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Re: [GMCnet] Tid Bits: Oil consumption. It's all in how/where it's consumed. [message #336533 is a reply to message #336532] |
Thu, 30 August 2018 09:56 |
Mike Kelley
Messages: 467 Registered: February 2017
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Jim H:
Very interesting - thanks for the history lesson!
Mike/The Corvair a holic
Sent from my iPhone
> On Aug 30, 2018, at 9:32 AM, James Hupy wrote:
>
> You guys need to listen to the guy that represents AM General ( they make
> the Hummer, both civilian and military versions) When they bought the
> production rights to the Hummer from GM, they bought the engine
> manufacturing production line, tooling, everything but the actual foundry
> where iron castings were produced. They did acquire a bunch of bare engine
> blocks, and when they set up the production line, they found out why GM got
> rid of the Hummer. High graphite content in the cast iron led to long
> tooling life, but crappy strength and durability in the engines. Threaded
> holes pulled out in service, lost their clamping ability, led to Internal
> coolant and combustion leak failures, short engine life, etc.
> When AM General switched to high nickel content in their new block
> castings, the used tooling that GM sold them failed quickly. Leaving AM
> General in a pickle. A few band aid fixes were tried, and failed.
> AM General bit the bullet, and did a total redesign of the 6.5 Diesel.
> That included castings, tooling, production machines, durability testing,
> the whole deal.
> The 6.5 that they build today is the same displacement as the GM built
> one, and that is about all they have in common.
> AM General spent BILLIONS fixing the shortcomings. So, the product
> development processes that GM used on our Olds engines in the 60's and
> early 70's, disappeared, and brought us products like Volera, Saturn,
> Fiero, Astro, to name a few. That led to the demise of Saturn, Pontiac,
> Oldsmobile, and a huge government bailout of what was left. Better? Not in
> my world.
> Jim Hupy
> Salem, Or
> 78 GMC ROYALE 403
>
>> On Thu, Aug 30, 2018, 6:59 AM Richard Denney wrote:
>>
>> On my old engine, I was getting about 15 psi at idle, and 30 or so at
>> speed. The engine had an uncertain history (valve covers were painted
>> black) and 90k+ miles, and I switched to Mobil1 High Mileage 15W-50.
>> Pressure was 20 at idle and 35-40 at speed after that. Which is plenty. But
>> I didn’t make that change to get higher pressure, I did it to get a
>> stronger oil film in looser bearings.
>>
>> Dick P once said that NASCAR racers can run all day at 30 psi and 8000
>> RPMs. Pressure is not what we need—an ever-present film is what we need.
>> The problem with worn tolerances is not so much that they relieve pressure,
>> but that they leak a lot of oil. A high-volume pump prevents those leaks
>> from causing starvation somewhere else.
>>
>> Do we need it? Certainly not for a tight engine. But I don’t worship at the
>> altar of GM engineering, either. They did as much cost engineering,
>> fuel-consumption engineering, and emissions engineering as they did
>> durability engineering. Their engines were tight not because they made the
>> parts fit (as we expect to do during a rebuild), but that they selected
>> parts with the right dimensions for the assembly task at hand. As I
>> understand it, parts were sorted across their manufacturing tolerance range
>> and the selected on the line as needed. They were auto workers, not
>> artists.
>>
>> Rick “who uses a mechanical oil pressure gauge” Denney
>>
>> On Thu, Aug 30, 2018 at 12:48 AM John Phillips
>> wrote:
>>
>>> What does changing the oil weight do the oil pressure? I feel my oil
>>> pressure is low. Would like to have a real gauge. Coach has 117k miles.
>> OP
>>> said it was reabuilt at 100k.
>>>
>>> --
>> Rick Denney
>> 73 x-Glacier 230 "Jaws"
>> Off-list email to rick at rickdenney dot com
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