Rebuilding fuel distributor

[SupercoolBill]

I am getting ready to try to rebuild my Bosch fuel distributor.
Looking for any advice out there. I have watched a couple you tube videos and it seems like something I can handle.
One question I have is what should I use to seal the unit?
Here's what I already have for options-67433

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[dn010]

I used gasket shellac compound, as suggested in the CIS Rebuild PDF linked to post #2 of:

http://dmctalk.org/showthread.php?352-K-Jetronic-System

[Mark D]

Not sure if this is one of the rebuild videos you've seen yet, but might be worth a watch. Similar K-jet unit from a BMW E21


https://www.youtube.com/watch?v=u0tyVQ1iXUg

[Bitsyncmaster]

I one time considered doing this for others. I did rebuild one and used the shellac sealer. I did not like that sealer or any sealer because the two half surfaces are so perfectly flat and when they are torqued all the sealer has to go somewhere (fill the tiny holes in the metal plate). The originals have no sealer so if I ever do another one I would try it dry. I do have a granite flat block I could resurface each half on it with fine sandpaper.

[82DMC12]

Never heard of shellac sealer. I would probably use Hylomar AF - it's fuel resistant and is made to fill those tiny microscopic imperfections between the metal gasket and the halves.

[SupercoolBill]

Too bad there wasn't something you could just spray a mist on there then put it together. Almost like spray contact cement (but not contact cement)
What if I put gas resistant sealer on the halves then wipe it back off just leaving a residue?

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[SupercoolBill]

I guess I could try putting it together without sealer. Nothing to lose. If it leaks pull it back apart and use sealer.

What about just a thin coat of grease?

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[Bitsyncmaster]

Too bad there wasn't something you could just spray a mist on there then put it together. Almost like spray contact cement (but not contact cement)
What if I put gas resistant sealer on the halves then wipe it back off just leaving a residue?

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There was a head gasket sealer that you sprayed on back in the day. Not sure if they sell that anymore.

[dmcman73]

I guess I could try putting it together without sealer. Nothing to lose. If it leaks pull it back apart and use sealer.

What about just a thin coat of grease?

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If you assemble it without sealant, make sure that all surfaces are spotless and there is no dust particles on it prior to assembly.

Grease? For? Grease wouldn't prevent it from leaking as it would just wash out.

[Helirich]

I use to use some red stuff made by OMC. (Boats) for metal to metal. It works great. I believe loctite also makes good product for that.

[SupercoolBill]

If you assemble it without sealant, make sure that all surfaces are spotless and there is no dust particles on it prior to assembly.

Grease? For? Grease wouldn't prevent it from leaking as it would just wash out.True,
I was just thinking if some of the grease got into the inner workings it wouldn't hurt anything but Mayne would still have enough resistance to leaking to work but yeah would probably just wash away.

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[82DMC12]

True,
I was just thinking if some of the grease got into the inner workings it wouldn't hurt anything but Mayne would still have enough resistance to leaking to work but yeah would probably just wash away.

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Hylomar AF would go on as smoothly as grease but it's a bit sticky compared to grease. I think I would lay the thinnest bead possible, spread it a little with a plastic tool, and set the metal gasket on and press down. You could also use your finger to spread it but wipe your finger off repeatedly to make sure you don't spread it where you don't want it. Make sure you don't have so much product on it that it squeezed out under the gasket. If it looks good, I'm sure it is now sealed, so I would do exactly the same on the other half.

That said I've never used shellac so I don't know how easy that stuff is to use. But I do have some experience with Hylomar so it's my go-to now. It would be nice to use on that metal gasket because the Hylomar doesn't set. If you ever need to go back in there again you won't risk bending the gasket trying to get it off of a set bonding agent like Loctite.

[Ron]

I one time considered doing this for others. I did rebuild one and used the shellac sealer. I did not like that sealer or any sealer because the two half surfaces are so perfectly flat and when they are torqued all the sealer has to go somewhere (fill the tiny holes in the metal plate). The originals have no sealer so if I ever do another one I would try it dry. I do have a granite flat block I could resurface each half on it with fine sandpaper.+1
I've put a full kit in several. I used the shellac in the How To on the first one. It is still OK. But the second one weeped. I tried Permatex spray sealer on it (new plate), but it weeped. I cleaned it up and installed it dry (same plate) and it is still OK. Ever since then, I've put them together dry and had good luck.
As mentioned, the trick is to be surgically clean!

[dmcman73]

+1
I've put a full kit in several. I used the shellac in the How To on the first one. It is still OK. But the second one weeped. I tried Permatex spray sealer on it (new plate), but it weeped. I cleaned it up and installed it dry (same plate) and it is still OK. Ever since then, I've put them together dry and had good luck.
As mentioned, the trick is to be surgically clean!

Did you torque the screws that hold the halves together to anything specific, or just tightened down by feel?

[Ron]

Did you torque the screws that hold the halves together to anything specific, or just tightened down by feel?Good question- I got conflicting information on that and finally used the pattern and torque(s) shown here:
https://k-jet.biz/wp-content/uploads/2019/06/Rebuilding-a-Cast-Iron-K-Jet-Fuel-Distributor-V2.pdf

[dmcman73]

Good question- I got conflicting information on that and finally used the pattern and torque(s) shown here:
https://k-jet.biz/wp-content/uploads/2019/06/Rebuilding-a-Cast-Iron-K-Jet-Fuel-Distributor-V2.pdf



Excellent! This is exactly what I was looking for. Thank you!!

[SupercoolBill]

Good question- I got conflicting information on that and finally used the pattern and torque(s) shown here:
https://k-jet.biz/wp-content/uploads/2019/06/Rebuilding-a-Cast-Iron-K-Jet-Fuel-Distributor-V2.pdfThanks for this info

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[SupercoolBill]

Done!! 6744667447

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[dmcman73]

Done!! 6744667447

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Did you use a sealant or just put them together dry?

[SupercoolBill]

Used a permatex sealant from Napa. It said "similar to Hylomar" on the package.
It didn't appear to have any sealant on it when I took it apart.
I wonder if the pieces are lapped to match and the diaphragm is supposed to be the gasket so to speak.

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[SupercoolBill]

From my rebuild thread on this same forum--

Today we installed the rebuilt fuel distributor on the intake assembly, hooked up all of the fuel lines to the FD, put the injectors in empty water bottles. Plugged in the fuel pump and jumpered the fuel pump relay.

We got all kinds of fuel out of lines #1 & #3 with the air flow plate not being depressed at all. Nothing out of all of the other lines. Pushed the plate down still nothing out of the other lines. Unplugged the fuel pump. Decided to swap line and injector #3 with line with injector #2. Plugged fuel pump back in.

Same thing,..no fuel out of line #3 (now on port #2) but all kids of fuel spraying out of line #2 (now on port #3). We pushed the plate down and eventually started getting fuel out of the other ports (#2,4,5,&6). So ports #1 & #3 are feeding all the time for some reason.

Needless to say we are pretty frustrated at this point. My guess is that the fuel distributor is shimmed incorrect so that ports #1 & #3 are feeding fuel when they shouldn't be.

The most frustrating thing of all is that the fuel distributor looked perfect inside. So the issue was probably just our injectors and maybe rich/lean adjustment.

Not sure where to go from here besides coughing up the money for a new fuel distributor.

Thoughts? Anyone know how to properly shim these?

I found out that other cars had the six port fuel distributor with an external adjustment for each port. Anyone know if one of these would work on a DeLorean? I really like the idea of the external adjustment vs. The shim design.

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[Bitsyncmaster]

From my rebuild thread on this same forum--

Today we installed the rebuilt fuel distributor on the intake assembly, hooked up all of the fuel lines to the FD, put the injectors in empty water bottles. Plugged in the fuel pump and jumpered the fuel pump relay.

