TEARDOWN

Prior to teardown, I cleaned the outside of the injector and used a permanent marker and made a line down the side to help put things back together properly. Having a second injector to double check against doesn't hurt. Digital pictures are helpful too.

First I removed the solenoid from the top of the injector. These are actually linehead screws but a T15 Torx bit works well too.





Below the solenoid is a spacer which can be removed along with the solenoid.

The Armature AKA Poppet Plate is held on with another linehead screw. This one is sometimes removed with a 4mm hex bit, edges ground down. A better fit is a 4.5mm linehead bit, commonly available on Ebay as a 4.5mm or large "Nintendo Tool"



Hold the Armature plate to keep it from turning while loosening the screw.. The Nintendo tool is not a very clean fit, so make sure it's on securely to avoid stripping the head. If it seems really tight, it may have had loktite used on it previously. Try heating the area to around 200 degrees F and see if that loosens it up. You may have to drill it out if all else fails...

Replacement screws are available with a more standard head

A Torx T20 bit fits the Linehead screws on the Oil Relief Plate.

Under the Oil Relief Plate:
-Oil Relief Spacer and Shim
-Sleeve
-Poppet Spring
-Poppet Valve

The Clamp, which fits around the body, can now be removed too

Next the Cap needs to be unscrewed from the body of the injector to access the internal components. The body has flat spots making it easy to hold, but the cap is round. Apparent on opposite sides of some of my injectors are faint marks which seem to have been left by a pipe wrench. Not the ideal tool in my opinion, so I decided to fabricate a tool to hold the Cap at the holes in the side.

I was originally going to use a block of aluminum, drill it for the injector, then drill holes from the sides for insertion of pins to hold the Cap. Then I happened on an easier and cheaper way.

Kragen (AKA Shucks, Checkers, Parts America) has the nut splitter shown at left for $11. The center hole happens to be just a bit bigger than the injector where the 4 holes are.

I removed the chisel portion, then ground it down to 1/4". Putting it in a drill and spinning it against a running bench grinder sped this up considerably. Shown is the finished tool. When mounted on the injector a few strips cut from an aluminum can fills the clearance and protects the injector Cap from damage.

With tool mounted, you can clamp the tool in a vise and break the body loose, or you could clamp the body gently and use a pipe on the tool to break it loose.

Once loose, remove the tool and finish disassembly by hand.

Below are all the parts under the cap in order. Split Shot and Single Shot parts are shown for comparison. (Sorry about the bad writing)












Below are all the parts in the upper part of the body. Pay close attention to positioning of the parts during disassembly. The spacer in the picture, should actually have the rounded portion up towards the connector on the solenoid. The side with the oil relief notches goes against the injector body.

ASSEMBLY


Extreme care should be taken to keep parts clean during assembly. Small tollerences and dirt do not mix well. Also I would assume oil should be used on the parts as they are assembled to protect them from wear during initial startup.
There is an O Ring inside the body where the Amplifier is. This makes the Amplifier Piston a bit difficult to remove.

There is another O Ring (not shown) inside of the Oil Relief Plate.

Assembly of the under cup parts is pretty much stacking the parts on them in order on the body. The Amplifier must be carefully inserted past the O Ring first.

With the components stacked in place, we find 2 areas where the springs hold the parts too far apart for them to stay in alignment as the cap is screwed on. (arrows)

Upper arrow:
The upper area dowels and lift spacer can be lined up as you lift the spacer sleeve (below the arrow) and stays lined up as you compress the nozzle spring.

Lower arrow:
The lower area requires that you line up the dowels while compressing the Amplifier spring.

Above Left: lifting the spacer sleeve to align the parts for assembly

Above Right: pressing the barrel down to align with the dowels

With pressure compressing the springs, everything stays lined up. The trick is keeping the springs compressed while screwing the cap on. Since the cap won't fit over my hand, a fixture must be used to compress everything while the cap is installed.

Prior to constructing a fixture, I made this mock up of the basics for reassembly.

-A rod with a padded tip is inserted thru the Cap.
-A clamp or clothespin (not shown) holds the cap out of the way.
-An arbor, Drill Press, Pipe Clamp, or similar holds the rod and is used to crate pressure on the springs while you align the parts.
-Once the parts are aligned and springs compressed, either lock the fixture in place or have your lovely assistant hold it tight.
-Remove the clamp holding the Cap and tighten it down by hand. Then remove the injector from the fixture and tighten it fully.


Above is my #3 Injector being re-assembled using a drill press. For the pilot that is clamped in the press and pushes against the injectors tip, I used an xacto knife handle with the head removed. It is hollow inside, so presses down against the outer part of the nozzle. Something longer would be better tho. The manila folder around the press was used to help keep contaminants from the press out of the injector.

Steps for final assembly::
-Set the injector with all components directly under the pilot (xacto handle). It helps to mark the location on the press before disassembly, as it must be centered to push straight down.
-Slide the cap up over the pilot out of the way.
-Easiest with assistance, start compressing the injector while holding the spacer sleeve up, and pushing the barrel down
-Once the injector is fully compressed, slide the cap down and screw it down snug.
-Remove the injector and fully tighten the cap using the same tool used for disassembly


Final note: The above injector was returned to operation in my truck and is working fine. While injector teardown may not be for everyone, based on my experience I would say it is about the same level of difficulty as an automatic transmission shift kit install, but quicker. If attention is paid to cleanliness, and proper assembly, there is no reason an injector in good shape would not function fine after teardown and reassembly.


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