Timing

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Fuzzy

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1965 Plymouth Barracuda 273 Formula S HI-PO
New Pertronix D144600
New Edelbrock 1405 600cfm with spacer
New Blue Streak 8mm plug wires
Cleaned and regaped plugs
Engine was rebuilt before I bought it, ported and polised, new oe cam and not sure what else.

My question is the timing jumps 10 degrees at idle ( 700 rpm)
I've sprayed carb cleaner around the base of everything and no signs of vacuum leak.
I've adjusted the idle mixture screws as best I can.
Timing is set at 10 degrees BTC with vacuum disconnected.

Any idea why I can't get the timing steady?

Tried to give as much info as I could.

Thanks Mike
 
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I run my total timing (initial and mechanical) at 36 degrees. That puts initial just about 16 degrees.

Let me add, it's a 273 Commando with a Pertronix ignitor II module in a custom curved distributor.
 
66fyssh said:
I run my total timing (initial and mechanical) at 36 degrees. That puts initial just about 16 degrees.

Let me add, it's a 273 Commando with a Pertronix ignitor II module in a custom curved distributor.
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Centrifugal not included?
 
Could be a heck of a lot of things, including parts worn badly in the dist, or the intermediate gear/ shaft/ bushing screwed. I don't know if a loose floppy timing chain would do that at idle, but you might as well check it too.

Did the Pertronix parts fit "as expected?" Don't they use a special part under the rotor for trigger? Does it fit nice and snug?
 
RustyRatRod said:
My guess would be advance springs too light, one of them is broken or possibly disconnected.
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I just received the Pertronix II distributor yesterday and installed it today. Odd if it would be possible but I guess anything is. I'll check tomorrow.
 
Fuzzy said:
I just received the Pertronix II distributor yesterday and installed it today. Odd if it would be possible but I guess anything is. I'll check tomorrow.
Click to expand...

New isn't always good and there is no way in hell it can be tuned to your combo out of the box.....unless it's pure luck.
 
67Dart273 said:
Could be a heck of a lot of things, including parts worn badly in the dist, or the intermediate gear/ shaft/ bushing screwed. I don't know if a loose floppy timing chain would do that at idle, but you might as well check it too.

Did the Pertronix parts fit "as expected?" Don't they use a special part under the rotor for trigger? Does it fit nice and snug?
Click to expand...
I'll check all that tomorrow.
 
I would also suspect the new distributor.

I bought the ignitor II only and put it in my factory distributor.
 
66fyssh said:
I would also suspect the new distributor.

I bought the ignitor II only and put it in my factory distributor.
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I did that also to my original dual point but it needed rebuilt so I decided to just replace it.
 
Break out the FSM and see where the curve should be by RPM. If it is way off something internally is wrong like a broken spring like RRR mentioned.
 
Hey also you need to use a metal ditrib gasket, could be searching for a ground. See that on the machines once in a while.
 
halifaxhops said:
Hey also you need to use a metal ditrib gasket, could be searching for a ground. See that on the machines once in a while.
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On a small block? What? Chrysler V8s don't use a distributor gasket. They use a rubber o ring. The distributor collar is where the ground is picked up against the top of the block, so the bottom of the distributor collar and the top of the block in that area should be clean and paint free. That is where the ground is provided. I've even seen some that had a ground wire from the distributor housing to the firewall, although I don't know if that was factory or something that was added. It sure isn't a bad idea either way.
 
Rob some dual points don have the grove for the o ring and you have to use the metal seal for a great ground. Yes it can go through the clamp also but most are painted housings..

images?q=tbn:ANd9GcRBLI1SJI7YU7GuFLrR0C7D5egGgrDihIJ86WMurwIjgn32mEHk&s.jpg

img_8851-jpg.jpg
 
No if it has one use it. Make sure where the distrib makes contact to the engine has no paint on it for a good ground. Was just pointing out some don't use a o ring and people put a paper gasket on instead of a metal one and they get a funky ground. I hear about it all the time from people thinking the distrib is junk and needs rebuilding when it does not.
 
RustyRatRod said:
New isn't always good and there is no way in hell it can be tuned to your combo out of the box.....unless it's pure luck.
Click to expand...
You win door number 3! It was the new distributor. Put the old points distributor back in and the timing is perfect and stable. now I hope that pertronix will stand behind their product.
 
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