Ballast Weight

[dan65]

As many of you know, Mark (108Vanguy) recently posted a video about a 92lb ballast weight mounted to the floor, just above the gas tank on 1964 Vans.

Well, my buddy Brian just bought a 1965 G10, and he has the ballast weight on his????

His Van is number 11,126 of roughly 35,000 made in '65. My Van is number 26,432, and I don't have the weight.

Is this pre-swaybar engineering? Does anybody else have one on their '65?

What was GM thinking with that?

[tinlizard]

The early Jeep FC150s (cab-over pickups) would literally stand on their nose if the brakes were applied too briskly while descending a steep incline. They added a heavy (450#?) cast iron weight above the fuel tank to counteract this annoying tendency. I've never heard of a van exhibiting such behavior, but I can imagine the engineers trying to improve the front/rear weight distribution a bit.

[CREWCHIEF]

Someone told me they were worried about them doing a nose dive when you raised it up on the old style lift.

[Simpkins]

I can tell you from experience that a 64 with the ballast installed can just about balance on two axle stands if you place them on the rails just behind the rear spring hanger for the front axle (close to where that floor brace is below the side cargo doors). That was with an empty fuel tank but that's also without anyone in the front seats. On a short wheel base vehicle (like these vans) having the center of mass close behind the front wheels makes the vehicle less stable in a straight line and under braking. I don't think there is really any concern for tipping nose first (while driving normally), but I can almost guaranty that the engineers added the ballast for better highway stability. Imagine how easy it would be to spin out a short vehicle with little to no weight on the rear wheels, now imagine that with no power steering. There was probably a sizable number of accidents caused by people loosing control of these vans on the highway.

[108VanGuy]

Good Points

So why did they discontinue the weight in 66 or late 65? What changed their thinking? Crystal ball please..
108VanGuy...

[jrinaman]

Mine definitely handles better with weight in the back, 500 lbs. makes a huge difference! Now I don't think I want a 500 lb. weight back there but the bed, batteries and whatever else I add will be in the back. 92 lbs? Don't think that's enough to matter.

[digz]

Don't have a before swap scale ticket to compare with but after putting the V8 and 700 trans in and a couple hundred pounds of interior (3620 lbs). The weight bias is 60/40 on my 65 with no rear iron. So I'm guessing in stock trim with the iron they'd be pretty close to 50/50. Don't know if that would be a good thing or not.

[Simpkins]

So I spent the evening doing some thinking instead of working on the van (I know, I know poor choice). Apparently I wanted to know for the sake of knowing, so I might as well share what I've come up with. At least if I share I can tell myself I did something of value, not sure how much value but its something.

The center of mass is about 39in from the front axle on a 64 with the ballast and standard equipment meaning that 56.7% of the total weight is on the front axle. If the ballast is removed that would move the center of mass to just about 36-1/2in from the front axle and thus 59.4% of the weight is on the front wheels. We only lose 92lb off the total vehicle weight and the weight only moves forward 2-1/2 inches, as jrinaman said it sure doesn't sound like it would do much.

So I pulled out some vehicle dynamics notes and did some more investigating. Apparently while going around sweeping corners these vans 'used to' have a tendency to understeer quite a bit more than what is typical. I say 'use to' because we no longer use the old bias ply (or cross ply) tires that these vans came with, our modern radial tires handle quite a bit better. They would still understeer quite a bit but no way near as bad.

in vehicle dynamics stability criterion there is a 'characteristic speed' at which the under steer would be so bad that a driver would effectively loose the ability to steer. The mentality is that as we increase the speed we reduce the ability to turn corners. Of course we already know this, they aren't as nimble if we go fast. The purpose here isn't to list the characteristic speeds but to compare how stable one setup is in relation to another. And of course all this is theoretical so take it with a grain of salt, there are more factors in this world than any math equation could ever account for.

