| [GMCnet] Engine operating temperatures [message #175317] |
Mon, 02 July 2012 11:34  |
emerystora
Messages: 4442
Registered: January 2004
Karma: 13
|
Senior Member |
|
|
Rob
You had posted questioning if engines ran more efficiently at higher temperatures.
Here is something that I posted about 9 years ago on this subject.
I continue to use a 195. I tried a 180 once but when winter came I couldn't get enough heat from my heater. The engines are actually designed for the 195 thermostat.
Here is something that I had post some time back that you might find of interest:
At 2:09 PM -0600 6/22/03, Emery Stora wrote:
> In the old days thermostats used to all be 160-180 degrees. Now they
> are 20 or 30 degrees hotter. Why was this done? Its fairly common
> knowledge that heat is the worst enemy of engines and oils. -- right?
> It's true that heat can be hard on an engine, but in the opinion of
> most automotive engineers, the benefits of hotter-running engines far
> outweigh the negatives. Engines burn fuel more cleanly and
> efficiently at higher temperatures. With the coolant at 195 degrees
> (instead of 160 to 180), you'll get better performance. less
> pollution overall, and greater fuel economy.
>
> While 30 years or so ago, using a 195 degree thermostat might have
> shortened the life of an engine, oils have gotten better. Now they
> perform much better in extreme heat, and give the engine plenty of
> protection without breaking down. Especially with the Mobil 1
> synthetic that you are using. Modern big block engines such as the
> 403 and 455 are optimized to run at 195 to 200 degrees and at that
> temperature no harm is done.
>
> Race cars are designed to run at even hotter temperatures with the
> result that higher compression ratios are possible as well as more
> aggressive ignition advance curves and leaner mixtures for greater
> fuel efficiency. While our GMCs are certainly not race cars, the
> same fundamentals apply.
>
> I will continue to use my 195 deg. thermostat. I rely on a 50/50 mix
> of antifreeze coolant, an operating 9# pressure cap (these usually go
> bad within two years) and a clean radiator and engine block to keep
> me from overheating. If your cooling system has problems, using a
> 160 or 180 thermostat will only give a very slight edge to slowing
> down an overheating problem. The engine can quickly pick up 30 or 40
> degrees when under load at high speeds or up grades.
>
> Another potential problem with running too low an engine temperature
> is that any condensation in the engine block must be evaporated by
> the heat of the engine to prevent the water from floating around in
> the oil pan and being picked up by the oil pump and getting into the
> bearings, etc. Water is not a good lubricant. It also will rust
> parts in the engine block.
>
> All engines will pick up water. When an engine cools the air in they
> crankcase shrinks and air is drawn into the block. Air contains
> water vapor which will condense into the engine. Most people that
> live in cold climate areas use higher temperature thermostats in cold
> weather to keep their heaters putting out enough heat to the
> interior. People in warmer climates often feel that they don't need
> as high a temperature thermostat but those living in the south where
> there is high humidity or even in the humid north still have water
> condensate in their engines which must be dried out. A hotter engine
> will do a better job of quickly evaporating this water before it does
> any harm.
> --
Emery Stora
77 Kingsley
Frederick, CO
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| Re: [GMCnet] Engine operating temperatures [message #175403 is a reply to message #175401] |
Tue, 03 July 2012 08:54  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
|
Senior Member |
|
|
My experience in dealing with RV dealers during ownership of 3 different
454-engined motorhomes is that they consider any 454 with 50,000+ miles to
be "over the hill".
Ken H.
On Tue, Jul 3, 2012 at 9:06 AM, Matt Colie wrote:
> ...And you ask.. "So why is the 454 so big if the 455 was better?"
> Three simple answers:
> 1 - It was in production longer.
> 2 - Parts are more plentiful (cheaper).
> 3 - It is a Chevy....
>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
|
|
|
|
| Re: [GMCnet] Engine operating temperatures [message #175429 is a reply to message #175403] |
Tue, 03 July 2012 13:47 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
|
Senior Member |
|
|
Those were cast shaft engines, were they not? We called them 'Tonowanda Turds'.
--johnny
From: Ken Henderson <hend4800@bellsouth.net>
To: gmclist@temp.gmcnet.org
Sent: Tuesday, July 3, 2012 9:54 AM
Subject: Re: [GMCnet] Engine operating temperatures
My experience in dealing with RV dealers during ownership of 3 different
454-engined motorhomes is that they consider any 454 with 50,000+ miles to
be "over the hill".
