Stamped numbers on oil pan rail: factory?

[Verne Frantz]

Gentlemen,
I have a '62 engine which has numbers stamped on the pan rail directly in line with each cylinder (both sides). The numbers range between "9" and "16". The double digit numbers appear to have been gang stamped, rather than individually, leading me to think they might have been put there at the engine assembly plant. Considering the production rate that had to be maintained, I find it hard to believe they might pertain to balancing specs.
Any thoughts on what they mean, when they were put there, would be appreciated.
Thanks
Verne.

[mikemccagh]

Re: Stamped numbers on oil pan rail: factory?

Verns is the engine stamp pad blank? I've had and seen overthecounter engines that had the assembly data missing fromt the engine pad but stamped on the pan rail. mike

[Verne Frantz]

Re: Stamped numbers on oil pan rail: factory?

No Mike,
The pad stamp is there, including the VIN. The engine was rebuilt once at S. Pete VanIderstein's in No. Jersey about '85-'86. I believe it was balanced then, but the gang stamping is definitely not something I would expect from a machine shop.
The stamps on this pan rail are not visable from the outside. They are on the oil pan gasket surface.
Verne.

[Clem Z.]

Re: Stamped numbers on oil pan rail: factory?

may be there to tell which piston went in that bore to get a select fit.

[John H.]

Re: Stamped numbers on oil pan rail: factory?

The numbers stamped on the pan rail are piston-size codes for each cylinder; each bore was air-gauged at the beginning of the engine assembly line, and that engine's eight size numbers, by cylinder, were stamped on the pan rail, and were electronically broadcast ahead to the piston/rod subassembly area, where a tray of piston and rod assemblies were made up specifically for that engine (there were about eight different piston sizes in those days to accommodate bore machining/honing tolerances). That tray of piston/rod assemblies traveled by conveyor, in sequence, to the "piston stuffing" operation, where the operators pulled them off the tray by cylinder number and "stuffed" each bore and installed the rod caps and nuts, which were torqued in the next station. The "stuffing" operation was something to see in those days - the #1 line ran at 170 engines per hour, and that station had two people on each side of the line "stuffing" rod/piston assemblies, with one engine every 20 seconds. The #2 line was similar, but "only" ran at 100-110 per hour

[Verne Frantz]

Re: Stamped numbers on oil pan rail: factory?

John,
Once again, your experience from actually being there is invaluable. I had first considered such an explanation, but knowing how fast the line had to run, I thought, naw............ they'd never take the time for that. I figured as long as each component met tolerance, they'd just grab them "blindfolded" and keep "stuffing" them together.
Thanks very much
Verne

[John H.]

Re: Stamped numbers on oil pan rail: factory?

Machining tolerances, cutting tools, honing methods, and sophisticated process control systems have eliminated all this in modern engine plants within the last 5 years or so; virtually every modern engine plant has one bore size and one piston size these days, and "piston stuffing" is now automated (which is pretty slick to see, considering how fragile today's narrow piston rings are).

[Verle R.]

Re: Stamped numbers on oil pan rail: factory?

John,

How did they compress the rings when stuffing the pistons?

Thank you,

Verle

[Terry M.]

Re: Stamped numbers on oil pan rail: factory? *TL*

They used an internally tapered cylinder to compress the rings. You can buy the same tool from Summit or Jegs. They used a curved rod with one end that hooked on the pan rail and the other pressed against the top of the piston. They pushed the assembly in with one swooping motion and the tapered cylinder stayed on the curved rod which was passed back up the line to be used on another engine.
The hand torquing of the connecting rods and main bearings was a sight to see also. I couldn't count the number of folks around the engine - maybe six or eight - but each had certain bolts to tighten, and there was one person who rotated the crank to the different positions. They all moved around the engine in a carefully choreographed ballet. They used Snap-on torque wrenches and calibrated them at the start of the day and at the lunch break.
This operation had to take an enormous physical toll on the participants, but none the less, it was disappointing to see the whole process automated in later years.