FE tuning question - heavy pinging under load

[DV65CustomCab]

I towed my race car on the trailer to NJ yesterday to a race. My good running 352 was fine on the highway, but on 2 lane roads and climbing moderate hills it was horrible. Lots of pinging and not much in the way of power. Unhooked the trailer, and it's a totally different truck.

Back when I had my $250 POS Slick, I had no trouble towing with a similar rig even up western PA's giant hills. Only thing I can think of to do is go to 92 octane. Any other ideas?

[R Pope]

Either too much advance or too lean. Try a few degrees less advance. Or shift it down sooner. A different power valve might help if it has a Holley.

[6166 Junkyard Dog]

are you still running points ??? on my Big Slick with that stupid Petronix system could never get the ping out of her, TILL I took it back to points and the ping went away with a set of points and that was with a load on her

[BarnieTrk]

DV65CC,
Retarding the timing may help reduce the pre-detonation (pinging) but less timing will positively hurt fuel mileage and power.

What related factors are different between this truck and your previous "$250 POS Slick"; such as:
a) - rear end gear ratio,
b) - type of transmission,
c) - diameter of rear tires,
d) - type of camshaft profile (RV versus hot rod versus OEM),
e) - amount of timing,
f) - Has the 352 been rebuilt - if so, was the compression ratio increased over OEM specs?

If the compression ratio is 9.5 or higher, you'd likely benefit from using a 92-octane, premium-grade fuel. The first thing I'd try would be a tank full of quality, name-brand premium fuel and see how it likes it.....

Over the past year or so, I've read more than a few times that regular-grade gasoline in general is being sold with a lower purity grade (not a lower octane rating, but lower in good quality gasoline additives & stabilizers) than what was available only a few years ago. It is now common to recommend NOT to leave gasoline to sit in a vented fuel can or in your lawnmower to your vehicle's vented fuel tank for more than a month - as the gasoline qualities deteriorate so dramatically that if not used up, it will gum/varnish up the works faster than ever before.

The general consensus is that if you tend to NOT burn up the fuel within a months time, you would be better served by purchasing a quality, name-brand mid-grade and premium-grade gasoline. For me, if I pay another dime or so a gallon for mid-grade fuel to burn infrequently in my lawnmower, chainsaw or my part-time driven Slick, it's worth it to me to keep the fuel system happy and flowing freely. Some folks claim the fuel additive, Sta-bil, is good stuff and helps preserve the fuel. Personally, I just buy mid-grade fuel and try to run them on a monthly basis; this practice has proved to be successful and trouble-free (as I knock on wood) for me thus far....... That's just my 2 cent opinion/input.

Please keep us all informed as to what you try/do as you search for a fix for your pinging and lack of V8 power.

Good Luck!
BarnieTrk

[Michelle]

Check and see if the diaphram in the vacuum advance is busted, I know that the ping is usually assoaited with too much advance and not too much retarding, but check it any way. Another thing to check. Any time I time any of my cars I plug off the vacuum to the advance diaphram to get a more accurate timing. If the spark port is leaking and drawing a little vacuum and you do not disconnect the vacuum port you can get inacurate true timing.

[Lowell]

Like michelle said check out your vacuum advance . also the little springs on the mechanical advance could be weak and letting it advance too far too soon.

[*motor*mount*]

Try better gas and chek the timming.

[DV65CustomCab]

Totally stock, never rebuilt engine. 2v carb, Pertronix ignition (I have a tough time believing Tom on that being the cause, sorry Tom!). The POS truck was basically identical. 352, 3 speed, 1/2 not-tremendous rear axle ratio (I forget right now what it is...2:73?). I'm pretty sure the timing is set to stock with the vac advance removed as per the Motor manual.

[banjopicker66]

Dwight, I am thinking the pinging might be caused by an air leak leaning the mixture out when the throttle plates are more open for towing than for the empty truck.
Have you checked the PCV valve, the hose, the PCV/EGR plate under the carb (if you have one) for cracks or such, and the throttle shafts for excess play?

Or, perhaps it isn't downshifting soon enough?

Just brainstorming here.

[64 f100]

2.73 with a three speed standard? Very high gears for pulling with a standard transmission. In fact, My guess would be 3.25 in the truck you have, Which may be part of the source for pinging. But original carb with throttle shaft play could be part of it. Any number of combinations coulb be the problme. 352 original compression should not be high enough to cause the ping in and of itself. To much advance maybe, ro depending on how much carbon buildup you have could add to the problem. Or just the brand of gas you used. I recall the 57 Coupe DeVille my father had would not run on regular gas because of the compression, and would ping. We ran premium but cheap grade premium would cause it to ping.

Rich

[DV65CustomCab]

Well, that was an easy fix. Sorta.

I filled it with 92 octane for the return trip and NO pinging. Ever. Not a powerhouse on hills, but not dying either. I agree, the diff ratio and the 3 gears (1st = not quite good for pulling out, 2nd = a little too low for hills, 3rd = useless for anything but highway at 65 mph) are probably the biggest issues.

I kinda remember dumping my Dad's gas can of mower fuel into the truck a few weeks ago but thought I would have burned through most of that before leaving. But, that may have been a contributing factor as that gas probably was 2 years old.

