Hi folks, I'm trying to set the timing on my 350Ci and i have a couple of problems .. keep in mind that i'm far from an expert so assume i know nothing Firstly, it seems that the engine number has disappeared so i cannot ascertain what year it was manufactured so i'm unsure of the timing setting. I can see te production code number between the left exhaust manifold and the two front spark plugs which is XB527 ( the best i can tell anyway). And there is a casting of "74" just by plug No. 1. Could it be as simple as it's a 1974 ? And secondly, if i try to set the timing and simply listen to the engine even out and speed up (maybe i'm listening for the wrong thing ) and check it with the timing light the timing mark is literally off the scale. What am i doing wrong ? or need to check ?
Set you timing with the vacuum line disconnected and plugged. There’s a good timing thread on here by Larry 70 GS. A dial back timing light helps. You can also look up the distributor number to see what kind of timing curve it had from the factory and read Larry’s post.
First, if your distributor has a vacuum advance canister with a line going to your carb, disconnect & plug it when you check/set timing. Initial timing is always checked with vacuum disconnected. I don't have specs for a '74 350 but suspect anywhere between 6 deg and 10 deg BTC should get you in the ballpark.
The only way you can use the stock timing specifications is IF your car has the correct part number distributor that it left the factory with. Unless you are the original owner, you won't know that until you check the distributor part number. In 1974, the engine could have come with a small cap points distributor, or the big cap HEI. Here is the spec page with part numbers from the 1974 Buick Chassis manual, http://v8buick.com/index.php?threads/power-timing-your-buick-v8.63475/
What you are doing wrong is trying to set the timing by ear. You can't do that. When you advance the timing at idle, the engine will like that, and it will speed up, and sound like it is running smoother. What you need to do is learn how to use a timing light to do more than just set the initial timing. There is a mechanical advance system as well as a vacuum advance mechanism that add timing as engine speed increases. The only time the engine runs at the initial timing is when it is running at idle. You can use the timing light to measure the timing at higher RPM, and set the maximum timing. http://v8buick.com/index.php?threads/power-timing-your-buick-v8.63475/
Yes . Use a timing light. I would suggest about 10 advanced myself. If you get spark knock, reduce 2 degrees. larrys thread on timing would give more direction
I would first check out the condition of the timing chain and even how stable your timing is now with the light before playing around with setting the timing to anything in peticular.
Thanks guys, all good advice so much appreciated. I've had a read through your "Power Tuning your Buick" thread Larry and very enlightening it is. I have a dial back timing light so i'll just use that from now. As i didn't have the correct engine year i didn't know what the correct timing should be, am i correct in saying i have a '73-'74 engine ( in my 68) ? If i use the dial back and find the maximum timing, do i adjust the distributor to get the max reading at around 2500 revs ( please correct me on the max revs to do this at). Once i have the max revs adjusted is that it ? i don't need to check or change and the idle timing is it is irrelevant. Sorry for even more questions Thanks again
First, do you have a points distributor, Or the big cap HEI, Look for the part number on the circumference of the distributor, right below the cap. When you set the maximum timing, you'll need to temporarily replace the spring weights with the lightest available. The Crane kits have some very light (yellow) weights that are ideal for this. Stock springs may delay full mechanical advance until as much as 4600 RPM, so revving it to 2500 will give you a false reading.
