2.7 cis parts replacement

[DohertyCM]

Lessons learned from this experience.

#1 . Be careful with starting the car WHEN IT WONT START!.....

#2 . Never disassemble a fuel distributor!...ITS NOT WORTH THE RISK, because even if you do find the problem and fix it, chances are the O rings inside are old and will stretch which translates into it will leak if you get it back together. And it will probably leak around the split line once its back together....leave it to the professionals with the proper tooling.

#3 Once you get everything back together, remove spark plugs disable the ignition system and motor the engine over...disable the fuel pump if able.
This is about getting the fuel out of the cylinders to prevent hydrolock.

#4 Last thing...before you start the car after its all back together.....roll it OUTSIDE and start....Gas will come out the tail pipe.

Ok I reposted part of this from another post I did, but I wanted to add some info for those of you who are looking for parts.

When searching for parts for the CIS system, dont limit yourself to just Porsche websites. Search for the Bosche stores, volvo dealers and repair shops, Deloreon parts places (yes I said Deloreon) and some mercedes places. They all used the CIS system and used the same parts as the 911. I found a brand new CIS fuel distributor for my porsche for $459 from a Deloreon guy. He only had the one, but it was the same part# as my original. He also had a new warm up regulator that he converted from a later model to work on my vehicle, Because the one I had was really "unobtainium". The other thing this guy would do was replace all of my plastic/nylon CIS fuel lines with Stainless Steel Braided HP fuel lines...
This guy was Deloreonautoparts.com ...the best thing is he was about 3 miles from my house..!!

My point is when you need parts, dont limit your search to just Porsche parts.

[manbridge 74]

I would only quibble with #2.

I've done a few FDs, not all Porsches. O-rings seem to shrink not stretch in my experience. Putting them in hot water helps on install.

And no leaks at parting line after carefully hand lapping each side to ensure flatness.

[DohertyCM]

I can respect that...However you seem to be the type person who I was talking about. The guy with the experience and tooling to do so.

I think of myself a good mechanic, (lots of experience working on jets) and very competent. But I recognize when I need training and tooling to do such a job.

The other thing, the guy i traded Fuel Distributors with almost didnt take it as a core because he doesnt take them after someone has taken them apart.
I got lucky and convinced him that I was extremely careful in my efforts.

Thank you for your comment.

[mixer911]

Originally Posted by manbridge 74

I would only quibble with #2.

I've done a few FDs, not all Porsches. O-rings seem to shrink not stretch in my experience. Putting them in hot water helps on install.

And no leaks at parting line after carefully hand lapping each side to ensure flatness.

Manbridge can you explain"hand lapping" and did you use sealant,and if so how did you apply it and where?oh and what kind of sealant

Thank you

[manbridge 74]

Sure. You'll need a thick plate of glass, a sheet of 1500 grit sandpaper, and some wd40 type lube. After cleaning top and bottom of FD with solvent and rag, you will tape your paper to glass and appy wd40 to paper. Then move FD sections in slow figure eight motion over paper. Stop and wipe off wd40 after it gets dirty and apply more. Rotate FD sections 90-180 degrees from time to time.

A machine shop could do this but they might get careless and remove too much.

Also the wafer thin diaphragm can be easily cleaned with naval jelly as it is ferrous. This will remove all rust/discoloration.

Sealing. I thinned permatex aviation form-a-gasket with 70% isopropol alcohol. Thinned to almost water like consistency. I used a small paintbrush to apply it sparingly. Bolted everything up and tested for leaks with compressed air. Then I took it apart again to check for any permatex squeeze-out into FD chambers. There was very little. Then, since it was still tacky, I bolted it right back up and installed it on car. So far no leaks and all injector lines flowed equal amounts.

[mixer911]

well explained,thankyou

Did you torque to any spec. or just a good even tightness?

[manbridge 74]

Good question.

Since FD parts are made of cast iron, I did not use actual torque spec though I'm sure there is one. Lets call it "gutentight." After years, I trust my right arm to deliver within 10ft lbs of each bolt. Assuming clean, chased, and lightly oiled threads.

But I did do one thing that might help. I marked all bolts to go in the same hole they came out of. And I made sure the diaphragm was in the same orientation as removed. But I am sort of particular about orientation on re-assembly of just about everything.

[E Sully]

If you take the fuel distributor apart, keep careful track of where each part came from. There are small shims under the springs and hats that can vary in thickness used to balance fuel flow. Also, the thin metal diaphragm has a small pin hole in it. Do not block this if you use a sealant.

[manbridge 74]

Ed is correct about the pinhole. Good catch.

About the shims.... I believe the unit for my 74 had no shims or I assumed they were spring seats as I measured them and they were all the same. As it has been a year, I cannot recall with certainty.

[Fidalgo911S]

I used a cold start valve made for a BMW 528i. Works perfect and about $200 less.

[mixer911]

Mine

[mixer911]

Mine had many pinholes,I must have the high performance diaphram.(lol)
do you mean the pinhole to the left of the crack?Any Idea what its for?

[manbridge 74]

Original pinhole for pressure equalization/anti-surge perhaps?

It is needed in any case.

[supdaf]

Pinhole is for transfer of incomming fuel pressure to the top of the fuel piston to enable the WUR to regulate piston height for a given air flow and thus control cold start enrichment and "hot lean out" (my term).

If it is plugged the piston goes all the way to the top with a small force. No counter pressure. I know this from first hand, I'll call it, "research". Oh the joys of CIS education.

[mixer911]

Originally Posted by supdaf

Pinhole is for transfer of incomming fuel pressure to the top of the fuel piston to enable the WUR to regulate piston height for a given air flow and thus control cold start enrichment and "hot lean out" (my term).

If it is plugged the piston goes all the way to the top with a small force. No counter pressure. I know this from first hand, I'll call it, "research". Oh the joys of CIS education.

I rebuilt mine ,(different diaphram)and the injectors would flow as soon as I turned the key.
I just took it apart again ,not only was the pinhole plugged with sealant,I had also flipped the diaphram,which blocked the hole.

Tonight I'll rebuild it again in the Mansbridge way.

It's a pain tryng to get the orings to stay in place while sliding them into the top of the FD.So once I get them in place on the cylinder,I'm going to wet them and put the cylinder in my freezer.
Hoping to freeze them on and slide it in.

[supdaf]

A tid-bit of note, at least to me, I was suprised to find that when I measured the old o-rings they all measured out to standard sizes. I was expecting to find difficult to source metric o-rings but found much easier to rake up standard ones. One of the nice lessons learned from CIS fiddling.

I used case sealant 574 I think. It has performed perfectly. I do however like the idea of the isopropyl thinned permatex.

[mixer911]

I was able to get orings off a donor FD,I used deep creep to help slip the shaft in(freezing didnt hold)
I did use 574.
Any Idea on a good dry time?
The sandpaper with a sheet of glass worked great( I hope havent installed yet)

[manbridge 74]

If both sides are true the sealant is just for minor imperfections/pitting. No dry time necessary.

[mixer911]

I,ll post results,