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Old 10-31-2016, 08:01 PM
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A los of power

I have a 1973 Z/28 5.7 350 When I step on the gas pedal it just loses power an dies the timing right at 8 below TDC is what the spec. but the timing mark jumps back an forth from 7 - 10 below. Put on a new gas filter, plugs, an wires, pvc, new HEI cap, 750 carb. Can any body help. Thanks

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Old 10-31-2016, 09:00 PM
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Need more info from you.

Is this a new vehicle to you??
Or have you owned it for a while and this issue has just started to happen??

Define "below"TDC as you say?? The correct term is Before TDC, standing at the front of the car the timing mark should be to the passenger side of the zero mark in order to be Before TDC.

Bounce in the timing setting can be sloppy weights and/or loose springs in the distributor mechanism, it can be too much enfplay in the distributor shaft between the gear and the end of the housing, it can be a worn loose timing chain, or it can be a loose/slipped outer weight ring on the harmonic balancer.
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Old 11-01-2016, 05:28 AM
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Quote:
Originally Posted by ericnova72 View Post
Need more info from you.

Is this a new vehicle to you?? No I had for 25 Yr. I been working on this car sent's I bought it. I built the engine 20 yr. ago it only has about 1000 miles on it. It been sitting for 15 yr. I started restoring it 5 yr. ago. I'm just a little rusty.
Or have you owned it for a while and this issue has just started to happens?? It started a coupe a month ago when I started driving it.


Define "below"TDC as you say?? The correct term is Before TDC, I know it was late. I just had it back words. standing at the front of the car the timing mark should be to the passenger side of the zero mark in order to be Before TDC. That where I was in front of the car and it is on the passenger side.

Bounce in the timing setting can be sloppy weights and/or loose springs in the distributor mechanism, it can be too much enfplay in the distributor shaft between the gear and the end of the housing, it can be a worn loose timing chain, or it can be a loose/slipped outer weight ring on the harmonic balancer.
Thanks for the help
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Old 11-01-2016, 05:48 AM
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Huh ???....
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Old 11-01-2016, 06:12 AM
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Is this a new vehicle to you?? No I had for 25 Yr. I been working on this car sent's I bought it. I built the engine 20 yr. ago it only has about 1000 miles on it. It been sitting for 15 yr. I started restoring it 5 yr. ago. I'm just a little rusty.
Or have you owned it for a while and this issue has just started to happens?? It started a coupe a month ago when I started driving it.


Define "below"TDC as you say?? The correct term is Before TDC, I know it was late. I just had it back words. standing at the front of the car the timing mark should be to the passenger side of the zero mark in order to be Before TDC. That where I was in front of the car and it is on the passenger side.

Bounce in the timing setting can be sloppy weights and/or loose springs in the distributor mechanism, it can be too much enfplay in the distributor shaft between the gear and the end of the housing, it can be a worn loose timing chain, or it can be a loose/slipped outer weight ring on the harmonic balancer.
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Old 11-01-2016, 06:18 AM
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JMHO, if you have MSD ignition (or similar CDI) and you are using an older type timing light (not rated for CDI), it may bounce around and not not read accurately. You may want to check with a vacuum gauge and a newer light.
Also, if your motor sat for 15 years, your carb probably needs rebuilding, as most likely all the rubber parts have deteriorated. The bog and die are classic signs of accelerator pump/carb problems. If the carb is new, check all adjustments to ensure they are correct, I have seen numerous carbs come out of the box with accelerator pump and other adjustments incorrect.
Believe it or not, sometimes you buy a new part but get one that someone has fiddled with and returned. Recently I had a new Holley that the accelerator pump was not even contacting the throttle cam arm, jets were wrong and the vacuum secondary had the wrong spring installed (opening way too soon). It made it a little challenging trying to tune someone else's mistakes.
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Old 11-01-2016, 07:32 AM
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A los of power

Inside your distributor you have a set of weights and two springs. If you have the GM HEI distributor remove the big old distributor cap. The weights and springs are under the rotor button so remove that too. Now that you can see everything make sure the weights are not covered with rust. Remove the two small springs, I use a small pair of needle-nose pliers. Move the weights in and out to see if they move freely. While you have it apart purchase an advance curve kit. It will come with new weights, 3 pairs of springs, and some bushings. Some come with just springs. If the stock weights are ok just install new springs. Try to match the springs you take off. Use your camera phone to take pictures of anything you remove in case you are not familiar with doing this. Be sure to re-install the bushings on all 4 post. If you open the distributor and it is full of rust you might want to purchase a replacement. https://www.summitracing.com/parts/s...t/model/camaro or you can do like some people do, take a chance on the Ebay distributors from $39.95 and up.
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Old 11-01-2016, 07:50 AM
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I got a new MSD distributor cap


