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Discussion Starter #1
Hey all...if you vaguely remember, I was searching for a timing light and wound up using a timing tape. I have a 355 SBC, Lunati bracket master II 292 duration. Dart iron eagle heads, forged crank and rods. MSD HEI, and a holley 750 VS.

I chose a timing tape over a light since I already had a light, and I'm cheap!

Ok, here's the problem. I bought a tape that a local shop had, Mr Gasket I believe, 8". I installed it, but in the back of my mind, something was wrong. I have a 7" damper...might be 6 3/4, but regardless, how far off would it put my timing? I'm thinking my timing caused my overheating issue.

I set it to 18 deg initial, giving me 36 total. I had a cooling problem last weekend...95 outside temp and I was running 55 mph. I have 3.73 rear gears so run higher rpm's than I would prefer, but anyway, my temps hit 215. I replaced my lower radiator hose, upper hose and check my 180 deg thermostat. I have a 3 core radiator, mech fan with clutch. I don't believe that my timing is that far off. I checked 2 plugs.....driver side was ash colored, the pass side white. I know believe I'm running a tad lean.

So, will my timing be close using the wrong tape?
 

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Timing will be off for sure. Meausre the the balancer diameter and install the correct tape Recheck the timing after the new tape is installed. RICK
 

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It going to be way off, 8" balancer tape is like 25 inches
7" is like 22 . What happens to the 3" of degreed marks??
You can't just cut it off.
 

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I just overlapped it, since the only important part is the first 40 degrees....or so I thought<G> See, this is why I come here....make sure I do things right.
they sell 6.75 timing tapes on ebay...buy the right one...only a couple bux:yes:
 

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But it is degreed to the circumference of the 8" balancer, and you have a 7" you think. Measure the diameter and install the correct one. It will be off something like 4 degrees per inch give or take.
 

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Yeah it'd be a good idea to get your own timing light when you can. Definitely worth the investment. Once you buy it you'll have it for a long long time.

Let us know how it goes when you guys finally catch up and stuff. I'd be interested to see how far off it was and to hear how much better it runs once you guys go through everything.
 

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I will....a buddy is coming over tomorrow with his advance timing light....that should settle the issue, and I'll get a timing tape corrected.
Not really, this is why the tape is needed, the adjustable lights are not good to use. Divide the circumference of the balancer by 360, mark a piece of tape at 0º and find the window where you want to set your timing (ei 30º-35º) and mark it on the tape. Correctly position it on your balancer and put white paint marks on the balancer where you need them and set your timing.
 

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Try a EMP/Stewart High-flow thermostat has three 3/16" bypass holes in it so to allow some coolant through even when closed--perfect for high-rpm engines. Water pump pushes too hard against thermostat,holding it closed. You can drill a 1/8" hole in yours,worked for me. Or you can play with the timing.
 

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I've read the same thing, adjustable timing lights are not good to use. Then I compared my dialback to my inductive light which was a known good light. My damper has degree marks in it, I already found TDC and I knew my timing marks were correct.

Checked initial with the inductive light and saw 16 degrees.
Checked initial with the dialback light and saw 16 degrees.

Made a mark on my damper so I could see the 32 degree mark better.

Checked total timing with inductive light and saw 32 degrees.
Checked total timing with dialback light and saw 32 degrees.

So I'm not sure why some guys seem to have luck with dialback lights while others get completely different results when compared to an inductive light. I have heard they dont work well with MSD boxes, but I have no firsthand experience with that. It seemed to work just fine with my engine though.

But that said, I think its a better bet to just use an inductive light with timing tape or a degreed damper because then you are relying on the physical markings on the damper rather than the dialback feature in the timing light which may or may not be accurate. If you do use a dialback light, you should at least test it against a known good light to make sure it gives accurate readings.

Sorry for the rambling on timing lights, thought it was somewhat relevant though.
 

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Discussion Starter #15
Ok, the results are in....an 8 inch tape on a 7 inch damper will give wrong results.

I had it set at 18 and 34 using the 8 inch tape. I took it off, and used a dial back. First off, it was my first time using one so after a quick learning curve, I checked my settings. 15 initial, and ready? over 40 for total.

Using the dial back I set it for 18 and 35. Runs good. Throttle response is a touch off, so will do more testing/setting after my 7" timing tape arrives from Summit.
 

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Taz, the only issue I would have with that method is that you are still using a timing light....therefore, possibly in error, correct?
Shouldn't be, but error is always possible, if a step is missed or incorrectly performed. The idea is, the dial back isn't required.


As to the post above about dial backs and testing, I've always gotten they same results too, but was inform dial back lights are for computer controlled engines. I have always used a marked balancer or tape.
 

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Correct, I read the same thing. It seems that some guys get identical results with inductive and dialback lights, while others get differing results. Best bet is to use an inductive light with timing tape or a degreed damper to verify total timing.
 
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