| Does my 6Kw Onan have the wrong flywheel? [message #278312] |
Sun, 24 May 2015 17:36  |
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RF_Burns
Messages: 2277
Registered: June 2008
Location: S. Ontario, Canada
Karma: 3
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Senior Member |
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I decided to install the Pertronic ignition kit by Gary Bovee. The 6Kw shows it should have a 25degree advance and Gary's instructions show it should have a mark on the flywheel for that. I have a mark for TDC and one for 20 degrees, but no mark at 25. By eyeballing up the degree markings on the valve train cover, the 20 degree flywheel marking lines up with 20 degree mark.
Judging by the where the points open, mine is currently running about 17 BTDC.
The flywheel has PN 170-2997, but the manual says it should be 134-2603.
Have I got a different variation and should use 20BTDC or have I got a different flywheel and should set it for 25 BTDC?
The Onan is a NH-1R/9000H on a 1977 PB built in Oct 76.
What say yea?
thanks
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
[Updated on: Sun, 24 May 2015 17:46] Report message to a moderator |
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| Re: [GMCnet] Does my 6Kw Onan have the wrong flywheel? [message #278338 is a reply to message #278312] |
Mon, 25 May 2015 00:15  |
gcbgold
Messages: 60
Registered: August 2012
Karma: -1
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Member |
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Bruce,
Just use the timing tape included in the Kit to determine where to mark a
25 degree timing mark on the flywheel.
You probably have the correct flywheel. It is doubtful that it has been
changed. The Onan in our Royale only has a 20 degree mark.
Gary Bovee
1978 Royale
Red Bluff, CA
On Sunday, May 24, 2015, Bruce Hislop wrote:
> I decided to install the Pertronic ignition kit by Gary Bovee. The 6Kw
> shows it should have a 25degree advance and Gary's instructions show it
> should
> have a mark on the flywheel for that. I have a mark for TDC and one for
> 20 degrees, but no mark at 25. By eyeballing up the degree markings on the
> valve train cover, the 20 degree flywheel marking lines up with 20 degree
> mark.
> Judging by the where the points open, mine is currently running about 17
> BTDC.
>
> The flywheel has PN 110-2997, but the manual says it should be 134-2603.
>
> Have I got a different variation and should use 20BTDC or have I got a
> different flywheel and should set it for 25 BTDC?
>
> The Onan is a NH-1R/9000H on a 1977 PB built in Oct 76.
>
> What say yea?
>
> thanks
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
> Hubler 1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
> _______________________________________________
> GMCnet mailing list
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| Re: [GMCnet] Does my 6Kw Onan have the wrong flywheel? [message #278341 is a reply to message #278338] |
Mon, 25 May 2015 01:22 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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Onan had a problem with a few engines burning holes in pistons due to detonation. The culprit was the unreliable push rod system opening the points. They retarded the timing spec several times to get away from the detonation problem. So the mark on your flywheel and the manual you might be reading will vary depending on when it was manufactured or written.
If you look at your timing with a timing light on the OEM points triggered system you can see the problem. After you install the Pertronix system look at it again and you will see how stable it is now. The stability will allow you to set the timing more advanced.
I met a retired Onan engineer a few years back and he told me that the Onan would run all day at 1800 RPM under various loads at 30 degrees BTDC but with the pushrod triggered system they could not get the stability needed to go to 30 degrees. I explained the Pertronix system, introduced to us by Lawrence Gaskins, along with the stability we were seeing and he said it would run at 30. Not being that adventuresome I settled for a setting of 26 BTDC on mine. I am not sure where Gary got his 25 number from but that is a nice conservative setting that ought to work just fine.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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