psychoideas

How wrong I was
In my quest to start the beast I had moved on to flushing the fuel system in an attempt to check the calibration of the fuel delivery.
After installing the new accumulator and filter I removed the injector nozzles and turned the fuel pump on only to see the number 5 line pumping fuel out into the engine bay.

Fuel distributor F*&$%d I thought to myself! I made a few phone calls only to find that a rebuild started at $350.

Got nothing to lose! I’ll pull it apart and see how it works.

psychoideas

Notice the small 'O' rings that have taken on an oval shape???

Notice how one of them doesn't look like an 'O' anymore???

Notice how that one looks like a FU*&(%G ‘C’???

I don’t know if there are any fuel distributor (FD) experts out there that will read this but I’m sure someone will find it interesting.

Those small ‘O’ rings are placed over the metal sleeves that are attached to the main shaft. When this shaft is pushed into the upper body of the FD those ‘O’ rings provide a seal. It appears that during the last assembly one of the ‘O’ rings (the ‘c’ ring) has flipped up and has been caught on the metal sleeve. The actual piece that was chopped out of it was in the next chamber and was what was jamming the number 5 valve open.

There is no way this could have happened through fatigue failure and must have happened during assembly.

You can also see in the bottom pic that the two 'O' rings in the upper left have "nicks" out of them.

psychoideas

Now I rang an Australian fuel injection specialist ( and I emailed one in the USA ) to try and get some ‘O’ rings but they refused to sell them to me or even tell me the size and section of them. Both businesses told me they will sell me an exchange one. One guy says, “It’s not as easy as changing the ‘O’ rings and putting it back together. It will leak for sure!”

So, if he’s so sure that I can’t repair it, why is he so worried about selling me the parts or even telling me what size I need???
Now, if I were him I’d sell me 10 bucks worth of ‘O’ rings and say,
“Listen mate, I know this isn’t going to work but if you want to have a go then here they are”
Then when it didn’t work I’d send it to him for repair.

So I’m going to give it a go and if it doesn’t work He won’t be getting my business!


He also said that he calibrates them.

Now under the springs in this pic are small washers/spacers/shims. I don’t know what you’d call them but I assume by “calibrate”, once assembled a fuel flow test is performed and measurements taken as to how much each injection valve is delivering.

Once that is determined the shims can be changed so that a particular valve opens more or less.
I’m sure that a fuel injection specialist has a selection of shims and that he knows that 0.01mm thicker will deliver X milliliters more fuel over a given time.

I have measured the shims and found them to be 1.38mm, 1.38mm, 1.38mm, 1.34mm, 1.40mm and 1.50mm.

These shim sizes would also depend on the age and strength of the springs and the sensor plate that they push on.

I have recorded which valve each one came from so they will go back into the same place.


Has anyone had experience with the insides of these??

theiceman

Frank
Wel All I really have to say is congradulations, you found your problem. It wouldhave been a real bummer if you had stripped it down and you had NOT found the root cause. I am sure someone wil chime in sooner or later with an oring supplier. I think this is the key for you for sure.

KRA993tt

Sorry I'm not able to help you at all. Have you tried posting this at Pelicanparts.com. They have an engine rebuild area for 911's and a lot of active mechanical posts. You may get some better feedback. Good luck.

TroyN

Since you have a caliper you could measure the rings and maybe use someone like: http://www.orings.com/productstock.aspx. Not sure if they'd sell in less than bulk numbers but others came up in a Google search for "o-ring".

TroyN

Another idea, maybe you could get a used fuel distributor from another type of car w/ CIS, like a VW. I just got one for my Scirocco for $20 (found on vwvortex.com). It's possible and maybe even likely that the o-rings are the same. Of course you might need two since these are only 4 cylinder cars.

psychoideas

Ice and Troy
Thanks for the o ring info. Trouble is, the way it was assembled before has me doubting that the o rings in it were the correct size after all.

What I need is a Bosch parts supplier. If I can get the correct o rings, the sensor plate and a selection of shims for calibration, I'll fix it myself. Just finding the correct parts is the problem.

