Valve settings on 3406E and C-15 overhead cam engines.

Discussion in 'Trucks [ Eighteen Wheelers ]' started by PROSTREET80, Jul 20, 2012.

  1. PROSTREET80

    PROSTREET80 Light Load Member

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    Is it possible or just in my mind that setting a overhead on any overhead cam cat engine with a different valve setting helps horsepower out some.
    I have played with a .020 intake and the oem .030 exhaust setting and just opening up the intake .005 thousandths seems to help out the horse power.
    now i don't mean like 75 or 100 hp just maybe like 25 or 30hp. I have tested this for a year but without dyno help just in high gear on trucks I really know with our fleet that I work on each week doing general maintenece. I test it on a quarter mile hill from a certain sign up to another sign running 50 mph when I pass the first one and it will always run 2 to 3 mph faster to the second one with this setting. It also seems a little more responsive but I was wandering what other techs and mechanics thought about this theroy.


    I tryed to pm Mr. Hanney and ask him but is pm box is full right now so I just thought I would start a thread and get everybody involved just curious.
     
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  3. Superhauler

    Superhauler TEACHER OF MEN

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    dont really know other than it probably doesn't make much of a difference for long because after a while as the valve seats wear that .005 extra gap disapears, plus the extra shock load on the rockers could increase the chance of breaking one. it could increase cylinder pressure a slight bit and cause premature headgasket failures, broken bridges, broke valve springs, mushroomed valve stems, and so on. in my opinion not worth the chance. but i have been told i've been wrong before!
     
    shawn1972 Thanks this.
  4. PROSTREET80

    PROSTREET80 Light Load Member

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    Well im glad you replied I like the input. Your right after time the valve does seet in more and take away that gap but it also does the same set at .015 to. I have been doing this on our engines for almost a year now and just run another tonight. where I usually find the valve setting on the intake to be about .010 it was .015 this time.

    I haven't had a rocker arm failure yet and its been about 150,000 miles since the last overhead. I just thought that if the exhaust can stand it at .030 than the intake should be able to stand it at .020 The rockers, adjusters and valve height appear to be the same on the intake and exhaust but im just playing and testing around with some things but so far no problems with doing this lol. It just feels like it makes a little more power this way from driving it in the seat but somtimes thats hard to tell when your talking about 20 to 30 hp. Ive been wrong before too I just like trying new things to see if it picks up a little power and I know its not like this helps much but its fun to do.


    I have also set the injectors a little tighter on a sdp C-15 cat that last engine they pumped out with all the regin stuff. OEM setting is O lash and 180 degrees. I set one test truck at 0 lash and 225 degrees and it wasn't missing or sounding bad. Than I set another at 0 lash and 270 degrees or 3\4 turn. It still ran good but it changed the combustion sound a little bit while idling. Its still running good with no problems but i coundn't really tell if if helped the performance much. Im gonna finnally break the camels back though if one ever bottoms out on me than I will probably get the ole reaming from the boss. He s pretty cool though we play with alot of manuall settings like than around here to see what it will do.


    So what do you think on the injector setting ideal. I know it can't bottom out or it will ruin it but do you think letting the plunger compress the fuel harder like that before it mists it out is better or do you think the OEM setting is better. Now you got to rember that when I say better I mean makes the engine make alittle more power or less power.

    The other thing I thought about was when im screwing that down tighter it also looks like it will limit the amount of fuel the solonoid lets in the injector body but IDK whats your opinion and what ever it is thats cool im just getting your input back on these test things im doing I just like getting the most out of somthing I can for the ECM hp setting it is I Know Mr Hanney can make some big time power with his programs but this is just small fine tuning to me on the mechanical side lol. So far these injector settings are working already got about 30,000 miles on them with no problems but next week could be different lol.
     
