I just ordered rebuilt fuel injectors N65 brown tags for my 8v71n. I am still confused on the difference between the color of the tags. Anyone have the lowdown on the color meaning. I found these online at a diesel parts store for about 50.00 each. Which is a great price from what I have seen online.
So, does anyone know what the colors of the tags mean.
My understanding is that the brown tag N65's were set up with internals that required or worked best with advanced cam timing in 71 series engines. There were white tag N65's that had different internals that let them be used with normal cam timing, they had the advance built in to the injector.
I found that in a couple of places using Google, I have no idea if it's true or not.
Brian
Ok... here goes. In short, the answer you don't want to hear is "No".
I asked this same question a year ago on this forum. No one really knew the answer. I went to the DD dealer in person and the parts manager literally said to me "We just install the same injectors that we take out".
There are dozens of different injectors, different sizes, different spray patterns, every one of them designed for a specific application. I installed a rebuilt engine in my 4106 last summer. The new engine came from a NYC transit that had a brand new block (black paint, custom NYC Transit Authority serial number stamped into it) and had 7G55 injectors. I only know that the 7G series injectors were specifically for better emissions, and the 55 is quantity of fuel injected per stroke (or something like that). There are numerous injectors for the industrial engines, as well as injectors for marine use.
I installed brown tag N65 injectors in that engine and it runs perfectly.
I'd say that if you're installing new injectors in your bus, the brown tag injectors are perfectly fine. Mine work perfectly.
Quote from: bevans6 on February 26, 2011, 10:26:16 AM
My understanding is that the brown tag N65's were set up with internals that required or worked best with advanced cam timing in 71 series engines. There were white tag N65's that had different internals that let them be used with normal cam timing, they had the advance built in to the injector.
I found that in a couple of places using Google, I have no idea if it's true or not.
Brian
Brian is right about the Advanced Timing with the N65s. I did advance the timing and at WOT it doesn't smoke at all. I contemplated going with N70 injectors which use standard timing, but smoke was a concern. I planned on using propane injection to with the N70s, but decided on simplicity and economy vs. the additional 50 HP the N70s and Propane would have added.
A good injector for a 8v71 is 7E65 you can get the same results as the N65 without changing to A timing the N and C are old technology you guys dig a little deeper then you can decipher what the lettering ,numbers and colors mean
good luck
I'm using standard timing on my turbo 8V-71. Between 1500 and 1900 no smoke (which is just where I run it). Good Luck, TomC
Tom.. Are you using n65 injectors. I was wondering how the n65 injectors would do on standard timing.
Chart1, reread luvrbus's post and think about it for a minute. ;D
Ed...I understand if I had 7E65 I would be in good shape on standard timing. But I have n65 injectors which I know work best with advanced timing. The thing I am not sure of is where my timing is set. I think the only way to tell is to tear the back of the motor apart to look where the timing marks are set.
OOOPS, i had forgotten that you had already bought N65's, sorry, disregard my comment. ;D
Is there an easy way to determine valve timing and injector size/number on a 8V71? I assume I have to pull the covers to see the injectors. Are they marked?
Yes they are marked there is a little round disc on them that will tell you what size and the disc will be colored. A different color for different specs.
When I first bought the bus, it had N55 injectors in it. I had the mechanic change them to brown tag N65 (which was an option on the bus). It had more power and smoked slightly at sea level under full throttle. But over 6,000ft, it really smoked and had big power loss. This is ultimately why I turbocharged the bus. Good Luck, TomC
My understanding is that the only "old style" injectors that used advanced timing were the N65's. So if you bus already has/had N65's and you are replacing them with the same type, the good guess is that the engine is advanced timed. If you are installing N65's when the bus had something else, it probably has standard timing. Everything I've read is that the N65's smoke and don't live up to their potential with standard timing. The idea is to inject the fuel a little earlier so that there is more time for complete combustion of the larger fuel load.
Brian
I have n65's in my 8v71 so I am assuming it is advanced timed. what are the advantages/disadvantages to the advanced timing vs. standard timing as far as power/torque output and rpm range or "sweet spot"?
A timing in a bus with a 4 speed auto or manual does very little that was a set up for trucks with a close rpm split going through gears most were 10 speeds the N65 works ok without A timing just more smoke 90% of the bus engines won't be A timed,have any of you A timers ever noticed nothing is ever said about A timing on a 92 series it never happens 92 series are standard timed because they don't use the needle valve injectors
good luck
N65 with advanced timing is what I had in my 8V71N, which was a Navajo Nation MC-5C. The combination shifts the peak torque from 1200 rpm to 1600 rpm, but you don't lose anything - the torque at 1200 rpm is still greater than N60's and standard timing. Mine smoke a bit on take off, never noticed anything climbing a hill.
Brian
You guys with A timing and N65 get up around 7500 ft then see what you have lol plenty of heat and smoke that is what you have
good luck
Whats the simplest way to check cam timing?
If the bell housing is on, there is no simple way to check but it's not rocket science. The method is to remove an injector, use a dial indicator to find top dead center on that piston, then re-install and time the injector and use the dial indicator to measure the amount of injector stroke at TDC for that piston (doesn't have to be true TDC, just for the piston you are checking). Standard timing is .230", while advanced timing is .262". If you've ever timed a cam, it's wouldn't be an unfamiliar task. The difference in injector stroke is substantial at .032", and if you had a way of telling where TDC was you wouldn't even need to pull an injector out. If the bell housing is off, you just look at the gears with the engine rotated so the marks line up. The trick is arranging for the bellhousing to be off...
The highest pass I ever took the bus over was I-26 at 4,000 feet. That was 45 minutes to an hour of 2nd gear on the governor and 30 mph, but it was a nice day, the scenery was pretty, and I was in a long line of trucks doing exactly the same speed. The highest pass I do normally is 2700 feet. Plus my new engine has a turbo...
I may well take the time to put a TDC indicator on the front pulley of my new engine, it could come in handy some day for something or other.
Brian
Thanks Brian. I have a dial indicator and degree wheel and all that stuff and know how to degree an engine. I was hoping there was an easier way, a cover you could pull or something. No banana there I guess.
Is the general consensus that an 8V71 with "A" timing and 55 injectors would have the highest low end torque at low rpm, and the best fuel economy?
No, I think the N55 injectors will not supply sufficient fuel to allow advanced timing to work to any advantage. The reason for the advanced timing is to allow more time for amount of fuel delivered by the N65 to fully combust. Don't forget that it also advances the timing elements for the exhaust valves, opening them sooner and reducing the time for the combustion to deliver power, and closing them sooner reducing the time for the intake charge air to enter the combustion chamber. It's all a balance. Turbo charged engines mostly run standard timing, all the ones I've found anyway.
Brian
Not all 6v92 or the 8v92 are turbo engines and they still have standard timing