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Author Topic:   NEED HELP!! Valve Lash
Rookieracer76
Dirt Maniac

Total posts: 182
posted April 16, 2003 08:14 PM
I have a 350 with a hydrolic cam in it. i have been told you need to adjust the valves with the engine running and tighten the rockers till the stop "clicking" but i have read in another book to lash them like a solid cam. What is the correct way to lash them? Thanks

rfb320
Dirt Full Roller

Total posts: 43
posted April 16, 2003 08:51 PM
i always set mine on the stand and never have a problem. what i do is tighten the rocker until zero lash(the pushrod will get tight when you are spinning it with your fingers)then give the rocker nut a 1/2 to 3/4 of a turn. you can do it when the engine is running also, back the rocker nut off till it clicks then tighten till it stops and then go with the 1/2 to 3/4 turn. If you are breaking in a new cam i would set them before you start it. Yuo dont want to try that with a fresh cam. Rick

jnewman44
Dirt Full Roller

Total posts: 72
posted April 16, 2003 10:27 PM
The best is to adjust when the engine is off. The cam must be on the base circle of the lobe you are setting the lash for.

rfb320
Dirt Full Roller

Total posts: 43
posted April 16, 2003 10:31 PM
jnewman44 is right,i should have added that you should be on top dead center on the compression stroke. that will put both valves closed. rick

The Rascal
Dirt Roller

Total posts: 13
posted April 17, 2003 07:47 AM
If we're still talkin race motors it's best to do it as accurately as possible...rfb320 put it very well in spinning the pushrod 'til it gets tight then go the additional recommended turns...our stuff gets an additional 1/8th turn for .008-.010" preload...for the most accurate method of getting on the base circle we...and many others...swear by the 90 degree method:

START AT TDC:
INT EXH
#2 #8
ROTATE 90 DEGREES
#1 #4
ROTATE 90 DEGREES
#8 #3
ROTATE 90 DEGREES
#4 #6
ROTATE 90 DEGREES
#3 #5
ROTATE 90 DEGREES
#6 #7
ROTATE 90 DEGREES
#5 #2
ROTATE 90 DEGREES
#7 #1

The above applies to standard 1 8 4 3 6 5 7 2 firing orders...Rascal

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"blessed mother of acceleration don't fail us now!" Elwood Blues

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