hey guys, I've searched around the flathead ignition stuff and still have a few questions. I'm going to be resetting the dizzy in my dormant flatmotor tonight and was looking for the generic starting points. I have a mallory dual point in it that was purchased and installed in about 1992. it has been pretty good up to this point despite all the bad mouthing I hear about them. it's got about 7-10k miles on it with no problems yet, points cap and rotor all look new. question is, what should I set my point gap and dwell at. I'm gonna set the initial timing around 5-6 degrees. I've heard you can get advance recurve kits from mallory to set these up with the right advance for a flathead instead of a SBC. anyone happen to know what recurve kit I would have to order? also, someone mentioned a replacement condensor from napa, would anyone happen to have the part# for that (just in case kinda thing). my biggest question is setting the dwell on this thing. do I just set the point gap on the leading and trailing points then adjust the trailing points until I get the correct dwell? thanks for the help! kevin
You probably want about 4 degrees static and enough centrifugal to take it up to about 20, and the curve should be fast, starting in right off idle and getting done before 2,000. This is of course a starting point for experimentation--every engine has its own tastes. Before engine is running, study it so: Get a degree wheel or protractor and either bore it out with a holesaw or make a special fitted one carefully drawn on cardboard so it fits snugly over distrib in place of cap. Be real careful to get centering right. Now grab the rotor and twist it in the direction of rotation till it stops, marking off starting and stopping point on rim of distributor. Repeat several times with eyeball right over it til you are satisfied marks are accurate, measure on protractor. This is distributor degrees of advance, multiply them by 2 to get crankshaft degrees. In other words, you are hoping for about 8 which would be 16 crank. There is an adjustable stop in there somewhere to reset total, don't remember details. You can't study rate of advance without either a running engine or a distributor machine, but if advance is stiff you will likely be needing lighter springs--Older Mallorys at least often use two very different springs, a very light one to allow quick start to advance and a heavier one with some slack that takes up later in the curve... Dwell: Setting points to spec will getit close enough usually, but better is to check so: 2 numbers, dwell for each point separately, dwell for both working together which will be roughly 10 degrees more. Hook up flashlight type light across points, stick a piece of paper between one set, rotate distrib and see how many degrees light is on. Repeat with other set, then repeat with both working. This should get you right on. If gap needs to be altered to get total dwell right, you mess with the first set of points to open, not the second one that controls firing. Static time it to the stock mark for starters...usually close enough for a starting point. Measure crank pulley, compute how wide a degree would be on the circumference, and mark it off up to about 30 degrees in maybe 5 degree steps. When running, you can then check the centrifugal advance and its rate with a simple timing light, revving the engine up to 2,000 in steps with a tuneup tach and timing light.
thanks bruce. initial is at 0 at the moment because I hadn't set the dwell yet. I was under the impression that the best way to set dwell on a dual point setup was to set the recommended point gap on both sets then adjust the secondary points after you put the dwell meter on it to set the final dwell. after you set the dwell you retime the motor.
to save a lot of typing here, www.centuryperformance.com/point-settings.asp then you'll be in business!! Good luck HellRaiser
Ok, that link didn't work for me either. The dwell is controlled by the design of the distributor (distributor point cam, point design, and adjustment). The point adjustment is simply how close each point set is to the point cam. The closer the points are to the point cam, the larger the dwell. Too much dwell can cause a late spark, rough running, lack of RPM potential, early point anc condenser failures. Too little dwell causes a weak spark, overheated points, "stuck" points, poor engine performance, and more. So you want to get the gap set correctly to get the most performance. On an 8 cylinder single point dual point Point gap .018 .022 Dwell each 29* 26* Dwell 29* plus/minus 2* 33* plus/minus 2* Setting a dual point Primary points are the ones that open first in the direction of rotation of the cam, the secondary points are naturally the ones that follow, or trailing points. Forget the second set for now. Block the second set by either putting a thin piece of cardboard or a matchbook cover between the points, or leave them completely out for now. connect your dwell meter, cap and rotor is removed, and it is best to have the plugs removed, so you can spin the engine more freely. Set the points with a feeler gauge to .022. Either with a remote starter, or have a helper in the car turn on the key and turn over the engine, check your dwell, you want to get 26*. So you may have to open or close the gap to get the 26* dwell. After you have the primary set of points set and the dwell set, block them off, and set the trailing points. Same method, set the points to .022. remove the cardboard from the primary set of points. Now adjust the secondary set of points, and (ONLY) the secondary set to get a total dwell reading of 33* or between 31* and 35* As for setting the timing on these ole Flatties, Bruce Lancaster gave the correct skinny. 4* BTDC is where ole Henry timed them, but idealy to me, once the points are set, and you've started up, use a vacuum gauge to set the timeing in the final stages. The reason is, if you live in Denver it will take more advance timing than say Texas or Florida will. Turn your dizzy to get maximum vacuum reading, then back it down by about 1" So how'd I do, the rest of you Flathead Guru's. I plagiarized all you taught me. HellRaiser aka Nirvana
hellraiser, that is exactly verbatum how I thought you checked em. thanks. checked it last night and it was right at 30 so I didn't have to mess with it too much. unfortunately that didn't do anything for the stumble it has. I have a new set of solid core wires with new rajah end caps coming for it today so by the begining of next week I will see if those do the trick. after the wires it's going to be condenser, cap, rotor, plugs, coil. I really think the plug wires are NFG though. had one come apart in my hand when I pulled her out of storage.
