tyrod

A friend of mine had a 500 Detroit that after drilling the return line restrictor out, they also "shimmed" the injectors. The truck out pulled their 600+hp Cat after the shimming. He is very competitive in nature and doesn't part with his tricks easilly. Does anyone know how to perform this procedure and how thick of a shim to use?

1-5-3-6-2-4

What you want to do is lap the aluminum block thats between the solenoid and injector body aprox .001-.003" ideally you want the truck on a dyno lightly loaded with DDDL software hooked up to match your injector response times. and change ALL your injector calibration codes to 75. 75 is the series 60 full fuel setting.

1-5-3-6-2-4

this is a DDEC III/IV engine I'm assuming though right? if you lap all the blocks down the same amount you'd be fine to make some more power and not change the idle characteristics.

but to really get the most out of that mod, you'd want to balance the injector response times like I was mentioning, to do that you would lap each block to a different thickness based on that injectors particular response time.

the thinner the spacer block the faster the response times, as measured in milliseconds by the ECM, and proportionally longer the solenoid stays open.

tyrod

Thank a bunch!!!!!! That is exactly what I was looking for!

1-5-3-6-2-4

no problem. theres a former Detroit mechanic from our shop who was the series 60 hotrod king around here. he fixed up an EGR 60 that put 800hp to the wheels on the dyno with all the ERG equipment intact and functioning.

1-5-3-6-2-4

heres a visual for you. this is a DDEC IV injector. you can see the aluminum block between the solenoid and inj body.




remove the solenoid by taking the 4 screws out from the top. lap the block. it must be lapped. no grinders or files. brakecleen the block and reinstall. you can remove the solenoid without removing the injector.




you can see a 2 digit number on top of each solenoid this is the injector calibration code. you need to change them all to 75.

tyrod

Great Info!!! Thanks for the time and effort of the pics! My friend did say he replaced the block with a shim he made out of razor blades. Thanks again!

1-5-3-6-2-4

No prob, I love this stuff

Heres a DDEC V injector. note new solenoids


Heres DD15 injector, common rail injection. no more unit injectors.

Underpsi

Wow thats pretty sweet. This same theory would work on C15 Cat injectors would it not? How do you know how big of a spacer to use? that one picture looks like the spacer is like 1/4 inch of more but then someone said that his buddy used razor blades to make spacers....

1-5-3-6-2-4

Honestly, when he mentioned a stack of razor blades I kept my mouth shut.

thats bush league. if it even actually worked.



the aluminum spacer is OEM. you lap that block down. thats why you want to have the Detroit software - DDDL hooked up to the engine. it can read the injector solenoid response times. you want to balance them at something around .8 milliseconds.

you want to find the fastest solenoid to start with. and bring the other 5 down to it. then take them all down the same amount.

this isn't exactly rocket science if you know what you're doing, but its definately not a hack and slash job either.

Gator1300

When you say "lapping" is the aluminum block lapped to a machined mating surface on the injector or are you putting a lapping compound on the aluminum block and lapping it on a harder flat surface like a steel plate. Could you explain the procedure in a little more detail.