Drivers would effectively loose the ability to steer at:
74mph for a 1964 with a ballast and bias ply tires
82mph for a 1964 with a ballast and radial tires
63mph for a 1964 without a ballast on bias ply tires
69mph for a 1964 without a ballast on radial tires

interestingly enough the 1966 panel vans have a different listed weight distribution compared to the 1964 panels without the ballast (what else changed?).

Drivers would effectively loose the ability to steer at:
65mph for a 1966 panel with bias ply tires
72mph for a 1966 panel with radial tires
66mph for a 1966 sport van with bias ply tires
73mph for a 1966 sport can with radial tires.

As for why GM quit installing them is a mystery, sorry no crystal ball here. Maybe GM decided it wasn't financially justified to add them or that they were difficult to source in high enough volumes to keep up with production. Maybe they displaced potential engine/transmission casting production and scrapping them entirely meant they could produce more engine/transmissions.

I wonder if they installed them at one assembly plant and not another in 65. The reason is say this is because vehicles intended for the northern snowy climates would have more need for ballasts than those destined for warm southern climates. It would be interesting to know where the two vans that dan65's talking about were produced to see if they are different.

[jrinaman]

Not sure what they meant by "ability to steer" but can say from experience 75 mph is about the cut off for feeling safe. The 292 added 50lbs?, my toolbox offsets that! I am certain there is 92 lbs. of other crap back there too. While I can cruise 75 comfortably, 85 becomes a white-knuckle ride. If I pull the pop-up camper, 100 mph is not a steering issue. With the short wheelbase and fairly light for its size, a slight breeze makes a noticeable difference. An early camaro, while much lower/aerodynamic, has another 18" of wheelbase and weights almost the same. More weight in the back would be a good thing.

[dan65]

My Van originally sold in southern California (I have the original registration), and I am pretty sure Brian's Van has spent its entire life here in Washington State.

After reading all this impressive information and thinking about it myself, having the ballast is probably a good idea. At first, the idea was to get rid of it, not anymore.

[gfleduc]

108VanGuy
By luck is there any P/N stamped on the weight?

[gfleduc]

Ballast Weigh

dan65

Two spot checks
VIN 6987 does not have the weight. Mine 16879 did not.

AutomaticAmie has a day one production 1965 - maybe she or Smiley can comment if it has one.

Others could make an easy check by the presence of the carriage bolt heads (or holes) in the aft area of the cargo bay.

Question some reference points from your friend's van - Five or six row grill? One or two dog house latches?

[dan65]

dan65


Question some reference points from your friend's van - Five or six-row grill? One or two dog house latches?

Yeah, he has the Bigger grill, double latch lid, and the old-style shift linkage arm, pivot ball location (mounted on the frame vs. mounted below it)

He also has internal, horizontal ribs that run along the body between frames. I know '64's all had those. Mine does not.

So it seems they changed things sometime after VIN # 11,000. It would also be interesting to know how many they produced in a day, a week, a month?

Did someone come running out of the engineering office yelling "STOP THE PRESSES!!!" We don't need no stinking weight!

[gfleduc]

1st Design vs 2nd Design

Well I have some loose tracking on different changes - I have a rough bracket of what I call "transition vans" for the Grill & Dog house latches. Your buddy's (does he have a name to share?) van is right in that transition time frame. This in based on empirical data - I have not found any documentation such as service bulletin incorporation. Heritage CTR has not been able to support too much. I have 11126 build date estimated at 5 Mar 1965 @ 26% through the production run.

To answer your question I have a calculation of ~ 118 vans produced per day.

dan65 - Question I not aware of the "horizontal ribs" do you have a photo?
Sending you an email

enjoyed "STOP THE PRESSES!!!"

[dan65]

When I say "body" and "frame," I'm talking about the Chassis. Inside the Vans' cargo area. He (Brian) has the horizontal stiffeners on the inside walls of his Van, between each of the frames.

I'm pretty sure the wikivan (1964, kookykrispy, Joe) has them on his, and other '64's I've seen.

I'd show a picture, buuut.............