advancing cam 4 degrees - Team Camaro Tech
Performance Our High Performance area

 
LinkBack Thread Tools Display Modes
post #1 of 8 (permalink) Old Apr 8th, 10, 07:09 PM Thread Starter
Senior Tech
Bill
 
Join Date: May 2008
Location: Livingston, NJ
Posts: 179
advancing cam 4 degrees

I have read here and on other forums that the engine performance can be significantly increased by advancing the cam by 4* when using the L-79 cam (327/350 HP engine). Is there any truth to this claim? Has anyone done this with this cam in a 327? How did this change affect the cars performance, idle, etc? Is it woth doing or not? Thanks in advance,
Bill
sbcBill is offline  
Sponsored Links
Advertisement
 
post #2 of 8 (permalink) Old Apr 8th, 10, 07:43 PM
Gold Lifetime Member
Tom
 
Join Date: Mar 2008
Location: the 02176
Posts: 5,754
Re: advancing cam 4 degrees

Do you know if the cam is ground advanced or ?

If it is supposed to be advanced and you install it retarded it is going to run like, well, not so good.

We once accidentally installed a 30/30 cam in my Dad's 327 vette "straight up" and it felt horrible. No low end, fouled plugs, poor idle, pinging, gas mileage... Took it apart, added 4 degrees advance and bam! back to it's old self.

I've messed with adjustable timing gears on Toyotas too. I don't have any hard data to show you and I don't recommend randomly advancing cams without knowing what you are getting into, but advancing it 4 gave it better low end response. Felt lighter and snappier.

I don't know if the factory performance cams like L-79, 30/30 are ground advanced or got advanced by the specific timing chainsets, though. Somebody else may know.

'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.
the Melrose rs - L30 327/275hp
Melrose RS is offline  
post #3 of 8 (permalink) Old Apr 9th, 10, 03:46 AM
Senior Tech
Tom
 
Join Date: Mar 2006
Location: Joplin
Posts: 1,377
Re: advancing cam 4 degrees

Try it, the cam advance kit is cheap, as are the gaskets.

BUT test performance at the strip before you do it. Also your MPG on the street.

If it helps you have proof instead of it "feels" better hopefullness.

71 Camaro 355 NA
11.1650 @ 119.30
1.5028 60'
hhott71 is offline  
post #4 of 8 (permalink) Old Apr 9th, 10, 05:44 AM
Senior Tech
 
Join Date: Mar 2000
Location: Allen Park, MI
Posts: 525
Re: advancing cam 4 degrees

unless it is a GM NOS L79 cam, then it most likely has 4 degrees advance ground into it already.

i always install my cams an additional 2-4 degrees advanced...

for instance, my 30-30 and 140 offroad cam were installed 7 degrees advanced in my engines... and they ran great that way.

the general rule is that advancing the cam picks up the low end at the expense of the top end,
and retarding the cam has the opposite effect.

most cam manufacturers grind advance in simply to take up the slack in the timing chain as it wears and stretches.

THanks

Aaron
69z28boy is offline  
post #5 of 8 (permalink) Old Apr 9th, 10, 02:58 PM
Gold Lifetime Member
Don
 
Join Date: Jan 2005
Location: 2 Dog Town in West Texas
Posts: 10,210
Re: advancing cam 4 degrees

This is a basic stock GM cam 3896929, if you are sure what you have. Should run well as it is but usually guys try to move 2 or 4 advance and it runs better but at the expense of the top end. If thats not an issue, then go for it as this cam is probably ground a 112 or 114 lsa. Unless you are adding additional above stock stuff to the motor, I would install it dot-dot. If you want to find out if its off some, put a degree wheel on it and check it out against its specs. If you have them.

Don
TC # 349
Zdld17:69 Z/RS,306, NOR141111, 9N554XXX, 12A, X3G, 59/59,723, AFR 195,CCC282/290HR, TKO 600, BU1122B1E
http://s102.photobucket.com/albums/m...t=115_1577.jpg
zdld17 is offline  
post #6 of 8 (permalink) Old Apr 11th, 10, 10:56 AM Thread Starter
Senior Tech
Bill
 
Join Date: May 2008
Location: Livingston, NJ
Posts: 179
Re: advancing cam 4 degrees

The cam is a new NOS in the box 151 GM cam. I know Chevy never ground an advance in their cams, I will keep it the way it is and use it dot to dot when installed. Thanks for the comments.
Bill
sbcBill is offline  
post #7 of 8 (permalink) Old Apr 11th, 10, 11:48 AM
Senior Tech
 
Join Date: Mar 2000
Location: Allen Park, MI
Posts: 525
Re: advancing cam 4 degrees

Quote:
Originally Posted by sbcBill View Post
The cam is a new NOS in the box 151 GM cam. I know Chevy never ground an advance in their cams, I will keep it the way it is and use it dot to dot when installed. Thanks for the comments.
Bill
i'd urge you to consider advancing it... especially if it has no advance ground in..

the advance is ground in to eliminate a retarded cam when the chain stretches..

advancing 4 degrees will indeed put a bit more bottom end in the cam, and as the chain wears or stretches, the cam will not retard in the process.

A
69z28boy is offline  
post #8 of 8 (permalink) Old Apr 11th, 10, 12:29 PM
Senior Tech
Ron
 
Join Date: Nov 2006
Location: North Channel Lake Huron
Posts: 3,930
Re: advancing cam 4 degrees

To install a cam in the position you want you need the Mfgr's Cam Specs and a Degree Wheel. After you have Determined TDC using the Positive Stop Method, the Location at which the Intake Valve Opens and Closes at .050" is generally used to Locate the Cam. The built in 4 degree advance really means nothing when Degreeing but does indicate a cam with a 110 ICL and 110 LSA is generally installed at 106 Degrees which is 4 degrees advanced relative to Crank Rotation. Remember the Cam turns at 1/2 cycles to the Crank. To increase Dynamic Stroke and Dynamic Compression, I have often installed a cam which calls for a 108 Degree ICL at 104 Degrees which is 6 Degrees advanced relative to the Crank. You should always do a Valve to Piston Clearance Check after degreeing a Hi-Perf cam where generally for every 2 degrees advanced the Intake Valve Clearance to Piston shortens by approx .010" and the Exhaust lengthens by approx .010".

Valve to Piston Clearances are closest when the the Valves 1st Open and Close. Advancing a Cam tends to improve Torque at Lower and Mid range; however, you should compare the results with a DCR Calculator in attempt not to foul the recommended 8.2 DCR Dynamic Stroke Ratio for Pump Gas Octane. It is important to know your Static Compression ratio when Selecting a Cam.

Z15CAM - There was a Viper in my Rear View
This was my 70 1/2 Z28
http://www.flickr.com/photos/28082975@N04

Last edited by Z15CAM; Apr 11th, 10 at 12:40 PM.
Z15CAM is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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 On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome