CIS fuel distributer cleanout w/pics

[Tim Hancock]

Mark, I presently use the Indian head gasket stuff with the silk thread on aircraft case halves and aviation form a gasket on other aviation stuff, but I think I might lean towards a thin film of the anaerobic type gasket products for this application (JW above mentioned loctite 574). I myself would probably research Loctite's different types of this stuff to see what is most recommended for fuel applications.

The company I work for builds silk screen gasketing equipment for Detroit Diesel and they use Loctite anaerobic sealant (looks like grape jelly) on metal to metal joints thru-out their engines with excellant long term results.

I am not saying the way you proposed will not work, I just thought I would share my opinion.

[Grezdlitn]

Here comes more pics and hopefully some explanations on what I've done. I was able to put about 4 hours into the project this afternoon and tomorrow should be able to report if it leaks or even runs.

In the first picture the round fitting with allen heads(adjacent to each fuel line fitting) is the only adjustment to the system I could find. These devices extend into the chamber and establish the tension on a small spring in each of the metering chambers. They are installed with lock-tite so I didn't remove them.



Under each of the fuel line fittings is a small filter and I do mean small. I put a dime in the pic for size comparison.

I soaked these in MEK and then blew each one out with compressed air. One was so impacted with rust and trash that It was partially collapsed.

To separate the halves I supported the FD on pine blocks and removed the large center nut (it has a lock tab) with a 24mm deep well socket. It was only hand tight. I then backed out the 6 thorx (size 27) about 6 turns and gently tapped the heads alternating till to bond parted. You can then tap on the center cylinder and the two halves will part. Refrain from twisting the two halves to separate them as the internal parts will drag across the diaphram and damage it
Dinner smells good.... more later!

[Grezdlitn]

The pictures didn't load on the first try. Here they are in the order of reference.

[Tim Hancock]

Hey Mark, I see your injectors in one of the pics. FWIW, I cobbed up a spider manifold with some fittings I had laying around and attached all the injectors at once to rubber hoses secure with hose clamps. This allowed me to fill the contraption with solvent and attach a regulated air supply to blow all six at once to check and observe flow rates and patterns. I know it can be done in the car, but while they are out seemed like an easy time to check them.

Thanks for posting the pics!

[Grezdlitn]

Originally posted by Tim Hancock
Hey Mark, I see your injectors in one of the pics. FWIW, I cobbed up a spider manifold with some fittings I had laying around and attached all the injectors at once to rubber hoses secure with hose clamps. This allowed me to fill the contraption with solvent and attach a regulated air supply to blow all six at once to check and observe flow rates and patterns. I know it can be done in the car, but while they are out seemed like an easy time to check them.

Thanks for posting the pics!

Tim,
Thanks for the ideas but I didn't have a extra spider or fittings yo work with but I did devise a method to clean them out. It is simple and everyone on the board has the tools to do it. I'm saving it for a new thread as soon as I finish detailing what I have done on the FD. I'll have more pics and details tomorrow.
Mark

[Tim Hancock]

Dropping an injector in a cobbed up container of solvent attached to a jitterbug sander (poor mans "ultrasonic" cleaner), by chance?

[Grezdlitn]

Tim, a great idea! That's why I got into the experimental aircraft side of avaition.....very few limits. Imagination, good judgement,checkbook and Guardian Angel being the only ones I can think of right off.

On with this mornings expose:
The first pic serves only to show the internal components. The large silver hexagon is the diaphram. I originally thought it was stainless steel but a magnet test revealed it to be a ferous alloy.
It is soft and is easily damaged. Cleaned with MEK and then polished with fine grade automotive compound. The three small parts are the moving pieces in the system and appear to only move as the internal pressure is changed by the WUR. The small piece to the left of the three is hat shaped and rests on the adjustment screw I mentioned in a earlier post.


In this next picture notice the two bottom openings with the parts lifted out. the two small bright spots that appear at about 6:30 in the chamber are the ends of the adjustment screws that extend thru the top of the FD. These were pretty corroded so I cleaned but did not remove them.



The next two pictures show my method for removing the center fuel divider.






The last two pictures for this installment show the fuel diverter as removed. Sorry about the pic quality. The o-rings were in good shape so I did not replace. I did check and they are generic sizes and available at any carparts store or seal and bearing place.

There are six o-rings around the base that fit over a raised shoulder. In the bottom of this cavity is a small slit. Almost undetectable! If this is stopped up or enlarged due to corrosion you are probably hosed and can send this FD in for a core.
I read in a previous thread where these rust out but this is a high quality steel part and I didn't find any damage.





MORE THIS AFTERNOON.... HOW I CHOSE TO RESEAL IT!

[Gunter]

I would try very hard to get a new diaphragm; see if any of the rebuild-places will sell you one.
It is my understanding that the deflection of the diaphragm on the nozzles has something to do with the metering.
That, and the reseal, seems to me of prime importance.
When the ss-looking diaphragm failed on me years ago, I didn't pursue it because I was in a remote area and just repaired as best I could.

[Tim Hancock]

Gunter, why would you suggest replacing the diaphram? If it worked when taken apart, it would seem to still work after reassembling right? wrong?

[Grezdlitn]

I think there is some thought that if the diaphragm flexed in operation it will eventually work harden and crack. Keep in mind this was a running car when I dismantled it. If you review the pictures early in the thread and if this thing were that sensitive how did it run in the first place!

I agree there should be rebuild kits available as Bosch manufactured thousands upon thousands of these things. Rebuilds shouldn't be that big of a deal unless you try to alter the delivery pressures.

Mark Hang with me as I will post on my seal process later today.

[acapella8]

Great pictures, I'm bookmarking this thread for later.

[cmonref]

Gunter: When you mention flexing of the diaphram, are you thinking of the diaphram in the warmup regulator? When THAT diaphram flexes, it alters the control pressure by closing/opening the metering port in the WUR.

[Sunroof]

Congrads Mark on the fantastic photos and look into the FD. Now I understand why the cost of rebuilding is high!! Now the big quesitopn is whats the differrence between those who charge $450 and those who charge $1500, yet both warranty for 1-year? I know if I keep my 73.5T, the last thing in the CIS system that has not been replaced is the FD.

Keep up the great effort.

Bob

[Grezdlitn]

Thanks on the kudos for the thread. I was unable to post last night as promised. Server problems.....more to come today!

Mark

[Gunter]

I see indentures in the diaphragm on two of the areas where the nozzles sit.
Would these indentures not affect the metering?
Bosch USA, or other rebuild places, might sell the diaphragm or a kit?
How many places for fuel injection rebuilds are there in the US?

[Tim Hancock]

Originally posted by Gunter
I see indentures in the diaphragm on two of the areas where the nozzles sit.
Would these indentures not affect the metering?
Bosch USA, or other rebuild places, might sell the diaphragm or a kit?
How many places for fuel injection rebuilds are there in the US?

Good eyes Gunter! Mark what are those dents from, can you tell if they are supposed to be there? Maybe they are not a factor?

[Gunter]

It is my understanding that the nozzles sit right against the diaphragm and that with various throttle settings which affects the metering center-plunger in the FD, the pressure-difference deflects the diaphragm under the nozzles and allows more/less fuel.
Why else would this thin diaphragm be there?
Any thoughts from an expert on this?

[Grezdlitn]

You guys are really observant! The dents are present and are formed by pressing against the nozzles. However they are not uniform (the same size for each nozzle position). The picture doesn't reflect this but the dents vary in depth from one side of the FD to the other. My only guess is a variance in pressure from one sie of the FD to the other. I didn't get real concerned about this as the various parts are indexed by indentions around the perimeter of the FD and all dents and the diaphragm will be in the same relationship as before you take it apart.

I'm with you Gunter, there should be a ready supply of rebuild kits.My way of thinking since there are no really sophisticated machined parts or exotic materials a kit shouldn't cost more that $100.

Mark

[vash]

wow. lots of effort to pause in the process to take pictures. that is fantastic! thanks

[Grezdlitn]

This is where I started. The mating surfaces are very highly machined almost a polished surface. I figured I wouldn't be able to stand a sealer that is to viscous or lumpy. I might not be able to torque it down evenly.

The Indian Head Gasket sealer is a shellac and is customarily thinned with denatured alcohol. I tried this but it didn't thin evenly.

Next comes Permatex High Tack gasket sealer thinned with lacquer thinner. It thinned very smooth and any consistency I wanted. Besides it was red in color (almost Guards Red ) so I was immediately partial.

I experimented with the Loctite 574 but the direction were in German and I had no Idea if I could thin it. It would probably work well but wasn't sure if I could ever part the halves after it cures.

I settled on the High Tack. You can't see it very well but I applied a small film with a cheap artist brush being careful not to get any in the chambers. I didn't apply any to the diaphragm just the two machined surfaces.



I then re-mated everything and torqued it to 13 ft. lbs. which is the high end for a high quality 5mm thorx screw.

The car is almost ready to test run. About two more hours work.
It's cold here so tomorrow morning looks good to finalize the process. Wish me luck!

Mark