Valve adjustment Help

Old 04-10-2008, 04:27 AM
  #21  
Cogburn
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Grab a cam and look at the lobes. That should tell you where you should set it. Some people like to pull each cylinder up to tdc and set valves but that will not be correct on many cams.

The EOIC (also KISS) method works because when the ex is opening the intake lifter is on the heel of the cam, and when the intake is closing the exhaust lifter is on the heel of the cam. No other method does that very well except maybe the one Crower has in the Crower book( I never really checked because the guys who race won't ever do it that way anyway).

You don't want to turn the engine over excessively because it is somewhat possible to start wiping a cam bearing from lack of lube and high spring pressure.
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Old 04-10-2008, 04:56 AM
  #22  
suicidebomb
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I'll be the first to admit I'm not very smart. So what cam, has a lifter on the opening ramp of the cam, on the compression stroke? Or what cam, does not have both valves completely closed at TDC on the compressiom stroke?
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Old 04-10-2008, 08:03 AM
  #23  
olds48
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Originally Posted by suicidebomb
I'll be the first to admit I'm not very smart. So what cam, has a lifter on the opening ramp of the cam, on the compression stroke? Or what cam, does not have both valves completely closed at TDC on the compressiom stroke?
I agree JMO
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Old 04-10-2008, 08:13 AM
  #24  
Cogburn
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There are a number of cams that will have a slightly different lash using the tdc method versus the EOIC method.
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Old 04-10-2008, 06:44 PM
  #25  
altune
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My bad,
exhaust should be almost entirely open,
intake should be almost closed.
dee de deee
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Old 06-08-2008, 07:33 AM
  #26  
rodsatheart
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Originally Posted by fishman1
Nobody has told me why it is the best way and the way i explained is the wrong way..i am getting opinions is all............i am going to the dyno on friday and i am going to try both ways to see what the diffrence is
Both methods are good, but the exhaust opening/intake closing is more accurate with large duration cams. The reason for not setting both valves at TDC is that the intake is still slightly on the closing ramp of the cam. I have seen as much as .015-.020 extra clearance on the intake with valves set this way and with Hyd. lifters will not center the plunger and not fully pump up resulting in lifter chatter.
The reason for the eo/ic method is it assures that lifter is on the true base circle of the cam and is highly recommended for large lift/duration cams. The reason is as the lift and duration increases the amount of available base circle decreases especially with flat tappet cams as the lifter requires a gentler ramp to keep the lifter off it's edges versus roller cams that don't require as much surface area and can utilize a faster more aggressive ramp and actually increase the amount of available base circle.
If you are going to use the TDC as fishman1 describes use the order for your engine as it needs to follow that particular firing order. If your curious if it is accurate for your cam go back and check with the eo/ic method and log any differences.

Here is a good article I found on this.
http://www.carcraft.com/techarticles...ash/index.html
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Old 06-08-2008, 12:39 PM
  #27  
john858
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when you all figure it out let me know,i didn't know it was that hard sorry ops:
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Old 06-08-2008, 01:56 PM
  #28  
bigs1975
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Originally Posted by suicidebomb
I'll be the first to admit I'm not very smart. So what cam, has a lifter on the opening ramp of the cam, on the compression stroke? Or what cam, does not have both valves completely closed at TDC on the compressiom stroke?
One thing not really mentioned is valve overlap.Thjats why large duratipon cams should be set EOIC.
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Old 06-08-2008, 02:29 PM
  #29  
rodsatheart
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Originally Posted by john858
when you all figure it out let me know,i didn't know it was that hard sorry ops:
Sorry. Lets simplify it some.
Small lift/duration cams like Comps 270 & 280 are good to set using oem methods.
Large cams like Comps 292 & 305 series should be set using eo/ic method due to lobe overlap.
Hope that helps some.
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Old 06-08-2008, 02:32 PM
  #30  
prostreet1972
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That CarCraft Tech article pretty much sums it up. Even talks about dyno results. I can completely understand why the other type of adjusting (no. 1 TDC and no. 6 TDC) is just a rough one of adjusting.

Another question though. I have a Lunati bracket master cam that I am about to set the lash with. Should I just go with the lash on the spec card, or would it be safe to tighten it up .005-.010? I feel that my motor would like the little bit more lift.
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