I've searched and read through this forum for correct timing advice on a stock 283 and am still confused. My question is am I aiming for no more then 32-36 deg of total advance at 3000 rpm? Does that mean mechanical weights at full fling? vac adv hooked up and the ideal base should be around what? I just ordered a recurve kit and adjustable vac.adv.can. So based on your responses I will try to dial it in on the button. currently if I aim for 32-36 @ 3000rpm my base ends up being around 16 deg and pings like mad and still capable of advancing farther at higher rpm almost to 44deg.Don't forget I also get about 18 more degrees out of my vac adv can.

Pings with what octane fuel?

If its a little tired or had carbon build up even the little 283 could need 91-93 fuel to stop ping esp if it uses any oil and you running a glide with like 273-308 gear which loads the motor a lot more (esp accell from a dead stop) then a th350 trans with 342-355 gear would.

With bone stock gm cam 4-8 base/34-36 total(not 32 too retarded) by 2800-3k rpm max.

But with even a mild perf cam 16 base/18-20 mech in dist in by 2800rpm for 34-36 total by 2800rpms.

Vac adv unhooked & pluged when setting.checking base & total timing. also,idle needs to be low like 550-600 rpm when setting base timing to ensure the mech adv isnt partially activated upsetting the base timing setting.

Then with all the other timing in with vac adv hooked back up your looking for 50-52 deg max timing when @ light load/part throttle cruise like at 3k rpms.

You will likely need to take the dist to a shop to have the mech adv recuevd to work with what ever base timing your running (depending on stock or mild aftermarket cam) .

You could also have them install a vac adv limiter plate mfg by crane cams sold by summit that cam be adj to limit/reduce the vac ad from full 20 deg where you said its at now to 14-16 deg thats better suited for 34-36 total.

Sending the dist out to have it properly setup will eliminate all the issues you having with getting it timed properly but you have to set base timing correctly for a stock gm cam or an aftermaket even mild cam that needs a lot more base timing then a stock gm cam does. GM stock vs aftermarket cams are 2 completely different base timing settings depending on which type cam you have which is key to get right esp with an aftermaket cam req 3x-4x more base timing then a stock gm cam requires.

Scott

Let me ge this srtaight. I want no more then 8 deg base timing? I want no more then 14-16 vac adv? so that means I should be getting no more then 28 deg advance out of the weights to be within the 52 deg total @2800 rpm? does that sound right?

currently if I aim for 32-36 @ 3000rpm my base ends up being around 16 deg and pings like mad and still capable of advancing farther at higher rpm almost to 44deg.

You've set your total at 44º so it should ping like crazy. Total is set wherever the timing is fully advanced in your distributor, not where someone that has no idea where your particular distributor in all in tells you. If the distributor has been recurved for a total @ 3k, that's where you set it but most stock distributors don't reach total until well past that.

You've set your total at 44º so it should ping like crazy. Total is set wherever the timing is fully advanced in your distributor, not where someone that has no idea where your particular distributor in all in tells you. If the distributor has been recurved for a total @ 3k, that's where you set it but most stock distributors don't reach total until well past that.
Yeah, you're right. I set it so that it's at around 35deg at 3000 rpm. I revd it up to 4k and it kept advancing up to 44deg. But the interesting thing is that it pings under load right off idle on WOT. I know the mechanical advance hasn't even had a chance to open up yet. So what gives? Bad gas? running hot? I've been using 87octane for a low compression motor it should be fine, right?

A stock `66 283 was designed to use regular leaded, which was closer in octane to today's premium in octane so I'm not surprised it pings on 87. When you increase your total you are also increasing your advance everywhere else. I'd rev it until it stops advancing (which could be higher than 4k) and set it to 36º (vacuum advance disconnected). If that results in an initial you don't like you'll need to recurve the distributor to change it. Keep in mind that initial is only at idle but the rest of the curve, especially total, determines what happens when you actually drive the car.

Hey Jerry, very nice statement you made " not where someone that has no idea where your particular distributor in all in tells you."

Why the SNOTTY REAMRK ?

You dont play nice at all with others do you !

Your right i had no idea where the dist was set in his motor which is why i was simply giving a couple possible senarios of where to set if running a stock or aftermaket cam.

I was also giving him some tips on how to determine if he has a stock or aftermarket cam along with a decent place to start for a street ign curve depending on which type cam he had .

