How much timing?

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Jun 26, 2014 | 09:30 PM

#21

Brians1

Burning Brakes

Joined: Nov 2013

Posts: 889

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From: Jax/St. Augustine FL

Rlsterling3....fellow 81 owner here...your research and Lars input are correct...best I get out of my timing is between 12 and 14. My CCC is fully operational just like yours...I was planning on the hypertech chip as well since I have done several mods as you have and I still run the E4ME.

Timing on our 81 is sensitive for sure esp with that primitive "computer" lol. Thanks for posting the videos, very informative. If you search the forum for my user name I did a post for how to use the original scan tool, the OTC monitor 85. It can be used to read the rpms, dwell, get trouble codes, etc....real time cost me 20 bucks on eBay. I use it often when I want to see what the CCC is deciding for my timing

Jun 27, 2014 | 03:12 AM

#22

RC81

Burning Brakes

Joined: Feb 2000

Posts: 774

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From: Middleton, Id

On my 81 with my ccc working I set it at 14. There are no springs in the dist to change, all electronic in there. There is a knock sensor in these engines so I run premium gas to prevent knock as the computer will pull back timing if it hears it. I also bought an OTC Monitor 85. Very handy for checking dwell and many other things on these cars. Not sure how to correlate it to 36 degrees though. If ya ran it on a dyno it would be interesting to see what setting made the most power.

Jun 27, 2014 | 11:59 AM

#23

rlsterling3

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Joined: Mar 2014

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From: Frankfort IL

Quote:

Originally Posted by Brians1

,thanks for the reply I've been on the look out for one of the monitor 85 on eBay. This winter I am lifting the engine and trans I'm going to do a complete overhaul. With that overhaul I'm installing new heads and a new intake manifold. Sometime next spring I plan on getting it on the dyno and see what im putting out total.

Jun 27, 2014 | 12:00 PM

#24

rlsterling3

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Joined: Mar 2014

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From: Frankfort IL

Quote:

Originally Posted by RC81

once I get this engine work done this winter I plan on getting it on the dyno when I do that I'll definitely post a video of the actual Dyno run or at least the numbers who knows maybe I'll get it out to the track next year for a little run through traps

Jun 27, 2014 | 02:02 PM

#25

hugie82

Safety Car

Joined: Mar 2007

Posts: 3,652

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From: Bridgewater nj

Quote:

Originally Posted by rlsterling3

I know I've been posting a lot lately with all sorts of questions, but I'm learning as much as possible. Currently running an. 1981 c3 original motor with some mods :

Bored.. 30 over
Keith black flat top pistons
Blue Racer Crane Cam WG-1173
• .050 Duration: 224° Intake; 234° Exhaust
• Advertised Duration: 298° Intake; 304° Exhaust
• Cam Lift: .290 Intake; .300 Exhaust
• Valve Lift: .465 Intake; .488 Exhaust
• Lobe Center: 107° Intake; 117° Exhaust
Polished and ported original heads
Super comp full length headers
2 1/2 exhaust
Flowmaster delta 40's
New dizzy, wires, plugs
Rebuilt & modified quadrajet E4ME
Currently have the timing at 12*

With the cam and additional stuff on here can I increase the timing for any more performance? Anyone have something similar that has advanced the timing to maybe 14 or 16?

slowly getting this thing running like I feel it should. Yesterday adjusted the spring fire the secondaries opening rate, maybe tonight I can warm it up and get the dwell dialed in... So close

You engine is no longer anywhere near stock specs and your idle vacuum is much lower that a stock 81 , so you have very little vac advance being added in. This isn't a bad thing but it has to be made up for cruising performance. Stock idle is 16-18 vac and now you're 12 vac.
Good luck

Jun 27, 2014 | 02:48 PM

#26

rlsterling3

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Joined: Mar 2014

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From: Frankfort IL

Quote:

Originally Posted by hugie82

Thanks. I don't think the vacuum has anything to do with it on am 81.i believe it's all computer controlled if I'm not mistaken

Jun 28, 2014 | 10:11 AM

#27

69427

Tech Contributor

Joined: Jun 2004

Posts: 20,905

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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.

Quote:

Originally Posted by rlsterling3

Thanks. I don't think the vacuum has anything to do with it on am 81.i believe it's all computer controlled if I'm not mistaken

Every decent engine control monitors the manifold vacuum, whether it's by a VA canister (which you don't have), or a MAP sensor (which you do have). The ECM reads the MAP sensor signal and continually adjusts the timing.
Disconnecting the distributor connector and running up the RPM won't give you any useful tuning information. There's a built-in advance curve in the 7 terminal ignition module (all model years IIRC) to supply a crude "centrifugal advance" in the event that the ECM fails. This backup advance just allows the engine to run a bit smoother during the drive to the dealership for repairs.
Unless you can get the RPM/Load timing curve from the aftermarket PROM source, or a readout of your instantaneous timing, you're going to have to do a lot of guessing on your actual timing.