1st engine start at the factory

[Tom P.]

Re: 1st engine start at the factory

If anyone here went on the plant tour (last year for St. Louis) during the 1981 NCRS Natls, you MAY remember that there was one car pulled into the bay at the end of the line for an engine R&R. If I remember correctly, we were told they could do an engine R&R in about 1hr.
Someone (who has been through the St. Louis tour) help me here. As I recall, the last stop on the line was a set of drive on rollers. Each Vette was driven onto the rollers, taken up to full throttle, then the driver would stand on the brakes during full throttle. If everything was fine, then it was driven out the back door and onto the lot for shipping.
If there was a problem or a failure, then the Vette was pulled over to one of three(?) bays at the end of the line for repairs.

[Jim T.]

Re: 1st engine start at the factory

A good friend of mine ran the Piston Department at Flint V-8 in the 60's, and I recall him saying that a really bad day was five or six hot-test failures (out of 5,500 engines). Of course, hot-test only lasted about 30 seconds - just long enough to fire it, check for oil pressure, set the timing, look for leaks, and listen for any weird noises.

That's pretty remarkable considering that Machining ran at over 200 per hour (on three shifts) and Assembly ran at 175 per hour on one line and 125 per hour on the other line on two shifts. Nobody builds engines at that rate these days, and nobody hot-tests them any more either.

Engine pulls in the car assembly plants were quite rare - one or two a month at St. Louis would be a lot.

True occurance. I wish my new 1970 Corvette's engine problem would have occured on the test fire of its engine.
Bought my new 1970 coupe 350/300, turbo 400, factory air, power brakes and steering, and optional interior sitting on the showroom floor at a Chrevrolet/Buick dealership in August 1970. Was told to come back the next day to pick it up.
The dealership was in a small town and closed at 5pm. The salesman and I were the last to leave the dealership after completing the paperwork. My new 1970 was brought from the shop area and parked outside.
The salesman and I were leaving at the same time. No one else was at the dealership. He pulled away as I was starting my 70 for the first time.
The cool air from the air conditioner felt good upon startup. Checking out the guages I immediately noticed there was no oil pressure indicated.
I shut the engine off and checked the oil. The oil was clean and showed full on the dipstick.
I started my new 70 again and the engine sounded okay. Decided the guage must be broken and left the dealership.
Drove a short distance and the engine started making noise.
The next stupid mistake I made was rejecting the car and going to another dealership in Dallas/Fort Worth and buying another new Corvette.
Was never told what the exact failure was. The dealership said they had to send the short block back to GM. I got a CE0A replacement short block.

[Clem Z.]

Re: 1st engine start at the factory

And even those may not have been a failure. My engineer-in-training project in 1969 was to analyze an engine knock you could hear when you jazzed the throttle on a fully-accessorized 350. All the accessory belts were pulling the crank up against the top shell of the #1 main bearing. When you accelerated the engine, the force on the piston pushed the crank down onto the bottom shell of the #1 bearing, and it knocked. I had a graph plotting the motion of the crank as this occurred. The bearing wasn't damaged or worn, just noisy. Tonawanda was selectively fitting the front bearing shell by measuring each #1 crank journal with an air gauge and selecting a bearing shell that cut the clearance to the minimum. I guess they were still getting some back on warranty and/or the process guys didn't want to pay for the extra measuring operation...don't remember. I was gone before the fix was in place.

i remember reading the TSB on this

[Bill M.]

Re: 1st engine start at the factory

Gee Bill, now you have my curiosity up. I would love to know what the cure was.

Terry:

I can tell you what didn't work. I figured that the knock was like a Diesel combustion knock; a rapid pressure rise. I proposed a wider front main bearing to reduce the pressure. The Tonawanda resident engineer (from Warren) asked me if I was sure, because it would be an expensive prototype. I don't remember my answer, but I was 22 and over-confident, I'm sure. We built it...it didn't work. The resident wasn't happy.

I'm not sure Tonawanda kept working on it when I left.

Anyway, Warren had much better test equipment; they probably came up with something. My next try (not sure I'd get one) would have been a thicker crank web to eliminate bearing edge loading...still guessing that the knock was a rapid pressure rise.

Bill

[John D.]

Re: 1st engine start at the factory

If anyone here went on the plant tour (last year for St. Louis) during the 1981 NCRS Natls, you MAY remember that there was one car pulled into the bay at the end of the line for an engine R&R. If I remember correctly, we were told they could do an engine R&R in about 1hr.
Someone (who has been through the St. Louis tour) help me here. As I recall, the last stop on the line was a set of drive on rollers. Each Vette was driven onto the rollers, taken up to full throttle, then the driver would stand on the brakes during full throttle. If everything was fine, then it was driven out the back door and onto the lot for shipping.
If there was a problem or a failure, then the Vette was pulled over to one of three(?) bays at the end of the line for repairs.

I don't know an hour sounds extremely fast. On the old style Chev Blazer (pre 2005) a very experienced repair tech I knew well would have an engine out and and replaced with a new one in one 8 hr shift without breaking a sweat. He could do them practically with his eyes closed and he reckoned he could do one in five hours if he had too.

Keep in mind they pay a trained flat rate dealer tech up to ten hours for the same job........

[Tom P.]

Re: 1st engine start at the factory

I don't know an hour sounds extremely fast. On the old style Chev Blazer (pre 2005) a very experienced repair tech I knew well would have an engine out and and replaced with a new one in one 8 hr shift without breaking a sweat. He could do them practically with his eyes closed and he reckoned he could do one in five hours if he had too.

Keep in mind they pay a trained flat rate dealer tech up to ten hours for the same job........

Maybe it was 1day instead of 1hr--------------keep in mind this was pushing 30yrs ago!

[Robert G.]

Re: 1st engine start at the factory

i remember reading the TSB on this

Vette Vues, Feb 2004 published TSB DR #742 from May 27, 1965 relating to "If a front main bearing knock is encountered on a 283 or 327 cu. in. engine, it is recommended that the bearing insert be replaced with the new style insert of the proper size." "This bearing is designed to better handle the extra load imposed on the front main bearing when optional equipment such as power steering is installed." The new bearing was .003 in. thicker on the upper shell and .003 in thinner on the lower shell.

[Peter M.]

Re: 1st engine start at the factory

I worked at a GMAD Assembly plant from 1966 - 1969. We assembled approximately 65 cars an hour, two shifts a day, 6 days a week for 50 weeks a year. Thats about 310,000 cars a year. I probably was on site 30% of that time. Sooooooo, I probably saw 80,000 - 100,000 cars a year come off the line. As I recall, roll test failures, where the car did not start & was moved off the line, were very rare in deed. I remember no more than a handfull a year. Thats probably 5 out of 90,000 or so. That comes out to .00055 of 1%. PRETTY SMALL FAILURE RATE.

FWIW