Mark J
Member
Posts: 19
Reg: 07-15-04
|
03-19-06 06:41 PM - Post#898992
I just got my 62 running with a 283 V8, HEI 50K billet distributor and Edelbrock 600CFM 4 barrel. Anyone know the proper stock 283 setting for the ignition timing? Do you set it with or without the vacuum line plugged?
Thanks
|
|
sgian
Valued Contributor
Posts: 4573
Loc: MO
Reg: 12-25-03
|
Re: Whats the proper igintion timing for a 283 V8?
03-19-06 06:57 PM - Post#898993
In response to Mark J
Stock is 4* BTDC with the vac line plugged. If it has an automatic it is in gear with the wheels block, otherwise it is in neutral.
http://www.carnut.com/specs/gen/chv62.html
Many people run with more advance than that, like in the 8*-12* range.
|
Mark J
Member
Posts: 19
Reg: 07-15-04
|
Re: Whats the proper igintion timing for a 283 V8?
03-19-06 07:17 PM - Post#898994
In response to sgian
Thanks for the assist sgian. Any idea what RPM the car should run in neutral? verses in gear? I'm trying to determine if the carb metering & springs are to rich or my idle settings & timing are off.
|
sgian
Valued Contributor
Posts: 4573
Loc: MO
Reg: 12-25-03
|
Re: Whats the proper igintion timing for a 283 V8?
03-19-06 07:34 PM - Post#898995
In response to Mark J
My Chilton manual doesn't have the rpm listed before 71 for novas. My truck manual lists 500 rpm for non-emissions controlled 283's in 1967 (680 rpm for manual transmission emissions in neutral, around 550 or 600 rpm for emissions engines with automatics in gear). It is normal for there to be a difference in rpm for automatics between neutral and in gear.
62 Novas came only with a four or six cylinder engine. Your engine is from a different vehicle, and if it has been modified then it may need a different idle rpm and timing curve (especially if it has a big cam).
Nova engines
http://www.novaresource.org/engine.htm
1962 vin codes so you can see what engine was originally in the car
http://www.novaresource.org/v62.htm
engine codes
http://www.novaresource.org/codes.htm
|
babydeuce
Senior Member
Posts: 551
Loc: Wichita Falls, TX
Reg: 05-27-00
|
Re: Whats the proper igintion timing for a 283 V8?
03-19-06 10:06 PM - Post#898996
In response to Mark J
a 600 is a little big for an otherwise stock 283. Hell, I have a pretty warmed over 283 and the 600 is a bit big!
Anyway, set your timing at 8 degrees advanced and go from there.
At idle, the only thing you should be touching on that edelbrock is the idle mixture screws on the front of the carb. The metering rods and springs play no part in the idle. They are part of the transition circuit. I would only worry about the metering rods and springs if you have a bog off idle, and then I would try a stiffer spring.
Jack
| 63 Chevy II SS, 283 .040 over w/vortec heads, edelbrock vortec rpm intake, comp cams XE256, and nothing else worth talking about! |
|
Mark J
Member
Posts: 19
Reg: 07-15-04
|
Re: Whats the proper igintion timing for a 283 V8?
03-20-06 05:34 PM - Post#898997
In response to babydeuce
Thanks guys. I'm learning as I go, so bare with me. I too had the same concern that 600CFM was to large(it came with the car). I've changed the metering rods and springs to lean it out (fixed souty exhaust)but I'm concerned its still to rich. The Edelbrock chart shows one jet/rod set lower and thats it. So using the two front screws I should be able to throttle down the idle? What position do you set the manual choke and auto trans when setting the screws? The car is outfitted with a beefed-up aluminum auto powerglide, new edelbrock performer series cam, lifters, timing chain and manifold. Also the manifold vacuum pressure (measured at the carb) is a steady 12Hg. That seems high, but then again I have nothing to compare it against.
|
sgian
Valued Contributor
Posts: 4573
Loc: MO
Reg: 12-25-03
|
Re: Whats the proper igintion timing for a 283 V8?
03-20-06 06:11 PM - Post#898998
In response to Mark J
Yes, you should be able to affect the idle speed a little with the mixture screws. If the screws are all the way in, it should run rough and/or stall. The choke should be off, and the transmission should be in gear with the wheels blocked so it won't move.
Make sure both mixture screws are the same number of turns out. Otherwise half the cylinders will be rich and the other half lean. I use a vacuum gauge, lean out the screws (turn in until vacuum drops), then back out until it reaches the highest stable vacuum. Factory method is the lean drop, in which you adjust the screws for the highest rpm, adjust the idle speed for the specified "before" rpm (often between 580-700 rpm), then turn the mixture screws in until it reaches the specified "after" rpm (usually 20-50 rpm lower).
12 is actually low for vacuum pressure at sea level. At high altitude, add 1" Hg for every 1000' elevation. Vacuum should be stable between about 15 and 22, the closer to 22 the better. Now if someone put in too much cam for the compression ratio, then 12 is to be expected.
|
babydeuce
Senior Member
Posts: 551
Loc: Wichita Falls, TX
Reg: 05-27-00
|
Re: Whats the proper igintion timing for a 283 V8?
