Change in valve lash and performance

Lash hot should be .020,,,,,realized it was at .025 !!
I reset everything to spec.....
Any comments on what effects on performance I might notice ??
Going to the track tomorrow.

Too many variables. Who knows it may go slower or faster but more than likely there will not be any difference.

It depends on how consistent the car is and how close the density altitude was and is now at race time

Doug I think it's gonna be at least a half second faster

Be careful it might slow down!

Thanks guys.
The correct lash was .020 and unbeknownst to be I had it set at .025. I will see what it does at the "correct" setting for now. Didn't want any uncessary wear if the lash was too loose.
Will see if it picks up or slows down. Thanks guys.

Case of beer to Prosport if it picks up a 1/2 second. Lol. Thanks Bob.

If it slows down 1/2 second Prosport has to send you a case of beer lol.

Good luck!

Car picked up all around. Was running 6.42s last week similar air. 6.39 off the trailer. 6.40 second run. 60' seems a bit better. 👍👍

Every Mopar that I have tighten the lash up on ran faster at the track Maybe you should try another .003 to .007 tighter now

I still don't understand why cam grinders specify such wide lash specs. I set mine at .012 so it's nice and quiet and it doesn't beat up the rockers and valves.
Gus

I have seen lash go away when the engine cools down and hang the valves open when too tight. Not a lot, just enough to not allow the engine to start.

Ran another 6.39 with bad 60' this time. (1.44 instead of 1.41). Was hoping for a 6.36-7 per my weather station. New best MPH @ 107.5 MPH. Not sure where that came from.

Well there you go,,, maybe I should put a little more time into my lash.

How do you guys go setting lash HOT ? Are you getting the temp right up, pulling plugs, covers, finding TDC firing and then starting the process ?
I have always followed the Mopar chart, tdc set 1in 8out rotate 90deg ect.
Buy the time you do all this it is half cold ???????

set .006 tighter when dead cold with alum heads on iron block , have checked this when hot and it seems to be right on.

Greg All,

what would you set cold at with Aluminum block and Aluminum heads with a roller cam?

Mark

Thanks Greg and old_racer .

Set it .010-.012 cold and check it hot. If it's still loose, tighten the cold lash to make up the difference.

I've set some all aluminum stuff as tight as .004 cold.

Mine is supposed to be .020 Hot,,,,,but did all my adjustments with it Cold.
I am now at .016 COLD
Sounds like I can tighten it up a bit to .014 cold according to old racer and Greg. 👍👍🍺👊🏻
Will keep you guys posted if the car picks up more.

Mine grows .017 edelbrock hemi heads and world block so if lash Is .024 I set .007...some people here set at zero lash as it will get to .017 hot...be carful as to always warm up before you rev.

In one of Crane Cams old catalog they recommend setting the lash .006 tighter with a iron block and aluminum heads and .012 tighter with aluminum block and aluminum heads.
I used those recommendation on a blown KB aluminum street Hemi block with a set of Dart water casting aluminum headson a motor I assembled and they prove to be dead on when I rechecked them hot on the dyno after running the motor long enough (20 to 30 minutes at or around 2500 RPM) to get the oil temp. up to 170F
I have seen those settings not work on a wedge motors with Eddy aluminum heads on a 400 iron block My old pump gas motor with those heads would vary right at .001 looser hot than cold(65 to 70 F shop temps. I would run the motor driving into town for 20+ minutes and the same amount of time coming back to the shop later and then check the lash hot on one side with the method of when exhaust opens, set the intake and then rotate the motor over clockwise until the intake opens all the way and starts to close a little past BTDC and then set the exhaust I would start the motor up after doing one side and let it run until I got at least 160+ F water temps agian on the temp guge and then do the other side.
In the morning with the motor cold and at or close to 60F in the shop the valves where tighter by .0005 to .0015

Cab, in a previous valve lash thread you recommended setting .002 looser when cold, with iron block and iron heads. Have you ever found that setting to be incorrect?

Looser lash is faster on everything I ever played with. I run the Valiant at .030

I has been a long time since I ran or raced a motor with iron heads, the .002 looser cold with iron heads and block is on that same chart recommending from Crane
The only time I used the stock recommended loose lash(.024 to .032) was on the old Isky and Mopar solid lifter cams and they always ran better with tighter lash, like .008 to .012 tighter hot
Try setting them at the recommended setting cold and then run it until warm(20 minutes +) and pull the easest valve cover and check two or three valves to see how they average, that way you know for sure what works on that motor for you

I set all my cast iron stuff .002 tight cold.

I have never seen valve lash close up on a warm engine, regardless of material.