Small Alternator

All things oily!
Post Reply
Westfield 129
Posts: 867
Joined: Sat Jun 04, 2011 4:20 am

Re: Small Alternator

Post by Westfield 129 »

How about a quick trip to the maintenance department for an AN6- whatever you need as far as length and shoulder ? There should be plenty of old take offs, or new ones.

It's also standard hardware or auto parts store. Remember, the system was once called "English"... I imagine that fractional bolts are still available.
jonclancy
Posts: 942
Joined: Tue Nov 01, 2011 9:30 pm

Re: Small Alternator

Post by jonclancy »

Hi Tim,

Nice one - thanks for digging that out. I'll PM you my details.

My philosophy here is bolt-on. And drill one 10mm hole.

No drilling, tapping, fabricating turnbuckles etc.

This philosophy will allow a non-technical owner to source some parts and bolt them on.

I hear both sides of the argument, but a small adjustable spanner is cheap and handy.

So, I am going to test the bolt-on solution before I dig out the (cheap and 'orrible) tap and die set.
Westfield 129
Posts: 867
Joined: Sat Jun 04, 2011 4:20 am

Re: Small Alternator

Post by Westfield 129 »

You don't have to tap anything if you don't want to, other than the turnbuckle. Even the conversion from the Lucas generator to the Lucas alternator requires another bracket, which occasionally has to be drilled to fit, and the lower bracket modified.

You already had to file the top alternator tab, so drilling to 3/8" will take about a minute to accomplish. The lower bracket stud on the engine plate should already be 3/8". If it is not long enough, get a longer 3/8" bolt and thread it through.

Even then, if you wanted to fabricate a lower mount, or use the old mount (I never bothered, as the turnbuckle simplifies the adjustment to just a few seconds without tools), you can.

3 each 3/8-24X2" bolts should do the job (with nylock nuts), with a few washers to get the turnbuckle clear of the alternator body. You will need two 3/8" rod ends and about 2 1/2" of hex material, threaded at each end, LH and RH.

The turnbuckle is not too complex (I know quite a few owners who have made one with LH and RH threads, and they were not fabricators, nor did they have machine shops). I supplied a couple as well in hex material, which makes the adjustment easier (your fingers can get a better grip).

The main advantage of the turnbuckle is that the alternator belt tension can be set with one's fingers, and the turnbuckle locked with a wrench. No possibility of slip as with a slotted, flat metal bracket. No pry bar to get the proper tension, and once set, the adjustment stays in place while the nuts are tightened. Fiddling under the alternator is eliminated as the turnbuckle locks easily with your adjustable end wrench, or a 9/16 end wrench.

The alternator installation should ease in-use service as well as be easy to install initially. Not having to mess with extra nuts behind the alternator, needing a pair of wrenches to make adjustments, and having the initial belt tension set without a pry bar or wrench really makes the installation work.

With the proper fasteners, installing the alternator on the engine and adjusting the turnbuckle takes about 5 minutes.

Yes, it is a little more complex, but when you are finished, it is very easy to maintain, and the adjustment never changes due to slippage. You don't need much torque to hold everything in place, and you will never take the skin off your knuckles when the wrench slips under the alternator.
biggles
Posts: 314
Joined: Tue Apr 10, 2012 8:10 am

Re: Small Alternator

Post by biggles »

Fate played a hand - it took moments - 'twas sitting at the top of the large Maxwell House tin full of old skool fasteners. Nut and plain washer was even next to it. I think it has been waiting for you since 'bout 1967.....

You will, however, have to find your own locking washer as I was on such minimum rest before going back to work I didn't have time to rummage the Nescafe tin...... :D
jonclancy
Posts: 942
Joined: Tue Nov 01, 2011 9:30 pm

Re: Small Alternator

Post by jonclancy »

Why use a locking washer when a drill jig and stainless locking wire are available?? :D

Some things I like to try....
Westfield 129
Posts: 867
Joined: Sat Jun 04, 2011 4:20 am

Re: Small Alternator

Post by Westfield 129 »

Or a nyloc nut?
jonclancy
Posts: 942
Joined: Tue Nov 01, 2011 9:30 pm

Re: Small Alternator

Post by jonclancy »

For info:

The water pump tab on my car is 17mm thick. I have modified some A2 stainless M8 part-threaded bolts to have a shoulder of 16-17mm with a washer (1mm) fitted. If anyone needs one of these, I can produce them to suit your own measurements and will drop it in the post FOC. A "thanks" for all the help I get from you lot.

