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By 55blacktie - 2 Years Ago
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In "Parts to Look For" on ford-y-block.com, John said that although the 1957-59 FEK/FEH distributors have centrifugal advance, they have too much advance for performance use. He went on to recommend 1959-up distributors for performance applications. My 57 tbird tach-drive distributor is an "FEJ," which falls into the FEK/FEH category. At what performance level should the 57-59 FEK/FEH/FEJ distributors not be used?
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By FORD DEARBORN - 2 Years Ago
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I try to shoot for a street curve of all in, 36* +/- at 3000 engine rpm. Most, but not all Y-block distributors (FEK) had cams designed for aprox. 17* which would be 34* crankshaft. To reach 36* max at the crankshaft, in this example, would require setting initial advance at 2* with a timing light. Not a good thing especially with a larger camshaft. A distributor cam limited to about 12* would require an initial setting of about 12* with timing light which would provide an idle we can live with. I am no expert at racing or building race engines but found the above curve to work very well. As for the factory Y-block distributors, the key is finding a distributor cam or modifying one limited to around 12*. Otherwise, there are modern distributors available with various stop limits that can be installed as desired. There are many variables that come into play when considering a spark curve. The vacuum advance is considered after the centrifugal advance has been worked out. I realize you folks know all this but I think the fact that most stock Y-block stribs have too tall of centrifugal advance to make use of a modern performance curve. Thats probably what John Mummert was referring to on his web site. When I rebuild one of these stribs I've been able to find a distributor cam from my stash, suitable for this curve. When they're gone, they're gone.
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By FORD DEARBORN - 2 Years Ago
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Edit - At what performance level should the 57-59 distributor not be used? I have used the above curve on a bone stock 292 2 barrel. My present truck is a 1957 clone, including the cam shaft and this curve works excellent. I'm sure I have it on paper if anyone would like to see it.
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By Ted - 2 Years Ago
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That’s the first I ever heard of not using the original ’57-’59 Y-Block distributors in a high performance application. This same style of distributor was also in the FE and M-E-L engines of the same period.
When the distributor mechanical advance is not up to par for a specific application, it’s just a case for taking the distributor apart and modifying that advance curve. With a distributor that’s supplying too much ignition advance, the slots in lower plate will need to be shortened. Welding and grinding/machining is a typical fix for this. If doing that modification while using a distributor machine, then getting the curve ‘just right’ is not a big deal but if doing it in a car, then it might get cumbersome removing that distributor 2-3 times to get that curve nailed in.
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By 55blacktie - 2 Years Ago
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Ted, was the advance curve of the CRT distributor you tested acceptable for performance use? I believe it comes with additional springs, and the vacuum advance is adjustable.
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By Ted - 2 Years Ago
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55blacktie (2/20/2022)
Ted, was the advance curve of the CRT distributor you tested acceptable for performance use? I believe it comes with additional springs, and the vacuum advance is adjustable.
Not sure where all this talk about particular distributors not being suitable for performance originated from. The L-O-M distributors come to mind as not being easily modified or suitable for performance applications but most 1957 & newer distributors can be taken apart and modified to suit specific changes to an engine. Factory distributors are typically conservative on how fast the timing comes in so lighter springs usually helps most of those without going so far as to actually change or modify the actual amount of timing. Some of the Ford distributors had the option of reducing the amount of mechanical advance by simply switching the lower advance plate 180° to the shorter existing slot. Where that slot was non-existent or was still too long, then brazing or welding one of the slots and grinding/machining that slot so it was shorter would allow the engine to idle at an increased initial timing setting and keep the total timing reasonable.
The CRT/TSB distributors are ready to run out of the box. They do come with bushings and springs similar to the MSD distributors in which to fine tune the advance curve. I have installed several now and on stock engines with mild camshafts, the advance curve is suitable as-is. Unlike the MSD distributors that come with the heaviest springs possible installed, the CRT/TSB distributors already have the lighter advance springs installed. With a performance camshaft and depending upon the compression ratio of the engine, the curve itself may need to be shortened just to restore idling characteristics while limiting the total amount of advance. That is done with a bushing change which only requires the rotor to be removed to do so.
The CRT/TSB distributors are also similar to the MSD distributors in that the mechanical curve adjustments can be made by just removing the rotor to access the mechanical curve mechanism. Unlike the MSD distributors, the CRT/TSB distributors do come with an adjustable vacuum advance cannister so that adds another level adjustment for tuning. Keep in mind that the vacuum advance is designed to only work during cruise situations. At full throttle, the vacuum to the vac adv chamber is expected to drop to zero eliminating the possibility of too much total ignition timing.
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By charliemccraney - 2 Years Ago
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I think it's written for the layman or just a "simple answer". For those who just want something to drop in or are spooked by the prospect of tuning, maybe a later distributor is the better choice.
If he says it has to be tuned, then he has to deal with calls asking if he can do it or provide parts or instructions for it. I can tell you from experience that if you tell a customer x job needs to be done, the next question from them is "can you do that." It saves a lot of time, if you don't want to do it or can't do it to not mention it. On the flip side, there's the possibility of engine damage because someone used a distributor they thought was ok.
Whatever the case, the Motorcraft unit that I got over 20 years ago, probably for a 1961 F100 application came with 36 degrees of crank advance built in, which is too much for performance use. So a later distributor at this point would probably not be any guarantee that it would be even remotely suitable so a check is required in every case and tuning is expected.
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By 55blacktie - 2 Years Ago
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For some, "Time is money." For the rest of us, no amount of money will buy us more time (unless it's counterfeit).
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By PF Arcand - 2 Years Ago
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Ted: Re the '57-59 distributor advance issue mentioned above: I vaguely recalled it & it took me quite some time to find it in Y Blk mag # 137, Nov - Dec 2016. John Mummert (Random thoughts #3 ) stated that using them with a performance cam can lead to excessive advance issues. Apparently in those years, initial advance was to be only 3 deg. & some of the dizzys had as much as 34 deg built in!. Because performance cams require faster idles & are often recommended to have up to 14 deg initial, can result in very excessive spark advance issues!.. Also, he mentioned that finding replacement Vacuum Advance units for the early units is more difficult. 1960 & up apparently have a more suitable advance curves of about 24-28 degrees. .
... He also listed about 8 other items to consider that can be nasty problems when dealing with our favorite engine. One being transmission input shafts that are "too long" & bind against the crankshaft thrust bearing.. & etc.
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