Timing Adjustment=GOOD

ok, since i've done the vacuum removal on the carb, my car has been bogging at low rpms. i had adjusted things to where it wouldnt flood and stall when giving it gas from a stop. so today i was doing the timing on this guys truck and decided to see how much mine was off. lets just say it wasnt even close to where it should have been. anyway, i adjusted it close to where its supposed to be. i still need to fine tune it, buts its definately an improvement. it idles without sounding like it has a mild cam and now i'm going to check the gas mileage. i have a feeling it may help some. also i want to see how my morning starts go because it would run very rich upon start up until the choke opens. out of this today i got a free timing light. my instructor had got a new one and he just gave me this perfectly good timing light! cant complain. oh, and as for performance, i dont know about the timing adjustment doing much for top power, but now i can really spin tires good. before it would chirp and bog before taking off. great for low traction situations, but bad if i have to take off real quick because sometimes it made it stall. anyways, i'm going to work on the timing some more to get it to how i like it. now, what can i do about the pinging that's happening at lower rpms? maybe just disconnect one of the vacuum lines on the distributor advance?

This may sound like a dumb question, but what do you look for when you time it? because lately, mines been idling really rough and i dont think it was timed correctly when the new belt was put on...

first off you will need a timing light, often called a timing gun. if you have that, find the hole to look through, its on the transmisson housing butted up to the engine block. usually has a rubber stopper piece put in there, or it should. anyway, once you find that hole, you know where to look through. then have your car warmed up and at idle. then you will plug the timing light on and then aim it into the hole you will look through. you will then see a timing mark. it should be set around 4 degrees if its to factory specs. mine is about 5 degrees and ran great after i set it there. you need a 10 mm socket for the 2 bolts on the distributor, and probley an extension. i did anyway. well check these notes out i got from school on it today, that would be the best thing to follow.
http://photobucket.com/albums/v260/H...h_60cd8f93.jpghttp://photobucket.com/albums/v260/H...h_2971347f.jpg
http://img.photobucket.com/albums/v2...7/60cd8f93.jpg
http://img.photobucket.com/albums/v2...7/2971347f.jpg

awesome, thanks man, i'm gonna have to check it out tomorrow

so anyone know where the sweet spot, if there is one, is to set the timing mark? it was a about the middle spot , then i put it closer away from 0 where its marked either 5 or 6. i dont know what to do about the pinging besides adding higher grade fuel? i'm using 87 octane.

ok, as of now, i have adjusted the timing within limits. that means its idle is as smooth as its gonna get. i've adjusted the carb a/f mix to where its supposed to be without being too rich. still has that ping or predetination. whatever you like to say. maybe i just need to run a bit higher octane fuel then? that's what i had said before. i dont know if undoing the ABC thing would work. i've already tried A and B by themselves unplugged. also, the cam timing was done back when i got the timing belt replaced about 96000 miles, now it has 127000 miles about.

the A/F needle only adjust the idle mix... you shouldn't need to turn it out that much.

You only have #2 vacuum advance hooked up right?

Try dropping the idle down as low as you can go, make sure the car is in neutral, the accessories off, the coolant and engine warmed up fully. Choke off (Fully Open), or removed.

Try to get below 500 rpm idle.

Then while the car is idling adjust the air fuel mix screw.

At such a low rpm throttle almost completely closed, as long as you don't have a vacuum leak or igntion or fuel problem... you should notice the effects of turning the screw. Hear the carb as well as the rpms vary as you turn the screw in/out. Also make sure your float level is correct before begining the proceedure.

Make sure the o-ring on the A/F screw is good... also there is a spring and washer in there.

You usually want to leave the screw where the idle stops going up... or a little after is or before.
Say you were turning the screw in, leaning the mixture then you notticed the rpms drop... so you turn the screw out, richening the mixture and the rpms go up... stop when the rpms don't go up noticably from the last time you turned the screw... turn the screw a half turn each time listening to the rpms and carb. 1.0 is a full turn .5 is a half turn.

It's difficult to tell when the needle is seated/closing off the A/F port all together. It's such a fine thread and the Hole is Aluminum as well as the seat so it's easy to dig in and or strip the threads and go further then you should, especially if you have a lot of leverage on the tool you're using to adjust the A/F screw.

You want to try and turn it in first before you turn it out.

I wish I knew what port to drill on the idle jet... if it is in fact the idle jet. That would help you out considerably... that or get a weber. :D

http://www.webcon.co.uk/
http://www.webercarbsdirect.com/carburetors

http://www.autoquip.co.nz/
They Offer OER DCOE Replacement DCOE Carbs... prices are not in US dollars, I think it's in Australian Dollars.

those two places and a third place I'm still looking for have some okay prices for carbs. The 40 DCNF has a different throttle shaft alignment the the DGV ad other 2bbls which actually some people found worked better on a 4cylinder then the 38 weber.

Also if you removed the vacuum secondary and went with mechanical secondary you will need to port your intake manifold to remove the dividing plenum wall it should help a little.

i dont have much of any leverage on the screw driver i use to turn the a/f screw. its pretty small. anyway, i had it where the idle woudnt go up any more. but still pinging. so i've turned it out a few turns more than it was and it has significantly improved. so i'm going to be watching that as i'm driving it.

or dual webers. i really do want to do a dual set up. i probley wouldnt go to a 32/36 or the newer one. probley 40mm ones. anyway, maybe this thread will help someone solve something like this again. after richening the mixture by the a/f screw i dont hear the pinging. i kept going back, adjusting, then test driving it. i hope this was all worth it, i want better fuel mileage for the most part. the idle is really smooth compared to how it was before i did this today. even sounds better when its idling, a very noticeable bit too.

from what i know pinging is BAD!!! if your motor is pinging use higher octane fuel or change your timing, i know bad during the muscle car era you would turn the dizzy till it started to ping then back it off, i must mention this is not very safe. i took a quick glance ove the rest of the thread tring to see if anybody else said this and didnt bother reading the rest cause this is important , YOU DONT WANT TO HEAR PING'S. a ping is the motor telling you
"im gona blow"

I think he knows that. but thanks for mentioning it anyways.
Strange he was pinging if he set it to stock specs though.

