do you set valve lash when engine is hot or cold???

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do you set valve lash when engine is hot or cold???

Post  racinghabbit on June 3rd 2012, 6:12 pm

do you set valve lash when engine is hot or cold???
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Re: do you set valve lash when engine is hot or cold???

Post  richter69 on June 3rd 2012, 6:27 pm

I always set mine cold, but I know how much it will change when hot.
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Re: do you set valve lash when engine is hot or cold???

Post  racinghabbit on June 3rd 2012, 6:32 pm

do you set them to your cam specs cold?
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Re: do you set valve lash when engine is hot or cold???

Post  richter69 on June 3rd 2012, 6:36 pm

the card will tell you hot or cold, mine are speced hot, but I know when cold there is approx .004 difference.
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Re: do you set valve lash when engine is hot or cold???

Post  Lem Evans on June 3rd 2012, 6:40 pm

It does matter a lot if the heads are iron or alum. With iron heads it does not change much from cold to hot. With alum. heads I set the lash .004"-.005" tighter cold.....then recheck hot....some are still a little loose.

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Re: do you set valve lash when engine is hot or cold???

Post  racinghabbit on June 3rd 2012, 6:44 pm

i have Iron heads. if the cam card says .016
where should i set them cold?
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Re: do you set valve lash when engine is hot or cold???

Post  Lem Evans on June 3rd 2012, 6:45 pm

.015"

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Re: do you set valve lash when engine is hot or cold???

Post  samiam on June 3rd 2012, 10:27 pm

Lem Evans wrote:.015"

If the camcard recomended 20/20 hot on aluminum heads, what would you recomend for this on iron heads
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Re: do you set valve lash when engine is hot or cold???

Post  Barney on June 3rd 2012, 10:50 pm

18/18 would be where I would start.
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Re: do you set valve lash when engine is hot or cold???

Post  cool40 on June 3rd 2012, 11:14 pm

samiam wrote:
Lem Evans wrote:.015"

If the camcard recomended 20/20 hot on aluminum heads, what would you recomend for this on iron heads
the same,20/20.the cam dont know what head you run,it knows what the lash needs to be.its best to check it hot.IMO
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Re: do you set valve lash when engine is hot or cold???

Post  curleysracecars on June 4th 2012, 10:02 pm

As the motor builds heat, everything expands...aluminum parts more so than steel obviously. That obviously plays a role in what to set the rockers at if the engine is cold, versus the engine being warm. On our big inch aluminum motor we set them cold at .003 and .009...when warm, they are right around .024-.026. There is ALOT of aluminum on this motor though...so as it gets warm, the rocker arm is actually getting further away from the cam shaft, which increases the lash setting.
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Re: do you set valve lash when engine is hot or cold???

Post  racinghabbit on June 7th 2012, 12:26 pm

So if i am running all Iron heads, and stainless steer full roller rockers the best move would be to check hot.. but If i where to set the valves cold. Go .001 under.? cam card says .016 ... so set it at .015 cold
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Re: do you set valve lash when engine is hot or cold???

Post  BRONCOBILLY7.5 on June 8th 2012, 11:09 am

I run a tight lash solid flat cam in my DOVE headed 466 and set mine cold .012-.013. When hot its .015-.016.
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Re: do you set valve lash when engine is hot or cold???

Post  bbf-falcon on June 10th 2012, 5:06 am

Obviously the BEST way is to set them say .004 tight on the engine stand,then when you get EVERYTHING up to operating temp. pull the valvecovers and check the difference.That way you will always know how much to set when cold.

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