i pulled my olds 455 out of my trans am just to clean paint the frame clean paint the motor and dress it up now heres my problem... i put it on TDC #1 compression stroke to get my spark plug wires ran... my timing mark is above 12degrees... but anywho wat my question is does anyone have a good starting point once its back in where i should start above TDC??? and everyone talks about 2800-3000 rpm to have 32-34 total timing how the h**l do you figure that one out??? any help will be greatly appreciaited thanks!

 

There are longer plastic timing tabs out there.OR, What I did was buy an advance timing light. It has a dial on the back. Easy , set to desired advance at rpm and it reads Zero advance on the balancer / tab when distributor is on

 

so if i run it at 3000 rpm set the advance on the back of the gun to either 32-34 then at idle it will be at 0 on the tab?? lol im kinda lost as i never heard of this be4 im a SBC guy n this is the first olds motor i ever messed with

 

The way the timing light I purchased works is set gun at advance you want , 30 degrees. Run power plant up to rpm 3200 rpm and balancer tab reads zero

 

then do u set the timing at idle after that

 

I set the timing at at zero while engine is at 32oo rpm , light set to 32degrees
timing mark reads zero

 

No, then the initial timing is wherever it belongs.

You can also tailor the mechanical advance and vacuum advance to suit. Many articles on this practice can be found on the internet. Recently I ended up changing the MA and VA to better suit the 9.7:1 403's needs. The idling advance ended up being close to 20 BTDC, with less mechanical, and then the VA got hooked to straight manifold vacuum, which made for much better idle and throttle response and vacuum for brakes, yet allowed easy starts due to less advance before the engine is running.

SBC timing setting procedure is no different from SBO or any other engine.

 

Hey There
When i am checking and setting the timing the vacuum advance is disconnected and plugged and the the vacuum source at the intake is capped.

 

my distributor never had a vacume line hooked up to it.. only vacume lines i took off the intake when i was pulling the motor was the brake booster that was to the carb and a vacume line going into the tranny that was all there was one on the front but it was blocked off

 

One other caveat, make sure your mechanical advance is functioning and the previous owner did not lock the distributer.

How this works is you set the timing light to say 32-34, you point it at the timing tab, line up the heavy "0" line on the balancer with the "0" mark on the timing tab @ 3200-3500 rpm. Move the distributer slowly and not much at a time. After you have it set, tighten the distributor down and run the rpms to around 4000 and make sure you don't have any more advance there. If you do, then let us know.

Once you set it this way, then check it at idle rpm. You set the timing light to "0", and point the light at the timing mark. It should show the line advanced of the "0" mark on the tab. While aiming the light at the tab, rotate the dial on the back of the light to where the balancer mark line aligns to the "0" mark on the tab. The number you read on the timing light is what your initial timing is set to.

 

Depending on your engine and how your distributor is set up, if you are getting 34 degrees at 3,200 RPM, where your initial lands may be too high. I'm only able to run 14 degrees initial, beyond that I have a problem with hot starts. Before I recurved my distributor, I was only getting 10 degrees of centrifugal advance, so the most total advance I could have was 24 degrees. If I had set total to 34 degrees, my initial would have been at 24 and I wouldn't have been able to start it. I then recurved my distributor to provide 20 degrees of centrifugal advance, and initial fell right at 14 where it needed to be.

 

alright im still kinda lost here... so to oldcutlass.. wat ur saying is run it to 32-3500 rpm turn the dial on my gun to 32-34 then at idle turn the **** back to zero?? haha idk wat u meant by the "heavy" 0 on the balancer all my balancer has is a line then the timing tab goes from 0 to i believe 12

 

o and all this mechanical and vacume advance stuff?? like mechanical is the timing that is already built into my distributor right? i have a accell distributor that goes into a accell supercoil... and on the distributor where the vaccume line would go there was never one on there should one be put on then plugged into the intake?? or can it just stay off like it was.. it ran pretty good until WOT then sometimes it would i guess i can say miss in a way... so should i hook up that vaccume line or leave it off?? and just do the full timing at 32-3500 rpm to 32-34 degrees??? like i said i was never an olds motor guy lol

 

