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Fasteddie313 · Joined: 29 Sep 2013 Posts: 2595 Location: MI

Does anybody know if any or what size standard compression fittings will work on/fit the OD of 931 fuel distributor hard lines?

Or suggest a way to measure them and compare?
like X size compression fitting fits X size line + or - X OD tolerances?

The smaller lines, dizzy to WUR specifically...

I don't want to just cut one and try because then I'm F'd if none work but I want to do some, uh, customizing, like usual...
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80 Turbo - Slightly Modified

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2595 Location: MI

Well... After a bunch of looking and measuring and mathing our fuel lines fall smack in between 1/8" and 3/16" compression sizes at 11/64" and I dont think its within tolerance to work.. I first got 11/64" on a lined slide caliper as it's the most accurate I have in SAE..

I do have a metric micrometer and I decided to get a bit more accurate, double check, and it gave me 4.055 mm, that got me thinking..

Turns out there is such a thing as metric compression fittings, they can be had in 4mm for wouldn't you know it, fuel specific applications..

They have to come from across the pond so it'll be a while before I see them. They are 304 stainless and I have extras coming incase anyone else would like a permanent install CIS pressure gauge with valve to see system and control pressures too if mine turns out well..

It should turn out nice and compact/small, I plan to custom tap the NPT pieces to fine tune the direction of the valve and gauge in relation to each other and make them seat as far in as possible to further compact the footprint depending on how they fit as is, which is a toss up..

I have a feeling this is going to turn out very cool, it will be an awesome cosmetically pleasing functional modification thats easy on the pocket..
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80 Turbo - Slightly Modified

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2595 Location: MI

Pieces before mods...

After threading mods... To compact its size as much as possible.. See how deep the gauge threads, the the block height is reduced, I also shortened the gauge threads..

Gauge alignment correct, lever alignment correct, gauge to lever clearance is near minimum..

Everything very tight, I tuned it to be as tight as logical at correct alignments..

Still waiting on my 4mm compressions, I'm getting there, tune them deep next and install..

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80 Turbo - Slightly Modified

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

How that isn't going in the cockpit.
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WeiBe (1987 924S 2.5t) - 931 S3

jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

Did you mean?....

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2595 Location: MI

No it stays under the hood.. Just off the fuel distributor in front of the cam sprocket.. Inline...
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80 Turbo - Slightly Modified

daniel · Joined: 18 Jun 2009 Posts: 686 Location: Sydney, Australia

I was able to buy banjo bolts and compression fittings from earls that work perfectly with the existing fuel lines
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Over the top of skyline, total brake failure.... hit the wall at over 200 kp/h at the dipper, so anyone who has to brake for the esses is a pussy.
1977.5 Race Car, CAMS Group S Spec
1989 944 Cabriolet

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

Another thing that can fail and cause a big fire.
You have some nice ideas, this is not one of them.
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Fasteddie313 · Joined: 29 Sep 2013 Posts: 2595 Location: MI

Even with Double Ferrule SS 304 compressions??

"used in Oil & Gas Industries, Petro Chemicals, Power Plant, Steel Industries, Chemical Industries, Pharmaceutical Industries, Fertilizers, Hydraulic & Pneumatic, Marine & any Process Industry.
When installed affixed to tubing it becomes a five piece connection to provide a solid leak free joint by the sequential action of the twin ferrules.
Double ferrule Tubing Fittings consist of four precision engineered components called the nut, the front ferrule, the back ferrule, and the body, all manufactured to very stringent tolerances under rigid quality control procedures. "

I sold my Hoffman for this, bought ALL NEW pieces, and did my due diligence in researching and acquiring the CORRECT metric high quality fittings.. The compressions are made specifically to fit 4mm OD tubing and my lines are 4.055mm by micrometer..

Valve..
450 PSI MAX PRESSURE, CHROME PLATED FORGED BRASS BODY
MAXIMUM TEMPERATURES: 356f @ 140 PSI 212f @ 350 PSI

BODY: CHROME PLATED FORGED BRASS
BALL SEATS: P.T.F.E. (same as what's in your teflon fuel lines)
BALL: CHROME PLATED BRASS
RING UNIT: BRASS
STEM: BRASS
O-RING: NBR 80 (many military rubber specifications for fuel and oil resistant O-rings require nitrile based compounds.)

