| Onan heads decarbon [message #116018] |
Mon, 21 February 2011 19:41  |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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My 73 Painted Desert, 23ft, has a 4kw Onan -- no hour meter but appears to have had low hours -- I thought it ran very well and rather quietly. This weekend however I replaced a few gaskets, did some cleaning and decided to decarbon the heads.
The first one did not look too bad, but the second one had a lot of build up. I did the work at the mini-storage lot, scraping first and then using a soft brass brush in a battery powered hand drill. I was very pleased with the results -- runs even more quietly, and very steady -- the small bit of vibration that I previously could feel while in the back of the coach was gone.
Pertronix in the near future -- will be interesting to see how much smoother it can be.
Just fyi.
Dennis
Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Onan heads decarbon [message #116023 is a reply to message #116018] |
Mon, 21 February 2011 20:46  |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Dennis,
Thanks for the heads up on the cleaning, I can ga-ron-tee you WILL be amazed
how much smoother the Pertronix makes the Onan run.
See my albums for the VW style, Ken H.'s for the "other" style. NOTHING is
meant by me using the term "other" I just didn't know what unit it was for
and I'm too bloody lazy to find out. ;-)
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Dennis Sexton
Sent: Tuesday, February 22, 2011 12:42 PM
To: gmclist@temp.gmcnet.org
Subject: [GMCnet] Onan heads decarbon
My 73 Painted Desert, 23ft, has a 4kw Onan -- no hour meter but appears to
have had low hours -- I thought it ran very well and rather quietly. This
weekend however I replaced a few gaskets, did some cleaning and decided to
decarbon the heads.
The first one did not look too bad, but the second one had a lot of build
up. I did the work at the mini-storage lot, scraping first and then using a
soft brass brush in a battery powered hand drill. I was very pleased with
the results -- runs even more quietly, and very steady -- the small bit of
vibration that I previously could feel while in the back of the coach was
gone.
Pertronix in the near future -- will be interesting to see how much smoother
it can be.
Just fyi.
Dennis
--
Dennis S
73 Painted Desert 230
Germantown, TN
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: Onan heads decarbon [message #116024 is a reply to message #116018] |
Mon, 21 February 2011 20:52 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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A few years back I did everything I could think of to get the Onan to run smooth. I fought the problem for over a year. Then I saw the label on the Onan that said to de-carbonize the heads every 200 hours. I did it and the Onan has run beautifully ever since. I did it the same way you did with a brass brush on an Dremel. After I put it back together, Steve F. suggested using a bead blaster to clean them. If I ever have to do it again that is what I'll use.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Onan heads decarbon [message #116026 is a reply to message #116023] |
Mon, 21 February 2011 21:15 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Rob,
Yes, I have looked over your album and KenH's as well as several others in considering the Pertronix.
Hard to believe my Onan could be much smoother but I an eager to proceed.
Thanks,
Dennis
| Robert Mueller wrote on Mon, 21 February 2011 20:46 |
Dennis,
Thanks for the heads up on the cleaning, I can ga-ron-tee you WILL be amazed
how much smoother the Pertronix makes the Onan run.
See my albums for the VW style, Ken H.'s for the "other" style. NOTHING is
meant by me using the term "other" I just didn't know what unit it was for
and I'm too bloody lazy to find out. 
Regards,
Rob M.
USAussie - Downunder
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Dennis Sexton
Sent: Tuesday, February 22, 2011 12:42 PM
To: gmclist@temp.gmcnet.org
Subject: [GMCnet] Onan heads decarbon
My 73 Painted Desert, 23ft, has a 4kw Onan -- no hour meter but appears to
have had low hours -- I thought it ran very well and rather quietly. This
weekend however I replaced a few gaskets, did some cleaning and decided to
decarbon the heads.
The first one did not look too bad, but the second one had a lot of build
up. I did the work at the mini-storage lot, scraping first and then using a
soft brass brush in a battery powered hand drill. I was very pleased with
the results -- runs even more quietly, and very steady -- the small bit of
vibration that I previously could feel while in the back of the coach was
gone.
Pertronix in the near future -- will be interesting to see how much smoother
it can be.
Just fyi.
Dennis
--
Dennis S
73 Painted Desert 230
Germantown, TN
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: Onan heads decarbon [message #116027 is a reply to message #116024] |
Mon, 21 February 2011 21:18 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Ken,
Yes, I think using a bead blaster would be excellent. I had also read where someone used oven cleaner. Next time I would like to remove more parts of the Onan including the exhaust and get several items bead blasted and refinished.
Dennis
| Ken Burton wrote on Mon, 21 February 2011 20:52 |
A few years back I did everything I could think of to get the Onan to run smooth. I fought the problem for over a year. Then I saw the label on the Onan that said to de-carbonize the heads every 200 hours. I did it and the Onan has run beautifully ever since. I did it the same way you did with a brass brush on an Dremel. After I put it back together, Steve F. suggested using a bead blaster to clean them. If I ever have to do it again that is what I'll use.
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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| Re: [GMCnet] Onan heads decarbon [message #116032 is a reply to message #116023] |
Mon, 21 February 2011 21:29 |
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I need to do the Onan head de-carbon, but those of you that know me
know that I am anal-retentive about cleaning and repainting things
when I put them back together. Having said that, does anyone
know of a source for high-temp Onan green paint?
On 2/21/2011 6:46 PM, Rob Mueller wrote:
> Dennis,
>
> Thanks for the heads up on the cleaning, I can ga-ron-tee you WILL be amazed
> how much smoother the Pertronix makes the Onan run.
>
> See my albums for the VW style, Ken H.'s for the "other" style. NOTHING is
> meant by me using the term "other" I just didn't know what unit it was for
> and I'm too bloody lazy to find out. ;-)
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Terry Taylor
'74 ex-Eleganza SE
San Lorenzo, CA
http://www.n6mon.org
http://dldesignstore.com
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| Re: [GMCnet] Onan heads decarbon [message #116035 is a reply to message #116032] |
Mon, 21 February 2011 21:44 |
Dennis S
Messages: 3046
Registered: November 2005
Karma: 2
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Senior Member |
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Terry,
The heads on my Onan were not painted -- only the shrouds.
I appreciate your preference to clean and paint -- Cummins/Onan sells a matching paint. I tried to find a match at the local big box stores but was unsuccessful. I only painted the carb and it turned out to be J Deere green -- so a re-do is in the future.
Dennis
| n6mon wrote on Mon, 21 February 2011 21:29 |
I need to do the Onan head de-carbon, but those of you that know me
know that I am anal-retentive about cleaning and repainting things
when I put them back together. Having said that, does anyone
know of a source for high-temp Onan green paint?
On 2/21/2011 6:46 PM, Rob Mueller wrote:
> Dennis,
>
> Thanks for the heads up on the cleaning, I can ga-ron-tee you WILL be amazed
> how much smoother the Pertronix makes the Onan run.
>
> See my albums for the VW style, Ken H.'s for the "other" style. NOTHING is
> meant by me using the term "other" I just didn't know what unit it was for
> and I'm too bloody lazy to find out.
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Dennis S
73 Painted Desert 230
Memphis TN Metro
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