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| Opinions Requested: Correct Oil for Propane Onan [message #347101] |
Fri, 30 August 2019 11:21  |
TR 1
Messages: 348
Registered: August 2015
Location: DFW
Karma: -7
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Good heavens, a motor oil thread! But one I've not seen on this forum before, so maybe it won't devolve into shouting and insults...
J/K 
So I'm now the happy owner of a dual fuel Onan, courtesy of the instructions provided by Jerry Work!
However, I'm now faced with the question of what oil to use, since I'm primarily running on propane...
From some quick research on the web, what I'm seeing is stationary engines that run at a constant RPM can benefit from a propane/NG specific motor oil.
What say you? Not looking for opinions on brands, or anything like that... Just should I continue with a normal oil, or convert to a Propane/NG oil....
Mark S. '73 Painted Desert,
Manny 1 Ton Front End,
Howell Injection,
Leigh Harrison 4bag and Rear Brakes,
Fort Worth, TX
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| Re: Opinions Requested: Correct Oil for Propane Onan [message #347102 is a reply to message #347101] |
Fri, 30 August 2019 11:31  |
C Boyd
Messages: 2629
Registered: April 2006
Karma: 18
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Don't know about propane, Onan manual says above 30* use 30 wt. below 30* use 10W30.
TR 1 wrote on Fri, 30 August 2019 12:21Good heavens, a motor oil thread! But one I've not seen on this forum before, so maybe it won't devolve into shouting and insults...
J/K
So I'm now the happy owner of a dual fuel Onan, courtesy of the instructions provided by Jerry Work!
However, I'm now faced with the question of what oil to use, since I'm primarily running on propane...
From some quick research on the web, what I'm seeing is stationary engines that run at a constant RPM can benefit from a propane/NG specific motor oil.
What say you? Not looking for opinions on brands, or anything like that... Just should I continue with a normal oil, or convert to a Propane/NG oil....
C. Boyd
76 Crestmont
East Tennessee
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| Re: [GMCnet] Opinions Requested: Correct Oil for Propane Onan [message #347109 is a reply to message #347102] |
Fri, 30 August 2019 12:25 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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My suggestion is to keep things simple,
Use Syn oil in Onan and engine, avoid carrying two type.
There will not be that big of a difference.
There are other factors that can be more detrimental to the generator than
type of oil.
On Fri, Aug 30, 2019 at 9:37 AM Charles Boyd via Gmclist <
gmclist@list.gmcnet.org> wrote:
> Don't know about propane, Onan manual says above 30* use 30 wt. below 30*
> use 10W30.
>
>
>
>
>
> TR 1 wrote on Fri, 30 August 2019 12:21
>> Good heavens, a motor oil thread! But one I've not seen on this forum
> before, so maybe it won't devolve into shouting and insults...
>>
>> J/K ;)
>>
>> So I'm now the happy owner of a dual fuel Onan, courtesy of the
> instructions provided by Jerry Work!
>>
>> However, I'm now faced with the question of what oil to use, since I'm
> primarily running on propane...
>>
>> From some quick research on the web, what I'm seeing is stationary
> engines that run at a constant RPM can benefit from a propane/NG specific
> motor
>> oil.
>>
>> What say you? Not looking for opinions on brands, or anything like
> that... Just should I continue with a normal oil, or convert to a
> Propane/NG
>> oil....
>
>
> --
> C. Boyd
> 76 Crestmont
> East Tennessee
>
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> GMCnet mailing list
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Applied/GMC, Newark,CA
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| Re: Opinions Requested: Correct Oil for Propane Onan [message #347129 is a reply to message #347125] |
Fri, 30 August 2019 22:59 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I want to discourage the use of any synthetic oil in any air cooled engine. Air cooled engines are built much looser so they can operate over a wider range of engine temperatures. Because they are looser they all burn oil. When synthetic burns it leaves a glass like deposit in the cylinders that is extremely difficult to remove. I have seen it twice. Once was an airplane engine we tore down after an owner decided to use synthetic oil in it. It was so bad the we ended up scrapping the cylinders. Aircraft cylinders are not cheap. Aviation engines use a special oil called AD or Ashless Dispersant to help combat the build up of by products of burning oil.