And one thing your forgetting (or maybe simply don't know) is when you tell him to set the timing for total only esp if the motor has an aftermarket cam requiring a lot more base timing that setting timing for total only in NG for street unless your just running at the strip or another type of racing and here's why.

His stock dist could easily have 25 deg mech .

So take a 36 total he sets the timing to and - 25 deg mech in the dist from that 36 total which leaves only 11 deg base timing .

Now if that 283 was ever rblt which it likely has been on 40 yrs and if it has an aftermarket cam which 9 of 10 motors rblt get then even a mild good idling aftermarket cam needs at least 16-18 deg base timing,mile aftermarket cams still have more duration then the stock gm cams had in those mild motors thus requiring 3x-4x more base timing.

So with only 11 deg base left when setting timing for total only that leaves the base timing 5-7 deg retartded which is substantial esp with an aftermarket cam in such a small 283 cid motor that needs all the help it can get.

Base timing being 7 deg retarded in such a small motor makes it feel very lazy/have poor throttle responce/wastes fuel decrasing fuel mileage due to the lost power/trq in lower engine rpms.

I also told him he would likely need to have the mech adv recurved /limited if he found he was running an aftermarket cam req more base timing to keeptotal reasonable @ 36 deg by 2800-3k rpm .

BTW,many motors back then ran with 50-52 deg timing when the total and vac adv was all in at low load part throttle cruise for best fuel economy/throttle resp/cooler running motors.

I also suggested to install a vac adv limiter plate mfg by crane cams sold by summit that cam be adj to limit/reduce the vac adv from full 20 deg that he said his had said to 14-16 deg thats better suited for 34-36 total to end up with approx 50-52 deg at low load cruise.

I suggested he try 91 -93 fuel too because todays non leaded/lower octane/oxygenated/ehtenoled fuel is a very different formulation then those old motors were ever designed to run on.

I felt i gave him good suggestions/advice for gettting things dialed in better that didnt deserve your smart ass responce .

Maybe you have been at this stuff longer then the 37+ yrs i have been doing it but doesnt give you any reason to be a wise guy while giving help/advice on this site.

Just my 2 cent's on that.

Scott

nicely put scott

Scott, my remarks were not directed at you and they weren't intended to be snotty. Over and over again there are posts telling people to set total at 3k or whatever without knowing what someone's advance is all in at. I agree that 3k is a good place to be all in at for most engines but, unless the distributor has already been recurved to do that, setting total at an rpm before advance is all in is a waste of time. If that offends you, tough. In this case, following the advice to set his total at 3k resulted in him having much more total than he wanted.

I have had the car both at around 6deg. and 16 deg base timing. Without knowing what kind if cam is in it I must say that it's much spunkyer at 16 then it is at 6.Only negative things I've noticed at 16 degrees is a low rpm load ping and worse milage. Based on that I'm going to have to assume that it has a stock cam and follow scotts instructions on setting up the Dizzy.

Since is ran fine and felt a lot more responsive (accept for ping) with 16 deg base timing means you very likely have a aftermarket perf cam so dont put base timing back to the stock cam's 6 deg setting,thats way to retarded IMHO.

Funny mileage is worse,its usually better when you give the motor/cam the additional timing it needs.

Are you sure you werent driving it a little more agressively/using more throttle because of the new found power/spunkyness feel the motor had with the additional base timing it needed? Just being a little more agressive with the gas comming off some of the stop light's or when accellorating will really show up in your fuel milage esp on a 40 yr old carb'd car like yours that may have a glide and 270-300 highway gear and a small 283 with not that much trq.

Did you try some 91 fuel yet to see if it stops the ping?

I would not be surprised if the mech adv in dist & vac adv are collectively adding too much timing esp with the 16 deg base timing your motor likes with an aftermarket cam.

BTW,Those 283 low comp/ perf motors were designed for approx 89 octane leaded fuel but " NOT THE NON LEAD/LOWER OCTANE/OXYGENATED/ETHENOLED FUEL MFG TODAY THATS A VERY DIFFERENT FORMULA FUEL,see what i am getting at?

Todays 91 seem's be about as good as 30 yrs ago 89 oct fuel as far as your 40 yr old motor goes from my exp with these motors over the yrs. So try 91 fuel with 16 deg base timing,if it still pings back off timing to approx 12-14 deg to see if ping will stop.

