| Author |
Message |
John Bessette (65.73.247.187)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 15, 2004 - 11:26 am: | |
What is the pro and con on S timing or A timing with N65 injector? I think mine is set at S timing
John 4106
Thanks |
Geoff (Geoff) (66.238.120.139)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 15, 2004 - 4:15 pm: | |
The significance is that the engine might smoke black with the N65's and standard timing. If your engine doesn't smoke under accelleration beyond acceptable limits I wouldn't worry about it. |
Daris (209.67.181.129)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 15, 2004 - 7:45 pm: | |
My 4106 has N65 with standard timing. It was rebuilt about 10,000 miles ago. I get a little smoke when it's cold and I accelerate. I also get some smoke on the hills. When I see smoke on the hills, I just back off the throttle a little.
I'm half thinking about replacing them with N60's. I've seen some postings that say that you might be getting a little less MPG with the N65's but I don't know for sure.
I've also seen posts that indicate you'll gain power at the expense of MPG with the N65's and advanced timing.
Advanced timing or not, and N60's or N65's, my 4106 isn't going to win any drag races. I'm seriously thinking about having N60's installed and enjoying the extra MPG. With a 140 gallon take, a gain of 1 MPG is a nice little bonus.
Regards,
Daris |
Tom Caffrey (Pvcces) (65.74.65.65)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 15, 2004 - 10:42 pm: | |
Daris, C-60s might be a little easier on the engine at low RPM, when you're starting up a grade, trying to back up or when you miss a gear. Peak torque is at 1200 RPM.
It might be easier on the engine when you drop down to 45 mph in fourth if you don't shift because you want to keep your mileage up.
And it might cut down on the amount of soot that gets into the lube oil between oil changes.
N-65s with advanced timing puts peak torque up to 1600 RPM, which is just fine for trucks with more gears to keep the RPM up.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher |
John Bessette (65.73.247.187)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 15, 2004 - 11:30 pm: | |
Thanks everyone for the come back.
Daris that is what i do is back off a little on the hills so it dont smoke to much but i still make it work. I dont get the mileage that some are saying they get 7 to 7 1/2 if i run easy and 6 to 6 1/2 if I dont. I got 8 once but that was down hill with a big tail wind.
Geoff thanks I was hopeing you would jump in there that is what i am going to do not worry about it. just keep it wound up Ha.
Thanks again
John
4106 |
Daris (209.67.181.129)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 16, 2004 - 11:30 am: | |
Thanks for the tip on the C60's. I'll discuss them with my mechanic. I'm getting married in September, so I probably won't do anything until next year. |
Jim Wilke (152.163.252.163)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 16, 2004 - 7:01 pm: | |
Size of injectors makes no difference in fuel economy IF you drive the same speed as before. It takes X amount of fuel to move the bus at 60MPH and whether you have 60's or 80's won't make a difference on flat ground AT A GIVEN SPEED. But the larger injector gives you more HP if you need it. Kind of like having 400hp in your pickup truck. You use it when you need it but you don't drive 125 all the time, right?
We have a V8 Explorer which gets the very same mileage on a long trip as our V6 Explorer does! (But not when Hot Rodding around town,)
We have driven our 4104 about 15,000 miles with N60 injectors. Mileage: about 9.9 on flat ground at 60-65 mph. I just changed the N60s in my 6-71 to N65s. Same flat ground mileage but I keep the same speed. (My max speed was about 73 and is 78 now.) But she goes up hills WAY better. And still no smoke except a small grey puff starting from a dead stop, same as before. I will be upsizing to either 70s or 80s as the GM 4104 book listed as max size 'till I get to where I get a little smoke when climbing hard. The governor on the 4104's 6-71 has a modulating device that limits full fuel when the RPMs get near full speed so the max size for the later 8v71 may be smaller.
I enjoy not having to downshift on overpasses now. If it costs 1 MPG in the mountains IT'S WORTH IT.
My $.02
Jim-Bob |
Tom Caffrey (Pvcces) (65.74.65.65)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 16, 2004 - 7:12 pm: | |
I don't know the actual length of injection stroke of the different injectors, but I would expect the higher RPM setup to use a shorter stroke.
Perhaps someone who knows how to get that information will post something interesting on the subject.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher |
Jimmci9 (209.240.205.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 16, 2004 - 8:07 pm: | |
the actual stroke length never changes...its whatever the rocker arms allow.... but the fuel rack controls the "scroll" inside the injector...the position of the scroll inside the injector is what determines the amount of fuel injected in each stroke....fuel is injected at "port closing".. depending on theposition of the scroll blocking ports inside the injector..... confused??? i'll try to find some pics.... |
Tom Caffrey (Pvcces) (65.74.65.65)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, April 17, 2004 - 11:40 pm: | |
Jim, I agree, the mechanical stroke is dependent on the rocker motion. What I was thinking of was the length of the injection stroke, which would depend on the point that the port closes.
I was thinking that a smaller RPM range(1500 to 2100 instead of 1200 to 2100) in the engine would mean that the injection stoke would need to be shorter to optimise the cylinder pressure as the fuel burned.
I admit I am just guessing here, but I figured the engineers would get a shot at any needed fine tuning for changing the operation of the engine from buses to trucks.
For what it's worth.
Tom Caffrey PD4106-2576
Suncatcher |
Jimmci9 (209.240.205.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 18, 2004 - 4:34 pm: | |
the length of time for the injection stroke is determined by "lift' of lobe on the cam that moves the injection rocker arm...the angle the "duration " is ramped, determines how fast the diesel is injected.... and the "duration" is how long the injector stays depressed..., because all the allowable fuel will be injected.....and this is also where the timing pins, that DD uses, comes into play....when you time a detroit injector, you are setting its maximum stroke, its dimension, that it can mechanically travel, from the base height of the cam...duration on the vexhaust valves, is important, because the blower needs time to 'scavenge" the cylinders.... |