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  #16 (permalink)  
Old 04-15-2009, 06:01 PM
techinspector1's Avatar
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Quote:
Originally Posted by speedydeedy
I read the title under your name and if you can"t be nice to help a beginner just leave him alone. Some people need a little more understanding than others. It doesn"t mean they are stupid ,just a beginner that doesn"t understand your short quips.
You have a nice day too.
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  #17 (permalink)  
Old 04-15-2009, 08:56 PM
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Quote:
Originally Posted by 72steve
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
thanks for clarifying it for me
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.
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  #18 (permalink)  
Old 04-15-2009, 09:11 PM
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no sweat guys life is too short to take everything to heart!
if it wasn't for the older guys where would the world be!
thanks guys for all your help i will be taking a crack at on friday and let you guys know how it came out.
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  #19 (permalink)  
Old 04-15-2009, 09:50 PM
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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.
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  #20 (permalink)  
Old 04-16-2009, 05:23 PM
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Good info Cobalt 327
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  #21 (permalink)  
Old 05-09-2009, 08:09 PM
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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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