I have a 68 Ford 289, VIN code C engine. In my tune up specifications there is a footnote that states "Valve lash-Auto adjustment". What exactly does this mean and how do I properly adjust the valves? I had a set of keepers fall out about a week ago and I suspect a loose adjustment. THANKS
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Joined: 12/21/2003 From: United States Status: offline
A C code engine is going to have hydraulic lifters. Hydraulic lifters will maintain adjustment and clearance once the initial "zero lash" is set. Solid lifters are set to a specified clearance at the valve and that is the clearance you will have (hence the tapping you get with solid lifters - there is no hydrualic "cushion" to maintain the "Auto adjustment' Also part of the reason solids require frequent adjustment, to keep that adjusted critcal tolerance. BAck to the hydraulic lifters - The first thing is to get the cold "zero lash" adjustment right, then most small block Fords call for 1/2 to 3/4 turn on the rocker adjusting nut - the hydrualic lifter will do the rest. Consult any good shop manual for hydraulic lifter/rocker adjustment.
I wrote you also about the same problem with adjusting my hydraulic lifters. Send you an e-mail, including my e-mail for you to contact and e-mail me at length.
99% of stock small-block Fords have a 'torque to spec' on the rocker arms. Only adjustable rockers will have zero-lash + 'X' turns. Basically, the idea is to set the piston in the lifter up to 1/2 way through its travel with the initial adjustment.
"zero-lash" simply means there is no clearance between the rocker and valve stem.
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ORIGINAL: 65GTin GA
A C code engine is going to have hydraulic lifters. Hydraulic lifters will maintain adjustment and clearance once the initial "zero lash" is set. Solid lifters are set to a specified clearance at the valve and that is the clearance you will have (hence the tapping you get with solid lifters - there is no hydrualic "cushion" to maintain the "Auto adjustment' Also part of the reason solids require frequent adjustment, to keep that adjusted critcal tolerance. BAck to the hydraulic lifters - The first thing is to get the cold "zero lash" adjustment right, then most small block Fords call for 1/2 to 3/4 turn on the rocker adjusting nut - the hydrualic lifter will do the rest. Consult any good shop manual for hydraulic lifter/rocker adjustment.
an easier way to find zero lash is to tighten the rocker arm intil all the play is gone from the pushrod.... that is if you have adjustable rockers and if you dont you should get some anyways because they are cheap and free up "horse power"
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1968 coupe.... 3mph top speed rolling in and out of the garage
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Valve lash adjustment - 
1968 coupe.... 3mph top speed rolling in and out of the garage
