Vavle lash

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younggun2.0

younggun2.0

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I am getting ready to fire my engine for the first time. what should i set my valve lash at for the first start. the engine will be cold. here are the specs.

383 stock bottom end
comp cams 525 lift 294 duration flat tappet mech. cam
eddy heads with bowl blend and mild pocket port
comp cams magnum roller rockers
stock length cromoly push rods.

newdownload012.jpg
 
your right. i am at work and dont have the cam card in front of me but yes that is the cam i have in it. it is for certain a solid lift cam. i was thinking of the duration of the cam i took out of it. i took out the mopar 509 purple shaft in place of the new comp cams one.
 
The theory is, it depends on the engine configuration, and whether the block and heads are iron or aluminum

Even so, I like to set them "a few loose" regardless.

One set of figures I found says

With iron block, iron heads, add .002

with iron block, aluminum heads, subtract .006

with aluminum block and heads, subtract .012

I use the "EOIC" method, which means:

When the EXHAUST valve starts to OPEN set the intake for that cylinder

When the INTAKE valve opens and is nearly CLOSED set the exhaust for that cylinder

If you can mark the dampener, Mopar puts out this handy chart:

http://www.moparts.org/Tech/Archive/motor/img/egspvl.JPG
 
I always set em at .020 on the street and .026 at the track on my custom grind solid cam in my 360.
 
I have built a lot of BBM with the aluminum heads. What ever the cam card says, set them .010" tight cold for the first run. After cam break-in, reset them while hot to what the cam card says. Then let it cool down over-nite and and check them with your feeler gauge. This is your cold lash setting and will be pretty close to being spot on when warm.

The cam has to take a set, so does the liter, pushrod and rocker. All these things will increase lash, so set them .010" tight for the first run.
 
MRL Performance said:
I have built a lot of BBM with the aluminum heads. What ever the cam card says, set them .010" tight cold for the first run. After cam break-in, reset them while hot to what the cam card says. Then let it cool down over-nite and and check them with your feeler gauge. This is your cold lash setting and will be pretty close to being spot on when warm.

The cam has to take a set, so does the liter, pushrod and rocker. All these things will increase lash, so set them .010" tight for the first run.
Click to expand...

I believe that's all you have to know, i'm certainly not gonna argue with Mike:).
 
OldmanRick said:
I believe that's all you have to know, i'm certainly not gonna argue with Mike:).
Click to expand...


x2
I also recheck after about 500 miles, and I do that hot, doing one side (head) at a time and running it in between to make sure the heads stay hot.
 
I agree with MRL, that's what I do but in addition I also use the Mopar lash decal. With the balancer marked carefully and setting on the marks each time you can keep accurate records and notice any trends in wear. Either too much or too little. This can help spot valvetrain problems before they get too serious. I don't like the EOIC method as this does not allow for consistent placement of the lobe on the lifter to keep accurate records.

I've got a pretty big roller in mine at 276/284 @ .050 and .700 net lift and the Mopar decal works just fine to locate the lifter on the base circle.
 
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