Home » Public Forums » GMCnet » Question: Which does the most damage to the engine?
| Question: Which does the most damage to the engine? [message #111865] |
Thu, 13 January 2011 08:21  |
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Tom Fort
Messages: 51
Registered: January 2004
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Many of our GMCs sit a long time between trips. I had heard that it is good to warm it up and take it on a short trip every two weeks or so. I wondered if those frequent start ups do more damage than just waiting just before you a planned trip.
What do the experts think?
Thanks, Tom
Tom Fort, KA4KGR
73 Painted Desert, Family owned Since 1973
Lugoff, SC
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| Re: Question: Which does the most damage to the engine? [message #111869 is a reply to message #111865] |
Thu, 13 January 2011 09:01  |
jknezek
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Registered: December 2007
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I think everyone would agree you are better off using it than letting it sit. Even short trips are good, although I guess it depends on your definition of short. I'm not a big fan of just firing up the engine and letting it idle in your driveway, but going for a 5-10 mile errand run is definitely a good idea.
Thanks,
Jeremy Knezek
1976 Glenbrook
Birmingham, AL
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| Re: Question: Which does the most damage to the engine? [message #111871 is a reply to message #111865] |
Thu, 13 January 2011 09:24 |
bryant374
Messages: 563
Registered: May 2004
Location: Pleasant Valley, NY 12569
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Question: Which does the most damage to the engine? Thu, 13 January 2011 09:21
Tom Fort
Many of our GMCs sit a long time between trips. I had heard that it is good to warm it up and take it on a short trip every two weeks or so. I wondered if those frequent start ups do more damage than just waiting just before you a planned trip.
What do the experts think?
Thanks, Tom
If I haven't used my coach recently, I delay the start up* with the intent of obtaining some oil pressure build up before the engine actually fires. I believe it has been demonstrated that "dry" start ups are significant wear contributors. Synthetic oils supposedly "cling" to parts better reducing wear at start up also.
* I have Turbo City fuel injection, to delay the start I turn off the fuel pump for several seconds to delay the start.
Bill Bryant
PO 1976~PB (owned 34 years)
1914 Ford (owned 70 years)
1965 Corvette (owned 39 years)
GMC Motorhome History
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| Re: Question: Which does the most damage to the engine? [message #111879 is a reply to message #111865] |
Thu, 13 January 2011 10:39 |
Rick Williams
Messages: 256
Registered: July 2004
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I guess it depends on where you live. Here in Michigan with snow and salt, there is no way that I will take out the coach unless I am headed for a salt free warmer place for a few weeks. When you live in a salt free place I think it would be good to run it once and a while. Besides, it's fun. Just make sure that you run it long enough to burn off all the moisture in the oil and in the exhaust system. As stated earlier, drive it, don't just idle in the driveway.
I do as Bill stated. I delay starting to allow the oil pressure to build when the coach has been sitting for a long time. In my case with a carb, I just do not pump it when first cranking. I would rather put a little extra wear on the starter than the engine.
Rick Williams
Bliss, Michigan
1978 Eleganza II
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| Re: [GMCnet] Question: Which does the most damage to the engine? [message #111881 is a reply to message #111865] |
Thu, 13 January 2011 11:28 |
Steven Ferguson
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Registered: May 2006
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I am not an expert but I am against warming up an engine occasionally during
long periods of storage. A couple of caveats here. One is if you start it
up and drive it until it is heat soaked, I just don't see any reason for
this to cause any more harm than taking it on a trip. The other reason
would be if you have an ele oil pump or accumulator hooked up to your oil
supply so you have oil pressure prior to turning the engine over. I think
this would also help prolong engine life under normal operating conditions.
You'll hear more here but that's just my opinion. Might as well run that
Onan until it's heat soaked also if that is what you chose to do.
On Thu, Jan 13, 2011 at 7:21 AM, Tom Fort <tomfort@truvista.net> wrote:
>
>
> Many of our GMCs sit a long time between trips. I had heard that it is
> good to warm it up and take it on a short trip every two weeks or so. I
> wondered if those frequent start ups do more damage than just waiting just
> before you a planned trip.
>
> What do the experts think?
>
> Thanks, Tom
>
> --
> Tom Fort, KA4KGR
> 73 Painted Desert, Family owned Since 1973
> Lugoff, SC
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Steve Ferguson
Sierra Vista, AZ
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| Re: Question: Which does the most damage to the engine? [message #111883 is a reply to message #111865] |
Thu, 13 January 2011 11:34 |
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warm up the engine to operating temp, and go do some errands in the beast. you will get some looks and questions from people who never saw one before, so make sure you are not in too big of a hurry. considering the duty that the drivetrain was originally derived for, short trips shouldnt wear it any more as long as proper lubrication and warm up are observed...
