| Author | Message | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Well, here I am back to "novice" status with something I have no experience with. hellllppppp/... You may recall that last month I added a set of jakes to my Cummins 220. Then I took it on a virtually perfect 1000 mile trip, zero engine problems as always. The engine in this bus has been such an excellent performer that I couldn't ask for more... no oil consumption, no water consumption, starts in a heartbeat no matter what the temperature...and until today, NO smoke out the back no matter what. (I have an altitude compensation turbo on it so it's as happy as can be) I started the engine three days ago to show Jim Stewart (he paid a visit) how it sounds up in the cab. As always, it started immediately and ran perfectly. Today I just finished fixing my power steering and decided to fire her up for a test. Then the nasties began... First, the battery seemed dead although I know it isn't. It wouldn't crank over. It'd go "yulp" about half a turn and then stop, just like a low battery might on a high compression motor. But it's a new battery and kept on a 3 stage charger so I know it's fine... So I pulled the compression release and got it spinning, and let it go... It started, BUT it sounded like I'd squirted ether in there... knock rattle knock...ouch... then that smoothed out after about ten hair-raising seconds and it began BELCHING tremendous quantities of white-bluish smoke. NOT water vapor, I smelled it and it's definitely oil or fuel... not black either though... Then it started to run away from the throttle setting... slowly sped up and made my sphincter get a bit tigher, then just as suddenly it got itself back in control and that never repeated... (didnt think Cummmins engines could run away) It was running smoothly but continued to BELCH that smoke... I let it idle at high speed for a long time, 15 minutes or so 'till the engine warmed up, and the quantity finally decreased but it's still looking like a badly tuned dumptruck humming down the road... Now, if I punch the accelerator, a black poof comes out, quickly replaced by constant bluish stuff. That makes sense because the turbo isn't keeping up with the punch and black unburned diesel is coming out for a moment. As of this writing it will idle cleanly now that it's up to temperature, BUT if I speed it up, out comes the smoke. Not nearly as bad as when all this started, but alarming for an engine that has never so much as made a puff of any kind in the last 4 years... So WHAT THE HECK HAPPENED? The engine is running smoothly and the smoke has decreased a LOT (at first it looked like i'd unleashed a theatrical fog machine on the neighbors) but it's still smokin and it's never done this even a tiny bit in the 20,000 miles I've put on it. Crankcase oil is proper, radiator water is at proper level... aargh... shall I take it on a long drive or am I in some kind of trouble I don't know about? EEEEEEEKKK  | ||
| Geoff (Geoff)
Rating: N/A |
It sounds like you had a leaky injector fill a clyinder up with fuel, that would explain why it stopped turning over with the starter and why you had a lot of smoke after it started. There is also the possibility you bent the rod so you aren't getting full compression on that clyinder now. --Geoff '82 RTS AZ | ||
| Dale L. Waller (Happycampersrus)
Rating: N/A |
Hey Gary, sounds like a improperly adjusted injector or injectors. On a cummins they can get out of wack then leak. Are they old?? Some of the cummins are hard to get adjusted right. If you have the means to do it check the adjustments. Then I would pull a compression check. Dale | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Half an hour later.... I went in, wrote my first post, took a shower, just went out to the bus a half hour later (minutes ago)and started it... business as usual, started right up, NO smoke this time... what the heck?? The injectors "should" be adjusted properly- when I did the jakes I adjusted everything to the book, and at least I thought I took my time doing it "right". Now it seems like half an hour ago was a bad dream. I'm perplexed... Dale, the engine is '69 but the guy I got it from said it was rebuilt by Cummins about 30,000 miles ago and I almost believe him 'cause it's clean as a whistle inside and been such a good running machine. So I have no idea of the injector age. I also wonder, since the injectors are mechanically-driven, maybe the last time I stopped it one of the injectors got left in the "inject" position and leaked fuel into the cylinder... maybe that's simply a one-in-a-million thing that occasionally happens...??? I don't think I bent any rods or the thing would probably sound horrible running, and as of a few minutes ago it sounds (and again acts) just like it always does, smooth and fine... This is too weird... | ||