03-20-06 10:24 PM - Post#898999
In response to sgian
I would say that Sgian hit the nail on the head! Best way to set the idle in my experience is by the vacuum guage as suggested.
I am curious as to what cam you have in it, as mine is not wild, but a tad large, and I pull 12 HG at idle.
I think you will find that the 600 will be hard to get "perfect" throughout the rpm range. You will either be rich at idle to keep it running with a large cam, or you will lean out at cruise. It will take some work to get it close to being stoich throughout the rpm band.
I have found the 500 cfm to be real good on the low end, but just does not give the top end. I settled for the 600, sacraficing throttle responce on the low end for the top end power I gained. Good luck with your 283, you will find it fun, but you will soon be longing for more 
Jack
| 63 Chevy II SS, 283 .040 over w/vortec heads, edelbrock vortec rpm intake, comp cams XE256, and nothing else worth talking about! |
|
mr5by5
Senior Member
Posts: 320
Loc: Hamlin, NY, USA
Reg: 11-21-02
|
Re: Whats the proper igintion timing for a 283 V8?
03-21-06 07:40 AM - Post#899000
In response to babydeuce
My '67 283 Nova has a 600CFM Edelbrock on a Performer and it runs fine with 3.36 rear and PG. It does not seem like too much carb to me, but I am going to "re-calibrate" to try to improve gas milage a little...
Make sure you use the right vacuum port on the E-brock for Dist. advance! It will bog-down like it is gonna stall if you pick the wrong one - from the picture on my "Car Domain" page ( http://www.cardomain.com/ride/706112 ) it looks like I am using the one on the driver's side...
I also have an Accel blueprinted dist. with Pertronix module and am running about 8-degrees static timing. I think I have the "medium" advance springs from the Accel. kit on the flyweights...
|
Mark J
Member
Posts: 19
Reg: 07-15-04
|
Re: Whats the proper igintion timing for a 283 V8?
03-21-06 06:38 PM - Post#899001
In response to mr5by5
Update: Turns out I was overlooking a simple, but critical adjustment. The hot idle screw adjustment on the throttle side of the Edelbrock carb. What a HUGE difference. I warmed up the engine and placed the manual choke wide open. Turning down the hot idle screw brought the engine right down to 700rpm. Next I disconnected and plugged the vacuum line leading to the advance, Connected the vacuum gauge to the left front port. No vacuum measured, unless the engine was throttled up. Plugged the vac gauge to the right side and BINGO its reading 18Hg. I turned the front mixture screws down till the engine nearly stalled. Then backed them out 1 1/2 turns. The car now idles up to 1K when the choke is pulled open and down to 700 rpm with it closed. The exhaust still smells a tad rich, so I'll purchase a set of leaner metering rods and jets.
|
mr5by5
Senior Member
Posts: 320
Loc: Hamlin, NY, USA
Reg: 11-21-02
|
Re: Whats the proper igintion timing for a 283 V8?
03-23-06 10:49 AM - Post#899002
In response to Mark J
BTW: Rear in my '67 orig. 283 PG car is 3.08, not 3.36! I got 3.36 stuck in my head for some reason and have to go correct another entry too!
|
merrill
Poster
Posts: 2
Reg: 11-01-18
|
11-01-18 05:17 PM - Post#2750205
In response to sgian
so if most people run 8-12 bdtc (I would imagine they do this for better perfomace)but stock is 4 bdtc how do you no when to go 4, 8, or 12.I no too far can damage things so how do I no witch to choose and when is to far
|
 Shepherd
Valued Contributor
Posts: 3442
Loc: Lake George, NY
Reg: 11-11-15
|
11-02-18 06:25 AM - Post#2750240
In response to merrill
Welcome to CT. Assuming you are using at least mid grade fuel and the vacuum advance works, I would say 8 degrees initial is a good starting point, drive it and see if you get any detonation on loaded acceleration. Btw, in the future, start a new thread, this one was really old.
Edited by Shepherd on 11-02-18 06:26 AM. Reason for edit: No reason given.
|
merrill
Poster
Posts: 2
Reg: 11-01-18
|
11-02-18 02:45 PM - Post#2750275
In response to Shepherd
thanks for the reply, and info, checking for detonation on loaded acceleration,I'm
a little lost, back firing while accelerating in other words? Or something different
|
Shepherd
Valued Contributor
Posts: 3442
Loc: Lake George, NY
Reg: 11-11-15
|
11-02-18 04:01 PM - Post#2750286
In response to merrill
Lets say you are in high gear at a relatively low speed, engine at operating temperature, accelerating from there without a downshift, if the fuel was low octane and/or the timing was too far advanced, it would audibly ping or knock.
|
Rick_L
Member #409
Posts: 28119
Loc: Katy, Tx, USA
Reg: 07-06-00
|
11-04-18 11:36 AM - Post#2750427
In response to Shepherd
And to add to that, a hesitation or backfire would indicate not enough timing.
|
bobb
Super Senior Member
Posts: 6686
Loc: paradise
Reg: 09-05-03
|
12-23-18 10:37 AM - Post#2755374
In response to Rick_L
that and possibly a weak pump shot. all this speculated tuning adjustments are just that. the engine is modified and the tuning parameters can only be dialed in by driving style.
| 70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails. |
|
|
Gain extra benefits by becoming a Supporting Member 
