E7 350 full mechanical Bosch pump

[Joey Mack]

Too bad we arent close to each other. I would time it for you.  

[Joseph Cummings]

17 minutes ago, allfritz123 said:

can't adjust governed speed without removing the pump as the cover is located next to the block

Your throttle lever is probably on the other side, but,,,,,,,,,,,,,,,

 

I think your pump shop is full of shit

Edited 21 hours ago by Joseph Cummings

[Vladislav]

Just now, Joseph Cummings said:

Your throttle lever is probably on the other side, but,,,,,,,,,,,,,,,

 

I think your pump shop is full of shit

What pump is this arrangement for?

I'm looking for info on how to increase top RPM's of Mabac pump. Currently it is set for 2000RPM.

[Vladislav]

Just now, allfritz123 said:

Thanks for all that info. I really enjoyed the YT video posted by BobWhite!  You can't beat videos like that for explaining everything that can go wrong.  I am getting ready to take my pump off to get the governor weights adjusted. It is a Robert Bosch pump on an E6-300.   The engine was only able to rev up to about 1550 rpm.

My earlier post from last year:

https://www.bigmacktrucks.com/topic/73521-e6-285-2vh-problems-and-solutions/

  Someone had it set for "economode".  I only have a puff limiter on it and I talked to the diesel shop and they said they can't adjust governed speed without removing the pump as the cover is located next to the block which allows access to the weights and springs.  I am trying to figure out how to take it off so that I can give it to them and then put back on later without adjusting anything.  The truck is running fine.

A question I have for the E6.  I find number 1 compression TDC and then back off counterclockwise until I get to port closure at 22 deg BTC after removing gear lash?  Is  22 deg the standard and the same for an American Bosch pump?  Just want to make sure 22 degress is correct position  to leave engine in when removing the pump. If correct, then I can open front cover and remove 4 bolts on the gear and take everything out with the assembly. 

If I don't use a timing light, don't rotate engine (leave gear in place or mark across the gears for positioning)  and mark position of 4 bolts in slots on gear, I should be able to get my pump out and then they return it to me and just put the whole assembly back in?    Just want to  make sure I get timing right.  Hope this is correct!

 

No, Ambac pump needs 18 degree initial advance. 22 deg is for Bosch. On the same engine!

[Joseph Cummings]

Just now, Vladislav said:

What pump is this arrangement for?

I'm looking for info on how to increase top RPM's of Mabac pump. Currently it is set for 2000RPM.

That is a Robert Bosch "P pump"

I'm assuming you have a Ambac PLM pump?

 

It's behind the little tin cover where the throttle shaft comes out

[Vladislav]

Just now, Joey Mack said:

I beleive the pump shop will have to set the timing on the bench. Key is not to rotate the pump when handling it. 

Jojo, life's good but I haven't understood two simple things. And probably the guy too.

First - do you need to disconnect (unscrew) anything under the engine front cover to just remove the pump off the engine? I belive the pump has composite coupling with splines and you just pull if off. Both on E7 and E6.

Second. When you set timing you may go two ways. Rotate the pump housing OR rotate a gear under the engine front cover which has 4 bolts. Right? I honestly forgot if the pump is rotatable in its place or has stationary mount.

[Vladislav]

Just now, Joseph Cummings said:

That is a Robert Bosch "P pump"

I'm assuming you have a Ambac PLM pump?

 

It's behind the little tin cover where the throttle shaft comes out

Are you sue that's high RPM stop? Much more seemed as just a limiter for the rack travel. Top RPM's are limited by that rotating weights setup. Can its operation be corrected just by a set screw in the throttle drive?

Yes, I'm talking about Ambac PLM at the moment, as on the picture. Had been to a pump shop a couple days ago, they reassembled and calibrated my pump. But the guy said he had no exact idea on how to correct the governor settings.

[Joey Mack]

The Robert Bosch pump has a coupler that is hour glass shaped. The pump slides out when the 4 bolts behind the cover are removed. Before that, you set the pump timing with the marks on the flywheel or balancer. When the pump is installed it will be bench timed. Which should be close. The slots in the gear allow a small amount of pump drive movement to adjust it to the correct engine position. Vlad, i hope i am answering your questions...

