Diesel engine has multiple explosions in exhaust when starting questions

Tinkerer · Feb 5, 2014

As the thread title says my Case 301D engine was making a lot of noise after I started it this morning. In cold weather it has always taken a several minutes of run time before all the cylinders would start firing. This AM it was 23°, not that cold really. I don't care to use any more ether than I need, to get it started. It started right up ok but I have never heard it have all these rapid explosions in the exhaust. After i let it run to warm up a little it ran fine. No lack of power and accelerated like usual. Does anyone have any experience with an engine doing this ?
The injector pump has less than 200 hours on it since it was serviced by a professional and the injectors are Case OEM with less than 400 hours on them.

jackleg · Feb 5, 2014

I wonder of you have an exhaust valve sticking open? Maybee a broken spring or a lifter that stays pumped up when cold?

grandpa · Feb 5, 2014

Take a temp gun and shoot the exhaust manifold.... that will tell you which cylinder/cylinders are miss firing.

frogfarmer · Feb 5, 2014

Several minutes of run time before all the cylinders come in sounds like mechanical issues. I would be taking a look at the valve lash. If the lash is tight it can cause this issue. Tight valve guides could also cause the issue but I would expect to see more problems when hot if that were the case.

mitch504 · Feb 5, 2014

when it's cold a lot of otherwise problem free old mechanical engines run on a few cylinders until they warm a little. I have no real guess on the bangs, it will be putting unburnt diesel into the exhaust until those cylinders fire, but I've never heard one light it off.:beatsme

Scrub Puller · Feb 5, 2014

Yair . . . Probably irrelevant in this case but I once started a diesel Ferguson that had been topped of with gasoline . . . it had no lack of power and started with a pop and clatter.

Cheers.

Tinkerer · Feb 6, 2014

Thanks for the replies. I have considered all of them. I don't really think it is a valve or lifter problem. The engine has a new camshaft and lifters along with new valves, springs and valve seats. Less than 400 hours on them. Mitch504 ; I agree a lot of unburned fuel gets dumped into the exhaust on a cold start. But neither have I seen or heard it light on the way out.
Scrub Puller ; That post about gas is interesting, but there is no gas in my (bio-diesel blend crap) diesel fuel. It has been treated with fuel conditioner. I have noticed there isn't much white smoke on these cold temperature starts while the engine is starting and warming up. That has me thinking that it is running lean on fuel. I am beginning to think one or two or even three fuel injectors may not be atomizing the fuel like they should be. There least one cylinder that is very strong when starting. I will have the injectors pop tested at fuel injection shop when the weather gets warmer. The machine sits outside and I don't have access to a enclosed building. It is -7° Fahrenheit outside this morning.

Scrub Puller · Feb 6, 2014

Yair . . . all the best with it Tinkerer. Man, I don't know how you blokes cope with the cold weather.

Cheers.

Tinkerer · Feb 6, 2014

Scrub Puller said:
Yair . . . all the best with it Tinkerer. Man, I don't know how you blokes cope with the cold weather. Cheers.

Well Scrub Puller, We get acclimated to it after a while. Kind of like you do in that world famous heat you have. I had to go to my shed in the backyard yesterday for some fuel conditioner. I am a little over 6 feet tall and I was wading through snow that was up to my knees.

frogfarmer · Feb 6, 2014

I think you already outlined the problem. New top end rebuild. I will bet the guides are a little too tight for the cold temps along with the springs possibly being a little weak. The piston will close the valve when it comes to TDC and smacks it but the closing is late causing the fire to be partially in the exhaust manifold and muff. If it were injectors I would expect quite a bit of smoke. If you dont break the head off a valve before they wear in you will be fine. This can and does happen but not common and most likely the result of the really cold temps.

Nige · Feb 6, 2014

I'm inclined towards the "tight valve when cold" theory as well. The only way that I can imagine for a noise like you describe is from fire within a cylinder getting out past an exhaust valve that is not fully closed. I don't think it's the unburnt fuel in the exhaust igniting.

Tinkerer · Feb 6, 2014

Frogfarmer and Nige ; Your comments make a lot of sense to me. Unburnt fuel in the exhaust system sure wouldn't ignite with the sound of a gunshot like I heard yesterday. If it could ignite at all. Yesterday was the first time I had it happen. Never before now. It would stop doing it as soon as I gave it a real frugal sniff of ether. I hate using ether and avoid it if I can. The machine is going to sit until we get another snow storm that will force me to go out and do snow removal. I do have an 1800 watt electric tank-type coolant heater that i have never gotten around to installing. If ever gets warm outside it will certainly be put to use. It has an OEM freeze plug style heater, but it doesn't seem to help much.

