So i finally bought a timing light with advance feature today. When i was checking timing i noticed that my engine idles at 30 degrees initial. (vac advance disconnected) and if i take it down to 20 it runs like a slug. at 3000rpm its showing roughly 40-46 degrees total(mechanical/inital). Maybe its just me but that seems a bit high even for my 70' 350. something seem wrong here?

 

Yes, it's too far advanced.

You need to check to be sure your timing mark hasn't moved, and if it hasn't you may have a different problem, such as a timing chain that's skipped a tooth.

You did connect the light to the #1 cylinder, right?

- Eric

 

As Eric said, simply verify the timing mark on your balancer by putting the #1 cylinder at TDC on the compression stroke and check where your balancer is.

i have a 72' 350 and my timing on the timing light is set to 10 degrees BTDC (vacuum can disconnected of course)

 

Yup timing light was on number 1. And chain should be good as timing set was replaced when i did my motor swap. Could it be that the advance feature on my timing light is off a couple degrees?

 

That is not accurate enough. We are talking 10-20 degrees here, not a lot. The wrong pointer or a spun balancer (seen that several times) can cause this. The only way to be cetain is to verify TDC using the cam degree method and checking it against the mark/pointer.

 

Okay so i just checked the timing again. It guessing its running 22-24 inital, with 10 mechanical and 24 vacuum advance, Kind of hard to tell to be honest as i cant see the numbers on the timing mark and dont know where 0 is when i dial in the advance.

Does anyone have a picture of a olds points timing mark? so i can figure out where 0 is and dial in the timing properly.
(when i installed the hei dist. i forgot to install a hei timing mark, in case your wondering why im asking for a points timing mark when i'm running hei)

I notice i get pinging in the higher rpms. So i might need to recurve the distributor,

 

The timing mark is the same for points or HEI, "0" is zero. "0" is generally the second mark from the right facing the engine. With vacuum disconnected, if you shine the light on the balancer and turn the adustment on the light to get the line on the balancer to line up with 0 on the timing tab, that will tell you what your engine is timed at.

 

Ok just checked again. and to get the timing to line up with 0 i have to turn the advance on my timing light to roughly 24. It starts easy and runs the best at this setting. If I back the timing down 4 degrees off idle acceleration and general performance suffer. I'm starting to think the timing mark on the balancer might have moved, will have to check that 1 of these days.

But in the meantime I'm gonna go to napa and order 1 of their gm hei recurve kits its only 9 bucks comes with 3 springs and a couple other things. So i can change up the timing curve for better performance.

 

You need to find out where your timing mark is at tdc with the rotor pointing to #1.

 

Obviously, it is close or it would not run. Eye-balling it is not going to cut it. He needs to go through the procedure used to degree a cam and find TRUE TDC, then see if that matches up with the pointer and slot in the balancer.
You could always do the old-school "power timing" method, though it is not fool proof by any means. Check the timing, drive it. If no "ping", add 2 degrees, if "ping", retard 2 degrees. Keep doing that until you find where it will not ping under load. As long as it starts and runs OK, and does not overheat, drive it.

 

Honestly, you might be better off just leaving it as-is. If you re-curve, you may have too much vac advance which would require a new adjustable canister. If you do go with the kit, keep the stock weights and use the springs only.

Here is my 350 SBO "recipe". The recurve kits come with 3 springs, light, medium, and heavy. Using the stock weights, use 1 light and 1 medium spring, set initial at 23 degrees, and add 12 degrees of vacuum advance. This has worked very well for me on multiple cars (in Florida).

 

Right, but it's a good preliminary check.

Although, you can easily pull off the valve cover with a dial gauge to rock and roll some measurments.

 

Here is pic of two dampners. Hopefully you can notice the "chisel"marks. I'm not sure if these will look like yours, since they are from different years. Another pic of one that has obviously spun.

You will have to clean it up well and look carefully for the marks.

 

OK, here I go again "arguing" when guys make erroneous statements.

It is NOT a good preliminary check. If it was off more than the eye could see, it would not run.

How will putting a dial gauge on the rockers determine when the piston is at TDC?

 

Ok, I'm half hijacking this post... I've noticed from the last few comments (and pictures too) that you can have a "spun" balancer? This may be my issue... I cannot check timing off a light as the timing mark is nowhere near where it should be. I will now have to check the balancer to hub marks (as indicated in the pics) to see if this is my problem! Thanks guys! Glad I followed this string of posts!

 

Here you go guys,
It is not rocket science. You can purchase a piston stop instead of making one.
http://www.summitracing.com/search/P...on-Stop-Tools/

 

Not all balancers have witness marks to confirm that they haven't spun.
I believe that they were added in the early '70s, though I am not certain.

You may need to find true TDC just to be sure.

Wow. You learn something every day.

I always thought you had to tap out an old spark plug if you wanted one of those.


- Eric

 

Even though this was someone else's post, I appreciate the video (Captain Jim), and the follow up (Eric), that my 68 may not have alignment marks to see if the balancer has spun. Makes easy enough sense using a piston stop, and remarking the balancer! Thanks again!
Shawn

 

It's not an erronius statement if you've read the cutlass service manual.

Page. 6B-31

CHECKING VALVE TIMING WITHOUT REMOVING FRONT COVER

 

I used this exact procedure and figured out my timing chain skipped a tooth.

 

Tony, this will show you roughy whether the valves are timed correctly with the crankshaft, but will not tell you whether the damper timing mark is accurate (notice that the mark isn't used in this procedure).

A "close" eyeball of the piston position (say, with a pencil sticking out of the spark plug hole) will get you within 5 or 10°, but to be really accurate, you have to use the bolt-in-spark plug trick, or a dial indicator.

- Eric

 

Well i tried! Maybe that'll work for others that had the same issue as me. (chain skipping thing)

I was trying to think of the most number of ways of verifying time without pulling the balancer. Which, is probably easier at this point and then you'll know for sure.

Eric, last i remember the keyway on the balancer points to TDC on #1 compression stroke? I have a picture of this somewhere...

 

This is exactly how I get my well-earned reputation as an "arguer". You are incorrect, valve timing is separate from the piston location. This procedure will not help you find true TDC of the piston or determine if the balancer has slipped. So, I point this out and you respond will an elaborate post defending your initial, but incorrect, position. Now I have to come back and say the same thing over again. Theoretically, you could maybe do this and work backwards, but there are so many variables, all it will do is get you close.