I have a timing light that does not allow adjusting to a specific timing setting. So, after reading Lars paper, I understand that you can calculate where to put the 36 deg timing mark on the harmonic balancer. I took a look at doing that - getting at the entire balancer with a seamstress measurement tape looks to be just short of impossible. I have to believe someone has calculated this before, and I would think (hope) that it should be pretty much the same, as long as I am comparing the right engine.
(My engine is a 79 350 L-82)

So what I am looking for is the dimensional amount in inches I would measure from the TDC timing mark (CCW) on the harmonic balancer that would represent 36 deg advanced.
Thanks for your ideas or suggestions.
Hef

 

Most timing tabs go have 24 degrees marked on them (12 btdc and 12 atdc) measure off 12 degree and triple it. Might not be 100% accurate but should get pretty darn close.

Or just find some change out of your vette seats or sofa and buy a timing tape and put it on the balancer.

 

The only way inches would be accurate is if the person had the exact same balancer. Many times these have been changed. Fevre's idea is a pretty good one.

 

I would rent a timing light or borrow one from a friend. Heck just get one. It's not like you won't use it. If you got the vette you gonna need it more than once.
My 0.02.
Good Luck!

 

 

Diameter of balancer times PI divided by 10 = 36 degree mark

and oh yeah, it's CLOCKWISE of timing mark for advanced, not CCW

 

I have a timing light, but its the type that you cant set the timing on the light itself. So you have to set where 36 deg adv is on the balancer.

Fevre thanks an excellent idea. I did just that and it seems to work out right.
Whats interesting, is if I did my measurements correct, I am getting the full adv I am looking for at 2500 to 2800 RPM which, I thought with stock dist springs, I would not be able to achiieve.

I set my initial timing to about 14 deg,
and I got about 34 deg at 2800 rpm.
Hef

 

Star, your Avatar freaks me out every time I see it. What is that? One of the demons that guards the Gates of Heck?

 

You did pull off the vac advance hose and plug it right?


That's just BatBoy from the Weekly World News

 

Hef,
If you look down the forums (posted from KB2FZQ) you'll see I just went thru the timing extravaganza recently on my 76 Vette. Lars turned me around and it works great. My HB is a 6.75" balancer and the 36* mark was 2.12" ( I figured a little over 2 1/8" on the sewing tape) CW down from the mark to hit the 0* mark on the timing tab. I also found that the mech advanced also stopped moving around 2500-2800 RPM as you've mentioned. It definately made a difference with my Vette...
Good Luck!!

 

Yes I believe I did.
Hef

 

Timing tape($6.00). Things can't be that bad where you have to resort to the seamstress stuff .

 

That is a pic of himself getting fustrated trying to get the timing correct using seamstress ruler.

 

I wonder why you didn't just get a advance timing light??

You can get them as cheap as $29.99 at Harbor Freight.. and they actually work

 

I sent an email to Lars when I did mine and this is what he said:

"If working with a non-adjustable timing light, you have to place a 36-degree line on your harmonic balancer, since the stock timing plate does not go beyond 12 degrees-or-so.

To do this, you can either procure and install a timing tape (available from any of the speed equipment retailers) of the right size for your balancer, or you can determine your own 36-degree mark.

To determine the 36-degree point, measure the circumference of your balancer using a flexible tape measure, such as a sewing tape. Take the circumference number measured and divide by 10. The result of this arithmetic is the dstance from your stock timing line on your balancer to the 36-degree point. Measure this distance clockwise from the stock balancer timing line as viewed from the front of the engine and place a mark on the balancer. In most cases, this new line will be between 2" and 3" clockwise from your stock line.

To correctly time the engine, pull the hose off your vacuum advance control unit. Using your timing light and observing the new timing mark, rev the engine until the centrifugal advance does not advance any further. This will be above 3500 rpm in most cases. Once the advance pegs out and does not go any further, you have hit total advance. At this point, the new line on your balancer should be aligned with the "0" point on your timing tab. Rotate the distributor until you achieve this spec. Once done, snug down the distributor and hook up your vacuum hose.

You know the centrifugal advance has stopped when you don't see any further movement of the timing mark using the timing light. When the advance is still advancing, the line will smoothly move counter clockwise as seen from the front of the engine as you rev the engine.

Lars"

I followed these simple directions and my vette is running a lot better. For my 8" HB, the distance was 2.51".

 

http://www.harborfreight.com/cpi/cta...emnumber=40963