the head keeps checking out OK then you will probably have to go deeper. The 188 engine is very forgiving. I had a 1968 and it ran on 3 cylinders for almost a month. I ended up having broken rings on #1. At that time, 1986, it was a cheap rebuild so I did the whole thing, mains, rods & cylinder kits. As far as I know that machine is still running. If it was not for the fact that the machine was outdated I'd still have it.
I had a feeling it was an ether job. I had one of those last year, rings all came out in pieces. Kits seem to be cheaper than they were 15 years ago. I think a 207 kit is about $1100 for everything except the cam and rod bushings. Great deal. Phil
OK Lets start with the basics: 1: A compression leak out of the intake or exhaust port can be caused by various reasons such as a burnt valve, blown head gasket, bent valve, cracked head, bad deck or head surface etc. 2: If you have verified that the head is indeed OK, no bent valves no hanging valves, no cracked valve seat, no cracks in head itself, deck is good etc then this would count this out. 3: The camshaft and timing are most likely OK due to the fact that #4 cyl exibits no ill symptoms. A well worn cam lobe could be the issue but I doubt it with what you have said earlier. 4: The injection pump and injectors are not the problem. 5: A compression test will show cross contamination of compression between neighboring cylinders but you can usually see signs of this on the head, block or gasket. This would appear not to be the problem. From all I have read that you have said and done I would suspect that the #3 intake valve is hanging slightly open. The most likley cuplrit is the lifter. It is probobly sticking up just a little not allowing the valve to close completely when the engine is running. If it is varnished up bad it can stick very easilly. Also make sure that the valve spring on the affected valve is good and not too weak. This will only compond the issue. A dial indicator on this valve will show if indeed this is the issue. Remember that the valve has to only be off its seat by thousandths of a inch to cause this problem. This slight amount will not cause the valve to interfere with the piston but will cause the compression leakage. Also verify valve lash settings before about 3 times before running, then start and run for only a few seconds and recheck valve lash. If it is out then you can be sure that something in the valvetrain is wrong and take appropriate action. I know I have been long winded here but these types of issues can only be solved through proper diagnostic steps eliminating one part/function at a time. Good Luck......Elast:canada
And the answer is...... plugged exhaust manifold. Thanks for all your help and advice. Looking back now it seems obvious. When I got the machine the pushrod was jammed next to the rocker on #3 cylinder. Evidently the guy ran it more than he let on, on 3 cylinders. Anyway, fuel and oil were pulled into the exhaust manifold and heat caused a plug. A good solid plug that needed a torch to blow through. Manifold is clean now, hope to have it running tomorrow. Cylinder doesn't appear scored, maybe I'll get some luck and not have problems with that too. Maybe I'll even be able to move snow with it this winter! This is a first rate forum, with great advice, Thanks again for all the help. Boots
I forgot to add that we did check the exhaust manifold, a couple of weeks ago, with a wire. When it stopped we thought it was at a bend and everything was okay. We were only able to find the plug with the air compressor. Thanks again:usa
Well isin't this something. I assumed(like an idiot) that you were running it without the manifold on. Don't know why I assumed this but i did. Glad you found the answer. Elast......You learn something new every day. :drinkup