Hi Keith,
Thank you I will have a look at pelican.


Hey Ice,

Summer coming your way soon, top off weather! For cars and ladies!

psychoideas

Hey Troy,

Just saw your last post.
Great Idea

I'll start looking right now.

Part No. 0 438 100 006
i think the last 6 means 6 cylinder so i might look for a 0 438 100 004

theiceman

You know cracking this distributor thing and release the hold that these rebuilders have on us would be great . As a group we are a pretty smart bunch ( according to my wife all take turns using only one brain anyway ) If we could get the parts I am sure we could rebuild these things.
Oring consistency will also be important. Failing getting an OEM part number could some one at least spec out your oring and tell you what it is made from an an approx size ? If we can get that we can all check local suppliers and see what we could come up with. For a few dollar investment we could crack this thing.

Oh by the way Frank Spring has finally sprung... +18C today .. now if I could only get that hand brake off I put on last september after washing the car ...


just kidding , everything is running great and we have already had some good get togethers. Check out the regions and check out Canada under the get together.. we have some great shots of some great cars..

psychoideas

I've got a mate who is at work right now and he has the samples. He rang earlier to say he has a selection for me to try. I'll be putting them in tomorrow.

The problem will be getting hold of the shims for calibration They are 10.3mm outside diameter and 7.2mm inside diameter with a thickness specified earlier. I'm guessing that they come in 0.02mm increments as I have them at 1.38mm and another one at 1.40mm.

If I get around to it I'll try Bosch Australia tomorrow.

srf506

I was about to ask if you'd tried to contact Bosch yet. They might even have a rebuid "kit" or at least tell you the right sizes and material. After all, these things are 20+ years old. They can't be that exotic, just maybe obsolete. ;-)

Cheers mate and keep us posted.

Jim P.

Peter Zimmermann

Many years ago, perhaps in the late '70s, I diagnosed a fuel supply problem on a CIS 911 as a faulty fuel distributor. Of course, back then, they were cheap and readily available. Knowing that, I thought that it would be worth a try to take it apart and look, but I was told by a Bosch rep that if I did they wouldn't accept it as a core, and I would have to buy a new one at 4x the cost. He then told me that I couldn't fix it anyway, because the halves of the body were sealed with a special adhesive, then placed in a 30-ton press for a period of time until that adhesive set up. Time went by, fuel distributors continued to be relatively cheap, the shop was always busy, and I ended up never taking one apart - maybe the only piece on the car that I've never explored. I'm very interested to see what happens with this project. By the way, I used to buy a wide variety of o-rings from a company in WLA, and I remember that they always wanted me to tell them the application; exposure to fuel, oil, hot oil, etc. Unfortunately, I've never seen any listing for a part number for those o-rings in the distributor, or sizing info. I think that fuel distributors are the Bosch version of the recipe for Coca Cola.

psychoideas

Hi Jim,
A friend of mine owns a one man garage in the small town we live in, so I was going to ring Bosch and tell them I worked at this place and we were doing a rebuild on a FD for a Porsche.......................you know where I'm going with this
Maybe Bosch will be more accommodating "within the trade" Surely they can't restrict their sales to fuel injection repairers only????

psychoideas

Hi Pete,

That’s an interesting story.
I’m sure the injection specialists down here don’t glue the halves together under pressure. That’s not a bad press to deliver 30T. Maybe those sent back to Bosch get that treatment.

A Land rover dealer in Canberra told me that I couldn’t put my R380 Gearbox back together without it leaking. Three years later still bone dry! Bare in mind it’s the only thing that doesn’t leak.

In relation to the Fuel Distributor, I’ve got nothing to lose. It didn’t work properly before. My mate is getting me some o rings for free. I’ve got some really good Loctite sealant in my tool box. I’m unemployed at the moment so my time is my own. If it doesn’t work, I’m back where I was yesterday. No biggy.

When you have a look inside them they’re quite simple really. I had no idea what was in there but once open it’s pretty easy to work out. It’s just a pressure differential to open the valves.

As I progress I post the results.