3B diaphragm replacement (5 Viewers)

[lynchmob]

What's the cause of them ripping besides age?

The diaphragm is leather so any long term exposure to motor oil or diesel will cause it to deteriorate.

 

[wesintl]

Has anyone tried the denso 090580-0022 ??

Appears to be the same thing with rubber?
Diaphragms for,MERCEDES BENZ,CAV,DIESEL KIKI, NIPPON DENSO,BEDFORD,SIMMS,PULSATOR,MITSUBISHI

 

[JoeCanadian]

biomechanical parts are cool eh. mabe someone in hick land is cloning them. hahaha

 

[MOTERRA]

I have alot of black smoke with any load it's most likely this diaphragm thats worn out???yes???

i'll have to get one now...

 

[Benihana]

So, not to completely hijack this thread or anything but I was just wondering if the fact that the injector pump on my 3b is pissing diesel all over my bottom end has anything to do with a torn diaphragm? Ideas?

 

[cruise diesel]

Lynchmob thanks for this post, most useful. I do have a question though after reading it. When you install new diaphragm do you have to lube it with something? I remeber reading somethng about Neet's foot oil, or something like that, being leather it must need something, or maybe I am way off here.

cheers,
cruise diesel

 

[lostmarbles]

Lynchmob thanks for this post, most useful. I do have a question though after reading it. When you install new diaphragm do you have to lube it with something? I remeber reading somethng about Neet's foot oil, or something like that, being leather it must need something, or maybe I am way off here.

cheers,
cruise diesel

Let me answer that for Lynchmob if I may.

The diaphragm comes "prelubed with neatsfoot oil" and is nice and soft. So there's no need to apply anything during installation. (Just keep engine oil and dirt off it as you install it.)

It is actually sold in a sealed bag with the neatsfoot as this photo shows:



To keep it nice and soft after it has been installed - Just add a couple of drips of neatsfoot through that "application hole" in the top of the diaphragm housing every time you change the engine oil.

 

[cruise diesel]

I just checked the part number for the diaphragm I ordered and it is a Denso #090580-0041. For whatever that's worth.

 

[cruise diesel]

Right on, I just went and grabbed the package, exactly as you described. Good stuff, now I just have to find the time to replace mine. There is a lot of parts in the way, but I love working on these trucks.

Thanks for the quick response.

cruise diesel

 

[lynchmob]

So, not to completely hijack this thread or anything but I was just wondering if the fact that the injector pump on my 3b is pissing diesel all over my bottom end has anything to do with a torn diaphragm? Ideas?

Not likely as the diaphragm is a vacuum diaphram and has no contact with fuel.

 

[lynchmob]

what he said.

Let me answer that for Lynchmob if I may.

The diaphragm comes "prelubed with neatsfoot oil" and is nice and soft. So there's no need to apply anything during installation. (Just keep engine oil and dirt off it as you install it.)

It is actually sold in a sealed bag with the neatsfoot as this photo shows:

View attachment 232076

To keep it nice and soft after it has been installed - Just add a couple of drips of neatsfoot through that "application hole" in the top of the diaphragm housing every time you change the engine oil.

 

[Moe R]

Let me answer that for Lynchmob if I may.

The diaphragm comes "prelubed with neatsfoot oil" and is nice and soft. So there's no need to apply anything during installation. (Just keep engine oil and dirt off it as you install it.)

It is actually sold in a sealed bag with the neatsfoot as this photo shows:

View attachment 232076

To keep it nice and soft after it has been installed - Just add a couple of drips of neatsfoot through that "application hole" in the top of the diaphragm housing every time you change the engine oil.

I noticed the dates on your iud boxes to have a difference of 14 years. Did you replace them for preventative maint. or did the diaphram give up the ghost? I just replaced mine (PITA) which had a hole in it, RPM's over 1000 but no smoke. It appears that mine was original which would make it 24 yrs. old 170000 K. Not bad for a constantly moving peice of leather.

 

[lostmarbles]

I noticed the dates on your iud boxes to have a difference of 14 years. Did you replace them for preventative maint. or did the diaphram give up the ghost? I just replaced mine (PITA) which had a hole in it, RPM's over 1000 but no smoke. It appears that mine was original which would make it 24 yrs. old 170000 K. Not bad for a constantly moving peice of leather.

Mine were replaced as part of preventative maintenance and I've never actually experienced any diaphragm troubles.

Wow. 24 years and 170,000km...... I might let this latest one last a little longer then.


(What's written on those boxes are the "dates they were fitted" and the "kilometers the previous diaphragms had covered". So what's inside that plastic bag is actually an old used diaphragm rather than a new one. ..... So in fact I "cheated a bit" in using that photo to show how a new diaphragm is supplied.)

 

[Moe R]

That's what I'm thinking. You could actually replace one with an old one . Still lotsa miles left on those used iud's lol. For me, diaphram failure was no big deal. I even drove quite a bit with the problem, while waiting for the new one to come in ($39.00). Used a bit of fuel though. Idle is nice at 650 now. Engine runs smooth with good power. If I have to do this again in 24 yrs I think I'll pay someone to do it.

