Fuel Injector O Rings

B

brycele

Daily Driver
I was just about ready to put the fuel rail back on my car when I noticed that all four of the o rings for the injectors seem to have vanished. Plenty of vendors sell the large and small seals as a kit but omit the o rings. The only one that does have them is Midwest http://midwest-bayless.com/Fiat-X19...-seal-kit-12x-fiat-sohc-wbosch-l-jet-new.aspx (those in the middle row) and no one appears to sell these by themselves. I'd rather not buy the whole kit and also have to wait for it to ship to me.

Does anyone know where I could score these and/or what their outer & inner diameter is? Also, my memory's a little fuzzy about where exactly they go (my manual isn't clear on that but does confirm that I should have 'em). IIRC they go around the outer edge of the hole in the runners where the injectors sit. If that's the case, then I should just be able to measure that distance and hope there is a universal o ring that's about the right size.
 
I came up with a couple of options in this thread

The Volvo PN for these was 960218 (not 947114). Edit: can't find my original notes on this, so I'm not 100% on the part number. The dimensions I wrote own will work though (either 2.00 or 2.75mm wall, 16mm ID)
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a decent hardware store might have o-rings to work, if they are Buna N (Nitrile), they should be okay for gas and heat (260), check though, hate to be wrong, a good seal is nice, this is bad; (my kid's Porsche after 0-ring fail and resultant engine fire)
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I believe it is Bosch 1280206702

Depending on the vendor it is sold in sets, as one, as 20... These are super common parts, used on about 60 different vehicle models from 1970 - 1987. Buy the Bosch part - I have to reiterate the fire hazard, 38psi blown over an exhaust manifold isn't worth a generic part.
 
bradartigue said:
I believe it is Bosch 1280206702

Depending on the vendor it is sold in sets, as one, as 20... These are super common parts, used on about 60 different vehicle models from 1970 - 1987. Buy the Bosch part - I have to reiterate the fire hazard, 38psi blown over an exhaust manifold isn't worth a generic part.
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That appears to be the square cut seal on the outside under the hold down - the phenolic spacer seal is a regular oring. The third seal on the injector that sits inside the phenolic spacer would be more likely to allow fuel to spray out - the spacer oring will mainly create a vacuum leak., since the nozzle is spraying straight through the spacer, not around it.

Still should use a correct oring, of course :)
 
You're correct, 1 280 206 703 is the "lower o ring" and 1 280 206 702 is the "body insulator." Sorry for the confusion.
 
bradartigue said:
You're correct, 1 280 206 703 is the "lower o ring" and 1 280 206 702 is the "body insulator." Sorry for the confusion.
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Those are pricey little suckers! I'm not finding any locally and online most are $10-$15 EACH - just for little bits of rubber. Rock Auto has the best deal at around $25 (including shipping) for a set of four. The set at Midwest is looking much better now and probably the direction I'll be going. I agree that I don't want to cut corners and risk a fire.

I've already lucked out a couple of times. Last spring, I ran the engine for a few minutes and turned it off only to hear a sizzling sound. Looking around I found the cause to be the small bit of rubber hose in the center of the fuel rail was badly cracked and sweating fuel onto the injector cooling duct and dripping onto the hot exhaust manifold.

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That prompted me to replace all of the other hoses regardless of how new they looked (cheap insurance). The scariest ones were those coming out of the gas tank. The clamps were in such bad shape that I didn't need to even loosen 'em - I could easily just pull the hoses off. I'm not sure how those could NOT have been leaking.
 
so these are the top and bottom numbers? nuts. I don't know then what the middle one is, I have no reference for it in any of the Bosch manuals.
 
bradartigue said:
so these are the top and bottom numbers? nuts. I don't know then what the middle one is, I have no reference for it in any of the Bosch manuals.
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MWB has them, I linked they listing above. I'm pretty sure the Volvo version is 960218, but I still can't find one of the old parts diagrams I had that shows the schematic with the three seals and the spacer / injector in place. IPD sells a complete seal kit (top, bottom & spacer oring), I think it's about the same pricing as other D-Jet (same injector setup as L-Jet) injector seal kits. Individual listings for 960218 cost the same or more than MWB lists them as, so I'd just get them from MWB if I were looking....
 
I bought o-rings from McMaster Carr. They were so cheap, I bought a few different sizes to make sure they fit.. If they're the wrong size, you can crack the injector spacer when you tighten them.

heh, now I have a few bags and can't recall which one was correct!! :(

BTW: Harbor Freight has a few nice little kits as well. (I think they have one that's Nitrile).
 
OK, just to be a little bit of a geek (but I know some of you will love it) -- I did a deep dive on what the injector insulator o-ring should be. And here is what I found (technical source was those in the aviation business, where adherence to tolerances can save a life!)

The O-Ring is a "#114 O-Ring". Its exact dimensions are 2.62mm thickness x 15.54mm ID x 20.78mm OD. The best material to use (which didn't even exist in the 70s) is Viton, which is resistant to fuel and ethanol and handles temperatures of 204°C and intermittent exposures up to 316°C.

I have a "few" extra if anyone needs 4!!!
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davejake said:
Vitol,
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Viton I think you mean? Viton ain't Viton - there are lots of grades but in all cases, LOW temperature performance is not as good as Nitrile. Viton glass transition temperature [the point at which it starts to become not a flexible seal] is typically -8 to -15 degrees C [17 to 5 F]. Nitrile is about -38 degrees C [about -36 F]. Yes, Nitrile ain't Nirile too :) Yes Viton has a higher top temperature, but we need strong low temperature performance too. Yes, Viton will handle the high end for longer [not forever]. Even in Australia, I would be twitchy about -8 as I do see that occasionally up at the farm. My personal view is that Nitrile is the correct material if you can get it.
 
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Steve Thomas said:
Viton I think you mean? Viton ain't Viton - there are lots of grades but in all cases, LOW temperature performance is not as good as Nitrile. Viton glass transition temperature [the point at which it starts to become not a flexible seal] is typically -8 to -15 degrees C [17 to 5 F]. Nitrile is about -38 degrees C [about -36 F]. Yes Viton has a higher top temperature, but we need strong low temperature performance too. Yes, Viton will handle the high end for longer [not forever]. Even in Australia, I would be twitchy about -8 as I do see that occasionally up at the farm. My personal view is that Nitrile is the correct material if you can get it.
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Ya, meant viton. I was told nitrile doesn’t like modern fuels and various additives often present. Airplanes engines won’t use nitrile.

What about silicone? Any better/worse?
 
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