We got all kinds of fuel out of lines #1 & #3 with the air flow plate not being depressed at all. Nothing out of all of the other lines. Pushed the plate down still nothing out of the other lines. Unplugged the fuel pump. Decided to swap line and injector #3 with line with injector #2. Plugged fuel pump back in.

Same thing,..no fuel out of line #3 (now on port #2) but all kids of fuel spraying out of line #2 (now on port #3). We pushed the plate down and eventually started getting fuel out of the other ports (#2,4,5,&6). So ports #1 & #3 are feeding all the time for some reason.

Needless to say we are pretty frustrated at this point. My guess is that the fuel distributor is shimmed incorrect so that ports #1 & #3 are feeding fuel when they shouldn't be.

The most frustrating thing of all is that the fuel distributor looked perfect inside. So the issue was probably just our injectors and maybe rich/lean adjustment.

Not sure where to go from here besides coughing up the money for a new fuel distributor.

Thoughts? Anyone know how to properly shim these?

I found out that other cars had the six port fuel distributor with an external adjustment for each port. Anyone know if one of these would work on a DeLorean? I really like the idea of the external adjustment vs. The shim design.

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Here is the data plate on my adjustable FD. This unit has always been on my car so don't know if anyone has opened it. I did a very small adjustment on one or two of the ports.

[SupercoolBill]

Here is the data plate on my adjustable FD. This unit has always been on my car so don't know if anyone has opened it. I did a very small adjustment on one or two of the ports.Interesting. Do you think someone swapped it out at some point or do you think it came origonal on the car?
I'm wondering if the adjustable ones were more expensive so they switched to the non-adjustable ones at some point.

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[dmcnc]

It's definitely not original. The #076 model came off Volvo 260s and it was non-adjustable just like the Delorean. The fact that the top section is adjustable means it came off a different unit during a rebuild. Hervey used to do this. Here is an example of a #109 unit (Original Delorean FD) with an adjustable top: https://www.specialtauto.com/node/123






Interesting. Do you think someone swapped it out at some point or do you think it came origonal on the car?
I'm wondering if the adjustable ones were more expensive so they switched to the non-adjustable ones at some point.

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[82DMC12]

There seems to be a lot of DeLoreans with the "green label" fuel distributor. My 1982 has it and it has had it since long before Hervey was ever a thing. I'm thinking it was just a common replacement part that mechanics or dealerships sourced when they couldn't find original DeLorean parts anymore after bankruptcy.

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[Bitsyncmaster]

Interesting. Do you think someone swapped it out at some point or do you think it came origonal on the car?
I'm wondering if the adjustable ones were more expensive so they switched to the non-adjustable ones at some point.

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I think mine was cheaper than a stock one. I would guess there were more of them on the market. I seem to remember Hervey sold them cheaper then his price for the stock one.

[SupercoolBill]

I think mine was cheaper than a stock one. I would guess there were more of them on the market. I seem to remember Hervey sold them cheaper then his price for the stock one.Hmmm....so you get a fuel distributor with more features for less money. Very cool.

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[SupercoolBill]

I mean correct me if I am wrong but wouldn't it be quite advantageous to have the adjustable one vs. the non-adjustable one? From what I have read and seen you want all of your injectors feeding exactly the same volume of fuel if possible. Not sure what you'd do to fix this on a non-adjustable one beside trying new injectors and hoses to see if that fixes it.
Am I over thinking this? Are the adjuster screws never really needed or used? Just another place for a leak?

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[SupercoolBill]

It's definitely not original. The #076 model came off Volvo 260s and it was non-adjustable just like the Delorean. The fact that the top section is adjustable means it came off a different unit during a rebuild. Hervey used to do this. Here is an example of a #109 unit (Original Delorean FD) with an adjustable top: https://www.specialtauto.com/node/123That is sexy,...I may have to buy it.

