GMCforum: GMCnet » 28SI Alternator vs 27SI

Home » Public Forums » GMCnet » 28SI Alternator vs 27SI

Show: Today's Messages :: Polls :: Message Navigator

Re: 28SI Alternator vs 27SI [message #360291 is a reply to message #360217]

Wed, 25 November 2020 12:22

TR 1

Messages: 348
Registered: August 2015
Location: DFW

Karma: -7

Senior Member

Thanks to you all for the input. I have (for now) settled on the 28SI. I ordered part# 8600313 which is the J180 short hinge in 200 amp. I found a new, genuine Delco Remy for $185 shipped from this site:

https://www.ironwingsales.com/product/borg-warner-delco-remy-electrical-alternator-224207/

They were very responsive to emails, fwtw. I'll report back when I receive the unit.

I will also post up some pics when I install it on the coach. Like I mentioned previously, I figure worst case I modify the alternator mount to shift the unit outboard to the left to clear the heads if I need additional clearance.

I still need to finish putting my engine back together before I can get to this project though... We have 2 kids at home remote learning in addition to work, etc. as well, so will probably be a few weeks till I get around to this....

Have a happy Thanksgiving everyone!

Mark S. '73 Painted Desert, Manny 1 Ton Front End, Howell Injection, Leigh Harrison 4bag and Rear Brakes, Fort Worth, TX

Report message to a moderator

Re: 28SI Alternator vs 27SI [message #360292 is a reply to message #360291]

Wed, 25 November 2020 12:35

mghamms

Messages: 466
Registered: March 2016
Location: Ware, Massachusetts

Karma: 2

Senior Member

Anyone know of a water cooled alternator that would work?
Just asking because they seem to last forever.

1977 Kingsley 455 as stock as it gets except lots of Ragusa parts

Report message to a moderator

Re: 28SI Alternator vs 27SI [message #360293 is a reply to message #360292]

Wed, 25 November 2020 13:14

TR 1

Messages: 348
Registered: August 2015
Location: DFW

Karma: -7

Senior Member

mghamms wrote on Wed, 25 November 2020 12:35

Anyone know of a water cooled alternator that would work?
Just asking because they seem to last forever.

I do not, but I did note the 28SI has dual cooling fans (one in front, and one in back) and was rated for 257 degrees, which seemed to be on the higher side compared to other available alternators...

I also noticed Delco has a series of brushless alternators. I would think this would also result in a more reliable alternator, though not sure if that is true in practice....

They look to be quite pricey as well....

Mark S. '73 Painted Desert, Manny 1 Ton Front End, Howell Injection, Leigh Harrison 4bag and Rear Brakes, Fort Worth, TX

Report message to a moderator

Re: 28SI Alternator vs 27SI [message #360294 is a reply to message #360293]

Wed, 25 November 2020 13:45

mghamms

Messages: 466
Registered: March 2016
Location: Ware, Massachusetts

Karma: 2

Senior Member

Brushless would be nice.

On my Alfa spider the alternator has a shroud over the intake with a duct to the cold air in front.
Something like that should keep the temps down and maybe also cool the engine compartment a little.

TR 1 wrote on Wed, 25 November 2020 13:14

mghamms wrote on Wed, 25 November 2020 12:35
Anyone know of a water cooled alternator that would work?
Just asking because they seem to last forever.
I do not, but I did note the 28SI has dual cooling fans (one in front, and one in back) and was rated for 257 degrees, which seemed to be on the higher side compared to other available alternators...

I also noticed Delco has a series of brushless alternators. I would think this would also result in a more reliable alternator, though not sure if that is true in practice....

They look to be quite pricey as well....

1977 Kingsley 455 as stock as it gets except lots of Ragusa parts

Report message to a moderator

Re: 28SI Alternator vs 27SI [message #360296 is a reply to message #360292]

Wed, 25 November 2020 17:23

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

mghamms wrote on Wed, 25 November 2020 13:35

Anyone know of a water cooled alternator that would work?
Just asking because they seem to last forever.

I have never seen a water cooled alternator. Some of the 6-71 bus engines had oil cooled units. I would like you to think I had that all figured out when I was sent to find out where the oil leak was on such a unit.....
At first this was a real head bender, but then I saw the oil lines to it and wrapped my head around it.

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

Report message to a moderator

Re: [GMCnet] 28SI Alternator vs 27SI [message #360298 is a reply to message #360281]

Wed, 25 November 2020 18:00

Ken Burton

Messages: 10030
Registered: January 2004
Location: Hebron, Indiana

Karma: 10

Senior Member

Matt,

Colonel Ken and I are not throwing lightning bolts at each other. I totally agree with him. I just wanted to point out that there are other losses in the system that simply installing a combiner will not take care of in a one wire system conversion. These could be exacerbated as the amount of current rises. The combiner will take the major loss which is the diode drop of an isolator.

