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  #1  
Old 02-01-2013, 10:17 PM
airguy's Avatar
airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,592
Default SD8 alternator adapter question

I got my SD8 alternator and tried to mount it up on the vacant vacuum pump pad on my IO360 tonight, and ran into a problem. The adaptor currently on the vacuum pump pad is (as close as I can measure it) 1 3/8" deep, and the SD8 will not seat fully on it, it appears that the adaptor need to be about 1 1/2" deep. Does this adaptor come in various thicknesses? I have been unable to find what I'm looking for online, and I have confirmed that the gear is indeed fully seated (the adaptor block itself would stand proud if it wasn't) and the adaptor block is firm against the engine block. Here is a pic showing how it fits up, the gap is right at 1/8".

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Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2021 dues paid
N16GN flying 900 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, IFD440, G5
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.

Last edited by airguy : 02-01-2013 at 10:23 PM.
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  #2  
Old 02-01-2013, 11:05 PM
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SMO SMO is offline
 
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Location: Salmon Arm, BC
Posts: 933
Default 1.25"

Greg, the adapter on my 540 is 1.25" - just went out and measured it - and the SD8 fits fine. not sure if there are any differences with a 360.
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Mark Olson
1987 RV-4 Sold
2003 Super Decathlon - Sold
F1 EVO Rocket, first flight May 31/14
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  #3  
Old 02-02-2013, 07:11 AM
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Walt Walt is offline
 
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Location: Dallas/Ft Worth, TX
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Default

I have mounted a few of these on O-360's and never encountered a problem. As far as I'm aware, there is only one size spacer/adapter available.
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Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
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  #4  
Old 02-02-2013, 07:55 AM
chaskuss chaskuss is offline
 
Join Date: Mar 2005
Location: SE Florida
Posts: 1,510
Default

Greg,
Judging by the gap, I suspect that the gear on your SD8 is not meshing into it's drive gear. Try rotating the gear one half tooth and try again. While you have it back off, measure the distance from the end of the gear to the gasket mating surface on the SD8's housing.
I have an SD8 in a box. I can measure mine so that you can compare them.
Charlie
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  #5  
Old 02-02-2013, 10:13 AM
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Default

I have confirmed that the gear is meshed inside the accessory case (otherwise the adapter will not sit flush against the case) and the SD8 is meshed with the gear splines but the end of the shaft of the gear sits out proud past the end of the adapter by about 1/8", and it needs to be flush or slightly recessed for the SD8 to mate up. Does that gear shaft come in different lengths? It looks for all the world to me like that gear shaft is about .150" too long. If I cut it down it will still make up to the oil seal, I'm just reluctant to start cutting a good engine gear if there is another way. With the gear meshed inside the drive case and the adaptor seated on the case, the spline shaft of the gear sits a full 1/8" proud of the open end of the adaptor. I have enough room on the spline shaft to trim it 3/16" or 1/4" and still seal up on the oil ring.

The SD8 is bottoming out fully in the splines, it's the gear shaft that is too long (or the adaptor is too short).
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Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2021 dues paid
N16GN flying 900 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, IFD440, G5
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.

Last edited by airguy : 02-02-2013 at 10:37 AM.
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  #6  
Old 02-02-2013, 10:31 AM
DaAV8R DaAV8R is offline
 
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Location: Lee's Summit, MO
Posts: 749
Default Gear

Someone else had a similar problem with their mags not seating properly not long ago and they had the wrong gear installed in the accessory case. You might check the deck height to the drive gear and compare to another engine.
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  #7  
Old 02-02-2013, 10:41 AM
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airguy airguy is offline
 
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Location: Garden City, Tx
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Default

Quote:
Originally Posted by DaAV8R View Post
Someone else had a similar problem with their mags not seating properly not long ago and they had the wrong gear installed in the accessory case. You might check the deck height to the drive gear and compare to another engine.
That's what I suspect is the issue here - the gear total length on mine is 3 1/16", and I think it should be about a 1/4" shorter.
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Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2021 dues paid
N16GN flying 900 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, IFD440, G5
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
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  #8  
Old 02-02-2013, 01:20 PM
mahlon_r mahlon_r is offline
 
Join Date: Jan 2005
Posts: 1,060
Default

4 cylinder and 6 cylinder vac pump adapters and gears are different lengths. But will fit in each other. I suspect you have mismatched installed.
Good Luck,
Mahlon
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  #9  
Old 02-02-2013, 03:49 PM
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airguy airguy is offline
 
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Quote:
Originally Posted by mahlon_r View Post
4 cylinder and 6 cylinder vac pump adapters and gears are different lengths. But will fit in each other. I suspect you have mismatched installed.
Good Luck,
Mahlon
Mahlon - what is the cheaper fix? Short gear or long adapter?
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Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2021 dues paid
N16GN flying 900 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, IFD440, G5
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.
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  #10  
Old 02-03-2013, 05:59 AM
mahlon_r mahlon_r is offline
 
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Default

see pm...
Good Luck,
Mahlon
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