[Joseph Cummings]

See the idle adj screw? High speed is under that cover. Almost looks the same, but it's shorter

 

 

[Joseph Cummings]

The fuel adjustment is under this cover

[Vladislav]

Just now, Joey Mack said:

The Robert Bosch pump has a coupler that is hour glass shaped. The pump slides out when the 4 bolts behind the cover are removed. Before that, you set the pump timing with the marks on the flywheel or balancer. When the pump is installed it will be bench timed. Which should be close. The slots in the gear allow a small amount of pump drive movement to adjust it to the correct engine position. Vlad, i hope i am answering your questions...

Yes, you do Jojo. Thank you.

I once took Robert Bosch pump off an engine. But that was E6 (or EM6) not E7. As I remember I didn't take the front engine cover off (and that small cover on it either).

[Joey Mack]

Yes.  There is a dowel in the drive hub on the engine side, and a missing spline in the pump coupler. 

[Joseph Cummings]

1 minute ago, Joey Mack said:

Yes.  There is a dowel in the drive hub on the engine side, and a missing spline in the pump coupler. 

Older ones with the steel coupler also had a dowel so you couldn't put it together 180 degrees out

[Vladislav]

Just now, Joseph Cummings said:

See the idle adj screw? High speed is under that cover. Almost looks the same, but it's shorter

 

 

Yes, I see. And I have that small cover removed from my pump at the moment. And saw that srew, I remember it. Just can't imagine how physically a srew which limits linkage that is supposed to move the rack can affect the rev limiting device.

If you sure that is that way and the matter is difficult to explain I can take this on trust and just experiment with the screw. Bad thing I didn't know that when the pump was on a test bench. Much easier to check than on a truck.

[Vladislav]

Just now, Joey Mack said:

Yes.  There is a dowel in the drive hub on the engine side, and a missing spline in the pump coupler. 

Yes, now I remember that dowel. 

That time I didn't reset/check the timing. Just needed to get the truck yard driving (actually to take it off the street into my property. One plunger got stuck and I couldn't get it free until took the pump off the engine.

[Joseph Cummings]

1 minute ago, Vladislav said:

Yes, I see. And I have that small cover removed from my pump at the moment. And saw that srew, I remember it. Just can't imagine how physically a srew which limits linkage that is supposed to move the rack can affect the rev limiting device.

If you sure that is that way and the matter is difficult to explain I can take this on trust and just experiment with the screw. Bad thing I didn't know that when the pump was on a test bench. Much easier to check than on a truck.

Moving the throttle shaft more increases the spring preload. The flyweights try to move outwards, and the spring tension pulls them back in. The centrifugal force pulls the weights out harder as the speed increases. The weights moving outward pulls the fuel rack back

[Vladislav]

Just now, Joseph Cummings said:

Moving the throttle shaft more increases the spring preload. The flyweights try to move outwards, and the spring tension pulls them back in. The centrifugal force pulls the weights out harder as the speed increases. The weights moving outward pulls the fuel rack back

Ok, so actually it turns out the weights try to pull the fuel rack back but you add pre-load to the spring just by your foot moving the linkage further up?

[Joseph Cummings]

1 minute ago, Vladislav said:

Ok, so actually it turns out the weights try to pull the fuel rack back but you add pre-load to the spring just by your foot moving the linkage further up?

Yeah, the throttle shaft controls the spring tension. The weights are fighting with the spring like a tug of war. The spring is fighting to increase the speed, the weights are fighting to decrease the speed. Putting your foot on the throttle makes the springs pull a little harder

[Vladislav]

Just now, Joseph Cummings said:

Yeah, the throttle shaft controls the spring tension. The weights are fighting with the spring like a tug of war. The spring is fighting to increase the speed, the weights are fighting to decrease the speed. Putting your foot on the throttle makes the springs pull a little harder

Interesting. Thank you for explanations. A plan is to take the governor apart to sandblast and paint the housing. But I don't know if I can do that and keep the key mech parts together to not loose settings. Or set them back in. Another task was to increase the RPM's up to 2300 since that's a hobby truck and I'd like to rev it up between shiftings sometimes. I asked the pump guy on my desires but he explained the matters only in general. He's not a specialist in Mack pumps/governors and I'm pretty sure there are neither of them in all the country. But he's very experienced fuel tech and said he could do the job if the settings are known. But they are not.