Factory engine testing?

[Edward C.]

Were the high performance engines for regular production in the late 60's and early 70's get bench tested at the engine assembly plants? Thanks Ed

[Joe L.]

Re: Factory engine testing?

Were the high performance engines for regular production in the late 60's and early 70's get bench tested at the engine assembly plants? Thanks Ed

Edward-----


All PRODUCTION engines were test-fired on natural gas prior to shipment to the vehicle assembly plants in the 50's as well as today. Most, but not all, COMPLETE SERVICE engines were also so-test-fired.

[Tom H.]

Re: Factory engine testing?

Edward-----


All PRODUCTION engines were test-fired on natural gas prior to shipment to the vehicle assembly plants in the 50's as well as today. Most, but not all, COMPLETE SERVICE engines were also so-test-fired.

Good info, Joe

How long would a "test fire" be. Was there an extended break in time, or just enough to be sure it lit and didn't make unusual noises ?

[Joe L.]

Re: Factory engine testing?

Good info, Joe

How long would a "test fire" be. Was there an extended break in time, or just enough to be sure it lit and didn't make unusual noises ?

Tom-----


It was/is a relatively short test. I think about 5 minutes.

[Tom H.]

Re: Factory engine testing?

Tom-----


It was/is a relatively short test. I think about 5 minutes.

That is neat to know. I always wondered about that. Was there someone assigned to this area to make adjustments or final tuning to these engines during run in ?

[Joe L.]

Re: Factory engine testing?

That is neat to know. I always wondered about that. Was there someone assigned to this area to make adjustments or final tuning to these engines during run in ?

Tom-----


Yes, there was. I don't think there was a worker for each engine, but there was definitely a worker present for each group of engines. For some engines, final balancing was done at this time. This included, at least, all C4 era LT1 and LT4 engines as well as many 87+ Gen I small blocks.

[Tom H.]

Re: Factory engine testing?

Tom-----


Yes, there was. I don't think there was a worker for each engine, but there was definitely a worker present for each group of engines. For some engines, final balancing was done at this time. This included, at least, all C4 era LT1 and LT4 engines as well as many 87+ Gen I small blocks.

Thanks for the info, Joe. Appreciate it !

[Clem Z.]

Re: Factory engine testing?

the new corvette engine are not started at the factory as they are only spun with a electric motor to makes sure it has oil pressure and to check that all other items work properly.

[Steven B.]

Re: Factory engine testing?

Edward-----


All PRODUCTION engines were test-fired on natural gas prior to shipment to the vehicle assembly plants in the 50's as well as today. Most, but not all, COMPLETE SERVICE engines were also so-test-fired.

Joe, why natural gas?

Thanks!

Steve

[Duke W.]

Re: Factory engine testing?

I think the hot fire test only lasted about 30-60 seconds. (John Hinckley knows.) Consider that Chevrolet was manufacturing about 5000 engines per day for all product lines. The initial timing was set, oil pressure observed, and the running engine was inspected for coolant and oil leaks and abnormal noise.

An adapter plate was lowered to the manifold flange to feed a premix of natural gas and air. This is much easier/safer to do than installing the carburetor and filling the bowls to do a "wet" test.

The engine configuration as tested was essentially a "long block" with the ignition system, inlet and exhaust manifolds added.

Engines were shipped to the plant in this configuration - less carburetors, and other front end accessories and integration hardware, which were installed at St. Louis before the engine was installed in the chassis.

Duke

[Terry M.]

Re: Factory engine testing?

I wish I could remember how long they "hot fired" the engines, but I think Duke has it about right. I remember at Flint they said they ran the Corvette engines longer, but again I can't recall how long. Maybe like 2 minutes. John Hinkley will have a better handle on this than I do.

During "hot fire they listened for knocks, set the distributor initial timing, and tested the balance and either added or took away (drilled) weight from the flywheel/flex plate and harmonic damper.

For the current engines (at least for 2008) the Wixom built engines are "hot fired" on natural gas, and the balance is set at that time -- no more setting the ignition timing though. The Canadian built engines are NOT "hot fired" any longer.

[Joe L.]

Re: Factory engine testing?

Joe, why natural gas?

Thanks!

Steve

Steve-----


I think it was a matter of manufacturing convenience as well as keeping the engines as "new appearing" as possible.

[Bill M.]

Re: Factory engine testing?

Were the high performance engines for regular production in the late 60's and early 70's get bench tested at the engine assembly plants? Thanks Ed

I worked the summer of '69 at Tonawanda. Duke and Terry have it right.

Ed, if you're asking if the engines were tested for power, the answer is no. We did test some engines for durability. They were run for 200 hours at mostly full throttle. Very few had problems. One dynamometer ran small blocks and one ran big-blocks.

Even the ZL1s were not tested for performance!

[Terry M.]

Re: Factory engine testing?

When I toured Tonawanda the employees, a few of whom claimed they worked there in the late 1960s, said they ran L88s on the dyno. It wasn't clear if their claim was that ALL were dyno run, or just some. The stories focused on the power output and noise from the roof-vented exhaust.

[Bill M.]

Re: Factory engine testing?

When I toured Tonawanda the employees, a few of whom claimed they worked there in the late 1960s, said they ran L88s on the dyno. It wasn't clear if their claim was that ALL were dyno run, or just some. The stories focused on the power output and noise from the roof-vented exhaust.

Hi Terry:

I remember your article from the Restorer; brought back fond memories. I remember you talked to Reed Johnson. He was one of the guys I worked with that summer of '69 in the dyno. lab. We ran L-88s with tubular headers and huge mufflers that vented through the roof. I could hear them running as I walked home; very sweet sound. All other engines we tested that summer ran through an exhaust system that ran under the floor; very quiet. The L-88s we ran (definitely not all!) were run for 200 hours for durability. The engines were run from peak torque to peak horsepower, so power was "measured", but it was incidental to the purpose of the test. I remember seeing a power curve from the Mark IV dyno cell that showed an L-88 putting out 560 HP. I remember from your article that Reed said they put out 430. The headers and big mufflers were installed the summer of '69, so maybe he remembered the 430 from earlier testing through the restrictive exhaust...or he gave a politically correct corporate answer. Anyway, I saw 560 on the dyno. Unfortunately, we didn't test a ZL-1 that summer.

Bill

I thought I should add that we never shipped an engine that ran on the Tonawanda dyno to an assembly plant. If the engine had a small problem (broken valve spring, burned rocker ball), we fixed it and kept testing to 200 hours. If it suffered a major problem (a broken piston would trash every thing except the opposite bank's cylinder head), the test was terminated. All dyno. engines were torn down and the parts mounted on display boards for the component engineers to examine, and then all the parts were scrapped.