350turbo411

Hello.. my buddy says my car is running at 17 degrees advanced. I told him thats where it runs good.. at idle...now its pinging...but..I told him that the car will barely idle when the timing is where it should be.....*** i dont think it would even run at 10....

When i installed the distributor...i just slapped it in...its like a tooth or two off.....I just turned the distributor until the #1 on the cap and the #1TDC matched.. this is OK..to compensate like this right??? He told me to set it correctly..and the car will run better...

I dont think that has anything to do with it right..as long as the rotor is lined up with #1 on the cap............

I can only get it to run..if i advance the timing pretty good..

non CC Dist
72 350
Holley carb
305 heads..

etc...

.488/.488 cam..

rob

ronterry

Yea, your right...It's all about where the cap & rotor line up in relationship to TDC...
Sometimes I work on getting it aligned so my cap is hafe way straight at 20°btc. That btw is where my non-CC-car likes to idle at. This will be different on any combo.
I don't know what he's talking about being a tooth off? There is no tooth match???

Now, one tooth off on the timing chain is a different matter.

-----
You might be having some trouble with your total timing...Make sure your not exceeding 36-38 at 3000+rpms...If you are than you need to limit your mechanical advance...I willing to bet you are...If you took a stock distributor, and moved it up 8 or 10° from it's stock setting, than your more than likley have 8 or 10° to much total advance...
You might also temporally disconnect your vacuum advance to rule that out...


Ron

91CamaroRS305

iTrader: (2)

my distributor was a tooth advanced and it ran weird and ruin my plugs i put in like 3 weeks ago, but with your mods it might not matter cause you seem no where near stock, but just my 2 cents

mrr23

in a v8 car doesn't matter where you drop it in at. you might have a stretched timing chain. or balancer as started to slip.

f-crazy

iTrader: (-1)

if it doesnt matter how you put it in then why does every rebuild book says to drop it in with the #1 at TDC with both intake and exhaust valves closed and the rotor to be pointing at the #1 intake valve?....sounds pretty specific to me


id say you should be running 10 degrees or so of initial and another 22-25 of advance

mrr23

to be consistent with the factory of assembling 100,000 motors. doesn't matter. period. you can position it anywhere you want. engine fires every 90*. if it was an oddfire buick 231 v6, then it matters.

considering my rotor points at the left tire and i run 12.43, maybe if i point it at the #1 cylinder i'll run 11's. dang it now i know why i can't hit 11's.

ronterry

'f-crazy' there is not tooth matching like on the timing chain. Now If I pull the distributor out, I will aim the rotor when inserting the distributor slightly to driver side when #1 is at TDC. To get the desired timing I rotate the base/cap.
The main reasons for aiming the rotor slightly to the driver side is because of plug wire reach.

Hell If I wanted to I could rotate the engine till it's at #1 TDC, than cut the wires for proper length, insert the rotor pointed toward the rear of the car, & install the wires in proper order starting with #1 inserted onto the contact the rotor is pointed at.

It makes no difference in performance what tooth your distributor is riding. Setting the proper timing curve/rate & total timing is everything in performance.

Ron

25thanniversZ

yep, I ran my 72 gms 350 180deg and rerouted the wires just to see if it would run like that and it did,but as stated it just keeps things simple dropping it on #1

OMINOUS_87

About the 1 tooth off thing. If you pull your distributor for whatever reason on a motor with known good base timing and then try to put it back in exacty how it came out with the intention of putting it back eactly the same way as to avoid using a timing light to properly set base again if you are 1 tooth off your timing will be jacked. So what does this mean? ALWAYS USE A LIGHT! Forget about the 1 tooth mumbo jumbo.

ede

agreed use a light and there is no "one tooth off" on a SBC, or BBC among others as far as the distributor is concerned. timing gears are another matter.

TomP

If you want to read more on it, check out the end of this message: https://www.thirdgen.org/techbb2/sho...threadid=60772 It says why you can drop a distributor in any 'ol way you want, as long as the rotor lines up with the correct cap terminal for #1 TDC compression... granted this was on the v6 forum, but same thing applies for v8's!

F-BIRD'88

Rob: Because of the rough idle nature of you camshaft,
The motor will like a fair amount of initial advance at idle.

You'll want to get an advance timing light or a balancer timing tape to allow you to set the total mechanical timing at high rpm.
It should be 32-36 deg at high rpm with the vacuum advance temp
disconnected.
12 to 16 deg advance at idle would be good.
This is controled by the weights and springs in the distributor.
You also will want to open the secondary throttle stop screw
to allow alittle more secondary idle air flow at idle.
(turn carb over). The big cam reduces idle vacuum requireing
more throttle blade opening.
This combined with the right power valve (3.5"-4.5") will make your idle mixture screws much more responsive.

You're always going to have trouble getting it to idle nice in gear with a stock converter. (too much load on the motor while in gear.) This is one reason why I recommended you hold out for a 10" 3500stall converter.

