My set up:
69 Olds 350 (just rebuilt)
stock pistons and bore
Edelbrock performer cam, double roller timing chain, performer intake manifold.
Holley 600 cfm carb on top.
stock distributor and points/coil
stock th350 Tranny
not sure on the stall convertor or the rear end gears.

I was wondering some opinions on timing (and on my setup in general). I believe Edelbrock's instructions said that with the vacuum disconnected and plugged to set the timing at 10-14 degrees. I had it set at 10 during the first 500 miles (the first 500 break in miles on the motor) which are now past.
I am trying to tune the engine up now because it feels pretty flat to me through the power band.
I think there is also some carburetor tuning to be done in the beginning where where I press on the gas and it stumbles for a sec before picking back up again.
But beyond that initial feeling, with the throttle depressed going from 0-60 I hear the engine getting louder (and I do go from 0-60) but I don't feel the power translating to the wheels I was expecting.
What was I expecting? well...
Before I tore it down, when it was all stock with a 2 barrel stock carb it had significantly more power. My good friend has a 69 Malibu and we always compared our rides. His car also had a stock 2 barrel carb but on his chevy 350 of course. My Olds was always much quicker off the line than his car (I drove them both). Mine could always chirp the tires through second gear when his could not. He swapped his intake to the Edelbrock Performer intake and Edelbrock 650 carb and his car was driving and reacting with those enhancements closer to mine was with a stock iron intake and a 2 barrel carb.
Now I have a fresh rebuild and a mild performance cam(Edelbrock performer plus 3712) , intake (Edelbrock performer 3711), and carb (Holley 0-804457S) and it feels like I've lost literally half the power I had before.

I am sure this is a complicated topic that cannot simply be summed up in timing, but should I start with timing? And if so what does everyone recommend?
What steps should I take going through this?
Thanks for the help ahead of time!
-Dan

 

Who built the motor? Was the cam degreed? Lots of questions could be asked in this area. Also, is the carb new or used? How is the float level, accelerator pump,etc. Olds like plenty of initial timing, might try bumping it up to 15 degrees. What is the total timing and what "curve" is set on the distributor? Is the timing coming in way late? Do you know how to re-curve if necessary? There are lots of possibilities here due to so many unknowns.

 

Thanks for replying. I knew it would be large subject, but I had to start somewhere.

I had the machine work on the motor done by local shop I trust.

The motor was assembled by a friend who has lots experience with Chevy and Pontiac and not admittedly not much with Oldsmobile. We referenced the original 69 service manual when in doubt. To his credit I will say that the motor started right up after assembly and has ran the first 500 smoothly, just without much power.

Degreed the cam? As I understand it, degreeing the cam is to ensure it is ground correctly? I don't believe this was done with the Edelbrock cam but I could be wrong.

The carb is brand new. It started the motor right up. The electric choke seems to be working great. The only thing I notice (or at least the only thing I think I am noticing) as far as the carb goes is the momentary stumble on take off.

I have not check the float level on this carb, so I don't know. Do you recommend I look into that? What do I want to make sure of when checking this?

I only barely understand the function of the accelerator pump (it dumps fuel on take off right?). But I don't know how to check it, or what to check for.

I can certainly set the timing up to 15 degrees. Is there any risk with setting the timing to 15? Is the worse thing that I would hear some pinging (ie pre-detonation) in which case I would know I went to far given current heads and octane?

Total timing. I check for that by reving the engine and seeing how far the timing goes up to right? I can check for that and report back.

I have never adjusted, changed, set, the curve on a distributor. I don't expect you to have to type up a whole tutorial on how to do that, but it sounds like I need to learn and check into that... correct?

Thanks again for your help so far!
-Dan

 

When I try to determine initial timing for a non stock setup I do it this way. I do this on a distributor that is fully adjustable in total timing and advance rate so that I can get total later. This of course doesn't apply to you because your using a stock distributor but the method can still be used. You'll just have to check your total afterward like you plan to do.

I've found most engines like somewhere between 10-16 degrees of initial timing so that's where I start, at 10'. I then start the car and see if it's hard starting. If not I go to 12', check starting again, next 14', etc. Once I find the point where the car is hard to start I back off two degrees and leave it. From there you have to set your total. With an adjustable distributor it is easy but with a stock unit you'll have to see how it goes. You may find your total is just right depending on the distributor being used as they have different advance built into them from the factory depending on the engine, etc.

The above procedure will at least get you in the ballpark.

GL,
George

 

1. Degreeing the cam has nothing to do with the production of the cam by Edelbrock, but the installation of the cam by the engine builder. If a cam isn't degreed properly the valve timing will not be correct and the car will not function up to it's capacity. Of course I'm assuming the builder at least knows how to find TDC.

2. A non-Olds engine builder isn't a death nell, but it is not helpful either.

3. Check the float levels on the carb. Perhaps a Holley guy can chime in, I run Edelbrock carbs. Just for the record, my new Edelbrock carb arrived 5 days ago. I took it apart and the float level and drop were perfect on one side but more than an inch off on the other, so new doesn't mean set up correctly. As pertaining to the accelerator pump, hopefully a Holley user will chime in as to how you can richen up the initial shot--may stop your hesitation off the line. Also, Edelbrock uses step up springs to handle this problem--Holley people chime in on how that's done with a Holley.

4. 15 degrees should be fine, but yes, as a rule, back off if you hear pinging. Total timing is checked the way you suggested, but with the vacuum advance on the dist. disconnected. Look procedure up on-line, it's fairly straight forward.

5. Re-curving a distributor involes the springs and weights used. They are located under the rotor (which is just under the dist cap). Usually just a simple spring swap is needed without having to change the weights. Heavy springs bring the timing in "later" and light springs bring it in earlier. You are shooting for a total timing of 34-36 by about 2500-3000 rpms.

Your engine builder should know all of this and be able to do all of this work (besides degreeing the cam if he forgot to) in about 15-30 minutes.

 

4. 15 degrees should be fine, but yes, as a rule, back off if you hear pinging. Total timing is checked the way you suggested, but with the vacuum advance on the dist. disconnected. Look procedure up on-line, it's fairly straight forward.

You mention "... but with the vacuum advance on the on the dist. disconnected..." I thought the vacuum advance was disconnected through out the whole timing process (both for initial and total advance) Am I wrong about that?

-Dan

 

George - Thanks for the timing tips. I will apply them.
-Dan

 

Wasn't sure if you knew to disconnect it or not, so I through it in for added help. Looks like others are coming to help you as well. Best of luck.

 

Just a partial update. When I checked the timing it was set to 4 degrees. I moved it up to 14. I messed with the air fuel mixture screws (as per the holley instructional video) until the vacuum was correct and it is already feeling like a different car. Throttle response is great now. There is still a flat spot arounf 2500 rpm but I think that might be a carb jetting issue.
Anyway I will update more later, but thank you for the help thus far.
-Dan

 

Also ensure your choke is fully deactivated when its warmed up and your secondaries on your carb are opening up fully. At 3500-3800 rpm with the vacuum connected to your advance you should have 45-55 deg btc on your timing.

 

Just a thought...have you had someone sit in the car w/ the motor off and test to make sure the new carb linkage is allowing for full throttle by pressing the gas pedal to the floor and checking under your hood? Just an idea if after swapping a carb you notice a drop off in power.

 

I have not checked for that yet. Thanks for the tip, I will check that this evening too.
-Dan