I also found that my waterpump to rearside tab measurement was around 52mm. Also, just measure your pulley depth and divide by two to find the centre for measurement purposes. Take a (2mm thick) steel rule as a straight edge across the back of the pulley, and you have a reference for how much you need to file off your new alternator.

I think I will need to relieve the boss on the block to allow the alternator tab to sit properly. I'll have a look at that tomorrow, but it won't take more than a minute with a grinding stone.

Once the alternator is hung, I'll work out where to fix the bottom of the turnbuckle. Might use the original hole (drilled out to M10) or find a new mounting point. The original fan belt is retained.

Once all this is clear, I'll order the turnbuckle and alternator plug. They should be in when I'm next back home and I can get it up and running.

It's taking a while, but it's a bind when it's cold in the garage (at least the new lighting is great!).
Westfield 129
Posts: 867
Joined: Sat Jun 04, 2011 4:20 am

Re: Small Alternator

Post by Westfield 129 »

You wont have to grind anything off the block, but you will have to space the turnbuckle forward (screwed to the front face of the lower mounting tab to clear the alternator body and make the adjustment easy if you use a hex turnbuckle. Standard 3/8" rod ends will finish the mounting with a 2.5" turnbuckle. Note that the turnbuckle will not be parallel to the belt but angled forward. The turnbuckle setup with rod ends doesn't have to be parallel to the belt to give an accurate and reliable adjustment.

Standard (Grade 8) 3/8" (AN6) bolts (9.4mm diameter) X 2" seem to work fine (this is the standard lower mounting bolt used for the old generator and generator) , as I just did another installation on a Bugeye with a 1275 last week. Shoulder was perfect.

Water pump bracket thickness is uniform from car to car (all of mine are 17mm as well, as are the spares on the shelf) so that the old OEM alternators and generators fit. So is the thickness of the top mount tab on the alternator. At least it is on all the cars I have seen here in the US.

Cut the back side of the alternator tab to 9/16" (13 mm) final thickness and that should get everything to line up with the alternator's standard pulley. Don't forget to cut back the alternator's mounting tab far enough so that the alternator has adequate clearance for adjustment.

The 3/8 X 2" bolts will fit both top and bottom alternator mount tabs after they are drilled, as well as the water pump mount tab, and the 3/8" bolt will fit the lower mount hole in the engine plate and use the existing spacer of you have one. This saves a lot of time measuring (guessing), and if you mark the alternator tab, you can see if the alignment will be good.

When you are done, you can service most everything on the engine (if not the entire car) with a 3/8, 1/2 and 9/16" wrenches.
jonclancy
Posts: 942
Joined: Tue Nov 01, 2011 9:30 pm

Re: Small Alternator

Post by jonclancy »

I have my turnbuckle and some other stuff. Very nice quality and service from McGill Motorsport - but I did opt for the slighly more expensive rod ends as they looked better finished in the photo.

I've looked and cant see the pics on your Yahoo site, Jan, but I'm trying to work out where to run the bottom turnbuckle eye to. Mine fouls the alternator body. I could (easily) drill the engine mount for that purpose, and I suspect that won't be a problem. But... thought it best to check.

Oh, and seeing as one or other of my bolts will have to be sleeved whether I got for metric or imperial sizes, I decided, after much deliberation, to opt for 3/8". :o :P

Once I get the mounting point settled, I can order up the required A2 fasteners (bols, not set screws) from Stigs, or somewhere similar and get this thing bolted on.

First run of the year is to Combe on 22 March for the WSCC Sprint. I hope to be there if the weather is good (spectating, not racing).
Westfield 129
Posts: 867
Joined: Sat Jun 04, 2011 4:20 am

Re: Small Alternator

Post by Westfield 129 »

The mounting points are OK, and it is very easy to fix the problem. It is normal for the turnbuckle to foul the alternator case on initial fitting.

You need to space the turnbuckle forward a little, using some washers. Pretty easy, and the resulting mount is rigid and vibration free.

Washers will be used at the engine mount plate and the mount tab on the alternator. It takes about 1/8" to get the turnbuckle forward and away from the alternator case.

No need to drill. If you don't like the washers, you can make a spacer for the mounting point at the engine plate.

You are about 5 minutes away from having your alternator installed.

I use 3/8-24 X 2" bolts, which have precisely the correct shoulder dimension and thread length.
Post Reply