Bill Smith · Feb 7, 2014

This maybe a long shot but is it possible the injection pump can go out of time on a cold start , or dumping to much fuel . Im not much of diesel mechanic but you see this in some gas engines

randy448 · Feb 7, 2014

Could this be the old Power Cell engine and not direct injection B series? If so they were bad about cold start mischief.

Curbster · Feb 7, 2014

I have what I call a "circulating heater" on my 426. I have always used a circulating heater on everything I have driven. Diesels like heat when it is cold. Yellowknife, NWT and -50 for days taught me many things about cold starts. Those little frost plug block heaters were useless and only effective if it was a balmy 0 C. or 32F. and even then very limited. Only problem we ever had with circulating or tank heater as some call them, was they would make the heater hose in the area where they were installed a bit brittle over a few years. In really cold weather we had to use a battery blanket, oil pan heater, and circulating heater. Rigs always started at -30 C. and colder. I just use a circulating heater here, where it is -12 C. this morning.

jimr · Feb 7, 2014

Just trying to understand and learn here, but if an exhaust valve is sticking open how would the fuel ignite before the valve closed? That is, wouldn't the valve have to be opening early to let fire into the exhaust manifold. The extra squirt of either makes sense, that would get the missing cylinders firing and dry up the fuel supply. If a exhaust valve was being held just barley open (lash too tight) would it create enough temperature rise for ignition and still leak fire into the exhaust manifold?

On the heater thing, I put a factory block heater in this winter and am really surprised at how much heat it puts into the motor. After the install it sat outside (no building big enough to get it in) for two days lows -20's and highs -12F and then I plugged it in for three hours, block was warm to the touch and she fired right up. I got the 750 watt because that is what it would have come with but there are 1000w and 1500w models as well.

frogfarmer · Feb 7, 2014

It would take a chain of events and more than one cylinder acting up to cause the ignition in the exhaust. It may be the nature of the beast given the cold temps. It is difficult to diagnose an issue from several thousand miles away.

Mobiltech · Feb 8, 2014

Does it sound like this http://www.youtube.com/watch?v=T9txUsXrTdk

powerjoke · Feb 8, 2014

jimr said:
Just trying to understand and learn here, but if an exhaust valve is sticking open how would the fuel ignite before the valve closed? That is, wouldn't the valve have to be opening early to let fire into the exhaust manifold. The extra squirt of either makes sense, that would get the missing cylinders firing and dry up the fuel supply. If a exhaust valve was being held just barley open (lash too tight) would it create enough temperature rise for ignition and still leak fire into the exhaust manifold?

I was going to make the same post, im not argueing im just curious how it could happen....... i could see it as timing on a gas engine but i cant wrap my head around it on a diesel

btw a 301 is a diesel right? i have no clue what era we are even talking of there isnt one on machinerytrader for me to get a pic in my head of lol

edit: do you feel that it's every cyl popping or just one or two ? could pump timing be a problem as mentioned earlier?

pj

Tinkerer · Feb 9, 2014

randy448 said:
Could this be the old Power Cell engine and not direct injection B series? If so they were bad about cold start mischief.

No it is not a pre-combustion type engine.
PJ; It is a direct injection 301 cubic inch engine. Case put hundreds of thousands of them in both Agricultural tractors and construction equipment. The same engine design was to become the 336 cubic inch with a blower on it. The popping seems to be random. I also wonder if it could be an injector pump problem. It sounds as if there is only one strong cylinder firing when it starts in sub-freezing temperatures. The exhaust popping doesn't start unless I increase the throttle to about 1000 RPMs or more.
I am wondering if it could be too much fuel conditioner in the fuel. I am using a brand called PenRay PowerPlus. I got a deal on it that I couldn't turn down. In cold temperatures it comes out of the bottle with the pouring consistency of syrup. I thought that was weird. I always used the 911 brand before and it has the same consistency as the fuel does, at any temperature. Now I just found out, that the $185.00 radiator repair I had done last summer has failed. The upper tank has a seam leaking.

Diesel engine has multiple explosions in exhaust when starting questions

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