Another timing question

[btoscano]

What's another week without another timing question?



During my KDP tabbing/timing case bolt tightening, I bumped the timing a bit to about 5/32 or so, it had been about 1/8. It felt advanced - really had some turbo lag!! For kicks I stopped by Cummins and let one of their mechs listen to it and he said it sounded good.



I loosened up the pump and it rotated back itself still about 3/32. The lower RPMs feel much better and the turbo can be heard sooner. However, top end appears lower. Also, in 4th, near top RPM with a bed of logs, I get light smoke at night. I can see it in the mirror from peoples headlights - clear enough to see through. I never had smoke before like that more advanced even with wood.



So, I'm going to try to bump it back up that extra 1/32 to 1/8" exactly and see. I think I will loose some of the smoke, the boost will be later, but still mostly tolerable, and the top end will be better. I think this is where I had it, but I loosened up the pump during my KDP tabbing/case bolt tightening project.



So my question is, how much smoke should I be getting when the timing is "right" ?



Brian

 

[bgilbert]

I can't help you with your smoke issue, actually don't want to get me started on that topic, I'll say something to the effect its a diesel... I've learned that with injectors popping at 3800psi is effectly retarding your timing.

 

[JLEONARD]

how much smoke should I be getting when the timing is "right

I think the amount of smoke is too dependant upon other things to say specifically... other than saying that advancing your timing should reduce it.

You may have to be your own judge.

 

[btoscano]

When I drove a Mercedes-Benz diesel car there was a certain amount of "accepted smoke" so I thought I'd ask. I guess ya'll do too much tuning to have a "standard".



I understand the injectors are probably retarding the timing somewhat. Its frustrating because I bought dealer reman hoping I wouldn't have to deal with any tuning. Sigh. And to make matters worse, the tappet cover gasket is still suspect. If only Cummins Mid South had one in stock I wouldn't be thinking about that anymore.



Maybe I'll have to make a trip up to Terre Haute and set things right



-brian

 

[btoscano]

I'm starting to think I should pull the injectors and return them to Cummins because they are popping too high, or just have a diesel shop reshim them to correct spec so I know they are right when I get them back.



When I advance the timing up, the turbo boost comes in late. So, if the injectors pop lower, I won't need as much advance, and can have the best of both worlds?



Sound like a good idea?



A great time to do this job would be when I have things apart for the tappet gasket replacement.



-brian

 

[bgilbert]

I'm starting to think I should pull the injectors and return them to Cummins because they are popping too high, or just have a diesel shop reshim them to correct spec so I know they are right when I get them back.

When I advance the timing up, the turbo boost comes in late. So, if the injectors pop lower, I won't need as much advance, and can have the best of both worlds?

Sound like a good idea?

I don't know Brian, I wish I knew, as I'm probly gonna be in the same boat soon. I'm having a set of injectors built, and in a quick conversation, I swore he said they set 1st gens to 3800psi, but he wasn't sure at the time.



There's gotta be smarter guys than me on here, they're just not adding their two cents... . chime in anytime . . for that $35 you get more than just 4 periodicals a year fellas :-laf .

 

[btoscano]

I talked to a local Bosch diesel injection service shop and gave them the CPL of my engine. They looked it up and said 250 bar (3625 psi) is stock setting. They said if they are popping a few hundred too high that might be a problem and certainly would reshim, but they were more likely to think the pump may have been rebuilt with settings on the low side.



Here is my plan:



1. Remove the injectors, let them test & reshim as necessary.



2. When I do the tappet gover gasket, let them put the IP on the test stand and turn it up to the max within stock specs.



I'll let you all know how it goes.



-brian

 

[bgilbert]

Can you take the injectors back to Cummins for a no charge test/reshim? Or is this a different shop and more money?



I wouldn't waste my money on having them tweak your pump. Unless its not too high. Yeah I know it will be on a stand and all, but most of us feel that we can get away with our own tweaks.

 

[btoscano]

Its a different shop nearby. I'm not going to deal with Cummins unless the injectors have the wrong parts inside. I have more confidence in the shop down the street who will test them when I put them on the counter. As far as the pump, I'll have to see. They charge $130 to put it on the stand. There is a certain confidence I would get knowing its within factory specs. I may be willing to pay for it.



-brian

 

[BushWakr - RIP]

Hey Brian... . in this thread you asked about... popoff pressures... >>



https://www.turbodieselregister.com/forums/showthread.php?t=148162



In that same thread (I mention this ONLY because I think it will help put you at ease and confirm your own feelings on this) I replied by saying... .