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[82DMC12]

I mean correct me if I am wrong but wouldn't it be quite advantageous to have the adjustable one vs. the non-adjustable one? From what I have read and seen you want all of your injectors feeding exactly the same volume of fuel if possible. Not sure what you'd do to fix this on a non-adjustable one beside trying new injectors and hoses to see if that fixes it.
Am I over thinking this? Are the adjuster screws never really needed or used? Just another place for a leak?

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Yes and no. No one is replacing the original non-adjustable FD with the adjustable just so they have the additional flexibility. If the original one is working correctly, no adjustment is needed. If the injectors aren't filling six jars evenly, it tends to be an injector problem and not a FD problem.

I would definitely not try to correct flow volume with the adjusters unless I had already replaced the injectors and all the fuel lines and confirmed correct fuel pressure with a gauge - and had the fuel distributor professionally rebuilt so you know there is nothing at all possible remaining except for fine adjustment per port.

I think you should just replace all six injectors and try again. When I test my flow rate, I use six mason jars and hold the air plate down maybe half an inch from rest and hold it down for about 20 seconds. While it's spraying, check each injector and make sure the pattern looks even like a narrow umbrella of atomized fuel. No drippage allowed. If the umbrella is cocked to one side, that's not good either. Release the plate and make sure there is no dripping afterwards. Then remove all six mason jars, remembering which one goes where and set them on a table and compare the fuel levels. As long as they are within a couple millimeters of fuel level, the engine is going to run fine.

[SupercoolBill]

Yes and no. No one is replacing the original non-adjustable FD with the adjustable just so they have the additional flexibility. If the original one is working correctly, no adjustment is needed. If the injectors aren't filling six jars evenly, it tends to be an injector problem and not a FD problem.

I would definitely not try to correct flow volume with the adjusters unless I had already replaced the injectors and all the fuel lines and confirmed correct fuel pressure with a gauge - and had the fuel distributor professionally rebuilt so you know there is nothing at all possible remaining except for fine adjustment per port.

I think you should just replace all six injectors and try again. When I test my flow rate, I use six mason jars and hold the air plate down maybe half an inch from rest and hold it down for about 20 seconds. While it's spraying, check each injector and make sure the pattern looks even like a narrow umbrella of atomized fuel. No drippage allowed. If the umbrella is cocked to one side, that's not good either. Release the plate and make sure there is no dripping afterwards. Then remove all six mason jars, remembering which one goes where and set them on a table and compare the fuel levels. As long as they are within a couple millimeters of fuel level, the engine is going to run fine.Ok thanks for the info (______<your name here)
I tend to think that the injectors are fine since they are brand new but you never know I guess.
What are these screens I see for sale online? Do they go in the distributor or in the inlet of the injectors?

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[82DMC12]

Ok thanks for the info (______<your name here)
I tend to think that the injectors are fine since they are brand new but you never know I guess.
What are these screens I see for sale online? Do they go in the distributor or in the inlet of the injectors?

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I've never taken those filters out but they go in the distributor under the hollow bolts for each injector line. I assume you had them out when you took your FD apart?

OK if you have the correct injectors brand new then we can assume they are OK.

[82DMC12]

Here's some good discussion to read -

http://dmctalk.org/showthread.php?12821-Fuel-Distributor-Rebuild

[SupercoolBill]

I've never taken those filters out but they go in the distributor under the hollow bolts for each injector line. I assume you had them out when you took your FD apart?

OK if you have the correct injectors brand new then we can assume they are OK.Nope haha. Never even noticed them in there.

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[82DMC12]

Nope haha. Never even noticed them in there.

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Doesn't seem like it's a big deal though since they are on the outlet side of the ports, not the inlet side, so they probably won't do much in regards to poor uneven flow to the injector. The thread I just linked to has some good discussion on other types of contamination though.

