MCI7 8v71 stranded grey smoke increasing with accelleration (injector issue?)

[luvrbus]

My favorite pin is the 1.466 for your engine dozens of pins will work it depends on what you want from the engine

[Dlsnow]

What I want from the engine
 - drive all over the country (WI, MI, CA, AZ, NM, CA, FL, AR, OK, TX)
 - be able to run from boulder to san jose over all those passes - is this a bit optimistic?
 - Is it ok to install this injector (after compression test - if over 350psi) and get to my next destination (Fayetteville, AR) before adjusting timing or running the rack?

I have heard "running the rack" is an art and a science
 - I do have the manuals and am able to follow specific directions
 - I also recognize art is difficult to document
 - is this a follow the directions job

[luvrbus]

Just think of that 8v71 as 2 separate 4-71's if both sides are not in harmony you have one side doing all the work not good, the exhaust temperature should be the same on both sides if not start over from the beginning not skipping any of the sequence 

Follow the book you will get it in couple of try's you could not be any worse off doing it yourself than the guy you hired to replace the injector I think I would ask for refund on that deal

 

[thomasinnv]

Like Clifford said if everything is not properly adjusted so that all the cylinders  are doing an equal amount of work you could have problems depending on how far out of balance they are. So the short answer to your question is NO, don't just slap in an injector and finish the job somewhere else down the road. Running the rack and timing the injectors is really not that tough, just take your time and don't be in a hurry and you can do it.

Sent from my PantechP9070 using Tapatalk 2

[luvrbus]

Look at the fuel rods (they work the injectors) and tell us do they have 2 screws or 1 screw for adjustment,I changed Derrick's over to the spring loaded 1 screw to make life a little easier for him the 2 screws adjustments take a little more patience to adjust

[TomC]

Ideally, you want the injectors to be balanced on acceleration. Taking a heat reading on the exhaust right after a hard run is the best.  If the injectors are adjusted properly with exhaust heat the same on all cylinders, whether or not the idle is smooth isn't important.

If you're ever out in Bakersfield, Ca, you should have Don Fairchild do your tune up.  He is a wizard and will squeeze the last drop out of your injection, and will tighten your Jake to the point that it really works well.  When I come down the 5 mile 6% northbound grade of the Grape Vine (I-5) pulling my car, I weigh in at 34,750lbs.  I have to switch between 1 and 2 heads so not to slow down to much with the Jake.  Good Luck, TomC

[Dlsnow]

The fuel injector rocker looks just like the book.  Rocker, lock nut, pushrod with square section for adjustment.

Ok-so my plan is as follows (thursday)
1. Set dial caliper to 1.466 and lock the slide (couldnt get the tool here fast enough)
2. Bar engine over till exhaust valves are full open
3. Check and adjust fuel rocker height until distance from base to top is 1.466
4. Secure lock nut while holding pushrod
5. Recheck height adjust again if necessary
6. Do all of them like above
7. Install new.injector
8. Set height as above
9. Start and verify it still runs
10. Run it on the expressway to get it up to temp
11. Use gun on exhaust to verify left and right temps are similar (post results)

Thanks guys...cant wait for the compression tool to arrive.  Hoping to not have bigger problems in this cylinder.

[lostagain]

Do you have the DD service manual for your engine? Just follow the tune up procedure to the letter. Not really hard to do if you have any mechanical sense. You can do it over again if not quite right.

JC

[luvrbus]

I take it you don't have Jake's ?

[Dlsnow]

No jakes...yet
With luck ill get the bus down to nashville then out to tucson then on my way to berkley stop in bakersfield to visit the Wizzard (who reportedly has some jakes for sale).
I have heard some say it needs jakes to get down the mountain, others say go slow up (like theres an option) and ride the transmission down.
I am sure someone can point me to a place to get jakes before bakersfield.

[lostagain]

Dlsnow, you can drive without Jakes untill you get to Don's. He can install them and adjust them like nobody else.

Going downhill without them, you have to be in a lower gear so that the engine will hold your speed steady so you don't have to use your brakes. Light applications of the brakes is OK, but if the gear is too high and you are using the brakes too much, they will get hot really quickly and fade. You have to have the engine hold you back so you can keep your brakes cool to use if you have to, like for the stop sign at the bottom, LOL. Jakes are nice to have, but all they do is allow you to use a higher gear to go down the hill faster. Start going down from the top with your four way flashers on, in first gear. If that is too slow, you can up-shift into second. A lot easier than finding out you are going too fast and having to apply the brakes hard to slow down enough to down-shift. Of course, you will not over-rev the engine through all this. Keep it below 2200 rpm.

JC

[luvrbus]

You will be in 3rd or 2nd gear anyway or you better be when in the 4th gear on a standard with a 3:73 gear don't put much faith in Jakes slowing you down it is not going to happen I don't care if my buddy Don adjusted the Jakes or not lol

[eagle19952]

here's a tip you might consider....
When I do injector timing with the proper tool, I have found that it is easier to feel and visualize the equality of the adjustments if you put a few drops of oil on the injector surface, then when you twirl the tool you can feel and visual the "wipe", if it takes all the oil or leaves a "film" or a thicker amount.As long as they are the same (IMO) a .001 diff won't matter. again IMO>)
Conversely, using your dial caliper (which I have never done/had to do) I would think about setting the dial to 1.464 and then using a .002 feeler  gage under the slide. You might get a more uniform adj.
squaring the caliper perpendicular to the injector tappet and gaging off the pin deckboss might not be easy w/o the feeler gage below...
Having the feeler/caliper set to your adj is a good temporary adj....but I would find the tool.

[Dlsnow]

So the seven cylinders with injectors in them are all set to 1.460 (on the hair).  Not sire who the PO had work on thia last but it seems perfect.  I dont want to change it as i dont think ill get as uniform a setup with a caliper. 

Hoping the compression test goes well.

While testing compression i will have to let the engine run a while. To get up to temp. 

Compression test (please correct me where im off)
1 install compression injectir adapter and holdown assembly
2 place line from fuel shpply to return
2 secure rockers and replace fuel rack arm and cover and hose and oil neck
3 startup and get engine up to temp...drive it around till 180 deg
4 shutdown
5 remove cover connect compression dial
6 start engine and set to fast idle
7 read compression dial (pray for 350+)

Im not going to hurt anything running only 7 cylinders (off balance?)

[eagle19952]

were i you..

1 startup and get engine up to temp...drive it around till 180 deg
2 shutdown
WORK FAST.
3 install compression injectir adapter and holdown assembly
4 place line from fuel supply to return
5 secure rockers and replace fuel rack arm and cover and hose and oil neck
6 start engine and set to fast idle
7 read compression dial (pray for 350+)
8 shutdown