Return to the home page...

Go Back   Moyer Marine Atomic 4 Community - Home of the Afourians > Discussion Topics > Troubleshooting

 
 
Thread Tools Display Modes
Prev Previous Post   Next Post Next
  #26   IP: 162.245.50.230
Old 01-12-2022, 09:35 AM
Dave Neptune Dave Neptune is online now
Afourian MVP, Professor Emeritus
 
Join Date: Jan 2007
Location: Grove, Oklahoma
Posts: 5,035
Thanks: 711
Thanked 1,289 Times in 839 Posts
Scratchee, you use the feeler gage just like when adjusting the valves between the tappet and the top (bottom on a flathead) of the valve stem. The clearance should be around .012 when the valve seats so using a thicker gage just give a little extra kick on the opening stroke. NOTE, the only time there is contact between the valve and tappet is when the cam is pushing it open and the valve spring is pushing it back down following the cam to the seat, once on the seat the tappet will drop another .012" giving your valve clearance. That is how a solid lifter tappet works.
There is a ramp angle ground into the cam that uses that .012" gap to "GRADUALLY" contact the tappet instead of just slamming into it. There is far more to a "simple" cam profile that most would think.

When a valve sticks it sticks while traveling back down following the cam profile just as it does on the way open, this is the "valve timing". As the cam pushes the tappet the tappet pushes the valve open against the spring pressure. Once the valve reaches fully open the "spring'' pushes the valve back to it's "seat" and holds it tight against the cam profile. So if the engine turns with stuck valves they are sticking on the top of the stroke or on the way back down. Because if they stick on the way open the engine stops turning or something breaks!!!

Adding a bit more "lift" by using a thicker gage just gives the valve a lil extra push usually breaking it free at the top. Once you have some motion of the valve the oil can get worked in and the valve should follow the tappet following the cam profile. It does not take much movement to get the motion started again and the spring will push it a closed a little more each revolution. Just don't add a bunch more spacing as you don't want to "bottom out" the spring coils.

I strongly suggest using the starter motor with the spark plugs removed and fully charged batteries. This spins the engine fast work the oil pump to keep the oil moving through the engine properly. Turning by hand will not keep the valve tappets oiled against the cam lobes.

Dave Neptune
Reply With Quote
The Following 3 Users Say Thank You to Dave Neptune For This Useful Post:
edwardc (01-13-2022), sastanley (01-12-2022), Surcouf (01-12-2022)
 

Tags
compression, other problems, rebuild, valves

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Delco distributor rebuild kit??? Surcouf Ignition System 9 05-12-2020 01:59 PM
HELP...leaking Carb. after rebuild. sproption Fuel System 13 05-13-2013 06:29 PM
To Rebuild or Not To Rebuild (That is the Question) jkenan General Interest 13 02-07-2011 03:29 PM
Proud Rebuild mike7a10 General Interest 4 04-21-2010 05:38 PM
Rebuild, Engine Rebuilder, Or PA ???? JasperWindvane Overhaul 1 01-22-2006 09:22 AM


All times are GMT -4. The time now is 11:34 AM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2024, vBulletin Solutions, Inc.


Universal® is a registered trademark of Westerbeke Corporation

Copyright © 2004-2024 Moyer Marine Inc.

All Rights Reserved