home register FAQ memberlist calendar

Go Back   Turbobricks Forums > Mechanical > maintenance & nonperformance

Reply
 
Thread Tools Display Modes
Old 08-09-2018, 08:51 PM   #1
2 old for this
Board Member
 
Join Date: Mar 2018
Location: Amarillo
Default Alternator id

I am embarrassed to say this but how are the Bosch ones identified as per amp rating. Also how about the Denso units. I have been doing this since 74 and never knew.
2 old for this is offline   Reply With Quote
Old 08-09-2018, 08:58 PM   #2
dl242gt
Can play the blues
 
dl242gt's Avatar
 
Join Date: Jun 2002
Location: S NJ, a suburb of Phila.
Default

The bosch units in 240s started at the 55 amp rating and moved up to 65 then 70 and the last version was an 80 amp. They all can interchange. Sometimes you may need to change the upper bracket and connectors but you can put them on any of the ohc redblock.

Denso units are only 80 amp with the small B+ terminal. Then 80 and 100 amp with large B+ terminal. You will have to change the upper bracket and possibly a connector depending on the car but they all interchange as well.

It's really nice to change to the B230F upper adjuster bracket. With the spacer from Volvo and a longer bolt the upper bracket fits all the redblocks and makes alternator belt tension easy to adjust. All the parts are available from Volvo or buy used.
dl242gt is offline   Reply With Quote
Old 08-10-2018, 05:21 AM   #3
John242Ti
LH-Jet & Carb Free Zone
 
John242Ti's Avatar
 
Join Date: May 2003
Location: Duvall, WA
Default

The older B21/23 alternators were also rated, amperage-wise, at an engine speed of 2000 rpm or 4000 rpm alternator speed. The B230 alternators are all rated at 3000 rpm engine speed. Hence why a Bosch 70 amp for a B23F will say N1 14V 70A20, whereas one for a B230F will be N1 14V 31/70A.

The Denso alternators are a much more reliable solution than the older Bosch units are. I highly recommend upgrading to them. One weird thing I've noticed about them, however, when you start the enigne, it'll seem like the warning lights flicker, then go out while cranking. That's normal for the Denso units I've used. I'm guessing it's because they excite more quickly than the Bosch units do.

-J
__________________

1982 242Ti - black, M46. 1985 245Ti - blue, M46. Formerly Blue245Ti, 245GT-Turbo, and, originally 242GT-Ti.
John242Ti is offline   Reply With Quote
Old 08-10-2018, 09:40 AM   #4
2 old for this
Board Member
 
Join Date: Mar 2018
Location: Amarillo
Default

Thanks for the replies. How are they identified? Are there difference in there appearance? Or markings?
2 old for this is offline   Reply With Quote
Old 08-10-2018, 12:41 PM   #5
dl242gt
Can play the blues
 
dl242gt's Avatar
 
Join Date: Jun 2002
Location: S NJ, a suburb of Phila.
Default

Yeah, they both look different. The denso type has an internal fan and internal regulator. The bosch units are external fan with internal regulator. So the housing looks very different with a stamped steel cover over the back of the denso units.

Thanks for that rpm rating info John. I would also suggest that whatever alternator you use. Be sure it is using one of the higher rated voltage regulators like a 14.4 or even a 14.6 Vsetpoint. That is more compatible to the new batteries in cars now.

If you do a google image search for volvo 240 bosch alternator. Then compare those iimages to a search for volvo 740 or volvo 940 denso alternator. You'll see the difference.
dl242gt is offline   Reply With Quote
Old 08-10-2018, 01:30 PM   #6
2manyturbos
Moderator
 
Join Date: Mar 2003
Location: Monroe, OR USA
Default

That's not what he is asking. How do you identify a 80A Bosch unit vs. a 100A unit? AFIK, you can't easily if the label is missing. I know my rebuilder can. He probably rebuilds them in his sleep.
2manyturbos is offline   Reply With Quote
Old 08-10-2018, 02:06 PM   #7
John242Ti
LH-Jet & Carb Free Zone
 
John242Ti's Avatar
 
Join Date: May 2003
Location: Duvall, WA
Default

It's pretty easy with respect to the old style Bosch 80A and 100A alternators. Same style case, but the 100A alternator is bigger. Big enough to cause unintentional welding when you try to change the oil filter on a B21FT or a B23FT with the 100 amp alternator in the stock lower mounting spot.

The 70 amp alternators, only way to tell without a label is to look at the upper mounting ear. The later one uses a thinner ear that has a square hole for the adjuster's carriage bolt. Earlier one has a thick ear with a round hole. B230 adjuster goes on the front side of the ear, whereas the B21/23 adjuster is on the rear side of the ear.
John242Ti is offline   Reply With Quote
Old 08-10-2018, 02:07 PM   #8
Jack
Banned
 
Jack's Avatar
 
Join Date: Jul 2011
Location: The Ass Cheek Of History
Default

I have a 100a denso forsale
Jack is offline   Reply With Quote
Old 08-10-2018, 03:10 PM   #9
dl242gt
Can play the blues
 
dl242gt's Avatar
 
Join Date: Jun 2002
Location: S NJ, a suburb of Phila.
Default

Then of course there is the 100 amp bosch unit that is Denso type design but is huge. Probably weighs more than a turbo. lol. These are on the later model 940 cars like a 93-95 if i recall correctly. they are internal fan/ internal regulator like a denso with a large black plastic back cover.
dl242gt is offline   Reply With Quote
Old 08-10-2018, 08:44 PM   #10
2 old for this
Board Member
 
Join Date: Mar 2018
Location: Amarillo
Default

Bingo !! Now I can sort thru the pile . The only Denso I had got installed on a one owner 1948 Plymouth.
2 old for this is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -4. The time now is 10:13 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2018, vBulletin Solutions Inc.