Which Timing Light?

[70spider]

Ok, when I changed my exhaust cam I had to reset the static timing. I miss-understood the manual and set the the static timing at 5*BTDC, in other words, the timing marks on the cams were lined up and the timing mark on the crank pulley was at 5*BTDC (or the center mark on the belt cover). It ran ok, but was hard starting and that's when I re-read the manual and realized my mistake. So today I reset the static timing, the crank pulley mark lined up at TDC or the third mark on the belt cover. I don't have a timing light to final tune the timing and was wondering which one is best for our cars?
I have it pretty close, but I am getting a little back pressure (popping) out the exhaust when I down shift and a little hesitation at higher rpms.

[baltobernie]

Your 1970 Spider has a mechanical distributor. When cars like these doesn't run right, an important step in the diagnosis is to verify the mechanical (and vacuum, if equipped) advance in the distributor. Many guys dive right in to carburetion when the car bucks or hesitates, but the problem is sometimes improper spark delivery. (Not to mention that distributors are a lot easier to sort out than carbs!).

For this reason, I like a timing light with a "dial back" feature. These lights will give you the ability to measure the advance vs. any RPM. You can then compare your measurements to factory specs.

For the home mechanic, a cheap light will suffice, as you'll use it only a few times in the cars lifetime. Harbor Freight has one for $33. Be gentle with it; they are quite flimsy.

[70spider]

Thanks. I found Brad's Fiat 124 Spider maintenance file (http://www.artigue.com/fiatcontent/Arti ... 124_MM.pdf) and he has a great section on how to set the timing. I used the ear method for now and the car is running great, still a bit rough starting so I'll get a timing light when I get back from vacation and check it.

[manoa matt]

It would be better to search your local craigslist for a used quality timing light, cheaper too. When I first got my car I bought the cheapest one HF had at around $15. It worked enough to set the timing but not for long. I then bought a non-advance Craftsman one for around $50. At some point when I was deep into carbs and distributors I bought the HF advance dial back version Bernie spoke of. Right out of the box it was a few deg off and the knob didn't advance or retard the timing proportionally.