timing/ other sparky questions

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duster wonder

duster wonder

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building 360 sb. so far kb107's, 30 over, stock valve size, about 9.3:1 compression, comp 20-222-3 cam valvetrain kit, weiand dual plane intake, eddy performer 600 cfm

1.clueless where to start timing, i know what stock is but will my cam need different timing numbers? .462/.470 lift, 262/270 duration

2.what should i do with my distributer? what i mean is any advise on spring advance changes, or leave it all stock? plan on rebuilding it. where is the ideal place to hook up the vacum? (street)

3.has anybody ran the cheby type distributor with the hei coil on top? lookin at the 60 buck ones on ebay.

4.what about spark plugs? should i run stock what the auto zone guy finds or buy something "better" (obviously not the cheap cheap ones)

5.thanks for any help you can tell if im asking these questions im gettin close!!:burnout:
 
for now id stick with the factory dizzy springs just to see how it does. also kill the vacuum advance, it literally retards timing at idle (high manifold vacuum) Static timing id start at 10 BTDC since most factory springs deliver 22-26 degrees of advance at approx 25-2800 rpm, that usually will get you close to the magical 37-38 degrees of full advance. As for plugs, im a fan of NGK V-powers, champion copper cores and platinum plugs do ok, but i noticed a much smoother idle and faster warm up time with the v-powers in my SB, and i dont run a choke either. chokes are problematic and big headache when they fail. if dieseling is experienced upon shut down, either retard the static timing a couple degrees, or turn the idle down. Hopefully this will get you in the ballpark. cheers.
 
66durgederp said:
for now id stick with the factory dizzy springs just to see how it does. also kill the vacuum advance, it literally retards timing at idle (high manifold vacuum).
Click to expand...

I don't know where you get the idea that vacuum at idle retards timing. NOT correct.

Frankly with such a big cam, I'd "start off right" Either get your dist. recurved, or buy and aftermarket dist. with an adjustable mechanism. Most performance Accel/ Mallory etc are of that type.

I would say you want 15-20* initial, and play with total mechanical as compression and fuel, engine and local temperature dictates, somewhere between 34-38 total.

Bear in mind that factory manuals and many specs on distributors are in DISTRIBUTOR degrees which are HALF of "crank degrees."

So if your stock dist weights are stamped "15" that is THIRTY at the crank, way way too much.

One thing you can do as a "backyard trick" until you get a different dist is to pull both springs out, and "total time" the engine for around 34*. It might not run great at low RPM as it may be "over" advanced until about 2000 but that's better than the alternative --- a long slow "over" advance from the stock springs.

IF you need to break in the cam, IE need to fire and immediately run the engine at 1800 or whatever the cam guys says, set your timing by:

Bring up no1 on compression, but do NOT set the marks at TDC, but rather at 32* BTC or so Drop in the dist, and adjust the housing so that the reluctor wheel is centered in the pickup coil core. This will be close enough to fire and get the engine "up there" for the break in. Once you get it stable, check for oil press, leaks, problems, you can use a light on it to bump it up a little if you need to.
 
demon408 thank you for the tech articles. I had a crude lack of understanding about the vacuum advance systems......thats was very helpful. Ill think things over before i open my mouth from now on.
 
Glad they helped. There's a lot of helpful well meaning people here, but it's in your best interest to be educated so you can sort through the B.S.
 
Demon 408 said:
Glad they helped. There's a lot of helpful well meaning people here, but it's in your best interest to be educated so you can sort through the B.S.
Click to expand...

Well said.
There is nothing wrong with asking a question, but bad answers suck.
General rule is to go what at least two people agree on. :D
 
I'd run that set up at around 15-16* initial and 18-20 mechanical, 34-35 total all in at 2200-2400. Should be a pretty safe tune up that will perform very well.
 
thanks guys goin to germany again in october and right when i get back that 360 is goin in, ill update my forum page on it when i get er goin
 
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