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Thread: New 408.......no bottom end

  1. #1

    Default New 408.......no bottom end

    Okay guys here goes......

    Just finished putting together what I hoped was going to be a torque monster, between speaking to Hughes, Comp, and a few engine builders this should have been making power off idle.

    What I am finding out is I have a truck that seems gutless until about 3000 rpm then it becomes a screamer for sure.

    Definitely not what I had intended for my full size Ram.

    I got my combination off somehow, probably too many chefs in the kitchen during my build:

    53x55 FB Throttle Body
    Hughes Airgap minor casting cleanup port job
    2.02 RT Heads, ported with Hughes 1110 Valve Springs
    KB 356 pistons 9.3:1 compression
    Eagle I Beam forged rods
    Eagle 4" crank forged
    Edelbrock headers
    Comp Cam 224/230 .536/.544 camshaft 114 LSA installed on a 112 centerline
    Factory Stamped Rockers

    At this point, what options do I have? Higher Stall, Boost, Cam and Intake Swap?

    Admittedly I have yet to get it tuned but the truck runs and idles great aside from the off the line lackluster performance.

    I plan to get the exhaust done and a Wideband put in within the next two weeks and then schedule a dyno tune to see what's going on.

    Thanks!

    Thomas

  2. #2
    niebs's Avatar
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    Youre on stock 360 tune? Get a tune then worry if its still gutless.
    Why such low compression? especially with that cam.

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    I know the Rams are pretty heavy, what gears are in it? Thats not a big cam for a 408, although 114 LSA does tend to more the rpm band up some. Not sure if it's the tune, the timing or the fuel sync. I would get it tuned before you change anything. I'm sure more people will chime in with ideas.

  4. #4

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    Could be the timing is retarded.
    Another possibility was how the cam was ground.
    If it were 4 degrees advanced, cl could have been 110.
    Wouldn't go to higher stall.
    Could be your cam is wrong for the rear gear set.
    Most torque would have occurred with a tighter lsa.

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    Quote Originally Posted by arro222 View Post
    Could be the timing is retarded.
    Another possibility was how the cam was ground.
    If it were 4 degrees advanced, cl could have been 110.
    Wouldn't go to higher stall.
    Could be your cam is wrong for the rear gear set.
    Most torque would have occurred with a tighter lsa.
    If you have the cam card, it would be helpful to post it.

  6. #6

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    image.jpg

    Hopefully the picture attached. Not that good with the phone.

    Degreed the cam in with a nice big degree wheel. It wasn’t ground with advanced but I did set the timing gears at 3 degrees advanced, it ended up being about 2.5 advanced.

    Compression was because of iron heads, not wanting to detonate on pump gas and had plans to boost. Still figured it would be better than it is though considering it’s still higher than factory compression.

    Fuel sync on the Snap on Mt2500 was +5-6.

    Gears are 3.92

    Will get a tune and see where I am at before I start changing components.

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    Quote Originally Posted by thomasfouraker View Post
    image.jpg

    Hopefully the picture attached. Not that good with the phone.

    Degreed the cam in with a nice big degree wheel. It wasn’t ground with advanced but I did set the timing gears at 3 degrees advanced, it ended up being about 2.5 advanced.

    Compression was because of iron heads, not wanting to detonate on pump gas and had plans to boost. Still figured it would be better than it is though considering it’s still higher than factory compression.

    Fuel sync on the Snap on Mt2500 was +5-6.

    Gears are 3.92

    Will get a tune and see where I am at before I start changing components.
    114 will more power up some, but will be good if you boost. Thinking the tune is holding it back.

  8. #8
    BIGROB's Avatar
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    Don't over think things before you get it tuned. You'll just pull your hair out. You dont have any tune right now, still factory?

    Project Maverick. I feel the need, the need for speed

  9. #9

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    No tune to speak of. I ran it up and down the road a bit on the factory tune, then I came back and uploaded the 91 octane flashpaq tune from my old Superchips tuner I used for my tire size.

    Didn't feel any discernible difference between the two.