Gauge...
Movement: Copper Alloy
Bourdon Tube: Copper Alloy
Window: Glass
Case: Steel case for protection in harsh environments (painted black)
Connection: Copper Alloy Center Back Mount

The Tee is made by Lincoln, as in Lincoln welders.. Think thats good enough..

Whats on your fuel lines there Rasta? They look welded, did you have the welds X-rayed? Was whoever that made those 100% sure of the Porsche fuel line metallurgy when selecting the filler material? You sure your oil filter dude is even a certified welder? Better make some frantic phone calls..

I better recall that chevy truck and chew the arse of whoever designed GM specific fuel line repair kits with their inferior single ferrule brass compressions even though it doesn't leak a sniff..

I can understand it being a bad idea to run high pressure fuel lines into the cabin for a dash gauge which I'm not doing anyway, sure.. But how would even that be any more dangerous if done correctly than running an in car fuel cell/lines/pump that some racing requires for "safety"??

It's not like I'm going to tape this on, how could I have done a better job? If it leaks (yeah right) I'll fix it, if I can't fix it (yeah right) I'll scrap it and then repair my fuel line with, wait..., the same correct compression fittings for the job..

Lindsey Racing doesn't seem to think it's too terrible of an idea on 24S's 44's 44S's 51's and 68's..

If you guys think this is a bad idea you're really going to shit when you see my home machined blocks to adapt my front Volvo calipers with their 2 lines directly to the OEM Porsche brake lines all in one piece, just need an m10X1.0 tap and it's on like Donkey Kong.. (failed he he)
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80 Turbo - Slightly Modified

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

EFI systems use 2.5bar, CIS uses more than double. Failing is easier at higher pressures.
Dont know what to say...if you can make it safe enough then go for it.
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jason c · Joined: 13 Jan 2014 Posts: 1018 Location: Nwi

I don't think its a bad idea to have it under the hood as long as the gauge & fittings are made for the pressure, fuel & heat.

It would be a bad idea to have fuel lines ran into the cockpit, you'd have to change your name to FriedEddie.

Sometimes less is better, sometimes its worth it. That's a decision you have to make.

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2595 Location: MI

SUCCESS!!!

Man it looks good sitting real low between the dizzy and charge tube. The compressions fit like a glove and don't leak at all.
I think I may need to move to a glycerin filled gauge though as the needle is a bit bouncy/vibrates about .2 bar with the engine running.
And the engine will remain idling if you shut the valve to see system pressure but goes lean and stumbles as expected, this is good though so you can just check system pressure with the engine idling and not have to jump the pumps otherwise..

It was a bit nerve wracking bending the fuel line, especially where it comes off the distributor as this needed quite a snake up over an injector line bolt (passengers rear corner), down the other side of the dizzy by the charge tube, and then turn right and up toward the cam pulley where it ends and the first compression goes on..

I ended up rearranging the order of the fuel lines in the first mount tower thing, I took the WUR line from its position as top front row, and replaced it to the 2nd down on the back row with the original 2nd down as the top on the back row and the original top back row becomes the top front row..

I'll get some pics up tomorrow as it got dark on me, I had to finish it by drop light tonight.

I got my Stahlwille vinyl decals in the mail from spain today too and may get pics of those installed in my beauty pics thread tomorrow also.. They are silver just like my Turbolader windshield banner and I think I'll put them across the tops of my rear side windows, I like them very much..
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80 Turbo - Slightly Modified

Fasteddie313 · Joined: 29 Sep 2013 Posts: 2595 Location: MI

Beautifull... I love it...

The top of the gauge is about 1cm lower than the top of the upper charge tube there where it turns to go down by the cam belt pulley.

Thats what's up...

Tomorrow I will fab a mount..
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80 Turbo - Slightly Modified

p-talk · Joined: 24 Aug 2007 Posts: 152 Location: Tucson, AZ

Nice! I built a similar test gauge for my Audi 200 TQA a few years back (also CIS). I mounted my gauge on the WUR.

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1984 Porsche 944
1990 Audi 200 TQA
1990 Audi 90S

Kenodog · Joined: 25 Jun 2003 Posts: 2669 Location: Vancouver,B.C.

Got one of these for free from Special T Auto when I had my WUR and FCU rebuilt. Haven't installed it yet but it looks well made. Cheap to buy as well, $60 full-pop retail.

http://www.specialtauto.com/porsche-parts/index.html

Leigh
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1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
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