got a buddy who has purchased a fresh motor from a very reputable racing person and the valves have not been set and does not have the cam card is there a common lash point that will/should work? small chevy roller cam

.024 hot so set them to .018

quote:

Originally posted by camaro77:
got a buddy who has purchased a fresh motor from a very reputable racing person and the valves have not been set and does not have the cam card is there a common lash point that will/should work? small chevy roller cam

That ain't good. Guessing is worse. I wouldn't run that till I looked at the cam and knew for certain what I was working with.

There's no telling what the lobe calls for without specifications.

Nothing to worry about, You can safely go .008 either side of spec with typical bracket cams. That said tell us what you know about this engine

steel bock/ steel heads
steel block/ aluminum heads
aluminum block / aluminum heads ????

It makes a difference .....

steel block alum head

Steel block/aluminum head will be about a .006 difference between hot and cold setting .018 cold and .024 hot should be plenty safe and in the ball park

Big block yeah, sbc nooo sir.

Not gonna say how much cuz I'm not gonna aid
abet the mans guess.

quote:

Originally posted by Big Steve:
Steel block/aluminum head will be about a .006 difference between hot and cold setting .018 cold and .024 hot should be plenty safe and in the ball park

As I stated.

Big Steve...KNOWS

BB chevy, steel block, alum head ^^^^^^^^ this ^^^

As technology advances, you will notice most grinders are getting away from flat tappet type of lash on roller cams…I would be a big fan of going .012 cold and it should put you at/about .018 hot. It would be better to lose a little low end than beat up valves, rockers and lifters with more than you need.

Any performance gain or loss with valve lash would be indicative of the cam choice to begin with.

If the motor is from a reputable source obtaining A Cam card and having the facts should not be an issue. Reputable shops keep records.

[QUOTE]Originally posted by Jerry Kathe:
As technology advances, you will notice most grinders are getting away from flat tappet type of lash on roller cams…I would be a big fan of going .012 cold and it should put you at/about .018 hot. It would be better to lose a little low end than beat up valves, rockers and lifters with more than you need.

Just silly. .024-.028 does not "beat up the valves" unless of course you have some junk azz valves.
I would not venture below .016 cold on an unknown cam profile. Remember, lash at the valve is attained after the rocker has multiplied the actual lash at the cam/roller.

Cams lobe profiles are designed for a specific amount of lash, and they are not all the same.

As long as you are in mid range it makes no difference other than how it runs power wise. By mi range I mean .030 would loose(way loose IMO) and under .010 would be tight,but they rarely tighten up when hot,ok probably never happens.

quote:

Originally posted by BG7X77:
If the motor is from a reputable source obtaining A Cam card and having the facts should not be an issue. Reputable shops keep records.

^^^ THIS. "A very reputable racing person" should have the cam card, or at a minimum, the cam Mfr & grind #, so that you can look it up or call and find out the recommended lash specs. Call him and ask for it.

since im making the switch this winter, how about aluminum on aluminum ? i normally set em cold and let her eat.

quote:

Originally posted by DRB Motorsports:
since im making the switch this winter, how about aluminum on aluminum ? i normally set em cold and let her eat.

Depends….for my Mopar “junk”, I’m .016 less cold than hot, but I also don’t use old school flat tappet cam lash settings, I don’t care what the grinder put on the card - lol.
I recall a time when a friend was determined to set his to the card recommendation using all aluminum, rechecked and reset when hot, then had negative lash when cold and couldn’t hardly get it started on a summer day! If you end up using one of the modern “tight lash” grinds, but be careful with that.

Always warm it up (~180º) and let it soak for several minutes before you even pop a cover off. It can be amazing how long it takes to stabilize the growth and how quickly it can cool down and start shrinking again – the reason I only set them cold once you know what that number is. I would think you will be somewhere in that .016 tighter cold than the hot target area.

FWIW - If you find power with lash variations, revisit the cam choice. Lash settings and maintenance is intended to be more of a diagnostic tool than performance tuning trick.

Just keep in mind. When using feeler gauges to set valve lash you are relying on your touch. What is just right to me may be too tight or loose to someone else. To keep setting consistent the same person should always set a he lash and use the same process every time.

quote:

Originally posted by Wooley:
Just keep in mind. When using feeler gauges to set valve lash you are relying on your touch. What is just right to me may be too tight or loose to someone else. To keep setting consistent the same person should always set a he lash and use the same process every time.

Spot on, if anyone is uncomfortable with the "feel" in the beginning, use a "GO" - "NO GO" concept until you get the feel. (one gauge .001 larger than target for "NO GO")

quote:

Originally posted by DRB Motorsports:
since im making the switch this winter, how about aluminum on aluminum ? i normally set em cold and let her eat.

I always set mine hot the first time then let it cool and measure them again. Then I set them cold after that. My Small block Aluminum heads says .026/.028 hot and it is .024/.026 cold.