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Crotchety Old Bastard
 
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Did you use the red selant to button it up? That's what I used on mine and it worked well.

I'm guessing that these events are not random acts to fix a flutter but rather a deliberate attempt to max-out the fuel flow of the head. Whoever added that Mercedes dampener is famliar with CIS. Was this engine modified when you got it, or had it been?
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 12-01-2007, 07:01 PM
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I made up the constriction piece since it was about as much work as pulling the fuel head off. So in the overall context of the saga, seemed worth a shot. There is a pic showing it inserted in the fuel head connector to the WUR line. I can pull it out with a magnet - it is a nice clearance fit.(or unscrew the union from the head).
The plate flutter definitely diminished with this in. Not gone completely, but much less violent (my size of constriction of course is a complete guess - I don't know how small they are in other CIS heads - never having dismantled one) . But I still had an issue with the fuel system - still pissing too much fuel. So pulled the head out again and split it again. Same problem - had torn one of the elongated O rings again. So, back to the drawing board. I am going to reassemble it a different way this time. I have separated the metering chamber from the body (left it attached last time - don't disturb anything you don't need to). I have scribed a couple of reference points where particular slits need to line up with injection holes in the body. I intend inserting the chamber while I can inspect all the O rings going in. Then insert the head (base) back on to the chamber.
I will post all my success and failure here so others can use the experience - or just treat it as cheap entertainment.
I may be speaking too soon, but I suspect there is nothing too difficult about this beast. But it is now Sunday and I don't have any more spare O rings.
Will keep you posted.
The one thing I regret in dismantling it, is not tracking each spring to its own chamber. The secret to setting these up to really perform is matching all the flows. Otherwise all your tuning figures are just a rough average rather than precise optimum. I may have disturbed that - assuming the previous monkeys who have worked on this car were even vaguely aware of this. It may be a need for recalibration of the injectors again. The allen head screws on top of the head by the injectors seem to alter the spring pressures, so it can probably be done in car.
What I would like to do is get the head running again, with my restrictor in and fiddle with the pressure on the extra component in my line. Between the two of them, I may be able to stop these spasms. Meantime I will try and organise some sort of fuel line that will let me bypass the mystery component and see if it all cures itself.
Meantime, I need to get a few other things around the place. I've spent about 200 hrs on this beast in the last month or so, travelled about 3 km in it, and it still sits on jack stands.
Regards
Alan
Old 12-01-2007, 08:51 PM
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Crotchety Old Bastard
 
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Alan,
It's not a bad idea to re-calibrate the individual injector fuel flow when you're all finished. I would assume them to be off now that the settings have been disturbed. It is not easy to do that with the engine in the car. Find an old set of injector lines and bend them up so you can fit the injectors into sight glasses sitting on top the engine.
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 12-02-2007, 07:38 AM
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Do you use the little allen screws next to the injector unions on the fuel head - seems to me that is what they are for?
I managed to check the previous flow in the engine, but like every other job in there, it is a squeeze. I don't have any spare injector lines, or even union fittings. I will probably have to try and do it in engine.
Would be really useful if someone with professional CIS expertise could clarify some of the mysteries of these things. For instance why has the 930 fuel head seemingly no constriction damping. Is it supposed to rely solely on one light spring?
What type of aberrant behaviour would cause such violent spasms in the air plate as mine is suffering. If I knew the cause I could zero in on the solution.
Regards
Alan
Old 12-02-2007, 10:17 AM
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Brian, I only just found one of your earlier postings. I used no sealant, and the head has sealed fine both times so far. Your suspicion of extra fuel enrichment may be correct. There was an EBC in the car, which I have removed. The engine supposedly has done 500 km on a top end rebuild due to melt down (oil leaks everywhere, and red sealant). There is, in the aftermarket header system, a blanked off boss, which I suspect had an O2 sensor. There are wires running from that locality inside the car to a small electronic box on the floor. I am suspecting some sort of mixture control in association with the EBC.
Goran, the fuel accumulator is in place.
I am very suspicious that the scoring on the metering piston may be unhelpful to the spasms. It seems the clearance of the piston in the bore is the seal between the pressure differential of the system pressure and WUR. Do you guys have any contacts expert in CIS rebuilds that I can get hold of. There will be no parts in NZ (still waiting for clutch clevis pin ex Germany), so may as well start somewhere familiar with the beast.
Alan
Old 12-02-2007, 11:12 AM
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A fellow Pelacanite
 
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The mixture box under the seat is a stock part which included the CO sensor and its wiring.
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1981 UK 930. G50/01 shortened, 964 3.8RS Fibreglass Body Kit, 18" Alloys 8.5" F & 10" R, 225's F & 285's R, Special Colour Metallic Blue Paint, FIA Sparco Evo's, A/C and Air Pump removed, Electronic Boost Controller, GHL Headers, Tial46 WG.
Fitting - New service kit.
Needs Fitting - Innovate XD-16 Kit, Kokeln IC. Stephen's K27 HFS, EVO Intake Assy & his Modded USA Fuel Head.

