Mercruiser 420 - Valve Adjustment
#1
Thread Starter
Registered

Joined: Jul 2014
Posts: 670
Likes: 117
From: Denton, MD
Does anyone have the appropriate valve lash/adjustment for the Crane valvetrain on the 420 mercs? I am picking up my cylinder heads from the machine shop tomorrow and was hoping someone has the information handy. I am reusing the stock rockers, lifters, pushrods, etc.
#5
Thread Starter
Registered

Joined: Jul 2014
Posts: 670
Likes: 117
From: Denton, MD
Adjusting them before you install the intake manifold is easier to see/feel 0 lash. 3/4 turn is about perfect for Crane cams and will give about .040 of preload.
https://www.youtube.com/watch?v=8ROU7D-6meY
https://www.youtube.com/watch?v=8ROU7D-6meY
#7
Registered

Joined: Feb 2012
Posts: 265
Likes: 16
From: Omaha, NE
Loosen, then tighten while spinning pushrod between fingers. Stop when you feel the pushrod has begun to feel resistance as it touches lifter and turn to desired lash.
#8
Registered
Joined: Sep 2012
Posts: 523
Likes: 38
From: new baltimore mi
well,,best way run motor motors till hear rockers are loose,,,then tighten,,,but it makes a big mess running motor with out covers..,,but i stand corrected tighten till u feel drag on push rod,,then tighten..






