Help...Need some numbers
Thread Starter
|
Senior User
Joined: Aug 2003
Posts: 152
Likes: 0
From: Maple Ridge BC Canada
Help...Need some numbers
Trying to get the advance curve, just right...Does anyone have any good input on mechanical / and total advance ?...Currently running 16 initial...38 by 2800 rpm..and 52 total...Seems to work OK but, hoping I can dial it in a little better....390-10 to 1, mechanical cam 228 @ .050..and edelbrock 750...Thanks....
Lead Driver
Joined: Apr 2001
Posts: 6,175
Likes: 21
From: Texas
I think we typically see max advance in the upper 30s. maybe some extreme FEs go into the loe 40s.....52 BTDC yikes!
It runs well, no pinging at the higehr revs?
The 16 initial is possible, with a bigger cam. Give us some cam specs. (my guess, is that you tried and teh server thought it was an email address :-)
Also, what ignition setup are you running?
It runs well, no pinging at the higehr revs?
The 16 initial is possible, with a bigger cam. Give us some cam specs. (my guess, is that you tried and teh server thought it was an email address :-)
Also, what ignition setup are you running?
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
Vacuum advance will only effect part throttle driving. It is there for gas mileage. To check your total timing you need to have this disconnected and plugged to simulate the engine being under load and pulling no vacuum.
If you are running a 52 degree total advance you are hurting the engine even if there is no pinging which I can't see there not being.
Some of these distributors had 18L advance cams in them. These are absolutely horrible for performance. This will give you 36 degrees of advance so if you are at a 16 initial you will end up at 52 degrees like you said. You can find an andvance mechanism from the junkyard that is a 13L. This will give you only 26 degrees of advance. This is the hot ticket for stock distributors in performance apps. I went the easy route and got an MSD distributor. I can change the advance limiter in about 15 seconds.
Once you get the right advance cam you can get a spring kit with lighter spring to make the advance come in at a lower RPM.
When posting cam specs here just put a space between the numbers and the @ symbol. I fixed it for you.
If you are running a 52 degree total advance you are hurting the engine even if there is no pinging which I can't see there not being.
Some of these distributors had 18L advance cams in them. These are absolutely horrible for performance. This will give you 36 degrees of advance so if you are at a 16 initial you will end up at 52 degrees like you said. You can find an andvance mechanism from the junkyard that is a 13L. This will give you only 26 degrees of advance. This is the hot ticket for stock distributors in performance apps. I went the easy route and got an MSD distributor. I can change the advance limiter in about 15 seconds.
Once you get the right advance cam you can get a spring kit with lighter spring to make the advance come in at a lower RPM.
When posting cam specs here just put a space between the numbers and the @ symbol. I fixed it for you.
Thread Starter
|
Senior User
Joined: Aug 2003
Posts: 152
Likes: 0
From: Maple Ridge BC Canada
I put a crane kit in the dizzy..The advance cam was installed with the short groove (cant remember the numbers) . With the vacuum line disconected, I get 38 degrees. With no load and the vacuum advance connected, I get 52 total..This is with a crane adjustable advance, backed all the way off.Just wondering if it was a little too much?...I need the 16 inital for starting...
The cam is a custom grind-solid, 228 @ .050 and .560 lift on 112 lobe seperation. Runs nice and smooth with a big kick in the midrange...
Ping is not a problem with 94 octane...Just been doing some research on timing, and some motors like a little less advance at higher rpm (dyno runs)...Was just hoping someone knew what made FE's happy....Lots of info out there on sbc's...And I know my Harley likes no more tha 36....But timing specs are hard to find for the beast we play with....
The cam is a custom grind-solid, 228 @ .050 and .560 lift on 112 lobe seperation. Runs nice and smooth with a big kick in the midrange...
Ping is not a problem with 94 octane...Just been doing some research on timing, and some motors like a little less advance at higher rpm (dyno runs)...Was just hoping someone knew what made FE's happy....Lots of info out there on sbc's...And I know my Harley likes no more tha 36....But timing specs are hard to find for the beast we play with....
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
It sounds to me like you are all setup. Once you floor the engine the vacuum goes down to 0 and no longer matters. Around town under partial load the 52 degrees helps out with mileage. You will find that your FE runs best at 36 - 42 degrees total timing.
Thread
Thread Starter
Forum
Replies
Last Post
austral
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
6
May 29, 2016 08:36 AM
hivoltj
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
13
May 15, 2016 06:01 AM
barca_texas
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
3
Sep 24, 2009 07:34 AM
