Keep trashing injector o-rings?

[amarokorg]

Some of you may have seen my posts in the main forum off and on for a while trying to get my '92 Vert back on the road.

I had a bad injector (resistance not in spec), so I decided to replace all four of them with a set from DeatschWerks.

After the install, the car would barely run. Someone suggested that the lower o-rings on the injectors were missing/damaged and I was pouring gas into the cylinders. Sure enough, popped the injectors out and all four were damaged.

I got another set of o-rings from DeatschWerks and reinstalled the injectors according their recommendations - used clean motor oil as an assembly lube, seat the injector as far as I could by hand, rotate the injector several times to seat the rings, then install the cap turning each screw half a turn on each side until snug. After installing the injectors, the car started and ran great. Shut it down, left it for 3-4 hours, and when I came back, the #1 cylinder wasn't running anymore. Pulled the #1 injector, and the o-ring was in the same shape as the first set! Replaced it with one of the old o-rings from the original injectors (not damaged), and installed it. Now #3 isn't running. Same thing, damaged o-ring. Replaced IT, runs great.

Let it all sit for a few days, come back and #1 isn't running anymore. Pull the injector, same thing, trashed o-ring. Replaced it with another old one, runs fine.

What could be causing these o-rings to fail? This isn't the first time I've replaced injectors, and I'm confident I'm installing them (and the rings) properly. I'm really at a loss to why these keep failing. Other than the old injector that failed mechanically, I never had this problem on the old injectors.

Ideas?

Thanks!

- Dave

[AZhitman]

Dave - A couple thoughts...

(I feel like the student leading the master here, so please don't take offense).

Motor oil = not a good assembly lube. Use Vaseline. Seriously.

Also, when inserting the injectors, you're doing everything right, up until the time you use the screws / caps to "seat" them - not a good method.

A "better" way is to seat them w/o the caps. Find a 1/4" ratchet, preferably with a nice flat back on it. Get a socket (I think 6 or 7mm) that fits *JUST* inside the ring on the top of the injector snugly. Get the injector oriented properly, place your palm on the backside of the ratchet, and press down. The injector should *pop* into place. This way, you're pressing it straight in, as opposed to "walking" it in. The caps are not meant to maintain downward pressure on the injectors.

I have seen people use a nut-driver (screwdriver handle with a small 6-point socket), but I prefer the control and added strength you get with a ratchet. That way, you're right down on the injector, less chance of it shifting sideways.

[amarokorg]

Thanks for the suggestions. So far, the current combination of old and new o-rings is holding, but I went ahead and picked up 8 new ones today at Courtesy Nissan. If another one craps out, I'll pull them all and try your suggestion on the next install.

Of course, all of this is moot since the radiator leak I'd sort of fixed gave out again and it's just time for a new radiator. *sigh* Not sure if I should bother with a junkyard pulled unit or just get one of the aftermarket replacements. This isn't a performance build at all, so I don't need one of the upgraded units (and I don't feel like paying for it either)... so a stock replacement will do for now.

If it's not one thing, it's another... maybe I'll get to drive my 'Vert for Christmas.