I just read the last sentance of the first post... Why do you have both #25 and #2 connected?

On the image in the vac removal how to it clearly stated that hooking both up can cause the problem you are having.
Did you adjust the distributor with or without vacuum advance disabled?

pinging is really not great for an engine, but its not something to freak out about. not like when detonation happens. thats is bad and something to trip on. i did it with and without the vacuum on the distributor hooked up. i didnt see much change, but i'll probley try it once more. i drove the car today and it ran well without the pinging. maybe i was running too lean? after adjusting it that cleared it up. so i dont know.

I would freak out if my car pinged. :(

Then I'd fix it. :)

yeah i mean you should take some time to fix the problem if you engine pings a bit, but its not going to kill the engine. not for a while anyway. now if the engine had done that over the course of a few years i'd worry about internal damage. but like i said, tuning the carb seems to have solved the problem.

actually i've never heard of that in an engine that's been timed correctly, maybe at high rpms, but not very likely if its timed right. the pings are caused by the combustion chamber heating up too much, in turn causeing predetonation of the fuel. that's what you hear if you are useing too low octane grade of fuel for you engine or its running lean, which i think mine was after doing the timing adjustment.

pinging is detonation. i don't think there's such a thing as pre-detonation. by definition it happens after combustion.
if you were getting pre-ignition you would know because very bad things would happen very fast.

Quote:

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Originally Posted by HondaBoy

actually i've never heard of that in an engine that's been timed correctly, maybe at high rpms, but not very likely if its timed right. the pings are caused by the combustion chamber heating up too much, in turn causeing predetonation of the fuel. that's what you hear if you are useing too low octane grade of fuel for you engine or its running lean, which i think mine was after doing the timing adjustment.

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I think you ment pre-ignition... ignition early when the pistion is still on it's way up... very bad cause you can get engine damage that way. Not that the spark plug doesn't fire as the pistion is going up... but it has to account for the time it takes the flame to spread, etc... anyways, ignition before the spark fires.

yeah, i meant preignition, and its one word for future reference. ok, by defintition it is abnormal combution, which is caused by something other than the heat of the spark. i'm sure most of y'all didnt know i'm going to school for auto tech. so most of this i'm learning right now. interesting stuff to know, makes thing make a lot of sence. oh and for an update on the car, its running great.

http://www.streetrodstuff.com/Articl...tion/index.php

this is a really, really good article.

its starting to warm up some, so i need to adjust the carb again for our hot temps we have here. but anyway, doing the timing and adjusting the carb as much as i have has made a bit of difference in the fuel mileage. i'm now getting better mileage. not sure how much yet, but its good. i did over 90 miles to 4.5 gallons. i still havent used up the 4 gallons though. so its lookin good.

ok, so fuel mileage is better. now that i've been putting in 89 octane gas its running a whole lot better with more power and not a touch of pinging. maybe it just needed some higher octane fuel?

I read somewhere that you find your N/A ballpark octane by CR

9.1:1 = 91 octane
9.3:1 = 93 octane

11:1 = 110 octane

when you think of all the N/A cars with about 8.8:1 CR that use 88 octane... or 87 since thats usually whats available

yeah, i was originally using some 87 octane. it didnt ping too much, but randomly it did it. after the change to 89 octane its quit all together. i'm going to probably retune the a/f adjustment again since i richened it up when i was using 87 octane.

Quote:

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Originally Posted by cke

pings are usually the pistons hitting the valves. ;/

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I remember reading in another thread....I thought it was decided that 3G's had non-interference engines....which would mean the pistons can't hit the valves, right?

ok, well i still had an intermitent pinging once in a while. i thought it was happening because the distributor had no advance vacuum hooked up. so i decided to try the port on the carb that originally pulled the secondary open, hooked up to the advance diaphram on the distributor. seems to have done the trick and even makes it run a noticeable amount better at wot. here's a pic of how the engine bay looks now. i plan to clean it up some with some black wire looms for the accessory wires and then take the rest of the old vacuum bs junk out thats still left just sitting in there. this way i have it hooked up right now is the best its run so far. only thing running off vacuum is the distributor advance and still connected to the ABC bleeder thingy.
http://img.photobucket.com/albums/v2...7/b2b904a1.jpg

Ahaha, :D

I guess you could go that route, but what is running the secondary?
you could always add a "T" fitting to tap both the secondary and the distributor to the carb.

You do realize that hooking the vacuum advance that way reverses the direction your advance moves in?

Normally Manifold vaccum will hold the ignition advance at one point then as vaccum drops the amount of advance changes.

When you use Venturi vaccum, the venturi vaccum drops when the throttle is closed but increases as the throttle is opened which you cause the distributor to advance/retard the timing the other way the more you open the throttle, untill it stops moving.

You've basically reversed the function of the diaphragm. You now have a Vaccum Retard Diaphragm :) hehe

I see a potential vacuum leak in your picture... plug the choke puller vacuum ports. It may be a minute leak but a leak is a leak.