914/6 2nd question of the day. Voltage regulators? Options

[Tdskip]

Second question mid build, as I mentioned on the other thread I’ve got a 2.4 L 911 engine going into my 1974 914. The 1974 9/11 would’ve originally had an external voltage regulator, I’m not familiar enough with my 911 set up to know if it also had an external regulator or if it was internal to the alternator..

Anyone able to drop some knowledge on that?

Thanks!

[lesorubcheek]

The '73 2.4 E engine I'm planning to use in our 914 presently has an external regulator. Started researching options for an alternator with an internal regulator and so far haven't found the definitive resource that explains all the 911 alternator ins and outs. Looks like there's the wosp high output alternators, but they're pushing 1k. At some point the diameter of the shaft changed, so I don't think it's just as easy as getting a later model one with integral regulator and slapping it in unless you have an appropriate fan that'll fit. May even need the housing, but not sure. The rear air channel piece also looks like changed, and haven't found out if it can be easily modified or if a new one would be needed. This is all from memory when I was researching a few weeks ago.

Dan

[Luke M]

The '73 2.4 E engine I'm planning to use in our 914 presently has an external regulator. Started researching options for an alternator with an internal regulator and so far haven't found the definitive resource that explains all the 911 alternator ins and outs. Looks like there's the wosp high output alternators, but they're pushing 1k. At some point the diameter of the shaft changed, so I don't think it's just as easy as getting a later model one with integral regulator and slapping it in unless you have an appropriate fan that'll fit. May even need the housing, but not sure. The rear air channel piece also looks like changed, and haven't found out if it can be easily modified or if a new one would be needed. This is all from memory when I was researching a few weeks ago.

Dan

The fan housings changed a few times. So, yes you need the proper housing to fit the internal reg alt. that will fit your engine. As for the air channel piece that can be modified. I did just that to make it fit on my brothers engine. I had to cut the lower portion to fit over the regulator. You could buy a new piece but I had a good one on hand that just needed the mod. After the mod it fit well. Mid 75 or 76 the housings changed with the internal reg alt. Then when the 3.0 came about it slightly changed again. I have all the info someplace and will post it here once I find it.

Attached a link from classic retrofit which has a good video/info.

https://www.youtube.com/watch?v=P9dy5wSbeHk

https://www.classicretrofit.com/products/co...175a-alternator

[lesorubcheek]

The fan housings changed a few times. So, yes you need the proper housing to fit the internal reg alt. that will fit your engine. As for the air channel piece that can be modified. I did just that to make it fit on my brothers engine. I had to cut the lower portion to fit over the regulator. You could buy a new piece but I had a good one on hand that just needed the mod. After the mod it fit well. Mid 75 or 76 the housings changed with the internal reg alt. Then when the 3.0 came about it slightly changed again. I have all the info someplace and will post it here once I find it.

Attached a link from classic retrofit which has a good video/info.

https://www.youtube.com/watch?v=P9dy5wSbeHk

https://www.classicretrofit.com/products/co...175a-alternator

Great info Luke. Love the table, it's very helpful. The classic retrofit alt looks like the wosp. Lots of info around, especially on pelican and rennsport. With the price of housings and fans, I'm likely gonna stick with what I have, at least in the beginning.

One question.... are you sure the internal reg alternator began use ~76 or was it just the housing that would work with them started being used in 76? A couple of posts on various forums implied the internal was first used around 81 or 82.

You'd think that converting older 911 engines to internal reg alts would be a common thing, but my searches for "Porsche 911 alternator convert from external to internal regulator" just don't turn up anything that's been enlightening. That's when I decided to just drop it and move on to the next problem.

Dan