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Idle speed too high.... and other questions

Discussion in 'The Garage' started by PhoenixZorn, Apr 8, 2005.

  1. PhoenixZorn

    PhoenixZorn 1/2 ton status

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    I am currently idling at about 1100rpm, and it's supposed to idle at around 800rpm. I am at Sea Level, the timing is set at 16 degrees without the vacuum connected to the carb, Holley 600, Edelbrock Performer Intake Manifold, SBC 350.

    I checked to see that my choke is all the way open on the carb and all the vacuum lines are attached in their proper locations. I called the engine shop that built the motor, and they said they test the engines at 5280 feet elevation with 12 degrees of timing and a quadrajet 750.

    They said if I can get it to 12 degrees without pinging, I should get some more power out of it.

    1. Any suggestions on getting my idle down to 800rpm where it should be?? at 1100, i can almost watch the fuel gauge move.

    2. Any comments on the timing being set 4 degrees longer at sea level than at 1 mile high?

    3. Its my understanding that my timing should be retarded when I floor it and advanced at idle to prevent detonation, but it's the opposite... at Idle, the timing is retarded, and at full throttle its advanced, but isn't detonating at all... What should i do about that?

    4. My truck looks like it's lifted, only because of the height I ride off the 31 inch tires... there is about 6-8 inches of clearance from the tires to the fender edge. Is there any way I can actually figure out how much it's lifted, or if it's lifted at all? There are no blocks, and it looks like the original spring packs. How many springs should be on the front and rear packs for a stock 1/2 ton k5? I think I have 3 springs up front and 6 or 7 in the rear. I'll take pictures of everything when I get home tonight... The truck rides level, but it's a very rough ride... like I'm going over boulders for every little crack in the road.

    5. When the truck is cold, it feels like the steering is very sloppy. While on a long turn at speeds as low as 25mph, and as fast as 65, it feels like the front end is slipping out from under me. I'll be taking the turn, and suddenly the wheels will start to turn back straight and then snap back to where they were on the turn with slight adjustment of the steering wheel. It feels like I'm driving bias ply tires, and I have all radials.

    6. The PO originally had 4 BFG Baja widetrack 31x10.5x15 tires on the truck, but curb checked one of them and ripped off the sidewall. He replaced it with a Laredo 31x10.5x15, and the tread width is only 8.25" compared to the BFG's 9". Could this potentially be causing my steering issues?

    7. I said in another post that I found the shocks... I'd like to replace them for as little money as possible, but I'd like to keep them all the same brand. They are aftermarket now, but are full tube shocks and are quite ugly. I also have an aftermarket steering stabilizer which would be replaced with the shocks. What brand would you guys suggest I get for the best possible ride after a future shackle flip and leaf spring swap.

    8. For the best possible road and offroad ride, what brand of leaf springs should I get, and what lengths front and rear if I do a shackle flip?
     
  2. wraenking

    wraenking 1/2 ton status

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    no other mods to motor? mine is set to about 14-16 with a 501 cam lift. why not try between the 10-12 range. should lower your rpms considerably.

    experts will chime on im sure, but it seems like 16 is a bit high for your application
     
  3. divorced

    divorced 3/4 ton status

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    If your front springs look like they arch up just a bit instead of arching down then they are probably stock.

    I like Rancho shocks because the price is decent and many auto parts stores sell them so I can buy them locally instead of ordering them.
     
  4. MTMike

    MTMike 1/2 ton status

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    Stock is supposed to be 8-10 of static advance at idle. I would start there and work forward, and if your idle comes down, run it and look at going into the distributor with heavier weights, lighter springs or a combo there of to acheive more mechanical advance sooner in the RPM band. 16 degrees sounds too high unless you're running a REALLY BIG cam.
     
  5. PhoenixZorn

    PhoenixZorn 1/2 ton status

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    My mech originally had it set at 12 degrees, but then another guy at the shop ran a timing light on it without the vacuum attached and got 16 degrees... they were going to change it today, but I had to get to work... I'm headed to my dad's house later tonight, so I'll have access to a timing light.

    The cam has 240 or 250 duration with .050" lift...

    The engine makes peak HP at 4500rpm, which is pissing me off considering the guy markets the engine as a truck engine and I never go above say 4000 even when I want to accellerate quickly, and makes peak torque at about 2800rpm, again much higher than it should be, but it has a smooth torque band from idle to 4000 where is stays above 350 torque all the way.
     
  6. PhoenixZorn

    PhoenixZorn 1/2 ton status

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    I was thinking about going with Rancho...

    My front springs actually look like they hang down rather than flex up... I.E. the ends are lower than the center... which is what I think you meant.
     
  7. MTMike

    MTMike 1/2 ton status

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    240-250 at .050" isn't big enough to need 16 degrees IMO... You're gonna get more power out of it if you're not pinging w/ 16, but at the price of a raised idle and higher engine temps.
     
  8. PhoenixZorn

    PhoenixZorn 1/2 ton status

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    That's what I was thinking... should I time it down to 12 degrees and see if she pings? or just idle it down on the carb?

    Also, I have awesome gearing for freeway driving, but with a 465, I have been unable to break traction in the rear end... I suppose it would have something to do with my broken tranny mount, but other than that, would my (likely) 2.73 gearing be causing me to not be able to "get up and go"?

    Well, it's not stock... but yeah, I get it. Would 12 be appropriate for the above specs?
     
  9. PhoenixZorn

    PhoenixZorn 1/2 ton status

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    Any comments on my other questions?? I can live with high idle, since it doesn't affect my driving at all, but the steering problem still has me stumped... it almost feels like the truck recenters itself over the tires if I do the Nascar style tire warmup routine... It only happens when the truck is cold, but its almost as if the tires are slipping while I'm in a turn, and then regrip the road after a split second of free travel. Problem is, I'm not going fast enough to break traction laterally, so that doesn't make sense.
     
  10. PhoenixZorn

    PhoenixZorn 1/2 ton status

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  11. MTMike

    MTMike 1/2 ton status

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    I'd say give it a shot at 12 and see where your idle is at and if your ass-meter feels any change in performance.
     

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