Too much timing?

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dartfreak75

dartfreak75

Restore it, Dont part it!
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I am tinkering around and playing with the tune on my 360. I was playing with the timing today with the vacuum gauge hooked up to the intake vacuum port. I used @318willrun method of timing i started with my idle at 800 in neutral bumped the timing up a couple degrees till the idle increased then reset the idle and continued to do that until it no longer increased the idle then took about 3 or 4 degrees out of it I ended up at 24 degrees! That seems like alot of initial timing to me. Im not getting any starter kick back it seems to run good i haven't driven it yet with this setup I wanted to check with yall first and make sure I don't damage anything by running to much. I know without vacuum I had about 34 total when I was at 14 intial so that's gonna put me at like 44 total now. That seems like too much to me?

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Yeah, that's probably a little much. Have you measured cranking pressure yet?
 
If it wants 24 at idle and it starts fine when hot, give it what it wants. Just make sure to limit the mechanical advance to compensate.

Does it stay at 24 when you reduce the idle RPM? At 850 with weak springs in the distributor, it may be advancing already.
 
mopowers said:
If it wants 24 at idle and it starts fine when hot, give it what it wants. Just make sure to limit the mechanical advance to compensate.

Does it stay at 24 when you reduce the idle RPM? At 850 with weak springs in the distributor, it may be advancing already.
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Im most definitely gonna have to limit the mechanical. I dropped it back to 14 and checked the total again im getting 40 total without vacuum. Thats 26 mechanical advance. I will check the timing with the idle reduced to see if the mechanical is advancing at 850rpm
 
dartfreak75 said:
Im most definitely gonna have to limit the mechanical. I dropped it back to 14 and checked the total again im getting 40 total without vacuum. Thats 26 mechanical advance. I will check the timing with the idle reduced to see if the mechanical is advancing at 850rpm
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You need an FBO limiter plate.
 
That FBO plate is nice, I welded the slots and used that to mark and check after filing it. that way I could use it on the next one or help a buddy out with theirs
 
I say run it, what is the engine ? a old 360 that had 8:0 to 1 comp.
If it doesn't ping and it starts when hot then I would run it. You might be surprised how much better it will run and get better fuel mileage.
 
Just checked the timing again I dialed it back to 14 and started over same thing this time used 700 rpm instead of 800 and I ended up the same place I turned it down to 20 it seems to like it. Im gonna have to limit the total tho. I drove it down the road it ran good at 20. I never really got into it but just cruised around 2200 rpm it feels really strong
 
brian6pac said:
I say run it, what is the engine ? a old 360 that had 8:0 to 1 comp.
If it doesn't ping and it starts when hot then I would run it. You might be surprised how much better it will run and get better fuel mileage.
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Its a 372, 360 .060 over 10:1 with iron heads.
 
One thing I noticed if get below 18 i fall out of the green on the vacuum gauge not sure how important that really is tho.
 
brian6pac said:
That makes a difference.
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Im running 90 rec gas non ethanol and so far I haven't had any issues with detonation. But I haven't really ran it hard yet either. I haven't had it over 3k but once or twice
 
dartfreak75 said:
Its a 372, 360 .060 over 10:1 with iron heads.
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And you MEASURED that at 10:1 if I remember right, so it's a true 10:1, right? If you have a compression gauge, get a plug out and get a compression reading. That will help us help you fine tune it.
 
dartfreak75 said:
One thing I noticed if get below 18 i fall out of the green on the vacuum gauge not sure how important that really is tho.
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That does mean something. It means it's getting out of its optimum vacuum range. You can do this. Twist in the minimum amount of timing it takes to get to the maximum reading on the vacuum gauge and see how it runs. Does that make sense? It doesn't always work on everything, but it's a good place to start. After you do that, check it with the light and see where it is.
 
That will be starting place. you’ll fine tune from there according to what the car wants. Yes, pull out the total that you added
 
vitamindart said:
That FBO plate is nice, I welded the slots and used that to mark and check after filing it. that way I could use it on the next one or help a buddy out with theirs
Click to expand...

I am thinking about getting another one and making my own based of of it. Don seemed very closed to the idea of producing one with smaller slots allowing for more limitation of the timing, which my slant six could benefit from. So I may do it myself.
 
low compression/cranking psi usually needs MORE initial with a performance cam, High compression/hi cranking psi usually needs less initial. my 360 with 11.3 to 1 and 205 cranking psi is fine at 8 degrees btdc ... i CAN add more initial no problem but then have to close my throttle plate more than i would like to get get a nice carb signal .
 
RustyRatRod said:
And you MEASURED that at 10:1 if I remember right, so it's a true 10:1, right? If you have a compression gauge, get a plug out and get a compression reading. That will help us help you fine tune it.
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Ok I will do that now brb
 
RustyRatRod said:
And you MEASURED that at 10:1 if I remember right, so it's a true 10:1, right? If you have a compression gauge, get a plug out and get a compression reading. That will help us help you fine tune it.
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Im getting 150 psi

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Your good, a little low so you can run a little more timing.
 
Are you running your cam straight up or adv, ret.
 
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