73 Canyon Lands, (a.k.a. The Yellow Submarine) West Los Angeles CA
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| Re: [GMCnet] Question: Which does the most damage to the engine? [message #111896 is a reply to message #111865] |
Thu, 13 January 2011 12:26 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
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Never start and let it just idel for long time.
Start it up and warm up for ony a minute then drive it alowly , then
the engine will warm up faster and not have problems with fuel washing
down the cylinder walls and valve guids with the rich fuel mixtere..
On Thu, Jan 13, 2011 at 6:21 AM, Tom Fort <tomfort@truvista.net> wrote:
>
>
> Many of our GMCs sit a long time between trips. Â I had heard that it is good to warm it up and take it on a short trip every two weeks or so. Â I wondered if those frequent start ups do more damage than just waiting just before you a planned trip.
>
> What do the experts think?
>
> Thanks, Tom
>
> --
> Tom Fort, KA4KGR
> 73 Painted Desert, Family owned Since 1973
> Lugoff, SC
>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: Question: Which does the most damage to the engine? [message #111897 is a reply to message #111865] |
Thu, 13 January 2011 12:31 |
fred v
Messages: 999
Registered: April 2006
Location: pensacola, fl.
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Dick Patterson talked about this once. he said to let it sit until you can drive it some distance and get it hot enough to boil the water out of the oil. when shut down the cyl. are well coated with oil and should be OK.
Fred V
'77 Royale RB 455
P'cola, Fl
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| Re: [GMCnet] Question: Which does the most damage to the engine? [message #111899 is a reply to message #111881] |
Thu, 13 January 2011 12:43 |
Gary Worobec
Messages: 867
Registered: May 2005
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Hi,
If you recall I asked the guy from Blackstone the same question at GMCWS LV
and he said NO. Do not start the engine. Whether the oil sits for 10 minutes
or 10 months it makes no difference. All you do is add water vapor to the
inside of the motor.
Thanks
Gary and Joanne Worobec
1973 GMC Glacier
Anza, CA
----- Original Message -----
From: "Steven Ferguson" <botiemad11@gmail.com>
To: <gmclist@temp.gmcnet.org>
Sent: Thursday, January 13, 2011 9:28 AM
Subject: Re: [GMCnet] Question: Which does the most damage to the engine?
>I am not an expert but I am against warming up an engine occasionally
>during
> long periods of storage. A couple of caveats here. One is if you start
> it
> up and drive it until it is heat soaked, I just don't see any reason for
> this to cause any more harm than taking it on a trip. The other reason
> would be if you have an ele oil pump or accumulator hooked up to your oil
> supply so you have oil pressure prior to turning the engine over. I think
> this would also help prolong engine life under normal operating
> conditions.
> You'll hear more here but that's just my opinion. Might as well run that
> Onan until it's heat soaked also if that is what you chose to do.
>
> On Thu, Jan 13, 2011 at 7:21 AM, Tom Fort <tomfort@truvista.net> wrote:
>
>>
>>
>> Many of our GMCs sit a long time between trips. I had heard that it is
>> good to warm it up and take it on a short trip every two weeks or so. I
>> wondered if those frequent start ups do more damage than just waiting
>> just
>> before you a planned trip.
>>
>> What do the experts think?
>>
>> Thanks, Tom
>>
>> --
>> Tom Fort, KA4KGR
>> 73 Painted Desert, Family owned Since 1973
>> Lugoff, SC
>>
>> _______________________________________________
>> GMCnet mailing list
>> List Information and Subscription Options:
>> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>>
>
>
>
> --
> Steve Ferguson
> Sierra Vista, AZ
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
_______________________________________________
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| Re: Question: Which does the most damage to the engine? [message #111909 is a reply to message #111865] |
Thu, 13 January 2011 14:05 |
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cbwoodsr
Messages: 1063
Registered: February 2004
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along the lines of the rest of the answers.. I 'let' mine
sit for 3 yrs, with aircleaner off, hatch open, well liners off, on dirt parking area at RV 'fixin' place..
(DONT get me started on that part!!)
Started right up after letting it spin some, did the same on the Onan except, I went to Walmart and got 2 batteries that said 6V on the side and put them in to start it up.
It spun pretty good for a bit then started right up.
