Valve adjustment Help
#21
Junior Member
APPRENTICE
Join Date: Feb 2008
Location: South Dakota
Posts: 10
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.
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.
#22
Senior Member
RACING JUNKIE
Join Date: Jul 2007
Location: Independence, Missouri
Posts: 1,181
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?
#23
Senior Member
RACING JUNKIE
Join Date: Sep 2007
Location: Montvale, VA
Posts: 1,431
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?
#26
Junior Member
SHOW GUEST
Join Date: Mar 2003
Location: Mena, AR.
Posts: 3
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
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
#28
Member
CRAFTSMAN
Join Date: Feb 2006
Location: Bastrop,TxBy way of Alabama
Posts: 64
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?
#29
Junior Member
SHOW GUEST
Join Date: Mar 2003
Location: Mena, AR.
Posts: 3
Originally Posted by john858
when you all figure it out let me know,i didn't know it was that hard sorry ops:
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.
#30
Member
JOURNEYMAN
Join Date: Jan 2008
Location: Newcomerstown, OH
Posts: 33
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.
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.