Its Aliiiiiiive!!!!!

[wally426ci]

  

Ive been in a low mood lately about the car. I was a little put off once i fumbled my way into a stationary car. After swapping plugs the other day, She runs pretty good.

Now, my timing was right on 34 degrees @ 2500 rpm, but i think i need to mess with the advance or jump up a notch on my main jets due to a sputter when you are at a cruise speed until you step on it.  and even a little hesitant at that point too. or maybe thats b/c i havent driven it much since January.

 

[GoodysGotaCuda]

sputter at cruise? is it kinda surging?

thats a sign of running lean like your plugs were showin. nice that its up and runnin!

[wally426ci]

So, Goody, would you suggest i go to a larger main jet size? ive never changed them. Im assuming that its something that an A/F mixture change would not fix. 

[GoodysGotaCuda]

You are running a edelbrock if i remember right? Do you have a tuning kit or know what jets/metering rods you have in there now?

I can walk you through the disassembly if you'd like so you can take a look. Very easy on an eddie

[wally426ci]

I have changed out the metering rods, but i cant remember what i put in. I have the kit. and the book, but it was easy. If i remember right, a certain size metering rod matches a certain size of jets? or can i sort of mix match? and yes, a sputter.

BTW, what was the initial timing im looking for? 12-14 if i remember right? so i should be looking for about 20 degrees at idle? cant remember..... 

[GoodysGotaCuda]

I mix and match since ive had to go wayy richer than edelbrocks chart goes for a 650 avs carb. little 318 is thirsty at WOT. You want to keep an eye on the diameter fuel can travel past. Such as if you have a 70x35 rod and a 101 jet you have .031" at cruise, and .066" at wot for fuel to travel through. You can also have a .110 jet with a 73x40 rod and get .037" and .070" wot. Totally different jet, but fairly close on the same mixture. So you want to take a look at those figures before you start changing stuff and see how far apart you are actually gettin.

fwiw i run 14* initial(idle) timing and 36* total

[wally426ci]

Cool, yeah after 1000's of posts that everyone has about timing, i still dont have the math right. I just want to get it straight. How can i figure out how much my advance is "advancing" 

I'll play with the metering rods later... 

[GoodysGotaCuda]

read your timing at idle. say. 10* with the vacuum line to the dist plugged.
bring rpm to 2500-3000 (full advance/total) say 35*

There is 25* of mechanical advance

To get vacuum advance, hook up the vacuum line to the dist again, bring rpm up to highest reading, say 50*. That will be your advance and cruising speed, vacuum advance is not a factor in wide open throttle tuning (since there is no vacuum ad WOT), and doesn't affect idle/initial timing.

[wally426ci]

Alrighty, I think its just a stupid misunderstanding on my end. Making it much harder then necessary. basically (haha) if the gun is in my fave what numbers at what rpm's am i looking at here  I hate to have Goody be the only one pulling his hair out here  so, i dont mind if anyone else chimes in. I know Chryco had a hell of a time trying to get the point across.... 





 

[MEK-Dangerfield]

OK you two, I'm jumping in...   


  A total timing of 34* is just about right for most of us, I think. I wouldn't mess around there. I think your problem is you are running lean. IF you had a Holley, I'd say go bigger 3-4 sizes on the jets in your primaries. I know if I'm off more than a coupe of sizes there, it feels like I have a "miss".


  Mike

[wally426ci]

 

Thanks Mike. Im gonna play around with it this weekend. Man, I havent had the car running right since we moved in. its rediculous. And just think, i thought i was pretty knowledgeable with these DA/\/\N cars! oh well, we all have something to learn i suppose.

 

I just wanted to make sure i had enough advance. you know, i did go pretty tiny with the jets back when i was running the stock motor..... so that sounds like a good place to start.

but then i cant figure out why id gas people out on the highway...... maybe that was my cousins Bee, we were cruising together... (insert coughing smiley) 

[Chryco Psycho]

Not to contradict Goody as he is usually bang on But the dist is connected to ported vacuum which is taken from the venturi not the manifold so at WOT you have maximum vacuum so under full load you will have 50* of timing ,,, to much to make power , if you connect it to manifold vacuum under load & increased RPM the timing will back off which makes a lot of heat but kills milage & power & ultimatly the engine & you have full advance at idle & deceleration when manifold vacuum peaks , not the correct way to hook things up

[GoodysGotaCuda]

Not to contradict Goody as he is usually bang on But the dist is connected to ported vacuum which is taken from the venturi not the manifold so at WOT you have maximum vacuum so under full load you will have 50* of timing ,,, to much to make power , if you connect it to manifold vacuum under load & increased RPM the timing will back off which makes a lot of heat but kills milage & power & ultimatly the engine & you have full advance at idle & deceleration when manifold vacuum peaks , not the correct way to hook things up

Thanks for that Chryco. However i did mention to plug the vacuum line because as soon as he revs his engine to check his total timing, that ported vacuum port in the venturi is now opened up and he will be reading his timing with vacuum advance. It may seem a little confusing the way i posted it because i put that 'plug the dist line' right next to checking initial timing. . sorry, just the way i do things rather than taking the line off and plugging it while the engine is running (i know since its ported it makes no difference).

However reading your reply you managed to make me confused on which port you are trying to recommend. lol. You say in one sentance that ported vacuum is not the way to go due to the fact at WOT that port recieves 'maximum vacuum' therefore advancing your timing, which kills power. Then mention about using the full manifold vacuum source so that the vacuum signal at high load and at high rpm the vacuum signal is decreased therefore getting rid of your advance (agree on high load/rpm vac signal goes down decreasing vac advance). The next sentance says you will get full advance at idle and decel (which i agree on) and is "not the correct way to do things"...

So if the ported vacuum take-off gives you 50* at WOT, and the full manifold vacuum soruce has full vac advance at idle & decel...Which to use?

As far as ported vacuum receiving full vacuum at WOT, im gonna have to test that one out for myself. Everything ive been taught has said otherwise because of the fact the throttle plates are at full 90* and there is now no restriction to make a pressure differential. (close to a diesel engine..they have no throttle plate, they make no vacuum. So throttle plates at 90* make very little if any vacuum at WOT). Sorry Chryco, not to say you are incorrect on that one, i just have to try it out myself (thats how i learn most the times).

[Chryco Psycho]

ported vacuum is the place to connect the advance so that it will advance with RPM , there is a allen screw to limit the advance curve to prevent over advancing & when using more than factory timing setting at idle , so if you have the initial timing at idle set at 16 * instead of 6* as the factory suggests you need to dial out 10* from the vacuum advance to keep it from over advancing

[GoodysGotaCuda]

Gotcha chryco, but are you still saying there is full vacuum advance at wide open throttle with using the ported vac port?