Key was (6V = 12v) rather than 6v.
In spite of everything, all ran well, even the 8+ year old tires with cracks on sides/etc; drove home around 25mph down regular streets, (no interstate) for around 15-20 miles from one side of OKC to MWC on the other.
Home now waiting for tires (& wheels) to do more.
FWIW
CBWood
77 Kingslay
MWC OK
ONLINE PARTS PROGRAM
www.GMCMHParts.com
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| Re: Question: Which does the most damage to the engine? [message #111938 is a reply to message #111865] |
Thu, 13 January 2011 18:06 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
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| Tom Fort wrote on Thu, 13 January 2011 09:21 |
Many of our GMCs sit a long time between trips. I had heard that it is good to warm it up and take it on a short trip every two weeks or so. I wondered if those frequent start ups do more damage than just waiting just before you a planned trip.
What do the experts think?
Thanks, Tom
|
Tom,
The simple answer is yes.
There are two things that are so hard on an engine that they are the center of most durability testing.
One is cold starts and the other is thermal cycles. They are not the same thing by any means.
A cold start is any time the engine is room temperature or less and it gets started and run. This is particularly hard on bearings and other part that require lubrication.
A thermal cycle is when the engine gets run to full operating temperature and shut down. This is rough on the sealing systems like intake and cylinder head gaskets.
WOT and other full load testing done to accentuate wear on loaded surfaces, but it has little bearing on real world durability for passenger service vehicles or even trucks, but it makes engineers happy.
Another not addressed by most recent testing is idle time. This is very hard on flat tappet valve gear. Roller followers are almost immune and that is just one of the reasons flat tappets are gone now.
Up the page, you were advised not to just start and run the engine "just because" and this is very true. A start-up and run that does not get the engine to full operating temperature will leave moisture in lots of places it should not be. Starting the engine for a few moments is a very bad thing to do as it will leave moisture and combustion by-products (acidic) on the cylinder walls and valve stems and bunch more in the exhaust system.
If you are going to store an engine for an extended period (like more than a year), that is a new ball game. It is nothing to be afraid of and no rocket science is involved, and many people "put up" marine engines at the end of the season this way and I have seen it save more than a few.
I was told once that the old "start it every other week" for old cars was because;
the leather seals would dry out and leak (they sure did)
the battery would loose its charge (though an old generator would not fix this at idle speed)
the leaded gas would get real bad (trust me on this) and gum up the primitive carburetors
(I'm sure there were others, but I had a limited attention span.)
That is my final answer on the subject.
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
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| Re: [GMCnet] Question: Which does the most damage to the engine? [message #111954 is a reply to message #111881] |
Thu, 13 January 2011 20:18 |
Bob Maxwell+
Messages: 75
Registered: November 2010
Location: Belén, New Mexico
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>> Might as well run that Onan until it's heat soaked also if that is what
you chose to do.<<
That is very important. Stay away from any GMC whose genset is OEM and
doesn’t have say, 12-1500 hrs on it. Generators have to be run monthly to be
in good shape. I've bypassed several units that advertise "Only 90 hours on
the generator, it's almost new!"
Bob Maxwell†
Belén NM
Life's journey is not to arrive at the grave safely in a well preserved
body, but rather to skid in sideways, totally worn out, shouting "...Thank
you Jesus ...what a ride!"
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| Re: Question: Which does the most damage to the engine? [message #111959 is a reply to message #111865] |
Thu, 13 January 2011 21:25 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
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I also question the cranking without spark and/or fuel so as to not get it to fire until oil pressure is up as a beneficial practice.
1) you are still putting compression loads on the bearings
2) the parts that get sling and splash lubrication (walls and pistons)are getting most likely none at all at cranking speeds
Getting it started ASAP and up to a reasonable safe RPM of 1500 or so in my mind is the best way to get the oil up and moving over a minimum time period, minimizing the dry time. Modern computer cars with IAC idle speed start that way when cold. Granted they are roller but they still have pistons and cyl walls and wrist pins. And Jim is right about idleing. A brief warm up of a brief couple of minutes (factored a bit longer for extreme cold conditions like below zero)and then easy normal driving to warm it up gives you the road load to get the engine up to the thermostat set point with some degree of promptness to minimize the water and acid in the oil by less time running below the optimum temperature and with choke enrichment.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Question: Which does the most damage to the engine? [message #111963 is a reply to message #111865] |
Thu, 13 January 2011 23:23 |
Luvn737s
Messages: 1106
Registered: June 2007
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Down the road from me at Pinal Air Park is a operation known as Evergreen Air Center where 80 million dollar jets are stored. The leasing companies pay big money to make sure those aircraft are serviced, started and run regularly during their storage. The only ones that are let to sit are the ones headed to the crusher.