Brian, 3350psi is a bit low as far a popoff pressure. The stock injector on our trucks has a popoff of 245 bar (3601psi). From that point the upgrade injectors all have a higher popoff pressure.

Regardless of which injector is installed in the truck I'd still have them set to no less than that stock setting.

The higher the popoff the more you'll need to tweak your timing... . not huge, just a tad because it takes a few milliseconds longer to charge the line/injector to popoff point.

I'd personally prefer to have stock nozzles set to 255-260 bar. This will give a clean crisp spray pattern without overworking the pump.

BTW, Bosch will "accept" a range of pressure as "acceptable... I understand that they consider a spread of 8 bar between the high/low popoff on a set of injectors as normal.



pb... ... .

__

I believe 3800 psi is 258. 5 bar. . or, to put it another way... right in the ball park for us guys... if you have a set that is using that rating... keep 'em in there and go for gold bud...



pb...



edit: just one last thing... . in our situation I wouldn't be worrying about '32nds of an inch... without perfect dyno conditions and/or using a dial indicator you can't really work timing that close using the "loosen/move/tighten" method.

 

[btoscano]

A shop pop tested the injectors at 3800-4000 psi (262-275 bar) before they were installed.



-brian

 

[bgilbert]

http://www.funsupply.com/airguns/psibar.html. Nice conversion bar to psi table, thanks to the member that linked it on one of my previous posts. I've bookmarked it. 3800psi ~ 262 bar.

 

[btoscano]

1 bar = 14. 5 psi





-brian

 

[paccool]

I have a question about the "turbo lag" that you talked about when the timing was bumped up. Before the twins, I was running 1. 7 on the timing. Turbo lag was never a problem either with the stock turbo or the PDR 35.



Did you adjust the smoke screw and starwheel to bring the fuel on quicker?

 

[btoscano]

Haven't turned any pump screws, just advance/retard it.



I got the pump back from the diesel shop. They, like Daniel, said the idle adjustment was way off so they adjusted both the idle and high RPM screws, and turned up the fuel. They said fuel was in the middle of the range, and now its at the top of the range. I should also have a slightly higher RPM.



I'm really not interested in turned screws and changing cones. I don't want to think about adjustments. I just want to drive it. I drive maybe 60-85Kmi/yr by the time its all said and done.



-brian

 

[bgilbert]

Haven't turned any pump screws, just advance/retard it.



I got the pump back from the diesel shop. They, like Daniel, said the idle adjustment was way off so they adjusted both the idle and high RPM screws, and turned up the fuel. They said fuel was in the middle of the range, and now its at the top of the range. I should also have a slightly higher RPM.



I'm really not interested in turned screws and changing cones. I don't want to think about adjustments. I just want to drive it. I drive maybe 60-85Kmi/yr by the time its all said and done.



-brian

I can't believe Daniel didn't tune your pump for you ?? They said thanks for your $100 and simply turned some screws that any of us, including you could have done.

 

[btoscano]

At Daniel's we left the pump stock since it was still under 6 months unlimited hours/miles warranty. I didn't want to break the warranty when we didn't even know if it was DOA. That was 3 months ago, so I didn't care anymore. The really had to mess with the idle, it was all wrong. They gave me a new return banjo bolt and said use the one we gave you, its calibrated for this one. As for the $142, I'm not really concerned as long as it helps.



Its just that damned tappet cover gasket... . I was going to leave it be, but when the oil level was down, drips on the ground, and coating on the fuel tank, I figured it was time for action.



I'm going to take the fuel pump off and get that blasted thing done. See ya'll in a bit!



-brian

 

[mysteryman]

injectors

The 93 injectors kind of suck ! You might want to get a set of "190's" from Piers and while your at it get a 16 cm turbo housing also... . Your truck will run a lot better for it... .

I'm starting to think I should pull the injectors and return them to Cummins because they are popping too high, or just have a diesel shop reshim them to correct spec so I know they are right when I get them back.



When I advance the timing up, the turbo boost comes in late. So, if the injectors pop lower, I won't need as much advance, and can have the best of both worlds?



Sound like a good idea?



A great time to do this job would be when I have things apart for the tappet gasket replacement.



-brian

 

[btoscano]

Why didn't Dodge put a 16 cm housing on at the factory?



Does the 18 cm housing help under extreme conditions? Such as pulling a house up the Grapevine in late August???



-brian