So my recommendations are:
1. DO NOT USE SYNTHETICS in any air cooled engine (Motorcycles, lawn mowers, airplanes, or Onans).
2. Use a high detergent oil 10-30 or 15-40. I use Rotella 15-40. you do not care much about byproducts from gasoline or propane. The major source of by products in an air cooled engine is from burning lubricating oil.
A side story about air cooled engines. A friend at my airport bought a beautifully restored 1929 Waco. It has a rare conversion by Tank Engineering in Milwaukee from a Curtis OX5 water cooled V-8 to air cooled cylinders. Only about 170 were converted and there are only 2 known running ones left.
The people doing the restoration also rebuilt the OX5. They kept destroying the engines. After several years and several engines, they gave up and our guy bought it for a song. He repaired the engine and the weird carb. It runs and flies beautifully.
What the problem was is they were using tighter water cooled specs on the rebuild. Jason re-did the engine to his own air cooled specs as the Tank Engineering air cooled specs were no longer available.
https://www.google.com/search?q=curtiss+ox-5&ie=utf-8&oe=utf-8&client=firefox-b-1-e
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Opinions Requested: Correct Oil for Propane Onan [message #347132 is a reply to message #347101] |
Sat, 31 August 2019 08:39 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Ken B I have heard that before and don't doubt you. Why does Mobil 1 make a specific air cooled synthetic oil then? Called Mobile 1 V Twin air cooled. 20W-50. FWIW have been using T-6 5W-40 up front and in the Onan for many years with no known issues. I don't ever have to add oil to the Onan between changes so that may factor in.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Opinions Requested: Correct Oil for Propane Onan [message #347134 is a reply to message #347129] |
Sat, 31 August 2019 09:06 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Ken Burton wrote on Fri, 30 August 2019 23:59I want to discourage the use of any synthetic oil in any air cooled engine. Air cooled engines are built much looser so they can operate over a wider range of engine temperatures. Because they are looser they all burn oil. When synthetic burns it leaves a glass like deposit in the cylinders that is extremely difficult to remove. I have seen it twice. Once was an airplane engine we tore down after an owner decided to use synthetic oil in it. It was so bad the we ended up scrapping the cylinders. Aircraft cylinders are not cheap. Aviation engines use a special oil called AD or Ashless Dispersant to help combat the build up of by products of burning oil.
So my recommendations are:
1. DO NOT USE SYNTHETICS in any air cooled engine (Motorcycles, lawn mowers, airplanes, or Onans).
2. Use a high detergent oil 10-30 or 15-40. I use Rotella 15-40. you do not care much about byproducts from gasoline or propane. The major source of by products in an air cooled engine is from burning lubricating oil.
<SNIP>
Ken and I have a small difference of opinion here.
I have seen the glass hard deposit that he is speaking of, and it can be a bear.
When my coach engine lost 120° of the rings, the oil consumption went high. There was that hard deposit on both the piston crown and in the chamber in the head. During my career in engine development and durability testing, I have seen it other places too.
I must take this time to mention that aircraft engines run at much higher BMEP (Brake Mean Effective Pressure - What make TORQUE) than most other engines. That, plus being continually tuned to near stoichiometric air/fuel ratio, makes for higher combustion temperatures that most engines ever see. As such, they have a propensity to form the SiO2 (quartz) deposits with synthetic lubricating oil. And yes, aircraft engines are also designed to consume more lubrication oil that are passcar or other engines. This is a way to keep lubrication in the upper cylinder to extend the engine life. After all, oil is cheaper than parts. As a comparison, the Lycoming 320 is 150 hp and is expected to run at that all day, but a ford 300-6 truck motor was 120 peak hp and you can't run it at that all day.
As a part of engine durability testing, I found out that little flat head engines are very hard on the lubricating oil because they do not have any real means to cool the oil. That oil (just like any other engine) has to cool the underside of the piston crown and all the other hot parts. It turns out that little flat head engines often die of lubrication failure because the lube oil has been cook into uselessness. Another bane of the small engines is that the lack of regular service means that they get ignored to death. This and the other problems cause by combustion by-products in the lube oil. These can attack conventional oils and is another good reason to run synthetic in little air cooled engines that get ignored.
The one thing I would not do is go with a very low cold weight. The new 0 and 5 cold weight oils are there for emissions purposes. The very low cold friction means that they can get off the cold start cycle sooner. That is all it is good for.