 

[rchalmers3]

Well the air-intake butterfly would still have some control over the engine rpm - but only through varying the engine's air supply.

The fuel would never move away from the "maximum pedal-to-the-floor" setting.

(Very smokey I would imagine and it certainly wouldn't idle smoothly or at the normal revvs.)

Hey, just reviewed this thread and while I don't have a diesel with the diaphram, I think I have something to contribute in the area of the hoses.

If you look closely at the profile of the throttle body, you should see that the tubes connect to the venturi at different heights.

Given the different configurations of our motors, this may explain the "crossed" and "uncrossed" hoses. Some throttle bodies may have different locations for the placement of the taps or just mounted to the manifold in a reversed position. By understanding why the hoses connect at different heights, guesswork is eliminated.

The different heights will give you indication of what tube goes where. Someone with a few minutes and who cares to do so can confirm this:

The tube that intersects the venturi lbelow the butterfly in the venturi will be your diaphram "signal" that increases and decreases vacuum offsetting the spring. This is because as the butterfly opens and closes, the available vacuum in the venturi rises and falls. NOTE: Look closely at the construction of the throttle body. There may be an internal difference of the outside hose connections and the actual position of the opening inside the throttle body.

From what I have read from your posts the spring pushes the diaphram rod towards rich, so the lower venturi "signal" hose should connect to the diaphram housing on the same side of the spring on the diaphram. Vacuum on the diaphram at idle pulls the diaphram and rod back against the spring, lowering the fuel supply.

The higher venturi hose connection is to equalize pressure on the diaphram in accordance with the presures in the intake above the butterfly. The net effect intended is to create a stable relationship across the diaphram that is solely affected by the throttle butterfly. This upper venturi hose is connected opposite to the spring side of the diaphram.

Feel free to confirm or prove otherwise and post your findings.

Rick

 

[lostmarbles]

...If you look closely at the profile of the throttle body, you should see that the tubes connect to the venturi at different heights. .............

Looking at my inlet manifold - Yes my vacuum (venturi) tube connection is located lower on the outside of my throttle body Rick. --- But it is barely discernible. (Maybe 3mm lower at most?)

(My photo in Post 21 makes it clear that it is lower - but it is actually not so obvious by normal eyesight in the engine bay!)

And I note that you are referring to the throttle body (the "cast alloy throat part" of the inlet manifold that houses the butterfly valve) as a "venturi" but there is actually a little "venturi tube" located inside it. And only one of the tubes actually connects into this little venturi tube. - The other tube simply senses the pressure upstream of the butterfly valve.

... This is because as the butterfly opens and closes, the available vacuum in the venturi rises and falls............

To reduce confusion, I find ya have to be careful when saying stuff like this to get it the right way around Rick.

You should be saying ... "as the butterfly opens and closes, the available vacuum in the venturi falls and rises" (because opening the valve lowers the venturi's vacuum and vice versa).

..From what I have read from your posts the spring pushes the diaphram rod towards rich, so the lower venturi "signal" hose should connect to the diaphram housing on the same side of the spring on the diaphram. Vacuum on the diaphram at idle pulls the diaphram and rod back against the spring, lowering the fuel supply.

Quite true.

..The higher venturi hose connection is to equalize pressure on the diaphram in accordance with the presures in the intake above the butterfly.........

All quite true (IMO) what you say here except I don't think you should be calling this connection a "venturi hose connection". As mentioned before, it is only the other hose that connects to the "real venturi tube".

(I accept that there is a tendency to label all "downwards-sucking air intake tubes" as "venturis" but I think it causes too much confusion to do so here.)

Here's a line drawing of the injector pump which may be a useful addition to this thread. It shows the internals - including the "rack" (22) and the spring (5) we were talking about.

 

[Tapage]

Dude can you post a pic of the other part of this diagram .. I wanna see how the HAC conect ( and control ) with the fuel " rod " inside the IP ..

 

[lowenbrau]

Dude can you post a pic of the other part of this diagram .. I wanna see how the HAC conect ( and control ) with the fuel " rod " inside the IP ..

It doesn't do it inside. It does it outside. The handle that you move to stop the engine is blocked from going the other way by the hac. It simply allows less max fuel at higher altitudes.

 

[lostmarbles]

Dude can you post a pic of the other part of this diagram .. I wanna see how the HAC conect ( and control ) with the fuel " rod " inside the IP ..

It doesn't do it inside. It does it outside. The handle that you move to stop the engine is blocked from going the other way by the hac. It simply allows less max fuel at higher altitudes.

Here's the lower half of that line drawing but it doesn't really help to show how it is connected:



Here is a photo from the manual showing how it is connected but unforunately photos don't reproduce well here:



I hope that together they clarify it.

 

[Tapage]

It doesn't do it inside. It does it outside. The handle that you move to stop the engine is blocked from going the other way by the hac. It simply allows less max fuel at higher altitudes.

I'm not clear on that .. it not only allow more fuel at higher alt .. coz I turn up my fuel there and im at sea level .. so it need to do something else in the hole range of fuel ..

Here's the lower half of that line drawing but it doesn't really help to show how it is connected:

View attachment 238327

Thanks .. clear as mud ..