How To Properly Tune A 12 Valve Cummins! (From The Expert Himself)

we got good old uncle wally traveling about six hours one way to turn this truck up so what we have here is a 93 d250 cummins take you on a little walk around an old single cab long bed pretty much everything is untouched in this truck a little bit of beauty mods needs a little bit of paint to it and she'll be good so he bought his truck 93 same as this one only his extended cab four-wheel drive from cummins uh from a dealership in 93. took it into the dealership had the guys look at it and turns out he wasn't pushing the horsepower he had a tech at the dealership come up to him and say hey maybe after hours i'll turn your pump up for you this wasn't even really well known in 93 this is almost a a good kept secret people didn't know about this so he's coming all the way down here tell me turn this up hopefully it rolls a little cold gets a little more horsepower all right let's do this all right so i want to show y'all what the good old exhaust looks like right now [Applause] so this guy was on this you just setting it in there and it has that tab right there that holds it on so we took that off and now there's our fuel screw right there we just got these wires out of the way this one that connects to here and here cool deal next we just have to get this screw right in here off and that's a 13 millimeter i think so okay let's do it it's just come straight out leaks down a little bit diesel you can see the crimp this was the crimp that was on there yep and that just came straight off yeah you wanted to no that's as far as you can go because the threads are beat up right now oh because of the crimp thing because it's got you so you're going to run this down finger tight and then just back it off like a quarter turn okay let's do it all right so make sure we're all the way we're all the way at the end right yeah okay so it's really hard to see back in here let's see if i can get up a little bit higher you can do me yeah there she is cool right in there cold 13 millimeter a long way going in yeah hey you got a ways to go was it a mechanic this first showed you this i can't confirm or deny anyone showed me yeah back it off half turn okay here we still have to tighten the jam nut back up let's get these loose yeah we get them out we'll just take them take them out because this thing will pop up a little bit just because there's a spring under it it's nothing huge there's your fuel pin look at that sucker okay let that spring out and just set it aside for now okay now see that clicker wheel yeah we want to take a screwdriver you want to crank that clicker wheel down why's that that that lowers your spring it takes pressure off and here's this little nylon deal i don't remember if i left mine on or took it off all right but you take it off or what i don't know all right i gotta see how we're just turning that down yep this is a threaded shaft right here yep i see that this takes pressure off it lowers the spring i got you okay which allows that fuel pin to move up and down faster requires less pressure to move it which means it dumps the fuel in quicker got it and we'll make it smoke that's that's not here that's bottomed out that's all that that will do she's bottomed out boys okay and we put the yeah back on yeah that's that's like dang near flush man yeah that's like it's just this thing's just gonna yeah all right i need to i need to just i need the light here then you get a speed see the difference in the shape yep this is kind of cut out a little bit yeah sometimes these don't get put in right and your fuel pin rides on the wrong side and so you don't get full feeling if you look see the grease mark yep see the slide stain yep that's where it was riding which is correct nice it's the deep side deep side goes in towards this way or out a deep side faces that fuel pin in the back gotcha right here pry this cap out got it because then there's a screw underneath this yeah and that will push down on that which pushes down on this and takes tension off that spring got you it's just another adjustment so this it looks like if you look at it it's an eccentric you see how it it's not straight it's not it's off-center yeah and you want to have great soft center with the top here and it actually looks like it wasn't quite in there correctly it wasn't bad i've seen more of them ride over here yeah which doesn't help you you want it on the other side yeah it was just it was off it instead of being right in the middle of that greasy stain yeah you see that yeah it needs to be just over here about 3 16ths of an inch got it see yep it's right in the center now yeah yeah we're gonna just turn that down a little bit because you can see how much that's off that is we turn that star wheel down yeah drop your spring down yeah for sure okay so i need to get back over here and see how it's looking okay um yeah so now we got to put that back on yeah yeah and then it just goes towards this way obviously because then this can ride back into it okay the screws are up top right here yeah you see there's a little less spring pressure on it when you're trying to put it back together oh yeah yeah yeah you just want to make sure that that's it it's lined up with the uh diaphragm and put together that one seals got it and just just you know get it started and do all four of them just get them all started that way they're lined up boom yeah i mean yeah they're on there pretty dang solid yeah let me just i'm gonna check them here yep yeah that's probably pretty they're all down pretty damn good pretty good yeah now we have to get a starboard drive for the [Music] yep okay so we just want to go how much wally on this one turn it down clockwise turn her down gotcha turn down for what yeah but you obviously have to have enough thread to put the nut on we'll just set the nut up in there and put the cap back on cool yeah it's all the way down yeah just crank it a little bit that's is it flush yeah that's good call that a day cool here's your nut back you had two parties and wherever your cap went up there it is nice and flush down in there set it on and call it a day and set your cat back yeah just push down with your thumb it'll probably pop in there probably and hold it in there because you might need to turn it back beautiful that's it there she is that's all that punk's gonna do you know so we're not without cracking it open and why don't you guess yeah just a little bit to get it in there definitely it definitely is it's all my feelings yeah because you know when it came out it it relaxed a little bit when it came out it's all fine field yeah it's still far in there yeah there we go yeah you're you're crooked no i'm going is it okay we're going in we're going in we're going in and then when that's said and done we'll have to pop this cap off to get to your idle you want to show them that trick yep so there's a screw right in there yep put a hammer or a screwdriver on it you whack it with a hammer and it loosens your nut so now it's loose super tight in there to get a wrench in there so it's loose you just gotta get it loose so we can turn it back right because then your idle right here goes back and hits against that screw oh yeah definitely yeah you got a good jump there yeah dude man that's just so crammed in here with that screwdriver man well and your screen driver doesn't have a very big head on it no it's freaking tiny it actually bent the head yeah there you go that's good yeah now i'll go ahead and restart it and let's uh let's see how that idle sounds there okay what are we looking for kind of a happy medium yeah a little bit faster than stock but not quite as quite as high as it was i said i like a little bit higher idle yeah we got 915. yep let's crack that open okay i like it see her smoke a little bit wally [Music] oh yeah [Music] six hours one way six and a half yeah thank you man yeah dude you're doing really good man okay you get yourself a 12-valve come down and turn it up for you very good hey easy enough to do aren't they yes sir yeah just had to have the master show me how how many of these you think you turned up huh i don't know 10 12.

Channel: KeepRTuned

Views: 37,684

Keywords: Cummins, 12valve, 1st gen cummins, Fuel screw, Diesel mods, Diesel trucks, Diesel, 1st gen, Dodge Cummins

Id: aS3LbnV44nQ

Length: 13min 1sec (781 seconds)

Published: Wed Feb 17 2021