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: Opinions Requested: Correct Oil for Propane Onan [message #347158 is a reply to message #347134] |
Sun, 01 September 2019 05:52 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I understand your argument. Aircraft engines are usually run at 70% - 75% of power for hours on except on takeoffs at 100%. An Onan is similar running at 1800 rpm and the power is probably 50% to 75 also continuously for hours. Having seen the damage / deposits I would never use any synthetic in any air cooled engine. You know they make a synthetic 2 stroke oil usually mixed at 50:1 and I have not heard any complaints with it.
On the other posting about mobile one, I have no knowledge on it. It is so much easier and cheaper to just use dino oil and be done with the possible problems.
Years ago Arch had a problem with his rebuilt 455 sucking extreme amounts of oil in one cylinder. He drove its several hundred miles to Jim B's place that way. When they tore the engine down he had the synthetic problem in that one cylinder.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: Opinions Requested: Correct Oil for Propane Onan [message #347161 is a reply to message #347158] |
Sun, 01 September 2019 09:02 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Ken Burton wrote on Sun, 01 September 2019 06:52I understand your argument. Aircraft engines are usually run at 70% - 75% of power for hours on except on takeoffs at 100%. An Onan is similar running at 1800 rpm and the power is probably 50% to 75 also continuously for hours. Having seen the damage / deposits I would never use any synthetic in any air cooled engine. You know they make a synthetic 2 stroke oil usually mixed at 50:1 and I have not heard any complaints with it.
On the other posting about mobile one, I have no knowledge on it. It is so much easier and cheaper to just use dino oil and be done with the possible problems.
Years ago Arch had a problem with his rebuilt 455 sucking extreme amounts of oil in one cylinder. He drove its several hundred miles to Jim B's place that way. When they tore the engine down he had the synthetic problem in that one cylinder.
Ken,
As usual, we agree way more than we disagree.
Yes, the Onan might be running at a big portion of its rated power, but the BMEP and therefore cylinder temperatures and pressures are way lower.
The change to 50:1 in two strokes was two things. First was the change in materials that allowed the lesser oil in the system. And then, as a reaction to oil pollution in some recreational waterways, OMC did an in depth engineering study into how much oil was actually needed. This also came along with ashless oils. And now spark plugs last a while too.
I cannot argue that conventional lube oils are cheaper. (But with Walmart's price for a 5g 15-50, not much.)
What I did not write about to any length is that when my engine lost 1/3 of the rings in #7 and the lube oil consumption went from less that one quart in 2K miles to greater that 1 quart in 500, I stopped feeding it M1. The hard deposit was part of my thinking.
If one is going to be conscientious about service and the engine use is not extreme, there is no advantage at all to synthetics.
There is another little difference that neither of us have mentioned. That quartz scale in an aircraft engine is a big issue because you cannot remove the cylinder head to clean it. if an engine has a removable cylinder head, we found that either steel shot or glass bead could remove it from the head casting. If you don't have that option, things get expensive real fast.
I bet that they didn't have to replace Arch's cylinder head and liner.
Looking forward to Mansfield.
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: Opinions Requested: Correct Oil for Propane Onan [message #347162 is a reply to message #347134] |
Sun, 01 September 2019 09:10 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Matt Colie wrote on Sat, 31 August 2019 09:06
The one thing I would not do is go with a very low cold weight. The new 0 and 5 cold weight oils are there for emissions purposes. The very low cold friction means that they can get off the cold start cycle sooner. That is all it is good for.
Matt
Please...some more depth to your statement about the "0" and "5" weights. 0W20, 0W25, 0W40, 5W30's etc.
Larry 
78 Royale w/500 Caddy
Menomonie, WI.
[Updated on: Sun, 01 September 2019 09:11] Report message to a moderator |
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| Re: Opinions Requested: Correct Oil for Propane Onan [message #347181 is a reply to message #347178] |
Sun, 01 September 2019 20:35 |
Larry
Messages: 2875
Registered: January 2004
Location: Menomonie, WI
Karma: 10
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Matt Colie wrote on Sun, 01 September 2019 19:52Larry wrote on Sun, 01 September 2019 10:10Matt Colie wrote on Sat, 31 August 2019 09:06
The one thing I would not do is go with a very low cold weight. The new 0 and 5 cold weight oils are there for emissions purposes. The very low cold friction means that they can get off the cold start cycle sooner. That is all it is good for.
