Unacceptable Idle Haze

Smokem said:
Raising the opening pressure 10BAR isn't going to eliminate idle haze, most often it is due to the cone angle or the nozzle's depth in relation to the piston bowl. I've worked on several sets of the Scheid nozzles, they are not billet.
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I honesty don't know the difference between a billet and non-billet nozzle. Easy to tell? There are no Bosch markings anywhere, just the scheid part number laser etched in to the nozzle. The description I posted was from the sellers ad, and if I remember right; when I called schied they verified the specs.

I figured my 23* timing would be fine with the 142* spray pattern, thinnest washers, and the .008 taken off the head while running the stock thickness gasket. Do you think I could benefit by turning say, .020" off the injector nut?
 
Taking anything off the injector nut will not lower the injector, it would need the injector itself machined where the washer goes on to lower it in the head. I had a set done that were 155 spray pattern 5*14's and were cut to set deeper in the head, on stock pistons. It was a noticeable difference and ran clean after it was warm, hazed pretty good when it was first cranked in the morning.
 
jasonc said:
Taking anything off the injector nut will not lower the injector, it would need the injector itself machined where the washer goes on to lower it in the head. I had a set done that were 155 spray pattern 5*14's and were cut to set deeper in the head, on stock pistons. It was a noticeable difference and ran clean after it was warm, hazed pretty good when it was first cranked in the morning.
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That's not nut I am talking about. Sorry for not specifying, I'm talking about the "nut" side of the nozzle.
 
The piece that is sticking out like a sore thumb to me is the racked barrels. While most pumps end up decently balanced when racked there are a few that end up with one or two cylinders that get a good bit more fuel at idle. This can lead to one cylinder being overfueled at idle and raw fuel smell coming from the exhaust.

A couple of field technicians told me to check each port on the exhaust manifold with a temp gun at idle. The COLDEST one is the one with too much fuel and an incomplete burn at idle. High rpm and boost it will be doing more work and be the hottest cylinder though. You can try and tap that barrel back on the coldest cylinder to even it out or just pull the pump and have it properly balanced.
 
timing, aftermarket cam, compression, intake porting, fueling mods will all affect how hard it pulls off idle before making a pile of smoke doing it.
VCO nozzles usually smoke a little less than SAC at idle. timing and fueling are probably the cause in your case.
Compression or extra airflow at low rpm might help with that. like, higher compression pistons or a blower over turbo setup.
lowering the injector into the bowl by milling the nozzle holder is an interesting idea I dont know how much meat is on that thing. but it shouldnt take much to make up for a degree or two of timing near tdc.

stock timing on mine is just so I can take off from a stop without smoking the crap out of everyone behind me. got tired of people zipping around and cutting me off because I wasnt accelerating fast enough from a stop, or they were pissed at the smoke.
truck still hazes no matter what I do.
 
I wonder if my cold haze is a mix of old dirty 5x14 or the 191's I too am at 23* when the motor is warm there is no haze . I may swap In the 181's
 
gman99 said:
The piece that is sticking out like a sore thumb to me is the racked barrels. While most pumps end up decently balanced when racked there are a few that end up with one or two cylinders that get a good bit more fuel at idle. This can lead to one cylinder being overfueled at idle and raw fuel smell coming from the exhaust.

A couple of field technicians told me to check each port on the exhaust manifold with a temp gun at idle. The COLDEST one is the one with too much fuel and an incomplete burn at idle. High rpm and boost it will be doing more work and be the hottest cylinder though. You can try and tap that barrel back on the coldest cylinder to even it out or just pull the pump and have it properly balanced.
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Took a temp gun to the exhaust runners after letting the truck idle for about 10 minutes. All cylinders were at about 145* except for #1 which was at 125*... Probably couldn't be a coincidence that that was also the injector that had the lowest pop pressure... looked like it was about 10bar out. Ill pull it after work today and see if I can get it shimmed up.
 
What about valve lash? I have been adjusting at .010 and .020 cold using 5in/lb to make sure they are all perfectly even. They tend to run a few thou tight but from what I read, that is how they do it at Cummins. Thoughts on this?
 
Got the pop pressure on #1 up to about 4225. Way closer than it was. still no noticable difference in idle haze. It does seem like it might idle slightly smoother. #1 cylinder is still consistently 20+* lower in temp at the exhaust runner. I was thinking though, wouldn't that make sense since it's the first cylinder that coolant comes across?...

Maybe I'll try loosening up my valve lash like 5 thou just to see what it does.
 
what kind of static compression is your motor making? any blowby? Youre running a stock cam right?
Are those injectors VCO or SAC?
I ran some 7x.009 148* SAC injectors for awhile, they seemed to haze less but they didnt make much power once the boost got high. with larger orifice sizes maybe its not so much of a problem with boost penetration
 
I reringed and rebearinged this engine in November. Deglazed the cylinders. Ported the head. Did a valve job. All that fun stuff. Another strange occurrence is that when The engine is cold, there is no visible blowby and a manometer reads close spec to stock engine. Once yo to temp, blowby is VERY visible and manometer readings show close to needing a rebuild but a few l/min lower. What is strange about it is usually blowby clears up the warmer you get...

I don't know what my compression is. Should be stock. Took .008 off the head which doesn't effect compression. Using a stock Cummins gasket.

Yes. Stock cam.

VCO.
 
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I did remove the cam gear and then put it back on during the refresh. But I made sure it was seated all the way when reassembled. Plus, it was smoking like this before the refresh, I was hoping it would fix it.
 
porting the intake side will increase volume and decrease air speed because the piston travel displaces a fixed volume. That supposedly has an effect on low rpm swirl which is what helps igniting fuel reach usable oxygen.
Not sure what that manometer reading is about. Maybe your turbo is pressurizing the crank via the oil drain? You could put the drain into a bucket while taking a reading to see what that does. Obviously youd do this around oil change time.
Could also check the vacuum pump seals if you are running it. Im thinking about pulling mine since I went with hydro brakes.
 
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