flathead timing?

I'll try again. Just put the msd ignition on my 51 8ba flatty in the shoebox. It wants to ping in the tpo of third gear. (bout 50-55mph) It's set at 2 deg. inital, 24 deg. total. It's supposed to be fully advanced by 2000 rpm-according to the instructions. No vacuum advance it has springs and a stop bushing. Anybody ever messed with one of these?
Cody

 

First, get real numbers on your engine. Measure your pulley diameter, compute circumference, figgerout a degree in inches, and mark off about 30 degrees on the pulley by distance in maybe 5 degree blocks or whatever seems convenient. You have centrifugal only, so it's a simple matter of revving it up slowly and checking timing on pulley up to the rpm that pings in high. Never trust anything--get the actual numbers yourself. It may well be this thing is advancing farther than the directions say, and there's no point in thinking about it until you really know. You can also get a quick, crude reading in distributor degrees by just marking how far you can twist rotor over and then measuring with a plastic protractor, but that won't tell you enough, like what is happening at what rpm.

 

wow.

 

Your car is your own distributor machine!

 

I may be in waaay over my head if I have to do that..

 

A Very Basic Question.

What is the CR and what gas are you using?? A flatty is roughly 2 CR points different than an OHV such as the SBC as far as octane requirements.
So a 8.5 in a flatty requires the same fuel as a 10.5 inna da Chebby.

 

It's basically stock. Headers and fenton intake with 2 94's, three speed. 89 octane enuff???

 

bttt

 

89 should be more than enough.
How about the plugs? I use nothing but NGK B6L.

Also have you done a compression test? Too much carbon and lead crud buildup will cause a higher cr as well as hot spots.
Slowly pour a 1/2 to full quart of ATF down the carb while keeping the revs up around 1000. Dont stand downwind or do it in a garage. Then take it out for a drive.

Good luck, Im off to bed.

 

Bigdog, here's how to do the testing easily--there's no wizardry:

1. Figure out diameter of pulley in area where your timing mark is.
2. Go to staionery rack at grocery store, get cheap compass and plastic protractor.
3. draw circle on piece of paper with same diameter as pulley measure.
4. Use protractor centered on circle and mark off 30 degrees of circle, mark that off in 5 degree chunks.
5. I think your stock mark may be 2 degrees or so--someone here will likely tell us. I'm at work with no books to check and don't work much with post-48 flatheads. Any how, mark off that many degrees at beginning of your 30 so you can put beginning point at 0 degrees.
6. cut a strip of paper mebbe 1/2" X 3 inches, curve it around your drawn circle at your degree marks, and mark it with 0, your original timing marks number, and 5 degree lines out to end. Lay this strip on pulley with mark for original timing mark aligned and mark off these marks onto pulley with a sharpy, a bottle of liquid paper white stuff, or whatever works. The marks may then be made permanent by whacking each with a punch or chisel. Save your piece of paper so you can tell what each mark is later on.
Now, with engine warmed up, all you need is your timing light and a test tach. Write down idle and advance shown, 1,000 rpm and advance shown, etc. up to your cruising speed where problem appears. Give engine a blip to see if still advancing beyond that point. You now can find and write down your actual curve, which will look like X degrees at idle, Y degrees at 1,000, and so on til advance ceases.

 

thanks for all the info we'll see what happens, gotta getr her goin good for the roundup!!!