If ping stops at 12-14 deg base timing maybe leave well enough alone if it seems to run good there. But if it still pings and you liked the perf better with the 16 deg base timing then maybe its time to pull the dist to have the mech adv recurved /limited to 20 deg max in by 2800-3k rpm by a reputable shop.

Then you will have 16 base + 20 deg mech iun dist for 36 total by 2800-3k rpms.

You can also have them either limit the vac adv to approx 14 deg for 50 deg when at part throttle low load cruise because i believe the full 20 deg you vac adv currently gives you will push the timing to 56 which is too much. Or he can install a new vac adv that only gives approx 14 def when fully deployed that works with your motors idle vacuum.

But to be safe just before you pull the dist to have it recurved verify that the total timing (vac adv unhooked/plugged) is over 36-38 deg at 3k rpm and above by reving to like 4k rpm to see if that's really whats going on. And then also reattach the vac adv to see how much timing its adding to the total you just found you had and if vac adv adds more then 14 deg then that will have to be tweaked/limited /or changed to give approx 12-14 deg fully deployed to work with 36 total.

Good luck.

Scott

I would just eliminate the advance curve altogether by spot welding or pinning the dist. Saves all kinds of trouble in tuning for streetability and racing.Both my daily driver and my weekend cruiser have been for years.Not for everyone,sometimes you might need a start retard box(cheap) ,a gear reduction starter,or just be careful starting the car.I tried hooking mine back up a few times with a curve kit ,installed light springs,med. springs,always had ahesitation.Now set timing at idle @35 and it blazes the tires every time.Easy.

Chris,this is a mainly stock exp for mild aftermaket cam 283 so he is really better of not welding/eliminateing the mech adv,thats mostly usefull for strip only or limited street us hi perf motors/cars like your reffering too.

If he takes the time to get the ign dialed in right for his setup & fuel he's running the motor should respond well to that. Then things should be ok after that unless he has missed telling something in his explination of the problem or has overlooked something mechanically along the way here too which does happen at times when trying to help people out.

Scott

Ok here's the latest. I installed a crane vac avd can that I adjusted to give me 16deg max adv. and also installed the silver/blue spring combo to give me full mechanical advance by 2800/3000 rpm. and dialed in 36deg at 2900rpm (vac disconnected). which left me with an 11deg base, 25deg of mechanical adv and 16deg of vacuum. for a grand total. of 52 deg of total adv at 2900rpm with (vacuum connected). It starts well and has a decent amount of pep, only thing now is that it does ping at the top of the rpm range. But before I take it down a couple of degrees I'm gonna take scotts advice and try higher octane fuel just to see if it helps.

If your happy with the perf with 11 deg base timing and the higher oct fuel stops the ping stay with it.

But if you want the better perf/power/throttle responce i wouls run the 16 deg base timing that you said had nice throttle responce /power and felt spunky which is becasue you had the correct amount of timing that cam/motor liked.

If you take the time to get the mech adv in the dist properly curved for in your case 20 deg max by 2800 rpm then you can run the full 16 deg base timing you motor liked for a 36 deg total it seems to run well with too .

Also,if you still have trouble with upper rpm ping when on gas hard maybe the vac adv isnt fully deactivating when under hard thottle pusing total too hi. You test that by unhooking/pluggin the vac adv and going for a test run.

If you find no ping under hard accel with vac adv unkhooked then you mat need to install a vac adv thats got a hoigher cuot out vac lvl thats at lest 2" higher then the motors intak vac when your under hard accell,you have to test that with vac gauges and goinf for a ride to gets int vac reading when under hard accel.

But you can like avoid all this additional tuning if you get thet mech adv properl curved as i stated above along with having them install a vac adv that adds an additional conservative 12deg max not 14-16 deg when your currently at which can be just enough to push it over the edge at time and ping. Or install cranes vac adv limiter plate to limit your current vac adv to 12 deg max as ,ong as its complete shutting down when at WOT .

Then if you run higher oct fuel with 16 base timing for best lower rpm perf/20 mech for 36 total by 2800 rpm and 12 deg vac adv thats properly matched for your mtors idle and wot int vac for a conservative a 48 deg timing when it's all in for low load part throttle cruise since you motor is sensitive to ping that should do the trick of having best perf all the way arround and still not ping.