Ok, but don't run those wires thru one of those metal wire looms, they may look pretty, but it's a quick way to get a short jumping thru the wire and shorting out on the inside of the loom. You'll never find it.
yeah, I'm just running the cheapy black plastic clips that hold the wires in place. they look like crap but they work... I have a tech request into mallory now to figure out which advance kit to get for the distributor. they seem to list to different kits for this thing...
You can always just go to Century Performance's main page and hunt around from there. Just spent the last couple days reading up on this same topic. Last week my truck decided not to start. Turns out my electronic unit died. http://www.centuryperformance.com/
Go to Rumbleseat's online flathead book and check the ignition section--he posts his recipe for late Mallory springs and limiter. Bruce
Does this dizzy have the two piece cap? Some of those models don't have adjustable spring plates. Mine doesn't but the plate is stamped 16. Mine also only has 4 lobes on the cam instead of 8. I think it's one of the old Rev-Poles. I bought it new in 1955. It has no vacuum advance.
bvm, this ones a dual point from the early 90's but i'll check out the site. bruce, thanks for the heads up, wouldn't happen to have a link to the site would ya? blown, it's a newer style dizzy. I've got NOS two piece cap mallory unit for the 283 that's in my 32 I think the chevy unit is a yc 310hp. if you send a tech request to mallory they can give you the specs on your distributor. THis is what I got back from mallory when I asked about it(the chevy dizzy): The curve was 24° @3200 rpm, point gap .018", 17°ea dwell with 34° total dwell. from the 1960's. The cap is a #4001,rotor is a #4215C, points #24875B. The big brass condenser is not avail. use a #400.
Go here: http://www.flatheadv8.org/rumblest/intro.htm Scroll down to the bottom, click the "ignition" chapter...then backup and print the whole thing. It's a very nice Ford encyclopedia, written and updated by a guy with a lifetime of experience.
Also, the Technosource clickable higher on the same page is worth a visit...it is sometimes a bit mixed, but has lots of good info.
okay guys, got some time yesterday to work on her and I'm getting frustrated! I put on the new wires, set the dwell to 30 and the timing at 5 degrees btc. started her up and she ran nice. idled smooth throttle response was great, just seemed to run right. so I took her down the road and the minute I let the clutch out and got on the gas it did nothing but sputter and backfire! I'm thinking I have a broken advance mechanism now. I put the timing light on it when I got back to the garage and as soon as you got around 1000 rpm the timing mark just dissapeared. It didn't slowly creap away from the timing mark it just jumped all over. still a tossup between coil, condensor and bad advance mechanism. ordering all three to be sure. should I get the mallory condensor or order one from napa like I've seen mentioned? also, there are two different advance kits listed for the 25 series distributors but I can't seem to be able to tell which one goes to this distributor. the dizzy is a 2527501
well guys I got her running great! ended up being a coil or condenser. replaced them at the same time and she run good. took her for a rip just added to the list of things I need to fix! second gear syncro's seem to be getting a bit tough and the rear is making some noise. it never ends!
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