1982 Frame Off Restoration

[SupercoolBill]

I wonder how the nozzles are held in. I would think they have to be sealed real well so suspect they are glued in. I would guess the whole assembly is then surfaced on a surface grinder.

Yeah or interference fit, pressed in like you said. Then probably lapped. I don't have a granite flat surface at my shop for relapping.

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[Ron]

Ron, sorry is don't have a better pic of the shims. They are basically just little washers, 12 total. None of them look the same as what you posted. What you poated looks like a top hat.

The old diaphragm has slight dimples but not at prominent as with the new one now.
Just had a thought. I put bolts in all of the ports to block them to glass beads blast the FD so I wouldn't get any media inside of it. Not all of the bolts were really short like I wanted so I had to stack up sealing washers on those ones. I specifically remember tightening one bolt in and meeting resistance before the sealing washers got tight so I took it back out and added more washers.
I am wondering if I inadvertently pushed down several of the nozzles. I thought that we checked it with a straight edge but maybe not. So if this is the case the reason that #1 & #3 is feeding when the others aren't isn't because THEY are the issue,...it is because the other nozzles are protruding too far.
Could this be possible? Could the other ports being "too tightly closed off" be causing the other ports to constantly feed fuel?
I might have to pop it open one more time. If the nozzles are protruding too far how should I push them back? 1/4" drive socket over the nozzle? Flat surface with some high grit emery paper? Or....just get a new top? Or just send it out to a pro?

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I finally found my reference material. After viewing THIS VID, I'm with you on the shims (Sorry, played with too many different systems over the years...;-).
What you are saying makes sense to me, IFF #1 and #3 shut off with the [air] plate all of the way up (and the CO screw backed out enough)...If #1 and #3 OK and are set up correctly (5.2mm to 5.3mm height), they should act normal.

"As the control plunger rises, and fuel flow into the differential-pressure valve increases, the fuel pressure deflects the diaphragm. This causes a proportional increase in the area of the fuel outlet to the injector and maintains the same pressure drop at the control-plunger slit. Even though there is more fuel flow through a more open slit, the differential between pressure inside the slit and pressure outside the slit is constant.It may seem, because the deflection of the diaphragm enlarges the outlet to the fuel injectors, that fuel metering is a
function of how close the diaphragm is to the outlet. But this is not the case. All fuel metering takes place at the control-plunger slits. The movement of the diaphragm acts only to maintain constant pressure drop-to eliminate pressure drop as a variant and maintain accurate metering to each injector, regardless of changing fuel flow rates."
(Bosch)

I'd suggest: open it up one more time, measure and record the stacked heights, and check if the nozzles are flush. That should tell you what is wrong here. If the nozzles are off, I'd just swap it out or send the whole thing off personally. (Not worth trying to get the precision required and risk leaks ect. concerning the nozzles.)

[Ron]

Yeah or interference fit, pressed in like you said. Then probably lapped. I don't have a granite flat surface at my shop for relapping.

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I wonder if the nozzle tip will stand milling...

[SupercoolBill]

I finally found my reference material. After viewing THIS VID, I'm with you on the shims (Sorry, played with too many different systems over the years...;-).
What you are saying makes sense to me, IFF #1 and #3 shut off with the plate all of the way up (and the CO screw backed out enough)...If #1 and #3 OK and are set up correctly (5.2mm to 5.3mm height), they should act normal.

"As the control plunger rises, and fuel flow into the differential-pressure valve increases, the fuel pressure deflects the diaphragm. This causes a proportional increase in the area of the fuel outlet to the injector and maintains the same pressure drop at the control-plunger slit. Even though there is more fuel flow through a more open slit, the differential between pressure inside the slit and pressure outside the slit is constant.It may seem, because the deflection of the diaphragm enlarges the outlet to the fuel injectors, that fuel metering is a
function of how close the diaphragm is to the outlet. But this is not the case. All fuel metering takes place at the control-plunger slits. The movement of the diaphragm acts only to maintain constant pressure drop-to eliminate pressure drop as a variant and maintain accurate metering to each injector, regardless of changing fuel flow rates."
(Bosch)

I'd suggest: open it up one more time, measure and record the stacked heights, and check if the nozzles are flush. That should tell you what is wrong here. If the nozzles are off, I'd just swap it out or send the whole thing off personally. (Not worth trying to get the precision required and risk leaks ect. concerning the nozzles.)