| Dale L. Waller (Happycampersrus)
Rating: N/A |
Gary, If she does it again (HOPE NOT) I would go back and check the adjustment. Some of those engines are very picky were the lob is on adjustment. They about have to be set up cold, hard to keep alot of heat in the engine while working on em. You may have to fudge just a little if you have to readjust them. If I'm thinking right they should have a cold setting or a hot setting (about .003 difference) Got my fingers crossed for you. Dale | ||
| jimmci9 #2 Rating: N/A |
if you have type "d" injectors, they can flood a cylinder with diesel by siphoning action if the engine stops with injector in the firing position.... "top-stop" injectors aren't as bad as the older 'd" style...contact me off the board at jimcat2@webtv.net if you want... | ||
| Dale L. Waller (Happycampersrus)
Rating: N/A |
I would say he has PT type d's. Some of our older equipment has the old D's, They will hydraulic if not started often to keep cleaned out. Be careful when asking for top-stop type (D) injectors. There IS a difference between top-stop type "D" and PT type "D" injectors. Dale | ||
| Marc Bourget Rating: N/A |
Gary, Do you have the ability to do a compression check or a borescope examination? (I'm not that familiar with Cummins') It may be that the rod wasn't bent but I've seen engines that ran with a bent rod and pistons with the crown collapsed from a "hydraulic" A bent rod could impart some high stresses and cause failure of the piston, even if the engine will still run. Much the same with a cracked or collapsed piston crown. I'm not telling you it is so, but I will say that it's better to fix it now (if so) than to have it happen on the road. Might be worth the effort. Good Luck! Hope it's all fine | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
Not easy to do a borescope or a compression check with these engines, other than I could simply crank it with the fuel solenoid shut off and listen- you can tell a lot about the compression just by listening to the cranking rhythm with no "ignition". When I set it up, yes I used the "cold" settings, as recommended by my version of "da book". I also verified with Cummins that this is the correct way to do it, because with the Jakes it's almost impossible to adjust them hot. RE: bent rods, It knocked a few times but I'm guessing that if fuel in the cylinder was the problem, spinning it with the compression released got rid of a lot of it. Just a guess though. It didn't sound bad enough that a rod might have lost it... however if it did, in a Crown, that means pretty much removing the engine to fix and if that's gotta happen I guess I'd rather take my chances and let it blow up... not much difference in the long run as I have a spare engine, and either way removal would take the bus out of service for 6 months- I've got a lot of trips planned between now and then. I've also got a good AAA policy that will tow me if I crap out, so hopefully I'm covered although it would be nice to just have it run forever without trouble, wouldn't it!! Don't know about the "D" injectors but the system is PT circa 1969 I've started it a few more times today after it cooled down and every time since, it's behaved perfectly with zero smoke, and sounds absoultely normal. So it seems like something weird happened that's not repeating... I'll keep an eye on it. Tomorrow I'll cut the fuel off and try turning it over and listen to see if any of the cylinders sound like they have weak compression... not a perfect test but not a bad one... | ||
| jimmci9 #2 Rating: N/A |
"d" style injectors torque to either 48 or 72 in lbs...(aluminum or steel rocker boxes). top stops torque to 6 ounces (zero lash)... so thats the easiest way to tell.... small cams set both injectors and valves on same cylinder... big cams set injectors before valves (in firing order on separate cylinders)... ive got a small cam 350 in a '77 kw truck... | ||
| R.C.Bishop
Rating: N/A |
Is the jake in an "on" position....any of your three or so switches? Just a thought. RCB | ||
| Bill Gerrie
Rating: N/A |
RCB might have something. I've had this same thing happen on a Detroit where the jake came on at idle due to a faulty switch in the tranny. It might be possible that you have a combination of the old "D" injectors and the jake on. Once you got rid of the fuel with the decompression lever the jake would make it sound like it is going to fall apart. You might want to get an oil analysis to check for fuel. Just a thought. Bill | ||
| Gary Stadler (Boogiethecat)
Rating: N/A |
