Thanks Ted. I Think I need to tweak it a little, since I do recall that I could feel a little bit of what I consider too much timing (no sound, just a little rougher sound & feel) at part throttle, no load, definitely when the ported vac was pulling in the 5 or 6 degrees I have in the vac. adv. I think that must mean It was around a lower rpm that I must be hitting total than I previously estimated. A small tug on the tangs with some trial & error should get the best of both worlds. It will have to wait until the snow clears since we just got a big storm last night, & the back of the truck is being used as garage overflow to fit the other car inside also.

I have a Brand new one piece dampener.

No slipping here!

I don't see it mentioned in previous replies so the first question is, are you sure your damper has not slipped giving a false reading at the crank?

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

“Safe” meaning the supplied curve in the distributor is short and lazy and in turn reduces the propensity for detonation to a lesser degree.  MSD is leaving it up to the purchaser to modify the curve where it’s optimum rather than provide a curve that could potentially hurt an engine from the initial install.  Having a curve that comes in too quickly can create a situation where detonation occurs when the engine is under a load.  Other players in this includes the octane level of the fuel, engine temperature, air/fuel ratios, amount of engine load, etc.

 

A light rattling sound from the engine when it’s under a load is the sure sign of detonation.  Signs of detonation can be read on the sparkplugs while evidence of detonation can also be observed at the engine bearings, under the main caps, tuliped valves, broken rings and piston ring lands, blown head gaskets, etc.  Reading the spark plugs is obviously the easiest way to prevent many of the more serious problems before they actually take place.

Lorena, Texas (South of Waco)

That plastic piece was NOT there... I also will note to those amateurs like me, DO NOT ATTEMPT to crimp the steel of the slot itself.... OOPSE! So that dizzy will nee to be used as the 15L only on dads truck until I get a replacement piece since the small end of the slot sheared off & went into orbit!



I ended up putting the petronix back into my original one that was a reman in the mid 80's (stake bed's dizzy) that has the "10 slots autolite style. I made sure that the spring combo I used felt around a similar tension when holding the gear & rotating the top by hand activating the advance weights as the motrcraft did before I chunked it. I used the little "tabs" that the spring holds on to to adjust the tensions slightly to get what I thought was a good "feel".....

I put it back in, & evidently did a good job stabbing it in as it hit on the first try!



The setup now is as follows:



Total advance: 38.5 crank degrees.

All in (need to get second person to watch tach) estimated at 2200-2600

This lands the initial timing right at 19-20 at an idle of 900 RPM.



My conclusion is that the stiffer of the two springs was limiting the total.



The truck idles much better & no longer has that "over timed feel" at idle.



The truck snaps like a mild 289 when I pop it to wot sitting stationary. It jumps to 2800-3000 in about a second. Out on the road you would be hard pressed to realize that it has 3:1 rear gears other than the tremendous road speed when you shift out of first @ 5000 & the speedo says 55, stay to 5000 in second & the truck is flat out hauling a**! I need better brakes & a better road, but I have no doubt the thing will pull steadily to 100, even with the ridiculous gears & 29" tall tires.



I wouldn't be that upset if the tranny fry's soon, that way I can put the AOD & 3.73's in it. Maybe i'll go 3.89's.



Sorry for the long post, just exciting to finally feel the results of the great technical info that you gents. are so kind to share with us young bucks.

Thanks again.





Quick question for you all:



Ted had mentioned the pro billet dizzy comes with "safe" curve. Can you elaborate more on an UN-Safe curve??

I don't want to fry this thing, & what signs can I look for that will point me to stiffen the tension a little? (such as plugs showing detonation, etc)

The little plastic pin cover can just be seen at the 6-7 o'clock position in this picture....

 
 Steve Metzger       Tucson, Arizona

The "pin" that sticks up into the slot of the later (Motorcraft) dizzy often has a piece of hard plastic tubing around it. Beause it fills some space in the slot itself - it changes the total travel. If the tubing is missing - the advance travel is a bit greater. If you don't have a ready way to change the 13L slot length - try crimping a small bit of tubing over the pin to make it fatter. As long as things are free and don't bind -just make sure the new addition won't get loose.

 
 Steve Metzger       Tucson, Arizona

Are there any signs of wear on the advance mechanism? You might have to weld or braze it to get the desired amount of advance. Another option is to search the local salvage yards for another to swap in. I had mine in the 13L slot and it only provided 25 degrees. They aren't exact.


Lawrenceville, GA

So I pulled the dist out of dad's y-block.(reman from about 8 yrs ago), the dist. out of the 58 272, & looked at all together.



Mine in the stake bed looks to have been a reman, probably sometime in the 80's. It is the Autolite style, with the "10" slot. Both springs were similar, one only slightly noticeably stiffer.



The motorcraft from the Blue & white beast(dad's truck I'm housing) has the usual 13 & 15 slots, as you all predicted. One spring really heavy, one spring short in the coil area & light.





The 58 is an autolite, had the strange ball bearing plate for the vac. adv, & had a long slot, significantly longer than the 10. (I apologize my mic. is not here at this house)



I logically thought I could cut my base from the 26 I was requiring before with the autolite to get the total to come up to 38 by using the motorcraft with the 13 slot.



Instead, I am only getting in about 11 base timing when total is at 40. I have the dizzy in the 13 slot, & removed the heavy spring & used one of the mr gasket springs.



What gives? I am counting 29 crank degrees here & this is all with vac disconnected. I will also not that my total is finally coming in about 300 rpm higher than before. Motor is obviously lazy on the bottom & no longer snaps when I pop the eddy to wot sitting stationary.





I would like to get about 18 base & 38 total, in by bout 2600 to 3000. just put new wires & don't want to change the ends to go to the pro billet dizzy.

The "slot" style upper rotor shaft (Autolite distributor) has a pair of openings that engage the flyweight pins -

The slots in this one were arranged to provide 20° at the distributor and 40° at the crank. Stiff springs are the norm. 

The later arrangement (Motorcraft Distributor) has two notch openings that can be switched to alter the travel stops. The stamped "13L" and "18L" markings are indicative of the distirbutor degrees they allow. There are more than a few variants. I've got a "10L" and "15L" before too.

This one has a 13° and an 18° - with the notch opening sizes shown. A 10L opening could be enlarged if you wanted - just takes a file.

 
 Steve Metzger       Tucson, Arizona

There are different '57 and up distributors. You might have an earlier one. Is it different than the one pictured on the first page of the first link I posted?


Lawrenceville, GA