  10. #10

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    You're not getting proper torque at lower rpms. Just increasing your cu ins should have supplied more torque even you kept eveything the same.
    You moved the torque band up with your 114 lsa and your bottom end is suffering.

    The 114 lsa cam you chose necessitates an increase in air flow to achieve bottom end torque. You say you have port work on the heads. That should have helped.
    Look at what GM does with their LS engines. Lsa's at 116 and above and yet they have all the power in the world. Why? Because their heads and intake flow like gang busters.

    Now barring something not right such as a dirty air filter, other considerations are:
    What is your lash set at?
    You chk compression at all cylinders? leak down test?
    No vacuum leak at tb base?
    Single exhaust could be restricting the truck as well. If you re-used the y-pipe and muffler set up, you could be losing a ton of torque.
    Change out your rear muffler to a 3" straight thru (not a baffle type) if you've done nothing for exhaust as yet.

    I don't think your timing is that far off. It is my belief you simply don't have enough air velocity at lower rpms for that cam.
    Once you get the timing advanced and make sure that is not the culprit, then you can experiment with other things.
    Last edited by arro222; 05-25-2021 at 03:34 PM.

  11. #11

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    Quote Originally Posted by arro222 View Post
    You're not getting proper torque at lower rpms. Just increasing your cu ins should have supplied more torque even you kept eveything the same.
    You moved the torque band up with your 114 lsa and your bottom end is suffering.

    The 114 lsa cam you chose necessitates an increase in air flow to achieve bottom end torque. You say you have port work on the heads. That should have helped.
    Look at what GM does with their LS engines. Lsa's at 116 and above and yet they have all the power in the world. Why? Because their heads and intake flow like gang busters.

    Now barring something not right such as a dirty air filter, other considerations are:
    What is your lash set at?
    You chk compression at all cylinders? leak down test?
    No vacuum leak at tb base?
    Single exhaust could be restricting the truck as well. If you re-used the y-pipe and muffler set up, you could be losing a ton of torque.
    Change out your rear muffler to a 3" straight thru (not a baffle type) if you've done nothing for exhaust as yet.

    I don't think your timing is that far off. It is my belief you simply don't have enough air velocity at lower rpms for that cam.
    Once you get the timing advanced and make sure that is not the culprit, then you can experiment with other things.
    Valve train is the factory stamped 1.6 rockers with preload to 21ft/lbs. per factory spec.
    I checked compression 175-185 on all 8. I think my gauge also reads about 15lbs low when I tested it with another known accurate gauge. I suspect those numbers should improve as well as the rings wear in. Vacuum seems great, but will check with a gauge today. Exhaust could be an issue, still have the factory exhaust system but also have a heck of a header collector leak since my y pipe is "rigged" up right now. Haven't leak down tested but can do so if it don't improve. I have a leak down tester I have used on outboards before.

  12. #12

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    The cam grind determines the behavior of the engine, as long as it is properly set up, with complementary components. A proper tune helps make the most of it.

    That cam is too big for your compression, and as a result, your dynamic compression is too low, since the intake valve has a later closing point, thereby further bleeding down your compression. You need a smaller cam, with an earlier intake closing point. That cam also puts you into mid-range, with less low-end torque.

    Comp usually grinds the cam with +4 degrees advance, which helps bring the torque on sooner. And, a tighter LSA, will help concentrate the torque at a lower rpm. But again, that grind is too big for the amount of compression you have, as well as where you want your torque.

    And a tune will make a world of difference.
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  13. #13

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    Quote Originally Posted by 98Dak408 View Post
    The cam grind determines the behavior of the engine, as long as it is properly set up, with complementary components. A proper tune helps make the most of it.

    That cam is too big for your compression, and as a result, your dynamic compression is too low, since the intake valve has a later closing point, thereby further bleeding down your compression. You need a smaller cam, with an earlier intake closing point. That cam also puts you into mid-range, with less low-end torque.