I agree

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[SupercoolBill]

I finally found my reference material. After viewing THIS VID, I'm with you on the shims (Sorry, played with too many different systems over the years...;-).
What you are saying makes sense to me, IFF #1 and #3 shut off with the plate all of the way up (and the CO screw backed out enough)...If #1 and #3 OK and are set up correctly (5.2mm to 5.3mm height), they should act normal.

"As the control plunger rises, and fuel flow into the differential-pressure valve increases, the fuel pressure deflects the diaphragm. This causes a proportional increase in the area of the fuel outlet to the injector and maintains the same pressure drop at the control-plunger slit. Even though there is more fuel flow through a more open slit, the differential between pressure inside the slit and pressure outside the slit is constant.It may seem, because the deflection of the diaphragm enlarges the outlet to the fuel injectors, that fuel metering is a
function of how close the diaphragm is to the outlet. But this is not the case. All fuel metering takes place at the control-plunger slits. The movement of the diaphragm acts only to maintain constant pressure drop-to eliminate pressure drop as a variant and maintain accurate metering to each injector, regardless of changing fuel flow rates."
(Bosch)

I'd suggest: open it up one more time, measure and record the stacked heights, and check if the nozzles are flush. That should tell you what is wrong here. If the nozzles are off, I'd just swap it out or send the whole thing off personally. (Not worth trying to get the precision required and risk leaks ect. concerning the nozzles.)

Interesting....so the nozzles aren't what is meter fuel to the individual injectors. It is the position of the plunger that modulates the flow. It might be worth removing the center tube and checking my six o rings I guess.

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[Bitsyncmaster]

I wonder if the nozzle tip will stand milling...

Probably would work if just milling a mill or two. But the surface grinder would give the best finish and maybe lapped on a surface block.

https://www.amazon.com/TTC-Thick-Gra...8128270&sr=8-4

[SupercoolBill]

I finally found my reference material. After viewing THIS VID, I'm with you on the shims (Sorry, played with too many different systems over the years...;-).
What you are saying makes sense to me, IFF #1 and #3 shut off with the plate all of the way up (and the CO screw backed out enough)...If #1 and #3 OK and are set up correctly (5.2mm to 5.3mm height), they should act normal.

"As the control plunger rises, and fuel flow into the differential-pressure valve increases, the fuel pressure deflects the diaphragm. This causes a proportional increase in the area of the fuel outlet to the injector and maintains the same pressure drop at the control-plunger slit. Even though there is more fuel flow through a more open slit, the differential between pressure inside the slit and pressure outside the slit is constant.It may seem, because the deflection of the diaphragm enlarges the outlet to the fuel injectors, that fuel metering is a
function of how close the diaphragm is to the outlet. But this is not the case. All fuel metering takes place at the control-plunger slits. The movement of the diaphragm acts only to maintain constant pressure drop-to eliminate pressure drop as a variant and maintain accurate metering to each injector, regardless of changing fuel flow rates."
(Bosch)

I'd suggest: open it up one more time, measure and record the stacked heights, and check if the nozzles are flush. That should tell you what is wrong here. If the nozzles are off, I'd just swap it out or send the whole thing off personally. (Not worth trying to get the precision required and risk leaks ect. concerning the nozzles.)

I watched that video like 6 times.
Interestingly he never shows removing the shims or really says much about them. This was part of the reason that mine ended up all over the work bench and floor. I was using this video as my guide.

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[Ron]

Interesting....so the nozzles aren't what is meter fuel to the individual injectors. It is the position of the plunger that modulates the flow. It might be worth removing the center tube and checking my six o rings I guess.

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+1

..and inspect the slits closely.

[SupercoolBill]

+1

..and inspect the slits closely.

Yeah ill check those again too

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[SupercoolBill]

Last night I took the FD apart one more time.
I couldn't find anything obvious wrong with it. Used a straight edge to check the depth of the nozzles. All of them appear to be exactly flush with the surface of the cover. The only thing I noticed was that the o ring on cylendar was damaged a bit. This seems to happen everytime even if we lube it before assembly. I don't see how this o ring being damaged would make only two ports feed too much fuel. Instead I would think if anything it would cause a fuel leak. Some of the o-rings on the slit ports look a bit funny, like they went in kind of dry. But non of them are ripped, or not over the little fuel ducts.
At this point I am throwing in the towel on this job. 20211129_161755.jpg20211129_161737.jpg20211129_161738.jpg

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