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Gm goodwrech low compression timing

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Old 05-31-2018, 02:46 PM   #1  
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Gm goodwrech low compression timing

So I was wondering I have a 86 trans am with a gm goodwrench 350 and I know they are low compression engines so I am wondering about the base timing instead of 6゚ advance would it change due to lower compression would I want to adjust it more retarded or advance due to the low compression for it to run better?

she runs good just maybe the 6 adv is not good enough due to different head and compression.
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Old 06-13-2018, 12:43 PM   #2  
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Re: Gm goodwrech low compression timing

Does anyone know?

thanks.

just shes running a little warm, around 220+/-, but figured its due to timing because after putting it at 6* tdc it runs cooler. But still gets up too hot, i have the factory fan and a 160* thermostat, and yes it is tuned so my fan is on at 165* just doesnt cool very well when im driving around town.

i have a good air dam on it so not sure why she runs so warm. She will get to 240*.... and thats way to warm.
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Old 06-13-2018, 01:41 PM   #3  
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Re: Gm goodwrech low compression timing

Lower compression and a "slow burn" combustion chamber will want more advance (generally speaking). Bump it up a little more to see how it acts.
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Old 06-13-2018, 01:47 PM   #4  
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Re: Gm goodwrech low compression timing

Advance the timing. Test drive it.

One of 3 things will happen:

Nothing;
It will run worse;
It will run better.

You will accordingly do 1 of 3 things:

Put it back and shut the hood;
Turn it back where it was, plus a little more;
Advance it some more.

Test drive it. It will be either better or worse.

Better: do some more of whatever you last did.
Worse: go back, plus a little bit more.

Repeat until no further improvement occurs. Shut the hood.

We call this process "tuning". Instead of telling the engine what we think it should have, we ask it what it wants. It answers by running better or worse.

If it RUNS good, it IS good.
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Old 06-13-2018, 01:51 PM   #5  
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Re: Gm goodwrech low compression timing

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Originally Posted by pancherj View Post
Lower compression and a "slow burn" combustion chamber will want more advance (generally speaking). Bump it up a little more to see how it acts.

ill bump it 2 degrees or should i go 4 degrees?
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Old 06-13-2018, 02:14 PM   #6  
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Re: Gm goodwrech low compression timing

"I like big changes"...(that's a quote from Roadkill). Sofa is giving you good advice. Make a 4 degree change and see how it acts.
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Old 06-13-2018, 03:52 PM   #7  
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Re: Gm goodwrech low compression timing

I would double it from 6 degrees to 12 degrees initial...
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Old 06-13-2018, 03:54 PM   #8  
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Re: Gm goodwrech low compression timing

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