Matt
Please...some more depth to your statement about the "0" and "5" weights. 0W20, 0W25, 0W40, 5W30's etc.
Larry,
I am not sure what you are not understanding...
The manufactures needed it after the change in the test cycle in about 2004 (iirc) and the oil suppliers came right along. The only reason new engines can survive with this is that manufacturing processes and materials have gotten that much better.
Matt
Well, are you saying that the "0" weight oils are not appropriate for our engines, and why not? It seems like the 0W40 Mobile one European formula would be a perfect oil for those of us that live in the north country. Dick Patterson has stated many times in his tech sessions that the majority of wear takes place at start-up. Seems like the "0" would get oil to the bearings in larger quantities quicker at start-up and warm-up, while maintaining the "40" at normal and higher operating temps. Just my relatively informed, off the cuff, back yard mechanic, gut level, eyeball it up and guestimate, thinking...
Larry
78 Royale w/500 Caddy
Menomonie, WI.
[Updated on: Sun, 01 September 2019 20:37] Report message to a moderator |
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| Re: Opinions Requested: Correct Oil for Propane Onan [message #347195 is a reply to message #347101] |
Mon, 02 September 2019 08:32 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Larry my limited knowledge is that the new wide viscosity spread range oils have more viscosity modifier added to "trick" the 0W to behaving like 40 hot. It's not a true 40 and may not behave as such as the additive package is depleted. The wider the range, the more viscosity modifier needed. A 5W-40 would need less of this added than 0W-40. In the 80-90s GM and Mopar older tech owners manuals for example recommended 10W-30 for temps expected above 0F and 5W-30 for temps expected below 0F. Since they are both 30 at operating temp, why not just run 5W-30 year round? Has to do with keeping less range spread and less viscosity modifier. The more additives you need, the less "oil" in the equation, the thing that actually lubricates. New cars might run a 0W-20 again a narrower spread than 0W-40. I have been running 5W-40 T6 and find this helped with super easy cold morning starts and no valve train noise after long sitting. I would not go to a 0W in our old tech engines, nor would I go over 40.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Opinions Requested: Correct Oil for Propane Onan [message #347196 is a reply to message #347181] |
Mon, 02 September 2019 08:48 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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Senior Member |
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Quote:Larry,
I am not sure what you are not understanding...
The manufactures needed it after the change in the test cycle in about 2004 (iirc) and the oil suppliers came right along. The only reason new engines can survive with this is that manufacturing processes and materials have gotten that much better.
Matt
Larry
Well, are you saying that the "0" weight oils are not appropriate for our engines, and why not? It seems like the 0W40 Mobile one European formula would be a perfect oil for those of us that live in the north country. Dick Patterson has stated many times in his tech sessions that the majority of wear takes place at start-up. Seems like the "0" would get oil to the bearings in larger quantities quicker at start-up and warm-up, while maintaining the "40" at normal and higher operating temps. Just my relatively informed, off the cuff, back yard mechanic, gut level, eyeball it up and guestimate, thinking...
Larry,
Now you have gone and changed venues on me! The discussion was about APUs possibly on LP and motorfuel.
Yes, they are not. Did you happen to notice that there have been some changes to passcar (what we really have) engines in the last 50 years? These changes were not all driven by federal emissions standards. Many were changes caused by market and a design standard changes. These changes are to numerous and esoteric for me to do into here and now, but if we meet at a rally and can sit down together for a significant time, I can probably lay them all out for you.
Did you ever start an old engine with hydraulic valve lash adjusters and hear it clatter for 20~30 seconds? That is the time that Dick was referring to. That time has more to do with the engine condition than is does the kinematic viscosity of the lube oil. Now we get to two separate sides of the problem...
All the engine lubrication pumps I have ever seen (in passcar) were crankshaft driven PD (positive displacement) pumps. They will pump the same volume per revolution with little regard for anything. This only changes if the system is so bound up by the viscosity that the relief opens. I have only observed this with a cold straight 30, never with anything with a "W".
Then, there is another little gotcha that nobody wants to talk about. Those low number oils number oils will run out of the system faster. That coupled with the faster start brought on by port fuel injection has caused a lot of unexpected warranty issues for some.
If I have not answered all of your questions, I am willing to try again. But this is Labor Day morning and I have places to go and people to annoy.
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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