19 replies to this topic

[Lmackattack]

Sled pull season is here and want a little more power. We removed the pump timing cover and see it can be adjusted. There are no marks on the gear just slots to pot the bolts in and adjust. I was hoping I could just bring it to tdc and advance the pump to say 24-25 deg and lock it down. Problem is I don't know where it will be at? What's the deal.

[39 Baby Mack]

To set the timing there should be marks on the vibration dampener.
They start at 35 degrees and go down to 0
If you wanted to set the timing to 25 degrees you would bar engine over in normal rotation (clockwise looking from front of engine) until #1 was on compression stroke and then stop when
pointer aligns with the 25 degree mark on the dampener.You would then break the ( 4 ) 3/8" bolts loose on the drive coupling, then with a 1-1/4" socket turn hub nut counter clockwise to full
retard position---- then slowly turn hub nut clockwise to obtain port closing on the pump- when this is obtained torque 3/8'' bolts to 35 ft./lbs. The engine will then be timed to 25 degrees
before top dead center.

To flow time the pump can be fairly easy or not so easy depends a lot on whether it has an Ambac pump or a Robert Bosch pump???
Let me know

Ron

[Lmackattack]

Ok I under stand finding the 25 deg mark on the dampened,. And then Lousen the 4 bolts on the pump drive coupling.however I can see that the coupling has slots that only allow you to advance/ retard the pump about 30 deg. How do I know when the pump is obtaining port closing?will I feel it or do I need a tool to know. I think it's an ambac pump. Will have to get a pic soon.

Thanks for your help

[39 Baby Mack]

If it's an Ambac pump a simple homemade tool will do the job, if it's a Robert Bosch it's not so easy.

On an Ambac pump first things first completely blow off area on top of pump with compressed air trying to keep everything as clean as possible.
You have to remove the inlet fitting and the overflow valve, these are located in the front and rear of the fuel gallery on the pump.
Use a1/4'' pipe plug in one and fabricate a fitting with a valve and air quick coupler in the other.
You have to remove the delivery valve out of the pump in #1---------after removing injection line for #1off the pump remove the big nut (1-1/4 socket) and long 1/2'' breaker bar.
after you remove this nut there is a fitting under it which is the part you see protruding through the nut that is what the line is attached to.
remove all this keeping everything as clean as possible. look down inside the pump and you will see the delivery valve and spring. Remove both the spring and using a pair of needle nose pliers carefully remove delivery valve( it will look like the old inlet valve for a carburetor only of much higher quality)
Keep in mind you have to be careful to keep everything as clean as possible.
Reinstall nut and fitting back into pump (without the delivery valve and spring) and torque to I believe 90 ft./lbs.( I will try to find out for sure, can't remember everything, it's been awhile!!!)
Now you need to make a test line out of an old injection line--------Remove one end of an old injection line.
Bend this line as necessary so that it can be installed on pump on #1 and the other end can be stuck inside of a clear glass bottle full of diesel fuel.
Now apply air pressure to fitting that you made for the pump---------just crack valve open until you see a steady stream of bubbles coming from the line in the bottle.
Now with the pump backed off to fully retarded position(counter clockwise) slowly turn injection pump drive hub clockwise (1-1/4" socket) while watching bubbles from the line in the bottle
at the exact time the bubbles stop you have reached port closing.
Torque bolts on the drive coupling to 35ft./lbs.
Also when doing this have the fuel linkage in the full fuel position some say it makes a difference although I never saw where it did.
You can double check your timing by rotating engine backwards past the degree marks on the dampener and then barring forward again watching bubbles in the bottle----when the bubbles stop
look at the timing mark on the dampener should be within a degree of where you want it.
Now remove all your test apparatus and reinstall delivery valve and spring, fuel fittings on pump, and injection line(torque injection line to 35ft./lbs. with 3/4" crowsfoot socket.
Now if you have one of those big red buttons from Staples push it----- " THAT WAS EASY"
That should do it, I will try to find the torque for the nut on the pump.

Ron

[Lmackattack]

Thanks very much for this info. It sounds fairly easy after you have a tool made up. I will get some pics when I have it set up to make sure I'm doing it right...its great to have people such as you with this kind of knowledge on this site. Can't get that kind of help in a book.