    Comp usually grinds the cam with +4 degrees advance, which helps bring the torque on sooner. And, a tighter LSA, will help concentrate the torque at a lower rpm. But again, that grind is too big for the amount of compression you have, as well as where you want your torque.

    And a tune will make a world of difference.
    Thanks Richard,

    Kinda aggravating because I called Comp and gave them all the information and this is what they specd. I even called them back and told them I wanted to go a bit smaller but was ensured that they nailed the cam for what I had intended the usage for. When I called back a third time to tell them I wanted it smaller regardless, they told me it was already in production. Lessons learned!

  14. #14

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    On hand I have two camshafts that I could potentially swap out and run. I will track down the cam cards and post them up to see if either would be more favorable.

  15. #15

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    Quote Originally Posted by thomasfouraker View Post
    Thanks Richard,

    Kinda aggravating because I called Comp and gave them all the information and this is what they specd. I even called them back and told them I wanted to go a bit smaller but was ensured that they nailed the cam for what I had intended the usage for. When I called back a third time to tell them I wanted it smaller regardless, they told me it was already in production. Lessons learned!
    This is disheartening.
    They once screwed up one of my cams like 8 yrs ago.
    Your cam was the right cam for your engine if you were going to race it and had a 3000 spd stall or you had a turbo or s/c ready to plop on.

    Sometimes it's better to keep your cards close to your chest. If you said you were going to "boost" this truck, then they look at that primarily and would rely on the extra airflow or oxygenation to match a cam with.
    It then becomes like having an HD t.v. with no HD programming if you're just trying to run the truck regularly w/o boost.
    You have a heavy truck. You needed low end torque.

  16. #16

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    94574341-B493-4475-868E-FFFEDD9E1026.jpg30D8F0F8-70FA-40F7-8525-CFABF63BE148.jpg

    I am not a cam wizard (obviously) but would either of these be worth swapping into the motor prior to getting the tune?

  17. #17

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    Cam Card.JPG

    Maybe this will be a better picture

  18. #18
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    Think it would be better to get the exhaust fixed and a good tune before you start throwing parts at it.

  19. #19

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    I am not a cam wizard (obviously) but would either of these be worth swapping into the motor prior to getting the tune?
    The 216/224 will bring the torque down to a lower rpm, and work better with your compression. The lower overlap will also make the tune happier. The .506 lift will work better with the OEM rockers, which are basically good for a .520-.525 lift, without notching the rocker slots for more travel. A proper tune will still make a difference.

    I ran a 220/230 .512/.512 108 lsa in my 408, with about 10.3:1 compression. It would not run properly without a tune. With a 4.56 gear, and a 2800 stall, major torque out of the hole.

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  20. #20
    niebs's Avatar
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    Quote Originally Posted by 98Dak408 View Post
    The cam grind determines the behavior of the engine, as long as it is properly set up, with complementary components. A proper tune helps make the most of it.

    That cam is too big for your compression, and as a result, your dynamic compression is too low, since the intake valve has a later closing point, thereby further bleeding down your compression. You need a smaller cam, with an earlier intake closing point. That cam also puts you into mid-range, with less low-end torque.

    Comp usually grinds the cam with +4 degrees advance, which helps bring the torque on sooner. And, a tighter LSA, will help concentrate the torque at a lower rpm. But again, that grind is too big for the amount of compression you have, as well as where you want your torque.

    And a tune will make a world of difference.
    ^^^X2. This is what I was getting at with your low static compression.

  21. #21

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    Quote Originally Posted by musky mike View Post
    Think it would be better to get the exhaust fixed and a good tune before you start throwing parts at it.
    I agree with this post. Until the exhaust leak is fixed and the tune is corrected you cannot make any judgement on how much power it is making or will make. Fix the known problems and then see where you are at.
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  22. #22

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    I think you need to get away from the 114 lsa if you're not gonna boost the truck right off and you don't plan on a piston swap to increase cylinder pressures and thus air flow substantially.
    You can cut the heads more to obtain a 58cc chamber and be fine with a 112 lsa. I'm at 9.5 with a head cut and thinner head gaskets and my 112+4 cam with cl'd at 108 .218-.226 runs fine.
    You can boost off a cam like that no problem.

