greenish colored o ring fuel distributor
05-15-2011 | 04:49 AM
#1
Thread Starter
Intermediate
Joined: Apr 2010
Posts: 33
Likes: 2
From: Haywards Heath UK
greenish colored o ring fuel distributor
Hi all,
Does anybody know the exact dimension of the greenish colored o ring in the base of fuel distributor as described in Richard Andrade's article? Richard measured 27.5mm ID X 30mm OD X 2.5mm thick. It is impossible to find in this dimension, has anyone used other alternatives successfully?
http://www.porsche928forums.com/down...CISRebuild.pdf
Cheers,
Dan
'82 928S Auto
Does anybody know the exact dimension of the greenish colored o ring in the base of fuel distributor as described in Richard Andrade's article? Richard measured 27.5mm ID X 30mm OD X 2.5mm thick. It is impossible to find in this dimension, has anyone used other alternatives successfully?
http://www.porsche928forums.com/down...CISRebuild.pdf
Cheers,
Dan
'82 928S Auto
05-17-2011 | 03:36 AM
#4
Thread Starter
Intermediate
Joined: Apr 2010
Posts: 33
Likes: 2
From: Haywards Heath UK
Please can anyone help with this ? A friend is in the process of refurbing the distributor, he has all the other o rings apart from this one which is too damaged to reuse or take a measurement from. Any advice greately appreciated.
Dan
'82 928S Auto
Dan
'82 928S Auto
05-17-2011 | 12:15 PM
#5
Drifting
Joined: May 2001
Posts: 2,747
Likes: 3
From: Owasso, OK
Dan,
Not sure of the size but any O ring larger than the locking nut, small enough to not interfere with the mounting screws and about 1/8" thick should work to preclude any vacuum leaks. It should not be exposed to fuel, so any rubber or silicon composition should work.
Dennis
Not sure of the size but any O ring larger than the locking nut, small enough to not interfere with the mounting screws and about 1/8" thick should work to preclude any vacuum leaks. It should not be exposed to fuel, so any rubber or silicon composition should work.
Dennis
05-17-2011 | 12:23 PM
#6
Three Wheelin'
Joined: Aug 2006
Posts: 1,765
Likes: 1
From: Atlanta
That O-ring is made from the best material ever. Nothing wrong with reusing it especially since you wont be able to find a replacement. It's all the other ones you need to worry about.
Edit: I just realised you said the green one was damaged. I don't know what to say. I was never able to find a replacement myself but lucked out becasue it was usable.
Edit: I just realised you said the green one was damaged. I don't know what to say. I was never able to find a replacement myself but lucked out becasue it was usable.
Last edited by Mike Simard; 05-17-2011 at 12:42 PM.
05-17-2011 | 01:23 PM
#7
Joined: Jul 2010
Posts: 692
Likes: 3
From: SW Ontario, Canada
Have you tried McMaster Carr in the US? See http://www.mcmaster.com/#metric-o-rings/=cci7mt for selection.
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05-17-2011 | 01:44 PM
#8
Chronic Tool Dropper
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From: Bend, Oregon
Measure the plunger with a micrometer and use that as a guide to get the correct ID. The perfect o-ring will just touch the piston enough to maintain a seal, but not so tight that it will cause much drag on the piston as it moves. Tough job! It might make sense to buy a few different o-rings with the correct ID for the piston but different sections to see which works best when clamped in the housing. Remember that the o-ring will be lubricated with fuel in service, so it's ok to add a very light oil as lubrication for your tests. Something like WD-40 in the US would be good.
When you do find the best size, please post back with your findings. Note that you may have best luck finding the correct material in a selection of AC seals; modern AC systems use the same material as that piston seal, where the original seals in th erest of the metering unit were black.
I'll confess that my significant CIS experience is with four- and six-cylinder applications. No 928, no big Mercedes V-8 metering units rebuilt. I did have a Mondial metering unit in the car a couple times, but it was boxed for shipping... Nonetheless, the only differences are the number of ports and valves to keep track of. Except for the differences in control pressure, his description and techniques apply equally well to virtually any CIS metering unit.
When you do find the best size, please post back with your findings. Note that you may have best luck finding the correct material in a selection of AC seals; modern AC systems use the same material as that piston seal, where the original seals in th erest of the metering unit were black.
I'll confess that my significant CIS experience is with four- and six-cylinder applications. No 928, no big Mercedes V-8 metering units rebuilt. I did have a Mondial metering unit in the car a couple times, but it was boxed for shipping... Nonetheless, the only differences are the number of ports and valves to keep track of. Except for the differences in control pressure, his description and techniques apply equally well to virtually any CIS metering unit.
05-17-2011 | 02:07 PM
#9
Drifting
Joined: May 2001
Posts: 2,747
Likes: 3
From: Owasso, OK
Measure the plunger with a micrometer and use that as a guide to get the correct ID. The perfect o-ring will just touch the piston enough to maintain a seal, but not so tight that it will cause much drag on the piston as it moves. Tough job! It might make sense to buy a few different o-rings with the correct ID for the piston but different sections to see which works best when clamped in the housing. Remember that the o-ring will be lubricated with fuel in service, so it's ok to add a very light oil as lubrication for your tests. Something like WD-40 in the US would be good.
When you do find the best size, please post back with your findings. Note that you may have best luck finding the correct material in a selection of AC seals; modern AC systems use the same material as that piston seal, where the original seals in th erest of the metering unit were black.
I'll confess that my significant CIS experience is with four- and six-cylinder applications. No 928, no big Mercedes V-8 metering units rebuilt. I did have a Mondial metering unit in the car a couple times, but it was boxed for shipping... Nonetheless, the only differences are the number of ports and valves to keep track of. Except for the differences in control pressure, his description and techniques apply equally well to virtually any CIS metering unit.
When you do find the best size, please post back with your findings. Note that you may have best luck finding the correct material in a selection of AC seals; modern AC systems use the same material as that piston seal, where the original seals in th erest of the metering unit were black.
I'll confess that my significant CIS experience is with four- and six-cylinder applications. No 928, no big Mercedes V-8 metering units rebuilt. I did have a Mondial metering unit in the car a couple times, but it was boxed for shipping... Nonetheless, the only differences are the number of ports and valves to keep track of. Except for the differences in control pressure, his description and techniques apply equally well to virtually any CIS metering unit.
Think you are confusing the lower O ring for the outside of the plunger cylinder with the requested O ring that goes between the base of the distributor and the lower plenum.
Dennis