assembling fuel rail - injectors very tight fit

[thechuckster]

hi folks,

Background:

have replaced the upper o-rings on the two rear injectors - one was leaking badly (and about 3 inches away from the turbo) the other looked pretty squished and not evenly round.

#3 had a tear in the o-ring (probably happened when last installed) which explained the potential engine-bay-fire.

I've re-assembled them using the o-rings from some of my spare 1G units (yes, i couldn't be arsed getting a rebuild kit and i know it's bad workshop practice).

The rail is a custom job milled (to toyota-sized holes) from a fuel rail blank i got from speed technology, the injectors are ex-4AGZE.

the problem:

unless i lubricate them with WD or similar, they're incredibly difficult to insert - instead of compressing into the slot in the injector, the o-rings catch on the edge (and in the case of #3, they tear).

my query:

is using a lubricant like WD40 OK for the o-rings? and what do other folks do when re-assembling fuel rails - particularly those with the small diameter entry holes (11mm from memory) like these injectors (5ME, 7MGTE, etc have a larger fitting like all other bosch injectors).

cheers and tia,
Charles.

[30psi 4agte]

Hmmmm
Vasalene / valvolive rubber grease would be better if they are tight.

Does the rail have a tapered injector hole (bit of a bellmouth at the start of the hole) like factory rails have? Or are they just drilled holes ??

[thechuckster]

has the taper - i gave the machine shop a genuine 4agze rail to copy (for holes& taper not spacing).

[Cuzzo]

Would it be possible to take to the rail with a fine round file?. Making sure you thoroughly clean out the shavings.

I always use engine oil when inserting the injectors into the rail.

[allencr]

Lubricate! Anything is much, much better then nothing.
I'd use spit or piss if nothing else was available!
If there is ANY doubt about how it feels when it slides together, pull it apart & look for nicks, tears and twisting of the O-ring.

[30psi 4agte]

ha ha ha lol

Yeah i usually use spit but my injectors go into the rail fairly easy.

Chuckster:One thing i thought of you may want to consider new o-rings. The reason behind this is that petrol can effect the o-ring over time causing it to expand. This will do you no favours at all when try to re-fit the injectors!

[thechuckster]

yeah - i put new o-ring/seats on these injectors when i first got the motor running, but this is about the 4th time i've removed the rail to do stuff. i'll see how this lot last for the next few weeks - if the leaks continue. i'll go new seals and also polish up the holes in the rail.

[BigWorm]

Vaseline for sure, when I first assembled my 4AGTE the fuel rail & injectors pissed out fuel, reassembly with some vaso and it was completely leak free. Make sure you grease up the o'rings before you put them on the injectors, you want the contact surface between the o'ring & injector lubed as well as between the o'ring & fuel rail. And new o'rings will save you the hassle of any potential leaks, fuel is the last thing you want leaking in your engine bay.

[oldcorollas]

new o-rings are like what? 5 or 10cents each? by a hundred pack
or, you could get non-nitrile o-rings (viton/siliconetc) and not worry abotu them hardening ever again..

are there drill marks in the holes for them to catch on? smoothing of corners is minimum.... hole should also be smooth to aid sealing..

[Ben Wilson]

I've always used a smear of vaseline on the o-rings, seems to work fine for me.

[thechuckster]

new o-rings are like what? 5 or 10cents each? by a hundred pack
or, you could get non-nitrile o-rings (viton/siliconetc) and not worry abotu them hardening ever again..

i know you're in the wrong country but any suggestions as towhere to buy bulk packs of O-rings in brisbne.

when i first assmbled the fuel rail, I ended up buying kits from repco which contained O-rings, upper and lower seats and a filter basket - not cheap from memory.

[Ben Wilson]

Try a bearing supplier.

[Matt-AE86]

It says not to use engine oil when inserting injectors into rails etc

[Cuzzo]

It says not to use engine oil when inserting injectors into rails etc

Really? Why is this? They arent leaking at the moment.

[ra65]

I got a quote just recently from repco. $30 for a single injector. I decided to reuse my existing o-rings.