1983 UK 911 3.2 Carrera Sport Coupe. Black, Black Leather with Red Piping, Black Alloy Gear Knob, K&N Air Filter Element, Turbo Tie rods.
Needs Fitting - K&N CO Sensor, Round A/F Dial Gauge, Factory Short Shift Kit.

http://www.danasoft.com/sig/Iamnotanumber.jpg

Last edited by NathanUK; 12-03-2007 at 01:30 PM..
Old 12-02-2007, 01:26 PM
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This box sits (on LHD) against the lower wall, by the floor about where your clutch foot (LSide)
would sit. It has Japanese writing on it. The external wires from the engine area go into this box. It is a bit bigger than a matchbox. The other possibility is it may have something to do with EGT. The car has a factory fitted exhaust temp warning light in the dash. Apparently it was compulsory on Turbo cars (only Porsche?) for the Japanese market. Altho what purpose that would serve, I'm buggered if I know. If the light came on what were they supposed to do. Stop for a cup of tea? Why? Why would the Japanese authorities be so concerned about you running your engine so hard the exhaust temp gets too hot?
Another of the mysteries of this car.
I have emailed the Aus Jetronic contact to see if they have some bits and advice.
Regards
Alan
Old 12-02-2007, 01:39 PM
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This may help you - this was on my engine when it was built by Gamroth.
Picture taken during subsequent engine rebuild/refurbish last fall: (ignore comments)


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- Craig 3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ -
"930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe
Movie: 930 on the dyno
Old 12-02-2007, 09:39 PM
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Crotchety Old Bastard
 
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Yes, the small screws are used to fine adjust each injector's flow.
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 12-03-2007, 07:46 AM
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Craig,
That is exactly what I have - except my plumbing is reverse of yours - my inlet to the cannister is your outlet. But I don't think it matters . I believe it is a cannister of fuel sitting over a spring loaded (adjustable) diaphragm. Why was it added to your engine - what is the function. The adjuster nipple at the bottom just vents to atmos?
Thanks
Alan
Old 12-03-2007, 10:45 AM
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I am suspicious of the state of the metering piston. It is the only mechanical defect I can find in the fuel head. I believe, and am happy to be corrected, the system relies on a perfect bore clearance fit between the piston and the metering chamber. The system pressure seems to enter at the waist of the piston, the WUR pressure at the spring loaded head. The only thing that separates this 50 psi gradient is the wall clearance at the piston head. Mine is scored. The only thing that separates the system pressure from bypassing the injectors and pouring straight into your airbox is the clearance at the lower end of the piston. This is my deduction.
I have had no reply yet from the Aus Jetronic people in Spuggys post.
So, posted is my attempt at making a new piston. Not quite finished yet - have left a bit of extra meat on the top and waist to allow me to balance it to the old one for weight. This has probably been my biggest challenge on the lathe - the dimensions are critical, and spent an hour or two polishing down to final size. (The wife doesn't seem to mind - she is used to it, and is beginning to wonder if this car is ever going to go. Me too.).
Hopefully in the pic you can see the scoring on the original piston (LH). What caused this I don't know - but I do believe it will happen if you try to run, or flush your system on alcohol. The fuel heads are not made for it and rely on the fuel for lubrication at this point. The tolerances are less than a thou. Whether the scoring has been caused by the plate spasms, or vice versa I don't know, but only one way to find out, without some specific CIS expertise.
My steel I purchased down the road for $2. Bosch probably spent some time researching theirs, altho it is ferrous. I intend checking the coeff of expansion of the two by putting them in the oven at 50 deg C (a guess at the fuel head working temp), and checking them with micrometer. If this thing seizes in the bore, it could be big trouble - leaness or hydraulicing on fuel. But at the moment it is a beautiful sliding fit in the chamber. The chamber has score marks visible, but nothing to feel - it seems much harder than the piston. You can feel the tears on the piston.
It makes you aware of how critical it is not to have any crap in your fuel - especially at this point. The smallest spec of grit will jam between the wall and hinder the piston.
I can't help thinking the banjo screens were removed to maximise flow. Are their banjo screens on your 930 heads?
Regards
Alan
Old 12-03-2007, 11:11 AM
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Function?

Actually........I do not know whay it was added.
Stability? Increased fuel? Don't know -
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- Craig 3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ -
"930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe
Movie: 930 on the dyno
Old 12-03-2007, 11:37 AM
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Alan, add your year of car to your signature, it makes it so much easier if you need help.

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1981 UK 930. G50/01 shortened, 964 3.8RS Fibreglass Body Kit, 18" Alloys 8.5" F & 10" R, 225's F & 285's R, Special Colour Metallic Blue Paint, FIA Sparco Evo's, A/C and Air Pump removed, Electronic Boost Controller, GHL Headers, Tial46 WG.
Fitting - New service kit.
Needs Fitting - Innovate XD-16 Kit, Kokeln IC. Stephen's K27 HFS, EVO Intake Assy & his Modded USA Fuel Head.