I learned a long time ago not to argue with the Colonel.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

Report message to a moderator

Re: 28SI Alternator vs 27SI [message #360299 is a reply to message #360217]

Wed, 25 November 2020 18:59

jhbridges

Messages: 8412
Registered: May 2011
Location: Braselton ga

Karma: -74

Senior Member

Leece-Neville shows a brushless alternator 170 Amp for $188, reasonable for any 170 Amp. I assume they do this by spinning high strength fixed magnets, like some of the newer electric motors. My concern is, I read someplace that the magnets lose strength over time, which reduces output. And then would have to be replaced. I wonder what kind of time frame that happens in, and what the replacement cost is gonna be.

--johnny

Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons. Braselton, Ga. I forgive them all, save those who hurt the dogs. They must answer to me in hell

Report message to a moderator

Re: [GMCnet] 28SI Alternator vs 27SI [message #360301 is a reply to message #360298]

Wed, 25 November 2020 19:12

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

Ken Burton wrote on Wed, 25 November 2020 19:00

Matt,

Colonel Ken and I are not throwing lightning bolts at each other. I totally agree with him. I just wanted to point out that there are other losses in the system that simply installing a combiner will not take care of in a one wire system conversion. These could be exacerbated as the amount of current rises. The combiner will take the major loss which is the diode drop of an isolator.

I learned a long time ago not to argue with the Colonel.

I didn't mean at each other. I have yet to see you two actually disagree on that subject. I will tell you and anybody else that cares that few people understand what happens in 12V systems.

Some rally, Ken, you and RFBurns(Bruce) should sit around a table and swap stories of stupid electrics we have seen. Actually, you three will beat me I am sure. Maybe we should include Johnny too.

Have a good Thanksgiving.

Matt

Report message to a moderator

Re: 28SI Alternator vs 27SI [message #360302 is a reply to message #360299]

Wed, 25 November 2020 19:18

Matt Colie

Messages: 8547
Registered: March 2007
Location: S.E. Michigan

Karma: 7

Senior Member

jhbridges wrote on Wed, 25 November 2020 19:59

Leece-Neville shows a brushless alternator 170 Amp for $188, reasonable for any 170 Amp. I assume they do this by spinning high strength fixed magnets, like some of the newer electric motors. My concern is, I read someplace that the magnets lose strength over time, which reduces output. And then would have to be replaced. I wonder what kind of time frame that happens in, and what the replacement cost is gonna be.

--johnny

I may try to find out more about that machine.

And yes, the old Alnico would loose strength. I had to have the flywheel of one of my outboards "Rejuiced" when the spark went out. Maybe rare earth does better.

My 1973 Honda 350 had a 55amp brushless alternator. It was actually very conventional. The field was fixed to the case and pole pieces with close airgap spun inside the stator and it have a separate regulator to control the field.

Have a good and healthy Thanksgiving

Matt

Report message to a moderator

Re: 28SI Alternator vs 27SI [message #360309 is a reply to message #360302]

Thu, 26 November 2020 10:51

mghamms

Messages: 466
Registered: March 2016
Location: Ware, Massachusetts

Karma: 2

Senior Member

I have been removing the "super magnets" from old hard drives over the years.
I used some to hold papers on my SS refrigerator after a period of time, 10* years, some will no longer hold.
Don't know how that relates to the alternator magnets, but it may.

1977 Kingsley 455 as stock as it gets except lots of Ragusa parts

Report message to a moderator

Re: 28SI Alternator vs 27SI [message #360512 is a reply to message #360217]

Fri, 04 December 2020 12:58

TR 1

Messages: 348
Registered: August 2015
Location: DFW

Karma: -7

Senior Member

If anyone is interested, the alternator arrived from the vendor I mentioned earlier in the thread 3 days later. I have not installed it yet, but did take some pics alongside the stock 27SI for size comparison if anyone is interested.

Remember, there is no external fan needed on the 28SI, so I tried to line the 2 up in the pics with where I believe the pulley will need to mount. Since this cheats the 28SI forward compared the the 27SI, I think we are talking less than an inch difference in where the rear of the alternator ends up, outside of where the lug connections are. I chose 8600313 specifically for these, as I did not want to mess with a harness adapter. The lugs should end up high on the alternator when mounted, so they should not interfere with the valve cover from what I can see so far.

Overall, it's not much bigger in any dimension, and smaller in overall diameter than the 27SI. Not bad for 200amps/140 at idle....

http://www.gmcmhphotos.com/photos/g7338-28-si-alternator.html

Not sure why that fist pic is fisheyed... The rest look ok.

Mark S. '73 Painted Desert, Manny 1 Ton Front End, Howell Injection, Leigh Harrison 4bag and Rear Brakes, Fort Worth, TX

Report message to a moderator

Pages (2): [ « ‹ 1 2]

Previous Topic:	Engine lubrication
Next Topic:	[GMCnet] Ride height.

Goto Forum:

-=] Back to Top [=-

Current Time: Tue Jun 18 08:18:01 CDT 2024

Total time taken to generate the page: 0.02724 seconds