Quote:
Originally Posted by camarodriver67 View Post
Inside your distributor you have a set of weights and two springs. If you have the GM HEI distributor remove the big old distributor cap. The weights and springs are under the rotor button so remove that too. Now that you can see everything make sure the weights are not covered with rust. Remove the two small springs, I use a small pair of needle-nose pliers. Move the weights in and out to see if they move freely. While you have it apart purchase an advance curve kit. It will come with new weights, 3 pairs of springs, and some bushings. Some come with just springs. If the stock weights are ok just install new springs. Try to match the springs you take off. Use your camera phone to take pictures of anything you remove in case you are not familiar with doing this. Be sure to re-install the bushings on all 4 post. If you open the distributor and it is full of rust you might want to purchase a replacement. https://www.summitracing.com/parts/s...t/model/camaro or you can do like some people do, take a chance on the Ebay distributors from $39.95 and up.
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Old 11-01-2016, 08:02 AM
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Quote:
Originally Posted by ericnova72 View Post
need more info from you.
Is this a new vehicle to you?? no i had for 25 yr. I been working on this car sent's i bought it. I built the engine 20 yr. Ago it only has about 1000 miles on it. It been sitting for 15 yr. I started restoring it 5 yr. Ago. I'm just a little rusty
or have you owned it for a while and this issue has just started to happen?? it started a coupe a month ago when i started driving it.


define "below"tdc as you say?? i know it was late. I just had it back words the correct term is before tdc, standing at the front of the car the timing mark should be to the passenger side of the zero mark in order to be before tdc. that where i was in front of the car and it is on the passenger side. Thanks for the help


bounce in the timing setting can be sloppy weights and/or loose springs in the distributor mechanism, it can be too much enfplay in the distributor shaft between the gear and the end of the housing, it can be a worn loose timing chain, or it can be a loose/slipped outer weight ring on the harmonic balancer.
1 2 34 5 6 7 8 9 10 11
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Old 11-01-2016, 08:11 AM
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No I had for 25 Yr. I been working on this car sent's I bought it. I built the engine 20 yr. ago it only has about 1000 miles on it. It been sitting for 15 yr. I started restoring it 5 yr. ago. I'm just a little rusty.
Or have you owned it for a while and this issue has just started to happens?? It started a coupe a month ago when I started driving it.


Define "below"TDC as you say?? The correct term is Before TDC, I know it was late. I just had it back words. standing at the front of the car the timing mark should be to the passenger side of the zero mark in order to be Before TDC. That where I was in front of the car and it is on the passenger side.

Bounce in the timing setting can be sloppy weights and/or loose springs in the distributor mechanism, it can be too much enfplay in the distributor shaft between the gear and the end of the housing, it can be a worn loose timing chain, or it can be a loose/slipped outer weight ring on the harmonic balancer. Today 07:48 AM

Quote:
Originally Posted by ericnova72 View Post
Need more info from you.

Is this a new vehicle to you??
Or have you owned it for a while and this issue has just started to happen??

Define "below"TDC as you say?? The correct term is Before TDC, standing at the front of the car the timing mark should be to the passenger side of the zero mark in order to be Before TDC.

Bounce in the timing setting can be sloppy weights and/or loose springs in the distributor mechanism, it can be too much enfplay in the distributor shaft between the gear and the end of the housing, it can be a worn loose timing chain, or it can be a loose/slipped outer weight ring on the harmonic balancer.
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Old 11-01-2016, 04:36 PM
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Cruzz - read : http://www.crankshaftcoalition.com/w...EI_distributor

Most all of the answers to 'how to' questions are answered in this article.

No one has mentioned but having your base timing set to 8 degrees seems a might bit low to me, even for a bone stock engine let alone anything with a performance cam.
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Old 11-04-2016, 04:22 PM
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Initial ignition timing depends upon the fuel you intend to burn, cam, and compression ratio.
Most SBC call for ~8 BTDC on pump gas. If running Alky, or Nitro, initial would start at ~ 16 BTDC or even earlier due to the slow burn.
Fords are oddballs, My 360 calls for initial to be TDC. But, if I were running some exotic high octane fuel, it would be way earlier.

Now the fluctuation described in the OP. leads me to believe the dizzy may have worn out bushings, allowing the shaft to wobble about, thus causing the timing to fluctuate.
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