Trent

[skip]

If you dont want to take out the delivery valve you can prime the fuel through the pump and wire the throttle to full fuel and turn the 1-1/4" nut at the front over a couple of times until you see fuel squirt out of No. 1 port. Then go back before the opening position and gently turn the nut at the front until you see fuel start to rise in the well of No. 1 port. Lock up the bolts at the front and that will be right. To do that you still position the engine on the timing mark you require. Im certainly not questioning the way listed above, as it is explained much better than this, but its just an alternative if you dont have the right tool.

[Lmackattack]

thanks for the into guys I have been so busy that I have not had time to make up a tool. One question I forgot to ask. Does the pump (when engnie running) turn in the same rotation as the engine?

[theakerstwo]

Yes

[Lmackattack]

Ok think I got it done last night. I was able to bar the engine over to the factory 19* BTDC.( Pointer on the 19* mark on the damper) I then had a friend put a wrench on the pump nut, we marked a refrence location with a scribe. I then slowly bared the engine to 25*BTDC and locked the pump back down.

[Rob]

Ok think I got it done last night. I was able to bar the engine over to the factory 19* BTDC.( Pointer on the 19* mark on the damper) I then had a friend put a wrench on the pump nut, we marked a refrence location with a scribe. I then slowly bared the engine to 25*BTDC and locked the pump back down.

Hi Trent, sounds like you are on the money for "port closing" timing if I remember correctly.

I may be up in Aurora within the next couple of weeks for additional training. What is your schedule looking like?

Rob

[Lmackattack]

Rob I am pretty much traveling every other week untill the end of September. just let me know when you think you will be up this way. Weekends or week nights are best for me.

Trent

[Rob]

Rob I am pretty much traveling every other week untill the end of September. just let me know when you think you will be up this way. Weekends or week nights are best for me.

Trent

I'm thinking the training runs from Thursday and ends on Tuesday in a couple of weeks so should be around on the weekend. Get to see my granddaughter again as I'll stay at sons' house.

Kinda fond of the "Rosotti's" pizza, (sp?).

Rob

[Lmackattack]

Yep They have some of the best "fast food" Pizza in Chicagoland. And whats best is you can eat on the south side or out in the far NW burbs and it still tastes the same!

Keep me posted!

FYI sled pulls are tomorrow night at Lake County IL

Trent

[Rob]

Yep They have some of the best "fast food" Pizza in Chicagoland. And whats best is you can eat on the south side or out in the far NW burbs and it still tastes the same!

Keep me posted!

FYI sled pulls are tomorrow night at Lake County IL

Trent

I'd like to make it but quite possibly going after another truck sporting a Detroit to make my nephew Ben proud.

Rob

[slpwlker]

But,But you got to get rid of the Cat powered X-Brand in the way now.

Just sitting here under the shade tree. looked over your newest addition.

[Rob]

But,But you got to get rid of the Cat powered X-Brand in the way now.

Just sitting here under the shade tree. looked over your newest addition.

Don't worry. That 6-71 Detroit and small nine speed on the back of the RL will slip right in there.

Be there around 3:40.

Rob

[slpwlker]

okie dokie

[39 Baby Mack]

Trent

You barred the engine backwards (counter clockwise) to 25 degrees B.T.D.C. right ?
This is a different way of doing this than I'm used to for sure but I guess it will work, of course this is assuming that it was actually timed to
19 degrees when you started with it. You actually have no way of knowing for sure unless you flow time it.
Hope it works out OK.

Ron

[Lmackattack]

yea we rolled it over to the factory setting of 19* BTDC. yes we are assuming the timing was at stock and never adjusted, We backed off the 4 bolts that hold the pump to the gear. Held the pump still with a wrench while we barred the engine back to 25* BTDC. then locked the 4 bolts back down. and put the timing cover back on.

here is the pull we did last Friday. She ran a little better and the RPMs did not drop as much when under full load. we made a full pull, 309' !!

[39 Baby Mack]

Cool--- thanks for the video!!!

Ron