This was recently posted on another forum. It's news to me.

Piston rings: "The top compression ring and the oil control ring on the passenger car are chrome-flashed to produce a coating approximately .0005" thick.". "On the Corvette the chrome plate on the rings is approximately .004 thick.". "These rings are used on all Corvette engines."

Bearings: "The Corvette 230 horsepower 283 differs from the passenger car 230 horsepower 283 in that the Corvette main and connecting rod bearings are of special material, Moraine 400. These same bearings are used in all Corvette engines."

info from actual Chevrolet printed specifiations

Now with that in mind, I have to wonder if Flint assembly was already aware of the suffix code to be used on those engines when they laid the bearing shells and installed the rings??? If it was ALL Flint engines, then some of them certainly wound up in passenger cars. (different suffix codes though)

Thoughts??

Verne

 

Verne,
Maybe someone like John Hinkley will know the answer for sure. But it seems unlikely that base engines, whether for Vettes or pass cars, would have received different rings and bearings.
Also, if such is the case, then it would have required a separate engine assembly line just for Corvette engines. And I'm not aware of a special assembly line for Vette engines. BUT, it is certainly possible, because by 61, ONLY Vettes got engines with solid lifter cam shafts.

 

 

Yes, they already knew the suffix code and production sequence number of each engine before the bearings, rods, rings, and pistons were installed, and each workstation had overhead charts that showed which parts went with which suffix codes.

There were two engine assembly lines at Flint V-8, but only for capacity reasons - neither line was "special"; Line #1 ran at 170 per hour, and Line #2 ran at 130 per hour.

The first station in both lines was the air-gage station, where the finished standard bores were air-gage classified within six to eight tolerance variations, and the block was assigned a production sequence number AND the correct suffix, which was grease-penciled on the side of the (upside-down) block, and identified Corvette vs. passenger car or truck application. Cam bearings and gallery plugs went in first as the engine went down the line.

The eight bore dimensions and suffix code was telegraphed to the Piston Department, where the pistons were cam-ground to the specified clearance dimension, rings were installed, and the pistons joined to the rods, including the rod bearing inserts - the 8-slot tray that "kit" was placed in was sent, in sequence, to the piston-stuffing station via overhead conveyor where the rods and pistons were installed.

Engine assembly was a very complex business at 300 per hour.

 

Now it all makes sense John. Thank you very much for the clarification. I guess they thought all those passenger cars just went to church and the grocery store........

At least the 409s got the "good stuff"....

Verne

 

Thanks also John,
Now even some more things from the past make sense.
First, I have seen the upside down codes on blocks and obviously they were applied by a worker when the block was upside down-----------------although, on several blocks I've seen, I thought the code was applied with a paint brush (because I've seen what appeared to be runs in the paint) instead of a grease pencil.
Second, the codes HAD TO HAVE BEEN applied on the bare block before being painted!!! DUH! That means, as you pointed out, that an engine's suffix was already known BEFORE assembly!
Last, since some of the smallest quantity engines (I'm presuming here) were solid lifter versions (ie FI/2x4), how did GM program just how many engines of each hp rating/application would be built in a given time frame?

Oh ya, was there a worker on each side of the block when the code/suffix was applied? I ask because the code on some blocks clearly have a different hand writing style on each side.

Regarding paint vs grease pencil for applying the code/suffix on blocks. One of the specific examples that I clearly recall is the std bore 265 that I built for John Neas 56 Sebring racer. John furnished 3 bare blocks for me to choose from for the build. The one I used had what clearly appeared to have had the code applied with a paint brush (with little care as to how it was applied). I took pictures before sending it to the machine shop (so that I could duplicate the brushed on code). I forget the code (doesn't matter), but on one side there appeared to be a couple of runs in the paint going toward the deck, which made it appear as though the worker probably had a can of paint with a brush in it and when he pulled the brush out of the can, he quickly painted on the code and the thick amount of paint on the brush resulted in some runs. Thoughts???
When I painted the block, I sort of lightly sprayed the area where the code was so that it could sort of be seen under the thinner coat of paint.

 

You would certainly HOPE that they were aware - Flint did the assembly stamping!

 

I agree that small paint brushes were probably used vs. grease pencils. The engine plants worked from continuous forecasts generated by the car assembly plants 30 days out, refined every ten days, based on analysis of their incoming car order flow - every engine that went out the door of an engine plant had been ordered by an assembly plant - none were built "on spec" and just sat around until they needed one. The hard part was the last ten days of the model year, trying to "hit the number on the money" so there were no excess finished engines, and no line-stop-critical engine shortages.

 

OOOOOOOOOOOOOOK John,
Now with that thought in mind, did SOME RPO engines ever get special attention during assembly, or were any parts given extra inspections so that the "best" parts went into the premium RPO engines? Such as the engines for the 1957 579D, 63 Z06, L71/89, etc. cars?
SURELY the run of the mill 62 FI cars vs the 62 FI cars that went to Grady Davis (Gulf Oil) and other bonefide racers were not "perfectly identical". Right?

 

There wasn't time, space, or resources to dedicate that kind of inspection/selection activity to regular production at 300 per hour; I'd expect that any of the engines for the "racers" were either built off-line where they could get special attention or were inspected at Engineering before shipment to St. Louis.

 

I agree. I worked at Tonawanda the summer of '69. Even the L-88s ran down the regular Mark IV assembly line and went to hot-test on a conveyor just like all the other engines.

The exception: Each '69 ZL-1 was assembled by one senior technician in a clean room and he personally wheeled "his" engine to hot-test. The tech. signed a sticker on the rocker cover.

(The twin-cam Vega engine may have also gotten special treatment, but I was gone by then.)

 

The Corvette engines got the Morraine 400 bearings. Don't remember for sure about the piston rings but I think that part is true also. That's a small piece of the differences though. In some cases, the pistons, pushrods, rocker arms, valve springs, crankshafts, timing covers, balancers, connecting rods, intake manifold, exhaust manifolds were all different between run of the mill passenger car and SHP engines. The rings and bearings were just a small part of the differences. It's commonly thought that passenger and Corvette engines were the same thing. In OEM form, that wasn't true.

It wasn't just Chevrolet/Corvette spec engines that created differences in parts. Also to be included were marine and industrial engines that had parts other than for truck/automobile use.

A friend worked at Tonawanda for a short time in the late '60's or early '70's. He once told me engines of one spec or another were batch/block built.