Factory Engine Assembly

[Mark S.]

I have two questions with Flint engine assembly, specifically in regards to 70 LT-1s but should apply to other years as well:

1. Were optional engines such as the LT-1 built in batches, such that the build dates would fall on a few days? For example if you could look at all engine assembly dates of LT-1s you'd find one or two days each month that most engines were built on and most days during the month where no or very few LT-s were built.

2. When was the exhaust manifolds attached? Could an original manifold have a date after the stamp pad assembly date?

[Terry M.]

Re: Factory Engine Assembly

1) Yes -- but most engine codes were built more often than one or two days a month.

2) Small block engine stamp was done after most of the engine was assembled -- cylinder case had been stuffed and heads were on. I can't remember clearly, but I think the exhaust manifolds were on when the engine was stamped -- if not they were installed soon after. I think the answer is that having exhaust manifolds dated after engine assembly date is unlikely.

Don't forget exhaust manifolds were cast and then machined. It took some time for that machining operation.

[Mark S.]

Re: Factory Engine Assembly

Thanks. I have an exhaust manifold with a cast date of 16 Feb. My engine stamp date is 3 Feb. Trying to determine the liklihood that the exhaust manifild is original.

[Terry M.]

Re: Factory Engine Assembly

There are stories of engines exiting the line and then being held for a while before shipment. I am not really up on Noland's C1 and C2 books, but there is some evidance that some engines were stamped with partial sufix codes and then a worker stamped the last character after the assembly exited the line. How long after exiting the line is the question, and I have no answer.

We don't have a good record of exhaust manifold dates aagainst engine assembly dates because for the most part we don't judge exhaust manifold dates.

[John H.]

Re: Factory Engine Assembly

Thanks. I have an exhaust manifold with a cast date of 16 Feb. My engine stamp date is 3 Feb. Trying to determine the liklihood that the exhaust manifild is original.

Mark -

I'd think it unlikely that it's original to the engine - it was cast at Saginaw, shipped to Flint V-8, and had to be machined before it was installed, and that took time. Most engines were in a rail car and gone the same day they were stamped; Flint V-8 had very little storage space after engine assembly, and they produced 300 engines per hour (5500 per day).

[Jim L.]

Re: Factory Engine Assembly

Flint V-8 had very little storage space after engine assembly, and they produced 300 engines per hour (5500 per day).

It's quite a tribute to the engineers who designed the engines and to the engineers who designed the manufacturing process that numbers like this were achievable. It must have been quite a sight to watch.....

Jim

[Terry M.]

Re: Factory Engine Assembly

You should have seen them stuffing the cylinder case and hand torque the rods and mains. Talk about AH & Elbows. One of the greater privileges of my life was to see that operation. I still am in awe of the men who did that day after day.

One of the popular Corvette magazines did a photo spread on Flint engine and they had still pictures of that process, but they don't do the teamwork and effort justice.

I think there were four of five guys -- no gender equality in that job -- and each one had a specific job at a specific time. The crank was rotated to a specific position and two cylinders were stuffed. A rod, piston and ring assembly was pushed into the cylinder with a curved rod that hooked on the pan rail and pushed the piston and rings through a tapered ring compressor. Then two guys placed the caps on the rods and torqued the rod bolts with Snap-On click type wrenches. One guy rotated the crank a set number of degrees, and they repeated that operation. Rotate again, and repeat, and then do it again. And then they all moved to another block to do it another time. Oh, and all the time this is going on the block is moving along, and they all had to move with it.

There were four or five teams -- one was on break, and the others working. And they rotated that ALL day. Even if there were five teams for 5500 engines -- figure it out. Oh they got a 10 minute break in the morning, 45 minute lunch and a 10 minute break in the afternoon, or so I was told.

Next time someone beefs about union labor -- think about those guys and their job. Would you do that day after day?

I was so impressed because there wasn’t a wasted motion. Each guy hit his mark, did his task in a minimum time, and moved on to the next task. I asked about the tools. They calibrated the torque wrenches each morning and at the lunch break, I was told. I should have asked how long they lasted. I bet they wore out more than a few.

That process was automated in the 1980s - sometime. Well after Flint had built 30 to 40 Million engines. And they automated it because the repetitive motion injuries were becoming too expensive to justify. That is the same reason they stopped steel stamping the assembly dates on the engines. Corvette got the last steel stamped engines.

[Mark S.]

Re: Factory Engine Assembly

Wow. That sounds like a pretty impressive operation. Thanks for the answer to my questions and the history.

Mark

[John H.]

Re: Factory Engine Assembly

Here's a photo of the piston-stuffing operation Terry so aptly described; note the "stuffing" operator in the foreground holding the rod journal protector/guide tool for the "stuffing" operator on the other side, and the traveling tray with rod/piston assemblies for each engine (arranged by bore location, with each piston sized for a particular bore diameter - air-gaging the bores was the first operation at the head end of the line).

[Jack H.]

Re: Factory Engine Assembly

Not every motor passed the hot engine test stand on its first pass...

I don't have a feel as to how long failed engines were put into set-aside 'quarratine' before techs were assigned to inspect and repair. But a 13-day interval between intitial test/failure and laying on a replacement intake 'seems' a bit long. John might have a better feel here.

Unfortunately, whether the intake is actually original to that particular engine becomes a mote point. It's not 'typical' of factory production and in cases where atypical issues surface, NCRS places the burden of proof upon the owner...

[Terry M.]

Re: Factory Engine Assembly

Thank you John. Your picture does show the AH & elbows aspect of it -- but as I said no still photo, or even series of still photos, can do justice to that operation. It was like a precision ballet, but the "dancers" were in work boots and blue jeans -- NO tutus around there.

After that rod journal protector/guide tool came off of where it is shown the operator in the background placed it over the rod bolts on the connecting rod attached to the piston that is ready to be inserted. Then the operator in the foreground pushed the assembly in and the guy on the other side removed the rod journal protector/guide tool. Trust me it all happened quicker than you can read this. And the rod caps have to go on and the bolts tightened and torqued, and then there are four more pairs of piston/rod assemblies to be done on this engine. Oops, here comes another one.

Edit add; I almost forgot -- those were "the good old days." Yea sure for some of us.

[Mark R.]

Re: Factory Engine Assembly

Terry and John:

Once again, thanks for helping us gain a better understanding of how are Corvettes were built. You both contribute so much in furthering an appreciation of the Corvette build process and are so deserving of your membership in the National Corvette Museum Hall of Fame. Please keep the information coming.

Best wishes to you both,

Mark