SBC base timing
 

What do you run for base timing in a non stock 350?
The new motor is .30 over 10:1 pistons 650 cfm holley and a mild cam(
valve lift Int .420 exh .443
cam lift Int .280 Exh .295
duration 278 288\
hyd lifters (not roller) )

Some people say to advance timing until I pings and then back off 2 degrees, others say to use a vacuum gauge. I just don't want to run to advanced.
starts and runs well at 14 degrees .not enough? to much? points dist with working vacuum advance.
opinions?

Re: SBC base timing
 

That sounds about right. I usually start at about 10 degrees than advance like you said until it starts to change than back off a little. Take it out and run it up under load, if it feels good and is not popping back thru the intake you are good.

Re: SBC base timing
 

I like to start at 10-12*. And then go from there.

Re: SBC base timing
 

Same combo and mine is base set at 12

Re: SBC base timing
 

Mine was set at 12 degrees for the initial start up and I adjusted from there, I'm at just under 14 now. I installed a vacuum gauge in the intake manifold and used that to tune it balancing timing and fuel adjustments to get the vac as high as I could.

Re: SBC base timing
 

Could my HEI be 180* off? (350)
I can't get the light on a crank mark.
Hooked on plug #1.

Can I just pull it up and spin the rotor and set it back in?

Does one full rotation do it?

Re: SBC base timing
 

IF your distributor was 180 out the engine would not run.it would not start and be popping back thru carb when cranked over.

Re: SBC base timing
 

It starts and runs fine. I just think the flash should light up a mark or two.
I won't worry, then.

Thanks!

Re: SBC base timing
 

I f your distributor AND spark plug wires is 180° off it will be like that. Check if #1 wire is in correct position.

Edit: Hmm..... maybe not. At a second thought it should lit the mark anyway

Re: SBC base timing
 

I'll scrub the wheel real good!*

*swear I saw a photo on here, of a guy cleaning his as it spun.

Re: SBC base timing
 

Pretty sure he said "hold my beer while I clean this". Then "where the H*** is my finger" when he woke up in the ER....

Re: SBC base timing
 

Most timing light clamps will have an arrow which is the direction of the spark plug.

Re: SBC base timing
 

make sure your clamp lead is not draping over other leads. That will cause it to pick up a different pulse.

Re: SBC base timing
 

I am refreshing my 1406 right now, so I will give the timing light
another try a bit later.
I also need to shim my new starter, too. It screams at me.

Re: SBC base timing
 

highsider, you may have a 305 balancer. The timer mark on those are at the 12 o clock position vs. the 2 o clock position for the 350 @ TDC.
Put the engine back to #1 TDC and see where you see the mark.
I like to be at 36 degrees total timing @2000RPM
Jeff

Re: SBC base timing
 

No kidding?
I never looked there.
I will see how close to 36 I am.
Thanks!

Re: SBC base timing
 

Never trust the balancer marks! Im assuming you know but no one mentioned to unplug vacuum advance when checking timing (and run advance on PORTED vacuum, not manifold vac.). Also I like to use a compound guage (vacuum guage) when setting timing to see when vacuum drops. I start base timing @ 12-14 deg. , total timing around 34, Also another really important setting w points is dwell and it should be around 28-32. Even with all this info I still try to set it up by ear if I think the balancer spun or it just doesn't run well. I always default to road tuning and whatever the engine reacts to. SOmetimes feel and hearing is the best tool.

Re: SBC base timing
 

Please define "PORTED vacuum".

- I tape the ends on the advance hose/ports.

- I have used the vacuum gauge and tried for the highest reading which was around 13-14 if I recall.

I make sure I like the way it starts, then road test it for any pinging and retard it slightly, get back in and test.

Any advice or tips will be considered!

Re: SBC base timing
 

ported vacuum is above the carb throttle plate and is always on the carb. It slowly pulls vacuum as the throttle valve is opened. If you put your finger over a ported vacuum source at idle it will be barely felt if at all but as you increase throttle it will pull more vacuum. Manifold vacuum is exactly what it is. It is a vacuum source pulled off the manifold or UNDER the throttle plate. Its vacuum will be constant and you will feel it pull a lot more vacuum at idle and usually if you unplug a manifold vacuum source while running it will run like crap until you plug it back up.

Re: SBC base timing
 

I use one of the small ports, above the throttle plate.
I was dense as to the term.
Thanks.
http://i48.photobucket.com/albums/f2...ps8f9a801a.jpg

Re: SBC base timing
 

Ugh, I hate edelbrock carbs. I have so many problems with those damn things. You need to get a holley! The big port is manifold for like a brake booster. The one on the left is ported I believe. the one on the right is manifold. but to be sure id test them like I mentioned earlier.

Re: SBC base timing
 

I just cleaned and installed floats and a kit, on the 1406, so I will drive it a while and see if I made any improvement.

Left outlet, is where the advance plugs in. Large one runs the PCV hose.

Re: SBC base timing
 

Wheelie-
You got me thinking when you said large center pipe "for a brake booster" and I have it on the PCV hose.
Here is where my brake vacuum hooks up. Should I swap it with the PCV port?

http://i48.photobucket.com/albums/f2...ps06d57740.jpg

Re: SBC base timing
 

You have it right, pvc goes to carb, booster and auto trans to the manifold.

Re: SBC base timing
 

Cool, Orrie. Thx.