But since you stated it had the best perf with 16 deg base and pinged and still pings with 11 deg base too i would not retartd the base timing any more loosing more perf. Do it right with higher oct fuel and vac adv backed off /reduced to 12 deg max and not 16 deg its currently at along with making sure its not still partially activated at WOT when test driving the car with a vac gauge installed,then the dist shop can install proper vac adv to shut down at WOT like it should be .

Just my 2 cent,

good luck.

Scott

In the beginning of this thread I was getting a PING on hard throttle (low rpm) runs. Now I'm getting a Ping on WOT but only at the top of the RPM range. No more ping on the lower rpm hard throttles. I'm gonna install the limiter plate and take the vacuum reading at high rpm and try to dial in the adjustable vacuum can to cut out just under those vacuum numbers.I'm also gonna add a brass bushing into the mechanical advance track in an attempt to limit the total degrees of mechanical advance to around 20 from the 25 i'm currently getting. That way it would allow me to run the higher base and still end up with a lower total. Will update later in the week as to the out come. Thank you for the advice.

Your going in the right direction,good luck and let us know how it works out.

Scott

I sure wish i knew what cam was in this motor. Am I correct assume that it is indeed a higher lift then stock by the fact that it will run well with a 16deg advance? Or even a stock cam will do that?

In general stock gm cams will not tollerate as much base timng as even a very mild perf cam needs. It's not as much the lift as youmentioned but its that the aftermarket cams/even very mild ones that have considerably more duartion then a stock gm 283 cam would thats where the difference is.

Most of the time when a stock 283 cam call's for maybe 4-6 deg base timing and you crank in 16 deg base timing it will either stall,or simply run like crap if its in fact a stock gm 283 cam in the motor.That's because the base timing is way adv past stock setting by 3x-4x but an aftermaket cam requires a lot more base timing to run well/spunky as you put it with 16 deg base will respond very well to the additional base timing.

Thats why i use that little test of cranking in 16-18 deg base timing to see if the motor responds well to it like yours did or if it stalls & or responds poorly to it running like crap which has worked pretty well for me over the past 37+ yrs workoing on thses motors.

This isn't a 100% accurate test but it's about the best you can do as a quick and dirty way to see what type cam is in a motor if you dont know and it idles much like a stocker being smooth etc. You could remove the v-covers and try to measure the lift etc but thats a PIA and many people dont have the equipment/experience/etc to chk a cam this way and the base timing chk can give some info on if cam is stock or not.

Scott

Well thats good enough for me. I've had it at 6 and 16deg. it idles smooth at both settings but definitely comes to life at 16.

I think I'm going backwards now. I took the dizzy apart to replace the rubber advance bushing that had deteriorated with a nice thick brass one. I obviously greased all of the moving parts while in there. Now instead of the 25deg of total mechanical advance I was getting before, I'm getting almost 35deg now. So 16deg base+35deg mech adv.+16 deg of vac adv= 67deg of total adv @ 3000rpm. Confirmed with my timing gun. So I tried to run it with the vac adv disconnected and the part throttle,low rpm ping was so bad I couldn't hear the radio. Could someone help me get back on track, please

Tack weld the advance mechanism together where it normally is .Or drill a hole through both plates and stick abolt through it,one on each side of the rotor.Do it on a spare dist if you like,youll never have to worry about the thing again.

Look, you want 16 degrees at idle and 36 at full advance ,so you only need 10 degrees of advance.woopdee.set it at full advance and what difference is 10 degrees going to make?Like I said do it on a spare and then check your mileage.

Tack weld the advance mechanism together where it normally is .Or drill a hole through both plates and stick abolt through it,one on each side of the rotor.Do it on a spare dist if you like,youll never have to worry about the thing again.
please explaine, are you saying an engine doesn't need any advance to perform well?

Look, you want 16 degrees at idle and 36 at full advance ,so you only need 10 degrees of advance.woopdee.set it at full advance and what difference is 10 degrees going to make?Like I said do it on a spare and then check your mileage.
you mean 20 degrees? or are you saying split the difference. Anyway it'll compression lock at full advance and not start.

Thats right it can always have 36. It will ocassionally kick the starter back if you dont have a mini starter.When you start the car just hit the key quickley once or twice to see if is will kick on you.I never have a problem with my big block.Or just buy a start retard box from msd ,theyre cheap and easy to hook up.