Fuel Injectors revisited

[chart1]

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.

[chart1]

So, does anyone know what the colors of the tags mean.

[bevans6]

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

[OneLapper]

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.

[OneLapper]

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.

[luvrbus]

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

[TomC]

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

[chart1]

Tom.. Are you using n65 injectors. I was wondering how the n65 injectors would do on standard timing.

[Ed Hackenbruch]

Chart1,  reread luvrbus's post and think about it for a minute.

[chart1]

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.

[Ed Hackenbruch]

OOOPS, i had forgotten that you had already bought N65's,  sorry, disregard my comment.

[artvonne]

  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?

[chart1]

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.

[TomC]

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

[bevans6]

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