    But as I first said, make sure your exhaust is not clogging up the whole works and you are not retarded timing wise. You can also degree in more advanced timing on your present cam.That'll be a lot cheaper and may be enuf for you.

  23. #23

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    Quote Originally Posted by arro222 View Post
    I think you need to get away from the 114 lsa if you're not gonna boost the truck right off and you don't plan on a piston swap to increase cylinder pressures and thus air flow substantially.
    You can cut the heads more to obtain a 58cc chamber and be fine with a 112 lsa. I'm at 9.5 with a head cut and thinner head gaskets and my 112+4 cam with cl'd at 108 .218-.226 runs fine.
    You can boost off a cam like that no problem.

    But as I first said, make sure your exhaust is not clogging up the whole works and you are not retarded timing wise. You can also degree in more advanced timing on your present cam.That'll be a lot cheaper and may be enuf for you.
    What piston dish do you have and what is your deck to piston clearance?

    Heads are already 58.5-59cc. I cc’d them before ordering head gaskets.

    Would have to get a different timing set, my pro gear only offers + or - 3*

    Don’t really wanna get into the rotating assembly, just want to make the most of what I have.

    I read a lot about keeping dynamic compression around 8:1 to make it pump gas friendly. It sure how I would stay below that while raising my static compression much higher.

    Gonna address the exhaust, tune and adjust accordingly. I will see how much timing they can tune into it and see how close I am to detonating before I decide if boost is worth it. Further research indicates I could probably downsize the cam a bit, and go with a 2300 stall and have a stump puller like I wanted

  24. #24

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    Quote Originally Posted by thomasfouraker View Post
    What piston dish do you have and what is your deck to piston clearance?

    Heads are already 58.5-59cc. I cc’d them before ordering head gaskets.

    Would have to get a different timing set, my pro gear only offers + or - 3*



    Don’t really wanna get into the rotating assembly, just want to make the most of what I have.

    I read a lot about keeping dynamic compression around 8:1 to make it pump gas friendly. It sure how I would stay below that while raising my static compression much higher.

    Gonna address the exhaust, tune and adjust accordingly. I will see how much timing they can tune into it and see how close I am to detonating before I decide if boost is worth it. Further research indicates I could probably downsize the cam a bit, and go with a 2300 stall and have a stump puller like I wanted
    Stock bottom end w Fel-Pro 1008 gaskets.
    Lucked out as my pistons weren't that deep in the hole for some reason. Some are as deep as.50.
    Be cheaper to get the 9 key-way gear set.
    There's more to static/dynamic than cr. A higher overlap cam bleeds out enough to diminish dynamic cr. That's what makes the stupid "lumpity-lump" sound people seem to be enamored with. You can run higher cr than you state and still be detonation free as a result. Throw away just about everything that articles seem to state. There are guys here running over 10 cr and adding boost later.
    It's all in the tune. Your cam spec isn't that big for a 408. It's the lsa on that cam that's holding you back. It's currently too wide for the air flow you currently achieve. It's made for your cylinders to fill up with the additional pressures boost provides. Your cam was cut for 1.6 ratio rockers correct? You can shrink it up some with 1.5 rockers but be aware, if you are using the stock stamped rockers, these have been notoriously out of whack being more like 1.45 ratio at best. Going to a proven ratio rocker with roller tip could improve your situation but not if your ratio is already at or below that.
    For now, leave everything as is until exhaust and any non conducive ignition timing is rectified.
    Last edited by arro222; 05-26-2021 at 04:26 PM.

  25. #25

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    Appreciate all the feedback. Going to get the exhaust straightened out and hope to order an HPtuners this following week. I have a friend that tunes his twin turbo LS no prep car and he told me I would be much happier with tuning it myself and learning than relying and paying someone each time I want to tinker with it.

    He convinced me that it would be a wise investment if I planned any changes (components, boost, gears, stall etc.) or was going to be doing tuning on any other motor.

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