What does advance timing on a cam mean? - PerformanceTrucks.net Forums



GM Engine & Exhaust Performance EFI | GEN I/GEN II/GEN III/GEN IV Engines |Small Block | Big Block |
Sponsored by:
Sponsored by:

What does advance timing on a cam mean?

Reply
 
Thread Tools Search this Thread
Old 03-31-2004, 08:33 PM   #1
14 Second Truck Club
Thread Starter
iTrader: (6)
 
Join Date: Sep 2002
Location: Bossier City, LA
Posts: 2,343
Thanks: 0
Thanked 0 Times in 0 Posts
Default What does advance timing on a cam mean?

This is probably a stupid question, but anyways here it goes. This is what I'm thinking it means, please correct me if I'm wrong.

If there was a 214/220 cam @ 114 LSA and it was advanced 4 degrees, would it make it act like a 210/216 @ 114 LSA?

And is the opposite called retarding it?

Thanks.
Hemi Killer is offline   Reply With Quote
Old 03-31-2004, 08:44 PM   #2
TECH Resident
 
mudz5.3's Avatar
 
Join Date: May 2003
Location: Glendale, AZ
Posts: 959
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Think of advancing is like bringing the power in sooner, and retarding the timing will bring it in later. Not sure on specs, BigTex can help you out on that if he chimes in.
mudz5.3 is offline   Reply With Quote
Old 03-31-2004, 10:02 PM   #3
TECH Junkie
 
Join Date: Mar 2002
Location: memphis tn
Posts: 3,019
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Advancing the cam timing makes to valve openings occur sooner and the cam behave like it has less duration at lower engine speeds.Retarding the cam timing delays the valve openings making the cam behave like it has more duration making more topend power at the expence of low speed performance.Not that it makes any difference on an LS1 motor,but on distributer equipped engines the ignition timing is changed a similar amount and must be corrected.
whitt1 is offline   Reply With Quote
Old 03-31-2004, 10:05 PM   #4
? ? ? ? ? ?
iTrader: (16)
 
BigTex's Avatar
 
Join Date: Nov 2001
Location: East of Dallas
Posts: 7,110
Thanks: 0
Thanked 1 Time in 1 Post
Default

The duration (214/220) and LSA will stay the same no matter what you do, they are ground in when the cam is made.

The cam spins and forces up the lifters, pushing up pushrods, which push on the rockers, who force the valves open. The cam spins one time per two revolutions of the crank. That relationship is fixed by gears on the crank and cam, connected by the timing chain.

OK, so the valves are opening and closing when the cam spins. Advancing the cam is when you use an adjustable chain and make the valves open and close sooner. Retarding is the opposite - opening and closing later in relation to the crank turning. This lets you have a little control on the powerband, as earlier closing of the intake valve builds better pressure at low rpms and makes more torque. Closing later allows more air to fill the chambers at high rpms, making more power up there. So advancing shifts power lower at the expense of peak upper rpm power. Retarding gives up some low end for more rpms and peak power.

So advancing doesnt change the duration or lift of the cam, it changes where the valves open and close. Most aftermarket cams you see have either +2 or +4 advance already ground into the cam - the lobes were moved 4* forward during the grind. Thats it to allow for slop in the stock timing chain and aid the mid range a little.

Personally, I'm tempted to go with a bigger cam and advance it a little more and see the results.
BigTex is online now   Reply With Quote
Old 03-31-2004, 10:37 PM   #5
14 Second Truck Club
Thread Starter
iTrader: (6)
 
Join Date: Sep 2002
Location: Bossier City, LA
Posts: 2,343
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Thanks for the info!
Hemi Killer is offline   Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Ls3 swap into my 06 rcsb OHsixLS3 INTERNAL ENGINE MODIFICATIONS 14 12-27-2016 09:30 AM
2006 RCSB 4x4 V6 to V8 LQ9 Cammed Manual 5 Speed Swap ARC GMT 800 & Older GM General Discussion 53 07-02-2016 10:08 PM
Oil pan Question? Help 05SilveradoSS GM Engine & Exhaust Performance 6 07-29-2015 08:34 PM
Lifter Noise? GRRR65GTO INTERNAL ENGINE MODIFICATIONS 2 07-10-2015 08:27 PM


Tags
53, advance, advanced, advancing, cam, chevy, duration, grind, hemi, horsepower, mid, power, range, timing, topend

Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 01:05 PM.


 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: