Factory engine testing?

[Jim T.]

Re: Factory engine testing?

Reading about all the engine testing for oil pressure after being built only makes me wonder how my 70 350/300 could go through the testing before being installed in my Corvette and have no oil pressure when I picked it up at the dealership, bought new off the showroom floor.
The dealership only said they were shipping the engine back to GM.

[Bill M.]

Re: Factory engine testing?

Thank you to all who posted, I really enjoyed it. The guy on the test stand without ear protection. It must have been like us working on the flight line in the Air Force with them running cabled down F-100's in afterburner on the trim pad. Dale

Dale:

The guy running the test stand had to use a tool like a long screwdriver to listen to the bearings. The engines had "mufflers". I remember they could have exhaust leaks (tick, tick) because of the quick-connect, but they weren't loud.

Bill

[Duke W.]

Re: Factory engine testing?

As I've said many times before, new GM production engines did not get a "camshaft break-in". In fact they got about the worst treatment you can give to a new engine -short run times that barely got them warmed up and lots of idling as they were driven off the line to the lot, then moved around for shipping and at the dealership.

So why didn't they wear out lobes?

Two reasons:

First, the lobe dynamics and valve springs are mild relative to aftermarket "racing cams" and their required high rate springs, so the lifter-lobe interface loads of OE cams are not pushing the limits of durability, unlike many if not most aftermarket flat tappet designs.

Second, the OE cams were Parkerized, which greatly reduced the chance of lobe failure during initial run-in.

OE spec cams from Federal Mogul and Crane are built to print and Parkerized, so they really don't need a typical "break-in" at 2500 for 20-30 minutes, but it certainly does no harm to do so along with using a "cam grease" on the lobes and a bottle of EOS with the initial fill of C-category oil.

As far as other vendors are concerned, especially with their own aggressive designs, you're on your own. Unfortunately, Crane appears to be gone for good, which leaves FM as the only supplier of OE spec cams that are built to OE quality IMO.

Stick with OE designs and OE quality replacement parts, and you likely won't have any problems. It's all the "hot rod stuff" that causes problems as you can surmise from reading typical new "engine problem" threads on this and other discussion boards.

Duke

[Bill M.]

Re: Factory engine testing?

What's the difference? How/why did Chevrolet get away with doing 'nothing special'?

Dave:

The Chevy engineers had total control of the system (parts, oil, EOS, process), and drove the system to its lowest cost.

If they had cam failures, they would know about it through warranty. If it were not an isolated issue, they would revise the sytem so that a break-in would not be required. The cost of a break-in process would be greater than a revision to design (parts, oil, EOS), and probably not as reliable. The cost of replacing a cam under warranty would be a big hammer when it came to driving a part change through the system.

Bill