HOME FORUM RULES CONTACT
     
   
   

Go Back   CLASS RACER FORUM > Class Racer Forums > Stock and Super Stock Tech
Register Photo Gallery FAQ Community Calendar

Reply
 
Thread Tools Display Modes
Old 03-19-2014, 11:04 AM   #1
richie 2
Senior Member
 
Join Date: Feb 2009
Posts: 971
Likes: 425
Liked 205 Times in 93 Posts
Default piston to valve cl. check

any difference in measurement between using a checking sping and using a race spring? stocker bbc engine.
richie 2 is offline   Reply With Quote
Old 03-19-2014, 11:20 AM   #2
Alan Roehrich
Veteran Member
 
Alan Roehrich's Avatar
 
Join Date: May 2006
Location: Murfreesboro TN
Posts: 5,107
Likes: 1,564
Liked 1,796 Times in 409 Posts
Default Re: piston to valve cl. check

There sure is. I check mine with a race spring and a fixture that uses the rocker arm to open the valve with a 1/2" drive pull handle, using a dial indicator on the valve spring retainer. I check every 5 degrees of crankshaft rotation from
25 degrees BTDC to 25 degrees ABDC for intake opening and exhaust closing. You will find valve train deflection in a big block Chevy Stock Eliminator engine to be impressive, to say the least.
__________________
Alan Roehrich
212A G/S
Alan Roehrich is offline   Reply With Quote
Old 03-19-2014, 11:49 AM   #3
randy wilson
Senior Member
 
Join Date: Jan 2007
Location: N/A
Posts: 882
Likes: 0
Liked 22 Times in 22 Posts
Default Re: piston to valve cl. check

Alan is right. There is a huge difference between actual spring pressure, and using checking springs. We've seen as much as .050. But that being said, if you get a min. one way, don't assume that min. applies when using actual spring pressure. In other words my min. is .035 intake, .080 exhaust with checker springs. I wouldn't use those numbers on actual spring pressure. At those settings I have seen the shadow of the exhaust valve in the piston. Other guys may have a very different take on this.
__________________
don,t have one

Last edited by randy wilson; 03-19-2014 at 11:51 AM.
randy wilson is offline   Reply With Quote
Old 03-19-2014, 01:52 PM   #4
Alan Roehrich
Veteran Member
 
Alan Roehrich's Avatar
 
Join Date: May 2006
Location: Murfreesboro TN
Posts: 5,107
Likes: 1,564
Liked 1,796 Times in 409 Posts
Default Re: piston to valve cl. check

If it is a rectangle port big block Chevy Stock Eliminator engine that makes enough power to be competitive, I'd be real surprised if you could not see the "shadow" of the valves on the piston.
__________________
Alan Roehrich
212A G/S
Alan Roehrich is offline   Reply With Quote
Old 03-19-2014, 02:14 PM   #5
DIV3CR
Junior Member
 
Join Date: Oct 2011
Location: WISCONSIN
Posts: 50
Likes: 0
Liked 3 Times in 1 Post
Default Re: piston to valve cl. check

Check the valve lift at retainer with both
springs and see the difference
DIV3CR is offline   Reply With Quote
Old 03-19-2014, 07:30 PM   #6
richie 2
Senior Member
 
Join Date: Feb 2009
Posts: 971
Likes: 425
Liked 205 Times in 93 Posts
Default Re: piston to valve cl. check

thank you.....exhaust im getting .105'' w/checking spring & dial indicator, .155'' w/race spring and clay method. The .028'' valve lash has been set while testing both ways...

Last edited by richie 2; 03-19-2014 at 07:56 PM.
richie 2 is offline   Reply With Quote
Old 03-20-2014, 07:38 AM   #7
richie 2
Senior Member
 
Join Date: Feb 2009
Posts: 971
Likes: 425
Liked 205 Times in 93 Posts
Default Re: piston to valve cl. check

thanks everyone....we are going with what we have measured w/the race spring installed. its well safe. The answer to the question therefore is "using the intended valve spring to measure p2v clearance gives appx. +.050'' more than what the checking spring method shows". sp.

Last edited by richie 2; 03-20-2014 at 07:41 AM.
richie 2 is offline   Reply With Quote
Old 03-20-2014, 09:24 AM   #8
Aubrey N Bruneau
Member
 
Aubrey N Bruneau's Avatar
 
Join Date: Sep 2003
Location: South Eastern Alberta, Canada
Posts: 311
Likes: 6
Liked 7 Times in 3 Posts
Send a message via Yahoo to Aubrey N Bruneau
Default Re: piston to valve cl. check

Quote:
Originally Posted by Alan Roehrich View Post
You will find valve train deflection in a big block Chevy Stock Eliminator engine to be impressive, to say the least.
THAT's impressive

!
__________________
Aubrey N Bruneau 6409 C/S
62 BelAir sport coupe, 409 HP 409
Aubrey N Bruneau is offline   Reply With Quote
Old 03-21-2014, 01:11 PM   #9
Robert Simpson
Senior Member
 
Join Date: Aug 2004
Location: Jacksonville, Florida
Posts: 808
Likes: 7
Liked 20 Times in 12 Posts
Default Re: piston to valve cl. check

Guys I wanted to ask a question about checking P/V clearance with a HYD/Shubeck set up? Do you put in a solid lifter and a longer push rod to make up for the overall length? Or do you use the shubecks and check as usual and figure in the approx .015 lifter slack? I would like to hear what you guys do to check the P/V on a SBC stocker set up.

Thanks
Robert Simpson is offline   Reply With Quote
Old 03-22-2014, 02:55 PM   #10
DIV3CR
Junior Member
 
Join Date: Oct 2011
Location: WISCONSIN
Posts: 50
Likes: 0
Liked 3 Times in 1 Post
Default Re: piston to valve cl. check

I use a solid lifter with the push rod I race with. You wouldn't
use a longer one it would be shorter and that .015 I
don't think would make a difference.
DIV3CR is offline   Reply With Quote
Reply


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


All times are GMT -4. The time now is 01:36 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2025, vBulletin Solutions Inc.
Copyright Class Racer.com. All Rights Reserved. Designated trademarks and brands are the property of their respective owners.