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Discussion Starter #1
I'm having trouble figuring out my total timing and stop the pinging on my freshly built 460 in my 1970 Torino with c6 and 3:50's. The 460 is supposed to be in the 435hp range with 500+ftlbs. It is zero decked with domed forged pistons and worked d3 heads with static compression around 10.3-10.5. It has a lunati 61602 cam, 219 int and 227 ext at 0.50. The distributor is a remanufactured duraspark re curved for the engine to idle at 14 degrees and 38-39 total.

I've set the timing at 14 initial and 38 total and i am running 94 octane (Vancouver Canada) but I get pinging under moderate load. I set my total timing at 38 degrees with vacum advance unhooked and hose blocked at 2500rpm. When I brought it to a shop the mechanic checked it with the vacuum attached and it read 51 degrees which he said is way too much. He told me to run it at 35degrees total and to leave the vacum advance unhooked, said vacumm advance only really helps with gas milage from 2000-3000 rpm range and it is better to leave it off, because with it hooked up and keeping my total timing at 51 degrees is hard on the engine especially in the heat.

But with it un-hooked I'm still getting pinging under load at moderate acceleration.


What's the proper way to check total timing? And as far as the pinging, do I just need to start knocking back my initial and drive it with no vacumm advance? Or should I run the vacumm advance and try and take out some advance at my adjustable dashpot on my distributor?

Thanks
Mat
 

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Try to see how it runs with 34 total and 10 initial. What are your coolant temps? You may possibly have a little extra fuel at the rpm you are getting fuel and may need to lean that circuit out a little or try a colder plug.
 

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Discussion Starter #3
Car runs pretty consistent at 180 creeps to 190 in traffic after hard driving. So total 34 with advance un-hooked???
Already running a cooler than stock plug.
Thanks mat
 

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1970 Torino with c6 and 3:50's= heavy. Small cam with 10.3 or more comp= less advance. You have 38 all in at 2500. I would say, it's coming in a bit too fast and 38 is a bit too high. Try to get it at 35-36 all in at 3000. Then you should be able to adjust the vac advance so it will work. Around 45 total w/vac advance is usually pretty good for pump gas around my place.
 

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Temps seem good, I would leave the vacuum advance hooked up once you have the timing set.

You may need to adjust the advance there should be instructions with most re-mans on how to do this. If you can find a shop that still has a distributor tuning machine that would be the way to go I think. The problem is they have pretty much all done away with these machines so it will be hard to find.

Yeah I would try 34 total 38 seems a little high with your compression and the otane available. From my experience factory cast heads like timing but compression and fuel limit this.
 

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The AMOUNT of total timing probably isn't your problen ... it simply happens WAY to soon for a 10.5/1 engine on 94 octane. As has been said, slow down the distributor advance curve with that much compression ratio on pump gas.
 

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Discussion Starter #7
Thanks for all the info. So to slow it down,'do I do this by backing some of at the vacumm advance????I think on my unit I just dial the whole vacumm diaphragm back, to rake out some of the advance, hence slow it down or making coming in slower, is this right????

Thanks mat
 

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Thanks for all the info. So to slow it down,'do I do this by backing some of at the vacumm advance????I think on my unit I just dial the whole vacumm diaphragm back, to rake out some of the advance, hence slow it down or making coming in slower, is this right????

Thanks mat
Bend the tabs holding the cam springs outward to apply more spring pressure. This slows down the mechanical advance. If that doesn't do it, put in heavier springs. It's the mechanical advance that you want to delay. I'd disconnect the vacuum advance for now until you get the initial and mechanical dialed in.
 

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Call me matt and i will walk you through this.


:D
 
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