How did you set up your timing on your Chebbies? It's almost exactly the same on Oldsmobile. Initial timing is what your timing is set to at idle. Centrifugal ("mechanical") advance is the amount beyond initial that the weights and springs inside the distributor add at higher RPM. Total timing is initial plus centrifugal, in this case, we're suggesting 32-34 degrees. If you set it to 34 degrees total at 3,200 RPM and then you check at idle and you've got 20 degrees, then your initial is 20 degrees, and you're getting 14 degrees centrifugal. The reason you set the dial-back timing light to 34 is because there is no marker on the timing tab for 34 degrees, it's more precise to set the timing light to 34, and then at 34 degrees, the indicator on the engine will be pointing to the zero on the timing tab. At idle, you may or may not be within the limits of the timing tab, so if you set the light to zero at idle and the timing mark is way off the tab, then dial back the timing light until the mark points at zero, and whatever the number is that's being indicated on the light, that's what your initial timing is set to.

Vacuum advance gives you additional timing at idle and cruise, when vacuum is high and you aren't necessarily getting a lot of centrifugal advance. The problem is that sometimes, you COULD get centrifugal AND vacuum advance at the same time, such as tipping into the throttle at a high-speed cruise. In this case, if you have your distributor curved properly and initial set right but your vacuum advance canister (the silver thing on the side of the distributor that's supposed to be hooked into manifold vacuum) is providing too much advance, you will get detonation. So in conjunction with getting your timing set correctly, you will want to either adjust your vacuum advance canister (if it's the adjustable kind, I would think it would be on an Accel distributor) or physically limit it to provide only about 10 to 12 degrees maximum vacuum advance. You want this hooked up, I found my car runs much better and is more responsive with it. It will also have a tendency to run cooler.

 

ok i got the whole timing part... now that u say my vacuum advance needs to be hooked up... heres a question to the manifold or carb? and if to the manifold there is a T where one of my vaccum lines for my tranny goes would it go there as as for the carb i got a holley double pumper i never had to mess with much timing be4 even on the chevys and when we did we jsut did it at idle where we thought it ran right i have never done all this **** be4 lol... but anywho... and how do u adjust that vaccum advnace just inside the distributor got to take it out... and u said physically only make it able to make 10-12 timing if u know a way i can do that ill just do that... but even be4 i pulled this motor out and that vaccum advance wasn't hooked up it had amazing throttle response only thing it did was wat people say "diesel" when i would go to shut it off when it was warmed up

 

There are manifold vacuum nipples on the carb, or you could just connect it with a T to the manifold. I would avoid using the modulator line to the trans, I'm not positive but I would think adding more vacuum draw on that circuit might cause a delay in one or both places.

If I'm not mistaken, if the vacuum canister is adjustable, there will be a screw on the inside of the nipple and also the canister itself should have a hex head on it. The screw I think adjusts the RATE of application, and the hex adjusts the limit. I don't know for sure, Accel might provide information on their website about it. If it's NON-adjustable, you could make a limiter plate. Here's a drawing of the one I made out of sheet aluminum. It goes between the bracket and the rod inside the distributor and physically limits the travel. You'd need to experiment with this, I set mine up and it limits almost exactly to 12 degrees. Definitely if yours is adjustable, using the built-in adjustability is the better way of doing it.

I'm familiar with the timing-by-ear concept, I actually have a Chebby friend who does the same thing ha ha.

 

Let's not hook up the vacuum advance yet. When you set your timing as described above. What were your final numbers at idle and at 32-3400 rpm? Also when you rev'd the engine up past there, did it advance your timing more? What idle rpm are you running?

The reason I ask this is to make sure your distributor is set correctly and your not going to run into detonation issues.

 

didnt set it yet im ordering parts from summit on tuesday won't be back in for a week or two then i will get the timing i was just wondering about all of this cuz even with that vacuum advnace not hooked up it ran fine i mean at high rpms like WOT it would sometimes pop n hesitate a little and it had a high idle when it was in it was like 1100 but then the linkage of my carb was messed up if i played with the linkage it went down to around 750 and was fine... and sometimes it would try to stay running once i would shut the motor off

 

For now get your timing set and lets leave the vacuum advance alone. If your running an Accel hei, you can set your idle timing to around 14-16 at around 700 rpm, and I'll bet you would be pretty close.

Get your throttle linkage straightened out before you start on all this as your rpms need to be lower.

 

u kno the best way to get throttle linkage to work better on a holley i tried lube n everything n it still messed up

 

Can you post some pictures?

 

I installed a degreed timing mark tape from Summit on my front crank balancer to give me degree readings all way around. Pretty accurate too. That negated me from having to get a dial back timing light.