  5. Kuzikan

    Kuzikan Bobtail Member

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    Jul 20, 2012
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    I am a fully certified cat tech, with my red seal in heavy equipment-I've worked for a cat dealer for 9 years now- my advice is to no screw with the injector setting (you can damage the internal poppet, and you will eventually get regen issues) as for the valve lash, cat makes a spec for a reason- personally I set my valves about .002" tight than spec (.013 on intake, .027" on exhaust, vva is a loose .020", and cat brake I set to 0.29" to get a little more stopping power) playing with valve setting will do nothing for your engine for por- it's only there for tuning and compensating for heat expansion. I do know of some ways to get more power, cheap for the hp you get (dyno tested, but it will not meet emmisins or warranty criteria)
     
  6. PROSTREET80

    PROSTREET80 Light Load Member

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    northwest AR
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    Have you ever got the chance to dyno you settings and compared them to the stock setting on the same engine just curious if there was any difference on the dyno hp. We play around with alot of stuff here this is somthing i didn't get to do when I was at the kenworth dealership everything was oem there because it was all customer trucks and you can't go wrong with stock settings to be dependable. This is a small fleet company I work for we don't really care to much about meeting emmisions up here in these hills everything is local and close to home for the truckers here.
     
  7. Kuzikan

    Kuzikan Bobtail Member

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    No hp gains with valve adjustments - you will notice mileage though. Are you after more power in general? Are your cats 475s, 550s. Curious as to why you would play around with valves for power.....
     
  8. PROSTREET80

    PROSTREET80 Light Load Member

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    They are all 475 hp sdp cats. The reason for messing with the valves is its just a setting change that don't cost anything unless of course it messes up somthing. I just like to fine tune things to try and get the max power out of the 475 setting its just things I like doing not neccesarilly to benifit the fleet but just to see if it will help on performance. All I do know is the valve settings helped it may not show up on a dyno as a hp gain but the drivers seem to think this setting does better for pulling. IDK though somtimes its easy to think it does and it really don't. I can say that I couldn't tell any difference in the drivers seat changing the injector settings. It didn't hurt the performance but it didn't help. But we are after better fuel milage too I guess all fleets are but all these cats we got are in 389 petes so that kind of a chasis is harder to get milage out of the best one gets about 6 mpg and the worst about 5 mpg and alot of that is the driver too. My settings havent really helped the fuel mileage as far as we can tell but it hadn't hurt it yet either.
     
    Last edited: Jul 20, 2012
  9. PROSTREET80

    PROSTREET80 Light Load Member

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    I know im talking about forced induction here with a turbo and diesel fuel but on a naturally aspirated gas performance engine Ive seen as much as a 20 to 30 hp gain out of valve settings only, on like a 500 cubic inch chevy engine but it may not do much for turbos and diesel power IDK.
     
  10. Superhauler

    Superhauler TEACHER OF MEN

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    man i feel for ya. sdp cats opened the hood on one of those once, just stood there and cried. what a shame to ruin a perfectly good engine by throwing a bunch of worthless junk on it. like i said before my personal preference is to set at specs. if it works for you cool! i like getting my hp the old fashion way--- throw money at it!!!!
     
  11. Mr. Haney

    Mr. Haney Road Train Member

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    To set the valves looser than spec is actually going to hurt performance. The reason for this is the valve isn't opened as wide as it would be normally. The wider the gap between the rocker arm and valve bridge, the less travel of the valve to max open position when the rocker arm follows the camshaft lobe. Setting them tighter would in theory open the valve longer and to push the valve head closer to the piston crown to allow more air flow.

    What do I set mine to.

    The specs are 0.015" Intake, 0.030" on the Exhaust + or - 0.003" this allows you to go to 0.012" Intake and 0.027" Exhaust. I go with 0.013" Intake and 0.28" Exhaust. Now keep in mind that to run the vales tighter also means you will have to run them more often to stay in the tolerance of + or - 0.003"
     
    JimmyWells and PROSTREET80 Thank this.
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