Centerline - CorvetteForum - Chevrolet Corvette Forum Discussion

Notices
C1 & C2 Corvettes General C1 Corvette & C2 Corvette Discussion, Technical Info, Performance Upgrades, Project Builds, Restorations

Centerline

Reply

 
 
 
Old 01-15-2018, 10:44 AM
  #1  
Dmnin
Junior Member
Thread Starter
 
Member Since: Jan 2018
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Default Centerline

Does the centerline have to do with vacuume in the engine? More or less for smother running engine. Every day streetcar. My cam 110 centerline with 240/242 donation.
Yes 110 between lobe centers and the 240/242 is the Valve duration @.050"
Would advancing help any with vacume along with Bottom end? Also possibly removing 1.6 Rockers and going back to 1.5s?

Last edited by Dmnin; 01-16-2018 at 09:46 AM. Reason: more information
Dmnin is offline  
Reply With Quote
Old 01-16-2018, 12:45 AM
  #2  
LB66383
CF Senior Member
 
Member Since: Dec 2002
Location: Long Beach CA
Posts: 1,922
Thanked 22 Times in 21 Posts
Default

Not sure I understand. Are you saying that your cam has 110* between lobe centers? Or are you talking about advancing or retarding the cam timing? And is the 240/242 the advertised duration or the valve duration at .050"?
LB66383 is offline  
Reply With Quote
Old 01-16-2018, 09:48 AM
  #3  
65tripleblack
CF Senior Member
 
65tripleblack's Avatar
 
Member Since: May 2003
Location: Ocean Township NJ
Posts: 4,800
Thanked 222 Times in 202 Posts
Default

Originally Posted by Dmnin View Post
Does the centerline have to do with vacuume in the engine? More or less for smother running engine. Every day streetcar. My cam 110 centerline with 240/242 donation.
Indirectly, yes.

Idle vacuum is a direct function of valve overlap (the period of time when both intake and exhaust valves are not fully seated). Overlap increases as durations increase and/or as lobe centerlines are brought closer together (i.e: lobe center angle decreases).

Simple explanation which I hope was helpful.
65tripleblack is offline  
Reply With Quote
Old 01-16-2018, 05:52 PM
  #4  
Avispa
CF Senior Member
 
Avispa's Avatar
 
Member Since: Mar 2009
Location: San Antonio Texas
Posts: 1,718
Thanked 52 Times in 48 Posts
Default

If your cam is hydraulic, 240/242 duration at .050 lift is on the long side for a street cam. It will idle rough and have low idle vacuum even if you advance the cam timing.
Avispa is offline  
Reply With Quote
Old 01-18-2018, 01:35 AM
  #5  
LB66383
CF Senior Member
 
Member Since: Dec 2002
Location: Long Beach CA
Posts: 1,922
Thanked 22 Times in 21 Posts
Default

Absoutely. The cam in my 383 stroker is 240* at .050" and it does have a rough, lopping idle and about 10-11" of vacuum at idle. But it is advertised at 270* duration. Advertised duration and duration at .050'' are normally very different things, and make a difference in vacuum and engine performance. As will lobe separation, as 65Tripleblack stated.
LB66383 is offline  
Reply With Quote
 
 
 


Thread Tools
Search this Thread
Quick Reply: Centerline


Sponsored Ads
Vendor Directory

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: