Initial Timing 350/300
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
Initial Timing 350/300
I have read BarryK's tech article on setting your timing and will go buy the tools tomorrow. I have been looking at the Chassis Manual for my 1969 350/300 with auto for the initial timing setting and under the Distributor tab and it states 4 degrees B. I think I am looking at the wrong number.
Can someone provide me the intitial timing degree for this engine?
I see the dwelll should be at 30 degrees and all in timing at 36 degrees. I plan to tackle this tomorrow as my car is acting up and I want to check the timing first.
Thanks
Can someone provide me the intitial timing degree for this engine?
I see the dwelll should be at 30 degrees and all in timing at 36 degrees. I plan to tackle this tomorrow as my car is acting up and I want to check the timing first.
Thanks
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
The manual does say 4*BTDC. But my experience with timing yesterday shows that a dwell of 30 with 36* all-in at 2500rpm (vacuum can plugged) yields an initial timing at 700rpm of 10*BTDC. From what I have read (Barry and Lars) it is better to go with the "all-in" rather than initial timing. I use a Sears dial light.
I believe it was Lars who said something along the lines of...you don't drive your car at idle, why set the timing at idle?
I believe it was Lars who said something along the lines of...you don't drive your car at idle, why set the timing at idle?
Last edited by Paul L; Jun 8, 2008 at 08:38 AM.
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
So disconnect the vacuum line put a rubber band around the weight and set at 10 degrees. The undo the rubber bands set the light at 36 on the dial and run up to zero about 2,500 rpms.
How do you determine the rpm setting? Does the timing light have this information or do you need another person to sit in the car and watch the tach?
I am off to Sears to by a dwell meter and timing gun with a dial
How do you determine the rpm setting? Does the timing light have this information or do you need another person to sit in the car and watch the tach?
I am off to Sears to by a dwell meter and timing gun with a dial
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
I checked the dwell it was at 35 and I adjusted to 30. Ran the motor up and down and the dwell did not change. The initial timing was 15 degrees with the vacuum plugged. I reset at 10 degrees per your input. With the vacuum still plugged set the dial to 36 degrees and reved the engine to 2,500. The line was coming up but not to the (0) mark.
So it seems my springs are too strong. Any recommendations on replacement of weaker springs so my all in timing at 2,500 rpms will be 36 degrees?
So it seems my springs are too strong. Any recommendations on replacement of weaker springs so my all in timing at 2,500 rpms will be 36 degrees?
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
Mr. Gasket silver and black. See Lars' timing paper.
http://www.vetteclub.org/technicalti...t%20Timing.pdf
http://www.vetteclub.org/technicalti...t%20Timing.pdf
Last edited by Paul L; Jun 8, 2008 at 07:15 PM.
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
I read Lar's paper and will order some new springs. However it was suggested to have the initial setting at (18) and all in at (36).
My initial timiming, suggested in this thread was 10 so that is where I set it. What is the real number my 350/300 should be at for the intial timing?
Also to retard your timing are you saying dropping the nummber i.e (18) to (16) thus retarded by (2)?
Please bear with me this is all new to me.
My initial timiming, suggested in this thread was 10 so that is where I set it. What is the real number my 350/300 should be at for the intial timing?
Also to retard your timing are you saying dropping the nummber i.e (18) to (16) thus retarded by (2)?
Please bear with me this is all new to me.
Intermediate
Joined: May 2008
Posts: 27
Likes: 0
From: Green Bay Wisconsin
The 2500 all in timing you are using may be diffrent for your motor. Your all in timing is determined by your springs and weights. what you need to do is find out what rpm your all in is at. I charted mine by starting at 1000 rpm then went up by 250 rpm each time marking on a chart what the timing is for each. at some point you will see where you chart flat lines this is where you all in rpm is. this is the point you want to set your 36 degs. then to test this you need to get on the highway in top gear broing you speed up so that you are at your rpm that is your all in, from here you can mash the gas and listen for ping, if you have ping back down to 35 deg and try again untill you have no ping, from here you have you all in timing. The springs help you get more timing up to your all in rpm if you do not have pingaccelerating up to your all in rpm you can go with lighter springs to give you mor timing, if you have ping up to all in then you need heaver springs. I am still reading and trying to figure out the vac portion of the timing but what is explained was shown to my by a local speed shop and it has worked well for me so far. Good luck.
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Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
Are you saying the higher the initial timing the harder it is to start?
If so then a setting of 12 initial that produces 35 degrees all in at 3,000 rpm is easier to start then 15 initial that produces 35 degrees at 4,000 rpm's.
Is this a correct statement?
If so then a setting of 12 initial that produces 35 degrees all in at 3,000 rpm is easier to start then 15 initial that produces 35 degrees at 4,000 rpm's.
Is this a correct statement?
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
15º initial is not an excessive amount of initial timing. In fact, depending on the cam it may be low although it's higher than normal on a factory cam.
Generally, initial timing level can be up to about 16-18º before running into possible hard starting issues although, again, if you have a more radical aftermarket cam the motor may actually want even more initial timing.
If you are running the stock cam than in my opinion using the 12º initial and 36º total is perfect and that's how the distributor is set up on my '65.
on the other hand, the distributor in my '78 L82 still has the stock 20º mechanical advance that most HEI's come with so to get the total timing at 36º the initial is at 16º and there is no problem with starting, even on a hot day.
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
I have a stock 350/300 - 1969 with the stock distributor. Engine builder had it set at 15 degrees and it ran fine, 1,000 miles on it until the other day. Bought some gas with 10% ethanol, first time it has had ethanol, and it leaned out. At a stop when accelarating it would bog down and backfire until it hit 1,500 rpm then cleanout and run well. It was a hot day to boot. It didn't do it everytime but once is enough.
I changed the fuel filter and the problem seemed to go away, on short drives after the change.
So I am going through the timing with a fine tooth comb before I start to think about the carb. I will also start running premium as it contains no ethanol. Tonight I will put new springs on the centrifugal arms and bring it to 36 degrees at 3,000 rpm.
Bought a mini vac to test the vacuum on the advance.
If this doesn't fix it then I will attempt to fatten the low end up a little.
I changed the fuel filter and the problem seemed to go away, on short drives after the change.
So I am going through the timing with a fine tooth comb before I start to think about the carb. I will also start running premium as it contains no ethanol. Tonight I will put new springs on the centrifugal arms and bring it to 36 degrees at 3,000 rpm.
Bought a mini vac to test the vacuum on the advance.
If this doesn't fix it then I will attempt to fatten the low end up a little.
Thread Starter
Burning Brakes
Joined: Oct 2006
Posts: 1,089
Likes: 43
From: Native Californian CALIFORNIA
Army
BarryK,
I set my all in timing at 36 degree and had to retard it two degrees because of very slight pinging condition at WOT. It responded very well and was worth the exercise.
Had the air filter element off and when it was cooling down from the last test run, engine off, the carb made a low hissing sound. Almost like the gas was perculating. This continued for a few minutes and subsided.
What is that sound, is it normal? Car has never been one to start right up, seems like the bowl is empty of gas and needs to be refilled by the pump before firing.
I set my all in timing at 36 degree and had to retard it two degrees because of very slight pinging condition at WOT. It responded very well and was worth the exercise.
Had the air filter element off and when it was cooling down from the last test run, engine off, the carb made a low hissing sound. Almost like the gas was perculating. This continued for a few minutes and subsided.
What is that sound, is it normal? Car has never been one to start right up, seems like the bowl is empty of gas and needs to be refilled by the pump before firing.