[Bitsyncmaster]

When I test my flow rate, I use six mason jars and hold the air plate down maybe half an inch from rest and hold it down for about 20 seconds.

+1

I did test one unit that worked very poorly if you pressed the air plate all the way down but with less press it worked great. I don't know if all units do that since I've only flow tested two units.

[SupercoolBill]

Well we gave it one more try. Took it all apart. Checked orings, sealant, measured the spring height, swapped two of the thinner shims but that was about it. [emoji2369]
Letting the sealant dry. We will test it tomorrow.67471
My wife's sloppy sealant job. At this point I am just letting her try to learn how to do this stuff.
67472

I'm not too confident that this thing is going to work right for us at this point. I think we will be buying a new (rebuilt) one.

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[dmcman73]

Well we gave it one more try. Took it all apart. Checked orings, sealant, measured the spring height, swapped two of the thinner shims but that was about it. [emoji2369]
Letting the sealant dry. We will test it tomorrow.67471
My wife's sloppy sealant job. At this point I am just letting her try to learn how to do this stuff.
67472

I'm not too confident that this thing is going to work right for us at this point. I think we will be buying a new (rebuilt) one.

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And old credit card will do the trick to apply it thin and even.

Also, Hylomar doesn't really dry like regular sealant, it remains pliable and workable.

[SupercoolBill]

Put it back on the car and tested it. Same issue. Ports #1 & #3 feed fuel all the time. Switched hoses and injectors around. Same thing. Whatever lines are on ports #1 & #3 keep spraying.
Trying to think what could be causing this. Seems like the following could be causing fuel to spray out of the injectors on #1 & #3:
1. Injectors are opening at too low of pressure (already disproved this as being the problem)
2. The spring, shim arrangement on these ports is too strong thus holding the port open.
3. There is some sort of solid debris on the face of these two ports holding them open.
4. These ports are somehow damaged (face of port not flat) allowing fuel to pass by when the diaphragm is push up against them.
When I looked at the ports it did look like at least one of them had a notch in it for some reason.
67482

I may try one more thing before taking it all apart again. I was thinking of trying the following:
Jump out the fuel pump relay, install hoses without injectors, put hoses in a container, plug in the fuel pump, push the air flow disk all the way down and hold it down for few seconds then release.
My hope, if there is any debris in there it gets washed out and then the flow will close off when the air flow disk is closed.

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[dmcman73]

Put it back on the car and tested it. Same issue. Ports #1 & #3 feed fuel all the time. Switched hoses and injectors around. Same thing. Whatever lines are on ports #1 & #3 keep spraying.
Trying to think what could be causing this. Seems like the following could be causing fuel to spray out of the injectors on #1 & #3:
1. Injectors are opening at too low of pressure (already disproved this as being the problem)
2. The spring, shim arrangement on these ports is too strong thus holding the port open.
3. There is some sort of solid debris on the face of these two ports holding them open.
4. These ports are somehow damaged (face of port not flat) allowing fuel to pass by when the diaphragm is push up against them.
When I looked at the ports it did look like at least one of them had a notch in it for some reason.
67482

I may try one more thing before taking it all apart again. I was thinking of trying the following:
Jump out the fuel pump relay, install hoses without injectors, put hoses in a container, plug in the fuel pump, push the air flow disk all the way down and hold it down for few seconds then release.
My hope, if there is any debris in there it gets washed out and then the flow will close off when the air flow disk is closed.

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Are you using a new stainless diaphragm or are you re-using the original one?