After installing a genuine FoMoCo heat riser gasket I managed to get about 2 hours of quiet out of it before it blew and started ticking again. I bleeping hate this bleeping heat riser and the bleeping exhaust system it calls home. The Hookers are sitting there in a box...yet I know that's another potential leaker. Aaargh.

Literally a dozen comments about the Slick as a tow rig for my race car. I'll try to link a pic...
Edit: won't hotlink. I'll try a clickable one:
http://hphotos-snc3.fbcdn.net/hs105.snc ... 2149_n.jpg

[6166 Junkyard Dog]

GLAD IT WS THAT And not any of my Cray ideas still beleve in old points though

[R Pope]

I've seen stock engines with Petronix conversions that had to be retarded from original specs. The hotter spark causes faster burning, in effect advancing the timing.

[DV65CustomCab]

That theory may actually fly. I know I tried some wild recommended advance numbers some time ago and wasn't at all happy with how it ran. Set at stock now it seems to be happy.

If I just had a little bit more torque I'd be satisfied, but I think that's going to be a 390 upgrade.

[BarnieTrk]

If I just had a little bit more torque I'd be satisfied, but I think that's going to be a 390 upgrade.

As Rich pointed out, if you do indeed have 2.73 rear gears, that isn't helping you at all in the torque department. I'd suggest you confirm what gears you have - you may determine that a lack of gearing is your source for the lack of torque - especially since you're running a 3-speed transmission. A 4.11 gear would make a world of difference with your 3-speed; however, your fuel mileage would also diminish accordingly. However, if you don't use your Slick as a daily driver, then fuel mileage isn't as big a deal.

I once had a 3-speed transmission (in a F250, with a 240, 6-cyl) and I tried to make that thing pull, but it always seemed to be a struggle. My earlier F100 with a 223, 6-cyl and a T-18 4-speed was WAY BETTER for towing loads. If your 3-speed gets tired or you simply get tired of it, I'd highly recommend you step up to a T-18 4-speed transmission - especially if you plan to continue to tow a race car more than twice a year.

Another thought: If your current 352 still has good compression & oil pressure, you may want to consider to just doing a camshaft upgrade, RV-style.
I'm sure you could find some extra torque easier, cheaper, and for less work with a newer RV-profile camshaft, new lifters and new timing gears/chain. However, considering the lack of final drive gear multiplication due to your 3-speed and possibly low (numerically) rear end, a change in either or both of them would result in a greater torque gain than a cam change. Just my

Good Luck!
BarnieTrk

[Jonas]

Cool Picture!!!

[DV65CustomCab]

The 4 speed would require cutting a hole in the floor, which I'm not willing to do.

I think the 4:11 gearset would be too low for highway cruising. One of the tracks I go to is a six hour interstate drive. I think something in a 3:73ish ratio would be a nice balance. Easiest thing to do of several, really. Some U-bolts, brake cables and bleed the lines and I'm done. Hmmmm.

[BarnieTrk]

The 4 speed would require cutting a hole in the floor, which I'm not willing to do.

I think the 4:11 gearset would be too low for highway cruising. One of the tracks I go to is a six hour interstate drive. I think something in a 3:73ish ratio would be a nice balance. Easiest thing to do of several, really. Some U-bolts, brake cables and bleed the lines and I'm done. Hmmmm.

I don't blame you for not wanting to cut up the floor on your good-looking Slick - however, and I'm not trying to argumentative, but doesn't your Slick have a removable transmission hump cover bolted to the floor that could be switched for a floor shift cover that has a shifter hole in it?
I don't recall if my column-shifted 3-speed Slick of years ago had a removable cover or not.....
Another thing that some folks don't like about a 4-speed is that it takes up floor space, hence, it may crowd a center/third passenger in the cab or if you want to use the area for a center console. Oh yeah, if you did go with a 4-speed, you'd probably eventually want to change out the steering column collar section as well.

Ok, so a 4.11 is probably a bit on the steep side, especially for 6-hour highway towing jaunts; so in that light, I also agree that a 3.73 gear would be a great improvement in delivering improved torque over the 2.73 gear ratio rear gears. It sounds like you've got a 9" rear housing, if that's so then if you just rounded up a good, used 3.73 gear already setup in a center section, then just exchanging the center chunks wouldn't be as tedious and an easier/faster job to do.

Good Luck & please keep us posted on your decisions & progress/results!
BarnieTrk

[mike starck]

doesn't your Slick have a removable transmission hump cover bolted to the floor that could be switched for a floor shift cover that has a shifter hole in it?
BarnieTrk

Discovered that the 3speed / automatic version don't have a removable floor pan.Solid. Went to the junk yard to get a blank when I removed the 4 speed tranny and was suprised to see a solid floor pan. that is on '65/66

mike

[DV65CustomCab]

Yep, solid floor pan. The logic of why Ford made two floor stampings escapes me.

I thought about just changing the center chunk yesterday myself. Is that just a matter of yanking the axle shafts out and then unbolting the pumpkin and replacing it?

One of the 'helpful' bystanders at the track said I should put a turbo on the FE and that would solve all my problems. He was serious.