Ken H.
On Tue, Jul 3, 2012 at 9:06 AM, Matt Colie wrote:
> ...And you ask.. "So why is the 454 so big if the 455 was better?"
> Three simple answers:
> 1 - It was in production longer.
> 2 - Parts are more plentiful (cheaper).
> 3 - It is a Chevy....
>
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
|
|
|
|
|
|
| Re: [GMCnet] Engine operating temperatures [message #175464 is a reply to message #175317] |
Tue, 03 July 2012 22:07 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
|
Senior Member |
|
|
Yes from what I have expereienced with the Big Block Chevy Mark motors the valve trains had some severe angular forces that lead to shall we say not the longest life.
And one more time on the Thermostat. It only sets how COLD the engine gets, not how HOT the engine gets. I have a 195 and will be driving in 100+ heat on Thurs so wish me luck so I don't have to eat my words. On the drive here the fan clutch stayed loose on the highway and then came on as I hit congested traffic so in my book I call it a "good".
John Lebetski
Woodstock, IL
77 Eleganza II
|
|
|
|
| Re: [GMCnet] Engine operating temperatures [message #175481 is a reply to message #175464] |
Wed, 04 July 2012 08:02 |
shawnee
Messages: 422
Registered: February 2004
Location: NC
Karma: 0
|
Senior Member |
|
|
| JohnL455 wrote on Tue, 03 July 2012 23:07 |
Yes from what I have expereienced with the Big Block Chevy Mark motors the valve trains had some severe angular forces that lead to shall we say not the longest life.
And one more time on the Thermostat. It only sets how COLD the engine gets, not how HOT the engine gets. I have a 195 and will be driving in 100+ heat on Thurs so wish me luck so I don't have to eat my words. On the drive here the fan clutch stayed loose on the highway and then came on as I hit congested traffic so in my book I call it a "good".
|
John,
With respect to the thermostat it will control the coolant temperature in an automobile, but in the 12,000lb. motorhome, it can only control the coolant temperature to not go below the stated degrees. It doesn't control the actual engine temperature. If you have a rusted coolant space the engine interior can run hot even if the coolant remains at the rated thermostat temperature. Some thermostats have leakage and the coolant temperature can be somewhat less than the thermostat rating. The engine itself will have many temperatures such as in the combustion area. If you use a Mr. Gasket 195 degree thermostat, it has a built in bypass and in the motorhome on a level road the coolant temperature will run in the 170 to 180 degree range. Stewart Racing drills three 1/8 inch holes in the Robertshaw housing for high powered engines and unless you specify different, that is what you will get and with a clean engine and good radiator you will be lucky to maintain 170 degrees. You must specify no holes drilled with them for the motorhome. The coolant temperature is only an indication of how the well radiator and coolant spaces in the engine is working.
Gene Dotson
74 Canyonlands
www.bdub.net/Motorhome_Enhancements New Windows and Aluminum Radiators
|
|
|
|
| Re: [GMCnet] Engine operating temperatures [message #175487 is a reply to message #175456] |
Wed, 04 July 2012 08:21 |
 |
USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
|
Senior Member |
|
|
G'day,
IIRC The Big Inch Cadillac book by Doc Frohmader notes that the Caddy 500
had the highest nickel content of any engine Detroit ever built. He goes on
to note that this was how they built an engine with 500 cubic inches
displacement that only weighed 100-150 pound more than a small block Chevy.
Finally he warns owners to be very cautious when drilling and/or tapping
holes in the Caddy block as the nickel makes it VERY hard!
I do not know if the levels of nickel in the Olds 455 were as high as the
Caddy 500.
Regards,
Rob M.
-----Original Message-----
From: jerrod winter
There is no doubt that some engines from the glory days still have potential
that newer designs lack. A different manufacturing strategy and different
material / labor conditions changed the game. I read somewhere that the BOP
engines from that era were a high nickel alloy that is not cost effective
anymore. I don't have any idea if that is true or not but it suggests that
its not always an apples and oranges comparison.
I wouldn't consider a GM 454 the recent modern day engine to compare
against. They haven't been produced since the late 90's. Even the 8.1 has
been discontinued for 5 years or more. The modern day players are the LSx
variety and have a lot of potential. They to will probably evolve to the
next design in the near future. EPA, performance, and other requirements
drive short development cycles now days.
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