The "pinging" may be caused by too much total advance, too much vaccuum advance, too hot a spark plug heat range, or a combination of these. This motor will want 91 to 93 octane gas too. 87 octane isn't going to cut it.
I use Champion RV8C plugs on my 305 headed 350.

Russ

350turbo411

I'm not sure if i even have a secondary stop screw on that carb......it doesnt seem to have many external adjusting capabiilities..

I SHOULD HAVE WAITED FOR THE 10" STALL......boy.....i'm kicking myself.........................


I'm really dissapointed in this motor but....hey ..i still have my performer manifold on..

the engine is only one factor though.. i mean i'm almost finishing up with a complete restore.... lots of body parts


I'm going to KS tomarrow.... should i buy new jets & things for the carb to detune it.... it is a 750...a little big... I found that it likes the purple spring....

Now the car is stumbling/missing all through range.. but i did have to throw 87 in it this week.... No money... i usually run 50/50 of 94 and 100.

Rob

350turbo411

timing is at 12. no vac advance right now... temporary...i have a medium/heavy set in the dist.

Are the springs in those heads good for my .488 .488 cam?

I use rt45 spark plugs...

72 350
.488/.488 Cam
305 ported heads
Holley 750 VS
Performer manifold
Edelbrock headers
Flowmaster 3" exhaust
Accel Super Coil
Hughes 2500 Stall
Turbo 350 w/B&M shift Kit
8MM MSD wires
Adjustable Vacuum advance
3" catco cat

Car is just as fast as my old 305!!!!

Rob

F-BIRD'88

The secondary throttle stop set screw is on the bottom of the carb base plate, turn the carb over.

No the carb is not too big. It does not need to be detuned.
The jetting is ok as long as it is 70/72 primary and 78/84 secondary.
Buy a 4.5" power valve. The big cam needs this to idle properly.
Stock in a 750VS is 10.5"( too high)

If you want to spend money, buy new ignition parts. ( wires,cap rotor, coil, plugs) RV8c(champion) or R42T Delco.
R45ts is too hot.

87 octane gas will not cause it to miss or stumble.
It will damage the motor if you allow it to ping.
More likely weak ignition parts.

F-BIRD'88

Get a balancer timing tape while at K&S, so you can set total timing with a timing light.

Yes those springs will handle that cam.

That cam would not be my first choice for either a car with a single 3" cat or Edelbrock shorty headers, or a Performer Intake.
Or a 2200/2500 stall converter.
It is too big.
Easier to change the cam then change everything else to match it.
Cheaper too (cam and lifter set)
With the right cam you will "like the motor better" Much better.
A smaller, milder cam will increase the drivability, increase the seat of the pants mid range torque, make better use of the other
parts u are using. Idle better. Drive better overall. And be faster.
(with the other parts you have)
Cam selection (for the real world) is where most of us go wrong.


For what you have and how you use your car, I'd recommend a change to a .442/.465" 214/224 dur @.050-112 cam.
or anything real near that.
Your cam is 232/234 @.050" .488/.488" 108
(an Edelbrock Torker-plus Cam or generic copy)
This cam likes a single plane intake like Vic Jr, 10:1 cr, a 3500 stall, 3.73/4.10 gears, long tube headers, no cats and full 2.5" duals.
The single cat and headers y pipe are probabily your biggest problem. The motor can't breath through that.

The spark plugs are wrong for that motor. They are for a stock low compression, low performance motor.
Those R45t(S) plugs are way too hot for a performance motor.
Use Champion RV8C or Delco R42T.

reguardless , That motor should be a tire burner, something is real wrong.
I'd start with a compression test.
Too bad you don't live closer, I'd help ya go over it.

350turbo411

Did i mention that i have a stock 1980 distirbutor.. with the heaviest springs in it....

What springs should i use in there..???

I really cant put the timing below...12 or it will not run....if i put it at like 13 or higher ..it pings...and thats without a vacuum advance..


Rob..

ronterry

You'll need to limit mechanical advance if your getting major continuous pinging at higher RPM. Not sure with the stock distributor if it's DIY?
There might be some shops out there that have a recurving machine.
The MSD Billet distributors use stop bushings that can be changed pretty easily. That's how I can run 20 idle, and limit the total to 38.

BTW: Springs control the rate @ which the timing opens up. I guess in some cases if you have to lose a spring it will ping at lower rpms, but will usualy quit at higher rpms if your total timing is correct.

The picture below is rough, but hopfuly will give you an idea, of how total mechanical advance effects total timing.

Ron

F-BIRD'88

It should not die when set below 12 deg initial. something is wrong.
How much total mechanical advance is there at high rpm?

RodsRideSS

I'm not sure about vac advance type dist....But my electronic dist was out of alignment between the reluctor and the magnet...not one tooth out and all that mumble jumble. Have a good look at your distributor for misalignment between the reluctor and the magnet...as the reluctor sweeps past the magnet, the magnetic field triggers the coil through the module . If there is any misalignment between these two parts the spark occures off the dist post and only gets worse as the vac advance takes over.

SpitotRs305

holly time machine batman... 2003...seems like a long time ago