Valve lash caps??

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j par

j par

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Are these common to use? I noticed the Speedmaster heads had a smaller circumference on the top of the valve then my Factory cast iron. Leaving a much smaller pad for the roller tip. I'm not sure how the geometry is going to work on all that yet. I've only opened up one engine that had them and thought them a little strange.. any experience or knowledge would be appreciated...
 
I have used them off and on the past years. Some say don't use and other say use. My experience is I have not had any issues with them.
 
I use them to keep the top of the valve stem from mushrooming. I've had a few problems with the stem gouging the bronze guide liners if I have to remove or replace a valve once in a while. But as stated above, be sure to check the geometry with the caps & rockers you are running.
 
I used them in my junior dragster motor program. With lighter weight titanium valves I needed to bring back the circumference of the valve tip to match the lifter size. Otherwise the tip would beat a hole in the center of the lifter creating all kinds of clearance issues and disassemble problems. Most generally they can be used to fix slight geometry issues, are used with smaller diameter stem titanium valves and higher rev motors. Street motors with no exotic metals. Nah, save the trouble.
 
j par said:
Are these common to use? I noticed the Speedmaster heads had a smaller circumference on the top of the valve then my Factory cast iron. Leaving a much smaller pad for the roller tip. I'm not sure how the geometry is going to work on all that yet. I've only opened up one engine that had them and thought them a little strange.. any experience or knowledge would be appreciated...
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Don’t do it. Lash caps are a pain in the arse. The ONLY time I use them is if I make my own valves and the valve doesn’t have won’t have a hardened tip.

If the swipe pattern across your valve isn’t .030-.040 (so no more than .040 wide) then you need to get a rocker geometry correction kit from Mike at B3. A lash cap won’t fix that. In fact, it will make it worse.
 
Required for a Ti valve...likely millions in use the last 30 years.
 
fishmens67 said:
and why did you think they were needed.
Please answer the question, thank you.
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First time using them was back in the late 1970’s early 1980’s. Back then to get our junk to run 10.0’s high 9’s we ran stock valves and big cams. .695 mushroom tappet and .750 lift roller cams. If you didn’t use lash caps it rolled the valve tips so bad you had to destroy the valve to get it through the valve guides. The next time I had to run them was long before geometry issues were even talked about and very early use of Edelbrock heads and Harlan Sharp rockers I was bending pushrods way more often then I should have. A well known Stock or Super stock racer told me to run lash caps. It fixed my issue enough that I never bent another pushrod. There are two more times I use them but that will stay in my vault.
 
pittsburghracer said:
First time using them was back in the late 1970’s early 1980’s. Back then to get our junk to run 10.0’s high 9’s we ran stock valves and big cams. .695 mushroom tappet and .750 lift roller cams. If you didn’t use lash caps it rolled the valve tips so bad you had to destroy the valve to get it through the valve guides. The next time I had to run them was long before geometry issues were even talked about and very early use of Edelbrock heads and Harlan Sharp rockers I was bending pushrods way more often then I should have. A well known Stock or Super stock racer told me to run lash caps. It fixed my issue enough that I never bent another pushrod. There are two more times I use them but that will stay in my vault.
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You gotta do what you gotta do, but most of that sounds like geometry issues and Harlan Sharp is at the fore of bad geometry.
 
I'm using the Hughes 1.6 to 1 roller rockers and they have pretty big rollers on them. They seem like they're going to be twice as big as the tip of the aluminum head valves... I would say that had about a .040 sweep across the dead center of my Factory 596 heads...
 
I'm hoping tomorrow after work I'll have some time to take a look and put some rockers on..
 
j par said:
I'm hoping tomorrow after work I'll have some time to take a look and put some rockers on..
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We ran them on the hemi , back in the day , w/ dick landy corrected rocker arms, they worked great , AND WERE ADVISED BY CHRYSLER/TOM HOOVER, FOR BIG CAMS/785 lift cam dynamics'' IN THE HEMI AT THAT TIME .
I TRIED THEM ON MY CURRANT 440/505 , AND IT THREW THE GEOMITRY OFF WAY BAD . Excuse the caps--------------
 
I have run them on all race solid rollercam motors, dating back to 84. All those setups were .750 lift or more although the need for lash caps would be there for any aggressive solid cam profile or Ti valves/small stems. I always assumed their function was strictly to protect the valve tips, providing a bigger contact area as well. I have never had one come off, despite some serious rocker and pushrod failures.
 
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gregsdart said:
I have run them on all race solid rollercam motors, dating back to 84. All those setups were .750 lift or more although the need for lash caps would be there for any aggressive solid cam profile or Ti valves/small stems. I always assumed their function was strictly to protect the valve tips, providing a bigger contact area as well. I have never had one come off, despite some serious rocker and pushrod failures.
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Yeah , seems like they form a slight vacuum or something, sosme times dam hard to get off.
 
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Did someone say that are for solid cams only? Hydro lifter preload is not enough to keep 'em in place if a lifter fails.
 
famous bob said:
We ran them on the hemi , back in the day , w/ dick landy corrected rocker arms, they worked great , AND WERE ADVISED BY CHRYSLER/TOM HOOVER, FOR BIG CAMS/785 lift cam dynamics'' IN THE HEMI AT THAT TIME .
I TRIED THEM ON MY CURRANT 440/505 , AND IT THREW THE GEOMITRY OFF WAY BAD . Excuse the caps--------------
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I enjoying reading your post Bob ! You always have actual info from a lot of the great Mopar racing people !! Thank you for that ! I grew up with my dad being friends with David Reher , the late Buddy Morrison, and the late Lee Shepard. Just being around those guys although not Mopar guys but professional racing people my dad picked up a lot and I did also ! Thank you for sharing with us !
 
Rmoore said:
I enjoying reading your post Bob ! You always have actual info from a lot of the great Mopar racing people !! Thank you for that ! I grew up with my dad being friends with David Reher , the late Buddy Morrison, and the late Lee Shepard. Just being around those guys although not Mopar guys but professional racing people my dad picked up a lot and I did also ! Thank you for sharing with us !
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Those were some of the sharpest guys ever too !----even if they were chevy guys !-----LOL
 
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