| [GMCnet] Oil Change Interval [message #254605] |
Mon, 07 July 2014 09:31  |
Olly Schmidt
Messages: 1265
Registered: February 2014
Location: Germany and Scottsville, ...
Karma: 8
|
Senior Member |
|
|
Looking at the oil change schedule of modern vehicles makes me wonder:
Do intervals for older cars come from worse oil in the past, or worse
material, or both?
Inquisitive minds want to know.
--
Best regards
Peer Oliver Schmidt
PGP Key ID: 0x83E1C2EA
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Best regards
Olly Schmidt
PGP Key ID: 0x18a9 3a1f 4196 bf22
'76a Eleganza II, VA
'73 Sequoia, SH, Germany
|
|
|
|
| Re: [GMCnet] Oil Change Interval [message #254610 is a reply to message #254605] |
Mon, 07 July 2014 09:40  |
Jeff Marten
Messages: 199
Registered: August 2013
Karma: 1
|
Senior Member |
|
|
1. The predominance of synthetic oils - they break down more slowly than dino oils and handle high temps better
2. tighter internal tolerances
3. much more efficient fuel injection means less fuel contamination in the oil
> Date: Mon, 7 Jul 2014 16:31:37 +0200
> From: posde@theinternet.de
> To: gmclist@temp.gmcnet.org
> Subject: [GMCnet] Oil Change Interval
>
> Looking at the oil change schedule of modern vehicles makes me wonder:
> Do intervals for older cars come from worse oil in the past, or worse
> material, or both?
>
> Inquisitive minds want to know.
> --
> Best regards
>
> Peer Oliver Schmidt
> PGP Key ID: 0x83E1C2EA
> _______________________________________________
> 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
1985 Gulf Stream 34' Sun Stream
1964 Falcon 'Vert
1980 Bradley GTE
1999 Chevy Tahoe
2005 Saab 93 Aero
1987 Suzuki Intruder 1400
1978 Glastron/Carlson CV23
|
|
|
|
| Re: [GMCnet] Oil Change Interval [message #254629 is a reply to message #254605] |
Mon, 07 July 2014 14:12 |
Steve
Messages: 506
Registered: September 2013
Location: East Greenville, Pa
Karma: 1
|
Senior Member |
|
|
In agreement with Jeff on all three points. The better oil and tighter build tolerances tend to get more attention. I think the fuel contamination point should get more discussion and education. If your old carburetor is leaking gas down into the intake manifold and ultimately down to the combustion chamber, it will get past the rings and have detrimental impact on lubrication and oil contamination. I stick to the old school oil change intervals for my classic/antique vehicles with carburetors.
1978 GMC Royal
Eastern Pennslyvania
1968 Chevrolet C20 396 Camper Special
1969 Chevrolet C20 Camper Special
1985 Buick Electra Park Avenue
1992 Camaro 25th Anniversary Heretage Edition Black
|
|
|
|
| Re: [GMCnet] Oil Change Interval [message #254644 is a reply to message #254610] |
Mon, 07 July 2014 20:06 |
mrgmc3
Messages: 210
Registered: September 2013
Location: W Washington
Karma: 2
|
Senior Member |
|
|
Jeff Marten wrote on Mon, 07 July 2014 09:401. The predominance of synthetic oils - they break down more slowly than dino oils and handle high temps better
2. tighter internal tolerances
3. much more efficient fuel injection means less fuel contamination in the oil
1)All oils are better today than 30 years ago. The primary benefit of synthetics is resistance to break down at elevated temps, particularly in the 275-300F range
2)Tolerances, yes modern machining is better; tighter tolerances and less variation. With that said you can rebuild with improved tolerances if you have a really good machinist. Modern pistons, rings, valves and bearings are improved.
3) most rapid oil contamination comes from cold start enrichment. You get this with carb or FI. The FI can be more precise and go leaner, quicker from cold start, but this depends on the system and the finesse of the calibrator. Also mixtures that are too rich under load, like < 10:1 will wash gas past the rings into the oil. There is a lower level of contamination due to blowby (unless you have sealing problems).
So the bottom line on frequency of change should be driven by frequency of cold starts (cold meaning sitting for > 8 hours), and amount of operation in stop and go, dusty or desert ambient conditions. You should change annually even if you don't drive at all. Under extreme conditions of short trips or extreme heat change maybe as frequently as 2500 miles, and with all highway operation and 500 miles between cold starts you might get away with 7500 mile intervals.
These engines are always pulling a "trailer load" (10,000 lbs) so they are never driven at real light load conditions.
Chris Geils - Twin Cities / W Wa
1978 26' Kingsley w/ very few mods; PD9040, aux trans cooler, one repaint in stock colors, R134a, Al rad, Alcoas, 54k mi
|
|
|
|
| Re: [GMCnet] Oil Change Interval [message #254663 is a reply to message #254605] |
Mon, 07 July 2014 22:51 |
Bob de Kruyff
Messages: 4260
Registered: January 2004
Location: Chandler, AZ
Karma: 1
|
Senior Member |
|
|
Peer Oliver Schmidt wrote on Mon, 07 July 2014 08:31Looking at the oil change schedule of modern vehicles makes me wonder:
Do intervals for older cars come from worse oil in the past, or worse
material, or both?
Inquisitive minds want to know.
--
Best regards
Peer Oliver Schmidt
PGP Key ID: 0x83E1C2EA
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
The major contributor to extended change intervals is due to better monitoring systems enabled by electronic fuel injection and monitoring of real duty cycles--not presumed duty cycles. All of the major operating parameters are mapped in the computer and the oil life monitor will be activated by that mapping. The other stuff is icing on the cake.
Bob de Kruyff
78 Eleganza
Chandler, AZ
|
|
|
|
| Re: [GMCnet] Oil Change Interval [message #254719 is a reply to message #254663] |
Tue, 08 July 2014 13:33 |
 |
Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
|
Senior Member |
|
|
From the refugee from dyno-land.
Most of what is posted above is largely accurate. But, modern engine build practices and controls are so far removed from what was available when the coach engines were installed as to make them almost a different species.
The only thing we can take advantage of is the newer lube oils, but they still get contaminated just as fast as they did forty years ago. If you are going to work the engine very hard, a synthetic will get you some advantage but the fact is the primary corrosion inhibitors and anti-wear additives are better, but not that much better.
What it really comes down to is that oxidation life of a dino based oil is still about six months and about double that for a synthetic. Mileage on oil is a guess at best. I am sticking with a too frequent lube oil change just because oil is cheaper than changing any part the lube oil touches other than the filter.
I won't tell you what the Detroit OEs do during the validation process or you be be scared to go near one.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
