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timing

2K views 20 replies 7 participants last post by  cobalt327 
#1 ·
can someone tell me the steps they take to tune the timing and the carb?
i have been reading different sites and forums but i am still unsure.

How do i check where it is currently set at?(what do i look for?)
and every other step after that.

this something i do want to learn so please bare with me
thanks steve
 
#8 · (Edited)
i have a 350 .030 bore
10/10 crank polished
forged flat top pistons
cam 465/480
1.5 aluminum roller rockers
edlebrock rpm heads
edlebrock rpm intake
edelbrock 1407 electric carb
50,000 hei

is this enough info?

sorry didn't know what you were asking :embarrass
thanks for clarifying it for me :thumbup:
 
#10 · (Edited)
techinspector1 said:
Those who would ridicule my demeanor and approach have not read the title under my screen name. :thumbup:
That means nothing to me. :D

That's why me and so many other ''GOOD'' people have left this site.I don't post much here any more because of smart a**'s like you.Give the man a break... This is the kind of sh** the mods should put a stop too.This was a place for the beginners to be able to find out what they need to know..Putting a beginner down isn't the way you should do it...Refer to post 4.....Give me a break man... :spank: Very very childish!!! the wording under your name, fit's you well.. :smash:
 
#12 ·
Steve,Any timing light will do but the one with a battery so you don"t have to have extra wires hanging to the battery and the dial to zero are the nicest to use.Start by warming up your engine so it will idle.Disconnect and plug your vacuum advance line coming from the carb.Make sure you block the carb side so you don"t have a vacuum leak.Then set your base timing .I like about 12 degrees before TDC but that is up for discussion depending on how your engine reacts to it.Then hook your vacuum advance back up and check your total timing.Slowly speed up the engine and watch the tining,when it stops advancing this is your total timing.If your balancer is not degreed this high that is where the dial timing light comes in.Again up for discussion I like my total timing around 36 degrees. Hope this helps. :thumbup:
 
#14 ·
Welcome to Hotrodders Steve. Ok guys...remember that this is the inter-net and its sometimes hard to tell if someone is kidding, joking, or being a smart aleck. Lets give Tech the benefit of the doubt...I think he was just kidding around trying to break the ice with a new member.......Senior Curmudgin......ha ha ha I think that might resemble a friendly old fart that is more than willing to help others. Thats got to be it because I have seen him help a lot of folks on here...especially beginners. Hats off to SpeedyDeedy for a good answer and description on timing...you done good! :thumbup:
 
#15 ·
NEW INTERIORS said:
That means nothing to me. :D

That's why me and so many other ''GOOD'' people have left this site.I don't post much here any more because of smart a**'s like you.Give the man a break... This is the kind of sh** the mods should put a stop too.This was a place for the beginners to be able to find out what they need to know..Putting a beginner down isn't the way you should do it...Refer to post 4.....Give me a break man... :spank: Very very childish!!! the wording under your name, fit's you well.. :smash:
Have a nice day.
 
#17 ·
72steve said:
i have a 350 .030 bore
10/10 crank polished
forged flat top pistons
cam 465/480
1.5 aluminum roller rockers
edlebrock rpm heads
edlebrock rpm intake
edelbrock 1407 electric carb
50,000 hei

is this enough info?

sorry didn't know what you were asking :embarrass
thanks for clarifying it for me :thumbup:
This will work for early computer cars. Yours won't have the TPS issue.

Basically same procedure for your engine just no computer.

Warm up engine to regular operating temp, and ensure idle speed stays below 1000 rpm.
Run engine at 2000 rpm for 2 minutes under no-load [in neutral, no accessories on]. Race engine 2 or 3 times under no-load, then run engine at idle speed. [this heats up the oxygen sensor so it is working]
Turn off engine and disconnect throttle position sensor (TPS) harness connector. [It's on the side of the throttle body facing the firewall - driver side of the engine, down low and past the brake master-cylinder]
Start engine. Race engine (2 - 3000 rpm) under no-load, the run at idle speed. [You may have trouble keeping it running with the throttle sensor disconnected. Depending on where your timing is set, it may stall. If so have someone sit in the car and press the gas *very slightly* to keep it running. Don't rev it up or you will not get an accurate timing reading/adjustment. Keep it at idle speed, about 800 rpm]
Check ignition timing with a timing light. It should be 15 degrees plus or minus 2 degrees Before Top Dead Center. [The timing mark at the extreme left (counter-clockwise) is zero degrees. There are lines at 5, 10 and 20 degrees to the right of it. There is a wide paint mark from 13 to 15 degrees, which the factory probably set yours to. Eyeball 17 degrees between the marks and that's what you want.]
From the 1991 Technical Bulletins, Beginning with April 1991 production,
the ignition timing mating mark has been changed as shown below.