The Jakes definitely weren't on. When they are, it's a totally different sound, different feel, different smoke... also I have an indicator light that comes on when the Jakes are engaged...it was off... and I tested them while it was running to be sure. Nope, definitely not the Jakes. Currently my thoughts are as follows: (1) I tried to start the engine the first time and it was hydraulic locked from an open injector. Why this has never happened before I dont know and I hope it never happens again. (2) When I then spun the engine over with the compression lever released, it spewed all that fuel out into both the exhaust manifold AND the intake manifold. (3) Then when the engine started, all that fuel in the intake manifold got sucked back into the engine in general, and made it run away for a few seconds and knock like hell for a bit (4) All the fuel in the exhaust manifold got shoved into the turbo and muffler, and smoked but didnt burn for quite a while, accounting for the massive white clouds the engine was apparently making... it would also account for why it slowly became thinner as time went on (5) Eventually it all got burned out of both manifolds and everything calmed down (6) After the half hour of sitting while I took a shower, what fuel was left had evaporated and the engine, once restarted, ran clean again At least that's the best I can come up with... why in the first place I have no idea. Pretty sure I didnt bend a rod or trash a piston- I did a check of turning the engine over with no fuel this morning and the compression sounds perfectly balancd between all cylinders as she spins. This obviously can't tell me the actual compression numbers, but if you have a good ear (I do) you can easily hear if there's any difference between cylinders. In my case, happily there is not. And when I finished that, I turned on the fuel and once again, a perfect & instant start, no smoke. That's the best I can come up with other than taking the motor out and taking it apart... not a job I want to even think about.... One last thing I need to learn about: I'm wondering how an injector stopped in the firing position can siphon fuel...at least in my engine with the PT fuel system... It would seem to me that since the way the PT fuel pump shuts off the engine is to cut the fuel off totally at the fuel pump (remember, a PT pump is not an injector pump. it's only a gear pump that supplies something like 80 to 300psi to the injectors depending on the throttle position; once the motor was stopped regardless of the cam/injector position, no fuel would be able to find it's way to a cylinder even if the injector was opened, 'cause it's shut off by the solenoid. But it apparently happened...What am I missing here? | ||
| jimmci9 #2 Rating: N/A |
fuel can siphon back thru the return line....the depending on how full the fuel tank is... and witht eh pancake engine in your crown, the fuel may be a gravity feed.. check to see if there is a check valve on the fuel return line... | ||
| niles steckbauer (Niles500)
Rating: N/A |
Gary - Jimmici9 may have something there - could your tank vent be clogged/blocked and pressurizing the tank? | ||
| Henry R. Bergman, Jr. (Henryofcj)
Rating: N/A |
Gary.....several possibilites. Do you have check valves on your return AND PRESSURE fuel lines? Do you have an aux. (electric?) fuel pump in the pressure side of the fuel line system? Where may this pump be exactly located? How full was/is your fuel tank? Full full or just half full? Only other thing I can think of is that somehow during your Jake installation, a situation potential (actual?) was created by some unknown/unintended action on your part. You have (I think) a 743 mill with the older style injectors, which (I think) can sometimes stop in the inject position and if fuel can backflow from the return line you may fill the cylinder with fuel??? Could your turbo seals NOT LIKE a Jake Brake and be leaking lube oil back down into the cylinder heads? I am reaching here as I really do not have a real clue. I will ask around up here in SW OR. CROWNS FOREVER!!! | ||
| Richard Bowyer (Drivingmisslazy)
Rating: N/A |
Since you have a compression release it might be a good idea to turn the engine over a couple of times with the release on every time you let it sit for awhile. Richard | ||
| Henry R. Bergman, Jr. (Henryofcj)
Rating: N/A |
Also Gary maybe perhaps your valve guide seals also do not like a Jake Brake and are now leaking sometimes maybe perhaps? CROWNS FOREVER!!! | ||
| dougtheboneifiedbusnut
Rating: N/A |
Hey Gary, Had the same thing happen to my 855. You definetly got raw fuel going into a cylendar. In my case it turned out to be a broken diaphram in my anaroid which let fuel seep right into my intake manafold. I think you have an open check valve in your fuel line letting fuel get by an open injector. Your engine is(as you know) below the fuel tank requiring there be check valves in both the supply and return lines as Henry said.Im curios as to what it turns out to be.Hope you make out alright. |