I just picked up a set of RC 440s SL9-440. When comparing these injectors side by side with a stock 1.8 injector there is a few physical differences.

The differences are mainly at the bottom of the injector where it inserts into the head.

Here's a RC Injector


Here's a tan top Injector


My concerns are....

1. The length of the "nipple" where it inserts into the head is shorter on the RC. The difference is 0.225in. From the top of the injectors to the the stepped area where the injector would rest on the head is the same so I know they will work. The only difference is the stockers protrude 0.225in deeper into the head.

2. The RC doesn't have any kind of dust cover/vacuum seal on the bottom.

3. The nipple on the stock injectors measure 0.375in Dia, the nipple on the RCs measure 0.360in Dia.

Being that RC specs these injectors as direct replacements for the stock injectors, I don't think I have any issues. Do you see anything to be concerned about? Am I missing a "cap/seal" on the bottom of the RCs? Am I missing 0-rings at the base of the RCs?

Am I just being a geek and over analysing this?

 

think about how these go into the head when the insulator is installed:







you will most likely need an insulator at the head. unless the diameter of the injector matches the diameter of the lower insulator/grommet/gasket.

 

Abe went through this as well. He was saying the lower grommet wasn't the right size. So he made his own grommet. I don't suggest that though.
The plastic cap on the bottom is the pintle cap, RC injectors don't use them because they're a different kind of injector with a better spray pattern.
Just make sure they fit tight in the rail when installing, lube the oring good. Long as everything fit's in there tight, there is no reason to be worried about them.

 

be sure to lube the orings, I tore one of mine easily