injector O-ring size difference???
Thread Starter
Burning Brakes
Joined: Mar 2005
Posts: 1,139
Likes: 0
From: Salina Kansas
injector O-ring size difference???
Is there a difference in size for O-rings between high impedance and low impedance injecors?
I got an aftermarket intake this week and the top O-rings on the injectors are almost all leaking. They didn't seem to be as hard to press in as the old setup either. I'm going to try the old injectors tomorrow (high impedance, Venom) and maybe even take those O-rings and put them on the Delphi low-impedance, 55 -lb injectors (new ones).
I talked to Dr. J's (company that did the intake) today and he thought I needed bigger O-rings.
Any ideas??
I got an aftermarket intake this week and the top O-rings on the injectors are almost all leaking. They didn't seem to be as hard to press in as the old setup either. I'm going to try the old injectors tomorrow (high impedance, Venom) and maybe even take those O-rings and put them on the Delphi low-impedance, 55 -lb injectors (new ones).
I talked to Dr. J's (company that did the intake) today and he thought I needed bigger O-rings.
Any ideas??
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
NAPA keeps o-rings behind the counter. Be sure to get Viton not Nitrile (Buna-N).
I ordered a 500 count set a few years ago and went through the ones that fit the fuel injectors already but found a score of uses for the other sizes.
FWIW: I use either canola or olive oil to lube them because of the high smoke point for those oils. I didn't use engine oil on them not because I thought the oil would hurt them but I have no idea what is in the additve pack of engine oil and didn't want to put anything on them that could disolve them.
I ordered a 500 count set a few years ago and went through the ones that fit the fuel injectors already but found a score of uses for the other sizes.
FWIW: I use either canola or olive oil to lube them because of the high smoke point for those oils. I didn't use engine oil on them not because I thought the oil would hurt them but I have no idea what is in the additve pack of engine oil and didn't want to put anything on them that could disolve them.
Last edited by 94z07fx3; Jul 5, 2008 at 10:09 AM.
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
dave there are two different o rings used in the aftermarket.. some new injectors come with a 14.5mm od with a .298id and a 15mm od and a .304 id.. they are both interchangable on the injector. Its the fuel rail that is machined to size.. There is no standard. Companies like Delphi use Both sizes as does Standard, Bosch and Seimens.. The Venoms probably had the larger GM oring as you ordered them for a certain application (gm not ford or chry) our rebuilts have the o ring for the specific app. but, sometimes we miss as guys have different rails such as TPIS etc. I would just swap the top injector o ring with the venoms if they are still good. They should be Viton. If not, I will send you a set of the Bigger rings. By the way nice intake.. Good luck!
Jon Sr.
Jon Sr.
Safety Car
Joined: Oct 2007
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From: :45 minutes from everywhere / E-I-E-I-O
Yikes! Upper injectors leaking?
You musta' had gas all over the place.
BTW, I used to live on Hartford Ct next to Schilling Elementary School. You been there all your life?
You musta' had gas all over the place.
BTW, I used to live on Hartford Ct next to Schilling Elementary School. You been there all your life?
Thread Starter
Burning Brakes
Joined: Mar 2005
Posts: 1,139
Likes: 0
From: Salina Kansas
That worked! No more leaks and I got it running. Any tips on general tuning things I can do in respect to the below changes.
Had 48 lb high imped injectors running at 50 psi before
I now have 55 lb low imped injectors ___??? psi pressure? I was thinking about turning the fp down a bit, maybe 45 psi?
Everything else on the motor is the same except for the ported intake and bigger Throttle body.
Had 48 lb high imped injectors running at 50 psi before
I now have 55 lb low imped injectors ___??? psi pressure? I was thinking about turning the fp down a bit, maybe 45 psi?
Everything else on the motor is the same except for the ported intake and bigger Throttle body.
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Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
That worked! No more leaks and I got it running. Any tips on general tuning things I can do in respect to the below changes.
Had 48 lb high imped injectors running at 50 psi before
I now have 55 lb low imped injectors ___??? psi pressure? I was thinking about turning the fp down a bit, maybe 45 psi?
Everything else on the motor is the same except for the ported intake and bigger Throttle body.
Had 48 lb high imped injectors running at 50 psi before
I now have 55 lb low imped injectors ___??? psi pressure? I was thinking about turning the fp down a bit, maybe 45 psi?
Everything else on the motor is the same except for the ported intake and bigger Throttle body.
what computer are you using,
