Hi, Eric,

That article you posted is standard balance procedure which I/my balance shop do every time. You'll have to spell out for me (us) what you wanted us to learn from it.

Here are the reasons I balance every engine nowadays:
1. Packard's balance wasn't that great to begin with.
2. I bore many 352"s to 374" and the pistons are 38 grams heavier.
3. Egge pistons aren't even close to the Packard piston weight.
4. On custom engines, such as the 364" truck engine I'm building now, everything is modified.

Putting a bare crankshaft between centers or on blocks on the bench and watching what it does/doesn't do won't tell you anything about its dynamic balance. It has to have bob weights attached to the throws; they equal 100% of the rod big end/bearing plus 50% of the piston, rings, clips, pin and rod small end weight. Then, it has to be spun to operating RPM. If it were statically balanced, it would be all wrong dynamically.

thnx, jack vines

I came to Packard V8s through the '56 Studebaker Golden Hawk. I've got a dozen engines, but no Packard.

thnx, jack vines

Congrats on a unique buy. I saw the car on our local cragslist and was mildly interested. The seller mentioned a left rear quarter panel problem but none of the four photos showed it. That omission kept me away to your benefit. Is it a 320" or 352"?

thnx, jack vines

FWIW, I no longer build a Packard V8 without balancing it. Since we don't have good technical data, who knows what should be where.

Here are some questions for which I still don't have answers after many years and many engines. Do any of you have thoughts or references for:

1. Why do the 352" and 374" cranks have the same P/N when the balance factor is 38 grams different?
2. What is the design weight for 374" pistons? I have 352" 24.763oz - 702 g, but no published weights for 374" pistons and no pin weight. BTW, oversize pins are heavier.
3. Why were there two or three different rod manufacturers? Why did Packard mix them in the same engine when the weights are definitely different? The "Atlas" rods seem to be heavier than the no-name rods with the sort-of-pentagon-logo them.d Anyone identified any other markings besides the P/N and batch pour number?

Bottom line - yes, any rebuilt engine should be balanced. The vibration can be noticeable, especially if the pistons are changed.

thnx, jack vines

Quote:

Lot more to it than that:

1. .050" off the top to match Packard compression height
2. .1875" off each inside of the pin boss
3. Press the bushing out of the rod and bore to Ford 1.040"
4. Rebalance entire engine - Use Mallory metal in the counterweights or add external balance weights to the flywheel/flexplate and front damper.

At retail, all this will cost about as much as custom forged pistons which are a drop-in. BTW, I just did all of the above last week because I'm building a Packard truck engine. Stand by for news.

thnx, jack vines

Greetings, Eric,

FWIW, I know John Erb, formerly chief engineer for Keith Black/Silv-O-Lite/United Machine. Five years ago, while he was still the man, I spoke to him at length about making Packard V8 pistons. I even guaranteed 100 sets. With all his leverage, he said it would be a bad business decision. He said then and as this thread proves, there is next-to-no demand for Packard V8 performance pistons. He checked the specs and the Chevy/Ford 4" bore stuff is a full 1/2" shorter compression height than the Packard V8. None of their molds or jigs would come close to making a Packard piston. There is one Ford truck piston close to the right height, but it is heavy-duty monster 125 grams heavier than the Packard V8, so the imbalance makes it not a real option.

Making a Packard V8 piston is more difficult than it seems at first glance, eh?

thnx, jack vines

Correct, on the V8 pistons, the word "Bohnalite" is often seen on the side of the pin boss in small letters.

thnx, jack vines

Easy to tell if one has handled a bunch. Hard to describe to anone who has not, but here goes.

1. The OEM Packard pistons have steel expansion struts cast in above the pin bosses. They also have OEM part numbers cast inside the skirt.
2. Egge pistons do not have the steel struts.
3. Aftermarket replacement cast pistons have the steel struts and their own part number cast inside the skirt. Some have a four-digit P/N stamped on the head of the piston.
4.The very few custom forged pistons I have come across do not have the steel struts, but don't look like an Egge casting. Forgings also do not have any part numbers cast inside the skirt.

thnx, jack vines

Let's add one more detail. How much would you pay for a set of current-state-of-the-art hypereutectic cast pistons? Egge's are $400 and custom forgings are $800, in round numbers. I'll pay $550 a set, for starters.

thnx, jack vines

Greetings, Men-Who-Own-One,

In another thread someone mentioned the possibility of late-56 engines being made up of the sweepings from the parts bins. We do a lot of 374" and naturally, these are later build engines.

On a couple of performance engines we have in progress just now, I note three different manufacturers of connecting rods. "Atlas" is the only one identified by name. These also have cast-in Atlas 8, Atlas 9 and Atlas 10, all in one engine set.

Working with these mixed sets of rods is a royal pain, because they are widely varying in weight. There is a balance pad left on the forging on the top and bottom of the rods. On some rods, the balance pad is virgin; no grinding for balance at all. On others, the balance pad is almost ground away.

When doing a performance balance, all components to less than a gram variance, we're finding for all their bragging, Packard was pretty sloppy with static balance.

We've got six more 374" cores on hand. Maybe the easiest way is to pull all them down, sort out the rods, and try to make sets from the same forging foundry and re-number them.

Question: on '55 engines, is it more likely all rods in a given engine would be from one manufacturer?

Question Two: One P/N for 352" and 374" crankshafts. Anyone know differently? The 374" pistons are 38 grams heavier than the 352" pistons. We balance most of our engines, but what about the dealer ordering a replacement crankshaft? They definitely didn't rebalance, so which crank did Packard ship and did they have vibration problems as a result?

thnx, jack vines