NEW marks at -5,0,5,10,13,white paint,15,20 B.T.D.C..
OLD marks at 0,5,10,15,20 B.T.D.C..

[Editoral note: there has been a lot of dicussion about the timing marks and basically it comes down to the easiest way to find the 15 degree mark after the early '91 production is to look for the white paint or the two marks that appear very close to each other. ]



-5 0 5 10 1315 20

| | | | ### |

^
17

If not, slightly loosen two bolts holding the distributor, and twist it [toward the front of the engine to advance, toward the cabin to retard] to obtain the desired timing. [Recheck the setting after tightening the bolts!].
Shut off engine and reconnect throttle sensor.
 
#19 ·
Making a semi-permanent timing tape is very easy, and removes any doubt as to where the timing marks are or were supposed to be- provided that:

1. You know (or verify) what line on the tab is actually "0" degrees (TDC),
OR-
2. You find TDC by using a piston stop and fashion a timing "tab" (often a stiff piece of wire secured behind a convenient bolt) that aligns with the line on the damper to represent "0" or TDC.

Once TDC is established, the rest goes like this-

Using either a string, ruler or a seamstress' cloth tape measure, measure the circumference of the damper. If you only have a straight ruler, measure the diameter and multiply by 3.1416 (pi) to get the circumference.

Once the circumference is known, 1/10 of this figure represents 36 degrees. Half of that is 16*, half again is 8*, etc. Doesn't matter what units you use- metric, inch, or nanoparsec's.

When marking your home-made tape, starting from "0", BTDC will be to the right, ATDC to the left of "0".

Careful measurement and marking of the degrees in this fashion on a length of masking tape can then be applied to the damper, aligning "0" on the tape to the line on the balancer, with the degrees BTDC to the right of this mark.

If you are going to invest in a timing light, you might consider an inductive light with an "advance" feature. This allows you to read the timing from just the "0" point, the timing light will then adjust itself to show whatever amount of advance you want, or read the advance without regard for a timing tabs marks, except for an accurate "0" mark.

They cost more than a standard light, but if you plan on tuning engines beyond the basics, it will pay for itself in the long run, IMHO.

This sounds more complicated than it really is. ;)

Good luck.
 
#21 ·
Correction To Post#19

In my post #19, above on making a timing tape, the paragraph that reads:

"Once the circumference is known, 1/10 of this figure represents 36 degrees. Half of that is 16*, half again is 8*, etc. Doesn't matter what units you use- metric, inch, or nanoparsec's",

SHOULD read:

"Once the circumference is known, 1/10 of this figure represents 36 degrees. Half of that is 18*, half again is 9*, etc. Doesn't matter what units you use- metric, inch, or nanoparsec's.

Sorry for any confusion this may have caused.

The correct procedure is as follows and is shown in its correct form in the Tech Article Wiki "How To Make A Timing Tape"

Making a semi-permanent timing tape is very easy, and removes any doubt as to where the timing marks are or were supposed to be- provided that:

1. You know (or verify) what line on the tab is actually "0" degrees (TDC),

OR-

2. You find TDC by using a piston stop and fashion a timing "tab" (often a stiff piece of wire secured behind a convenient bolt) that aligns with the line on the damper to represent "0" or TDC.

Once TDC is established, the rest goes like this-

Using either a string, ruler or a seamstress' cloth tape measure, measure the circumference of the damper. If you only have a straight ruler, measure the diameter and multiply by 3.1416 (pi) to get the circumference.

Once the circumference is known, 1/10 of this figure represents 36 degrees. Half of that is 18*, half again is 9*, etc. Doesn't matter what units you use- metric, inch, or nanoparsec's.

When marking your home-made tape, starting from "0", BTDC will be to the right, ATDC to the left of "0".

Careful measurement and marking of the degrees in this fashion on a length of masking tape can then be applied to the damper, aligning "0" on the tape to the line on the balancer, with the degrees BTDC to the right of this mark.

If you are going to invest in a timing light, you might consider an inductive light with an "advance" feature. This allows you to read the timing from just the "0" point, the timing light will then adjust itself to show whatever amount of advance you want, or read the advance without regard for a timing tabs marks, except for an accurate "0" mark.

They cost more than a standard light, but if you plan on tuning engines beyond the basics, it will pay for itself in the long run, IMHO.

This sounds more complicated than it really is.

Good luck.
 
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