Having operated equipment for many many years, I have seen the effects (and paid the bills)of letting them sit idle and I can tell you without hesitation that mechanical equipment needs to be operated regularly - not sporadically or mothballed.
The cost to own a GMC will rise dramatically if you choose to let it sit.
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
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| Re: Question: Which does the most damage to the engine? [message #111967 is a reply to message #111963] |
Thu, 13 January 2011 23:37 |
Keith V
Messages: 2337
Registered: March 2008
Location: Mounds View,MN
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| Luvn737s wrote on Thu, 13 January 2011 23:23 |
Down the road from me at Pinal Air Park is a operation known as Evergreen Air Center where 80 million dollar jets are stored. The leasing companies pay big money to make sure those aircraft are serviced, started and run regularly during their storage. The only ones that are let to sit are the ones headed to the crusher.
Having operated equipment for many many years, I have seen the effects (and paid the bills)of letting them sit idle and I can tell you without hesitation that mechanical equipment needs to be operated regularly - not sporadically or mothballed.
The cost to own a GMC will rise dramatically if you choose to let it sit.
|
A Jet engine being run according to a multimillion dollar service plan has what bearing on servicing my poor ol GMC???
Keith Vasilakes
Mounds View. MN
75 ex Royale GMC
ask me about MicroLevel
Cell, 763-732-3419
My427v8@hotmail.com
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| Re: Question: Which does the most damage to the engine? [message #111970 is a reply to message #111967] |
Fri, 14 January 2011 00:10 |
Luvn737s
Messages: 1106
Registered: June 2007
Karma: 2
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| Keith V wrote on Thu, 13 January 2011 22:37 |
A Jet engine being run according to a multimillion dollar service plan has what bearing on servicing my poor ol GMC???
|
If they see the benefit of keeping their equipment in regular running order, why shouldn't we? It's not the money spent to keep it active, it's the dedication to doing so.
If I sound emphatic about this it's because I am. The stories of breakdowns attributed to varying degrees of neglect are what scare potential owners off. Without them we are one generation away from the end of GMC ownership as we know it. So I strongly encourage people to regularly use their GMCs as often as weather allows. Of course there are caveats: if you are in cold climates, use a oil sump heater and for anyone, drive for a substantial distance.
But to put a vehicle away for 6-8 months, you are bound to find things breaking that might not otherwise if they were being kept in regular use.
Anyone else need the soapbox? I think I'm finished with it!
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
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| Re: Question: Which does the most damage to the engine? [message #111989 is a reply to message #111959] |
Fri, 14 January 2011 08:59 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| JohnL455 wrote on Thu, 13 January 2011 22:25 |
I also question the cranking without spark and/or fuel so as to not get it to fire until oil pressure is up as a beneficial practice.
1) you are still putting compression loads on the bearings
2) the parts that get sling and splash lubrication (walls and pistons)are getting most likely none at all at cranking speeds
Getting it started ASAP and up to a reasonable safe RPM of 1500 or so in my mind is the best way to get the oil up and moving over a minimum time period, minimizing the dry time. Modern computer cars with IAC idle speed start that way when cold. Granted they are roller but they still have pistons and cyl walls and wrist pins. And Jim is right about idleing. A brief warm up of a brief couple of minutes (factored a bit longer for extreme cold conditions like below zero)and then easy normal driving to warm it up gives you the road load to get the engine up to the thermostat set point with some degree of promptness to minimize the water and acid in the oil by less time running below the optimum temperature and with choke enrichment.
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JohnL,
In my experience:
Line 1 - Compression loads are nothing even near firing loads.
The shock of firing load can easily break down the oil film if no hydraulic wedge has been established in the bearing. That makes metal on metal and that is never good.
Line 2 - The practical matter is that the things that need splash lube do get some lubrication even at cranking speeds once the lube oil system pressure has been established . Unfortunately, a cold engine can take 15~30seconds of either cranking or idle to fill the lube system and establish pressure.
Our old engines are WAY out of band on a cold start, but that is the best that the old fuel systems could do. This leads to wet fuel washing the cylinder bores, lube oil dilution, and many other things that you are well to avoid.
If you crank a cold engine with the choke open, there is almost no fuel getting into the engine as what does go in probably sitting on the floor of the intake runners until the engine gets to idle speed or greater.
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
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