[82DMC12]

Put it back on the car and tested it. Same issue. Ports #1 & #3 feed fuel all the time. Switched hoses and injectors around. Same thing. Whatever lines are on ports #1 & #3 keep spraying.
Trying to think what could be causing this. Seems like the following could be causing fuel to spray out of the injectors on #1 & #3:
1. Injectors are opening at too low of pressure (already disproved this as being the problem)
2. The spring, shim arrangement on these ports is too strong thus holding the port open.
3. There is some sort of solid debris on the face of these two ports holding them open.
4. These ports are somehow damaged (face of port not flat) allowing fuel to pass by when the diaphragm is push up against them.
When I looked at the ports it did look like at least one of them had a notch in it for some reason.
67482

I may try one more thing before taking it all apart again. I was thinking of trying the following:
Jump out the fuel pump relay, install hoses without injectors, put hoses in a container, plug in the fuel pump, push the air flow disk all the way down and hold it down for few seconds then release.
My hope, if there is any debris in there it gets washed out and then the flow will close off when the air flow disk is closed.

Sent from my SM-G970U using TapatalkIt might work. I had two injectors that had sideways spray pattern, did as you did and after a few aggressive pushes of the plate, it blew whatever out and the pattern fixed itself.

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[SupercoolBill]

Are you using a new stainless diaphragm or are you re-using the original one?New diaphragm. Although the old one looked really good.

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[SupercoolBill]

Well, I give up. We tried after more things with no luck whatsoever. Put on the new fuel distributor hoses without the injectors. Ran the fuel pump and pushed the intake disk all the way down to try to flush a bunch of fuel through the distributor. We did this a few times. Then put empty water bottles on the injector hoses. The same thing happened again. The hose for cylendars #1 and #3 constantly feeding a bunch of fuel. Other hoses feeding little or no fuel.
Took EVERYTHING APART AGAIN. Opened up the fuel distributor AGAIN. Found a tear in o ring on the center tube.
Looked more closely at the metal diaphragm this time. Noticed dimples on it from it contacting the nozzles. As one might expect there were no dimples on #1 & #3. So this verifies what we were thinking. For some reason these two ports are never closing off. My wife measured everything again. She thought she had it figured out. She swapped around some springs. We put everything back together. Put the distributor on the car and hooked EVERYTHING BACK UP AGAIN.
Guess what? The same thing happened. Lines #1 & #3 constantly fed fuel.

We are done...time to get the distributor rebuilt by a professional.

Anyone ever used Special T Auto for a WUR or fuel DISTRIBUTOR? Their prices are a lot less than anywhere else. 6751567516

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[Bitsyncmaster]

Anyone ever used Special T Auto for a WUR or fuel DISTRIBUTOR? Their prices are a lot less than anywhere else. 6751567516

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John Hervey passed away some time ago (he owned Special T). Don't know if anyone else has taken over his business.

It sounds like your FD needs a slight surface machining to even out the contact points of those little tubes. I don't know how those tubes could have worn down. Not sure if even a pro rebuilt would fix it.

[painterdave72]

I had mine rebuilt by fuel injection corp in california last year.. quality work and was right around 400 or so .....totally worth it for a part like that..

[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.

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67546675476754867549

[SupercoolBill]

Update-
I figured out the issue. The distributor is working perfectly with no leaks.

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[dmcnc]

So what was it?

[82DMC12]

So what was it?

I think he wants us to guess

[SupercoolBill]

So what was it?Well, I spent a lot of time thinking about how the distributor works, reading what others said, reading information on line. I came to the conclusion that I was looking about and worried about the wrong part of the fuel distributor. I was totally focused on the nozzles, the diaphragm, the springs, and shims. I realized that these thing just "fine tune" how much fuel goes to each injector. Two ports that constantly fed fuel wouldn't be because of anything to do with these parts. It would have to be some sort of an issue with the hollow tube and the ports in the body of the distributor. This made sense because the past several times that we took the distributor apart and put it back together we never pulled the center tube out to check it. So I pulled it out. It looked like perhaps a couple of the o rings didn't stay over the ports when the tube got pushed in during the rebuild.

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[SupercoolBill]

When I took the tube out a couple of the o rings look kind of like they were pinched. Unfortunately I didn't take a picture.
Basically picture a o ring that looks like a "D"

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