Converting Delco 28Si to external regulation

[CatNewBee]

Originally Posted by Federico993

Where did you find a screw for the upper installation hole?
I can see it is a 1/2-13 UNS screw but I can't find it.
Where can I find this screw?

Thanks!

Isn't it standard metric?

[Federico993]

No, it is an US size. I tried some metric screws but they don't fit.

[evm1024]

I just go to my local Ace hardware store.

PM me if you get stuck. I'll pick one up and put it in the mail to you. USA to Italy should not take more than a week or 2.

[Q Xopa]

Originally Posted by Federico993

No, it is an US size. I tried some metric screws but they don't fit.

Yes 1/2" -13 UN'S' is usually referred to as UNC. Ie United Course thread, which in 1/2 inch diameter is 13 threads per inch.

In 1/2" bolts it will be the most common thread.

There is UNF which are 20 TPI, but not as common

Or you could probably, there, should be enough metal, to tap it to 13x1.5. Then you can just stick to metric which is easier to come by in Italy and many other parts of the world. You can even get metric resonably easily in the US these days.

[CatNewBee]

Originally Posted by Q Xopa

Yes 1/2" -13 UN'S' is usually referred to as UNC. Ie United Course thread, which in 1/2 inch diameter is 13 threads per inch.

In 1/2" bolts it will be the most common thread.

There is UNF which are 20 TPI, but not as common

Or you could probably, there, should be enough metal, to tap it to 13x1.5. Then you can just stick to metric which is easier to come by in Italy and many other parts of the world. You can even get metric resonably easily in the US these days.

or just re-cut a proper metric thread on the hole, not a big deal

[Q Xopa]

Originally Posted by CatNewBee

or just re-cut a proper metric thread on the hole, not a big deal

Agreed, 13x1.5 is a 'proper' metric thread I was suggesting to 'tap', or as you say re-cut. I think we are saying the same thing?

[CatNewBee]

Originally Posted by Q Xopa

Agreed, 13x1.5 is a 'proper' metric thread I was suggesting to 'tap', or as you say re-cut. I think we are saying the same thing?

M12x1.25 or M14x1.5

[Q Xopa]

Originally Posted by CatNewBee

M12x1.25 or M14x1.5
Attachment 223789

Ah I see, its not on your chart.

Ok so its not as common as M12 or M14, agreed. But I dont know you can say its not a 'proper' metric thread. Its common Oil pan drain plug size. https://www.amazon.com/Best-Thread-R.../dp/B07GCK4GTX

Trying to convert from Imp to Metric is not always an exact answer as they are in between sizes. So my suggestion was because you wouldnt have enough metal to create an M12 thread from a 1/2 UNC. M14 is going to take a lot of metal and probably not going to fit through the adjuster bracket hole etc.

Of course any of these, and others, could be made to work with a bit of extra messing around, drilling larger holes, putting a bushing in etc.

There are obviously any number of solutions to this question.

[CatNewBee]

Originally Posted by Q Xopa

Ah I see, its not on your chart.

Ok so its not as common as M12 or M14, agreed. But I dont know you can say its not a 'proper' metric thread. Its common Oil pan drain plug size. https://www.amazon.com/Best-Thread-R.../dp/B07GCK4GTX

Trying to convert from Imp to Metric is not always an exact answer as they are in between sizes. So my suggestion was because you wouldnt have enough metal to create an M12 thread from a 1/2 UNC. M14 is going to take a lot of metal and probably not going to fit through the adjuster bracket hole etc.

Of course any of these, and others, could be made to work with a bit of extra messing around, drilling larger holes, putting a bushing in etc.

There are obviously any number of solutions to this question.

You can stick a M10 bolt trough and fix with a self securing nut or 2 nuts and a washer behind too.

[Q Xopa]

Originally Posted by CatNewBee

You can stick a M10 bolt trough and fix with a self securing nut or 2 nuts and a washer behind too.

Agreed, one of the many other solutions.

Although its slightly less convenient as now you need 2 spanners, and 2 hands etc.

[darylat8750]

I'm having trouble locating high temp wire like you used. SF2/SEW-2 wire Do you know of an online source for this. Is it required (or a "really good thing") or would regular marine wire be satisfactory ?

[GordMay]

Allied Wire ➥ https://www.awcwire.com/productspec.aspx?id=sf2-sew

[darylat8750]

Thanks Gord

[evm1024]

Originally Posted by darylat8750

I'm having trouble locating high temp wire like you used. SF2/SEW-2 wire Do you know of an online source for this. Is it required (or a "really good thing") or would regular marine wire be satisfactory ?

Internal temps and vibration in the alternator can get quite high. Typical marine wire is rated at 105 C and the insulation is "soft".

I speced the high temp wire in my build to add in a safety margin. I think that high temp wire is essential.

Best of luck!

[noelex 77]

Originally Posted by evm1024

Internal temps and vibration in the alternator can get quite high. Typical marine wire is rated at 105 C and the insulation is "soft".

I speced the high temp wire in my build to add in a safety margin. I think that high temp wire is essential.

Best of luck!

Oversized and/or “high temperature” wire is worth considering for the alternator, especially when a high output alternator is used.

Typically high output alternators run at 75° C + which does not leave much leeway for wire temperature increases due to voltage drop.