1983 UK 911 3.2 Carrera Sport Coupe. Black, Black Leather with Red Piping, Black Alloy Gear Knob, K&N Air Filter Element, Turbo Tie rods.
Needs Fitting - K&N CO Sensor, Round A/F Dial Gauge, Factory Short Shift Kit.

http://www.danasoft.com/sig/Iamnotanumber.jpg

Last edited by NathanUK; 12-03-2007 at 01:30 PM..
Old 12-03-2007, 01:26 PM
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His engine # decoded as an '86 930/68 (US), IIRC, despite the car being a 1982 Japan model. It was on another thread.

Pay attention
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'77 S with '78 930 power and a few other things.
Old 12-03-2007, 01:51 PM
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Thanks Spuggy. The 66 & 88 engines don't have it, only this S version M148.
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1981 UK 930. G50/01 shortened, 964 3.8RS Fibreglass Body Kit, 18" Alloys 8.5" F & 10" R, 225's F & 285's R, Special Colour Metallic Blue Paint, FIA Sparco Evo's, A/C and Air Pump removed, Electronic Boost Controller, GHL Headers, Tial46 WG.
Fitting - New service kit.
Needs Fitting - Innovate XD-16 Kit, Kokeln IC. Stephen's K27 HFS, EVO Intake Assy & his Modded USA Fuel Head.

1983 UK 911 3.2 Carrera Sport Coupe. Black, Black Leather with Red Piping, Black Alloy Gear Knob, K&N Air Filter Element, Turbo Tie rods.
Needs Fitting - K&N CO Sensor, Round A/F Dial Gauge, Factory Short Shift Kit.

http://www.danasoft.com/sig/Iamnotanumber.jpg
Old 12-03-2007, 01:58 PM
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Thanks guys - looks like it is primarily a damper. (I may be able to make it work better with some pressure adjustment). I must say the 928 K jetronic system looks quite similar to the 930. I have been touch with NZ Bosch fuel injector service unit. He just laughed when I asked for parts. He could not even supply me the union ferrule and nut for the WUR inlet hose into the fuel head - so I can bypass this unit. It appears from Craigs pic, my lines have been adapted to this unit and are hard wired to it. I can't use them to bypass it - need to make new line. The Bosch agent said the only K jet bits they were ever able to get were whole new fuel heads - and they ceased 15 yrs ago. I did get some injector banjo screens off an electronic injector system - which I am going to fit - after I drill the banjos out a bit to take them.
Meantime, I will press on with my piston and see if it cures the problem. He said that dirt in the fuel would cause scoring.
Regards
Alan
Old 12-03-2007, 02:41 PM
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The gadget looks like a bosch L-jetronic fuel pressure regulator from the late 70's.
They were hooked up to the end or middle of the fuel rail and bled fuel off the rail and returned it to the tank maintaining base fuel pressure in the rail to the injectors at around 40psi with no intake manifold vacuum going to the vacuum connection, depending on the car it's made for.
Some guys looking to raise the fuel pressure would take two 3/8 drive sockets of the right size and place one at each end of it and squeeze the cannister in a bench vise to bend the side with the vaccum line inwards or slightly concave.
This would put more tension on the spring that pushes against the diaphram in side. The result is a slightly higher base fuel pressure.
Intake manifold vacuum also works with the spring to raise fuel pressure when accelerating and lower pressure when decelerating.

I read somewhere that Porsche and Bosch used the CIS fuel distributor from the early Mercedes 4.5 liter V8 and blocked off 2 of the fuel ports so only 6 remained... you can see where they were.

I know this doesn't help you much... just felt like adding to everything already said.
Old 12-03-2007, 03:22 PM
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I got the fuel head filters from Imagine Auto - and interestingly the return addy indicated some dedicated CIS parts house (!)
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- Craig 3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ -
"930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe
Movie: 930 on the dyno
Old 12-03-2007, 03:35 PM
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Let me know if you need something...I am sure I can source it for you.
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Old 12-03-2007, 07:15 PM
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OK Guys, My fuel head is back in the car and appears to be leak free. The injector settings are at about 30% variance max-min. Whether my piston works yet I don't know - the settings are very different now.
I am trying to set everything back to factory spec as a baseline. My system pressure pegged my gauge at 110++. I'm guessing 120-130 psi. My WUR cold pressure is 50 psi!! The manual says 20. So, I pull my WUR apart and remove one of the 2 springs. I then google the part No and find it is off a 3.6 Turbo. Maybe 50 psi is right for it, but with one spring removed I get 20 psi. Does anyone have access to the 1993 3.6 T WUR specs?
Not sure which way to go with this.
Have reduced my system pressure to 85, have 4 spare shims now - only using one.
Alan
Old 12-04-2007, 12:22 PM
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