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Alternator modernization


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Hi There, I think about dedicating some time to the mod and improvement of my electrical system over wintertime. One of the thoughts is either 1) overhauling my generator or 2) exchanging it to a modern alternator.

1) can the regulator be overhauled as well. Are there modern exchange parts available with the housing original?

2) what needs to be modified? (Pully, belt, regulator, harness...?

Your input and recommendation welcome!

Cheers

Oliver

 

 

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Hi Oliver,

It depends on how original you want your car!

Personally I went with upgraded dynamo to alternator spec but not going to the very expensive route. Alternator unit housed inside a dynamo body with an appropriately rated regulator.

The advantages of this it fits without any modifications to pulleys or bracket or loom. I have more than enough capacity for modern quartz halogen lighting, LEDlights, heater,wipers etc. 

Change over to an alternator means potential mounting faliure throwing the belt off causing the water pump to stop.

Works for me, but I like the engine bay to look original as possible.

Rod

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Hi Oliver

i went the alternator route after the mounting lug on my dynamo broke.  The extra output means I don’t worry about elec fan use etc.
 

lots of help from the forum sourced the parts and the reliable info that enabled me to do it myself. 

Including the control box alterations - and I am no way an auto electrician!!!!

i added a diy heat shield as I have a competition exhaust and I use full revs in competition.

plenty of “how to” on the forum
 

 

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Lots to think about Oliver.

The original dynamo is OK unless you have added extra gizmos to your car which need a lot of current particularly when the engine may be idling - like an electrical cooling fan.  Dynamos don't provide much output at low engine speeds but an alternator does because it runs faster.  If you haven't experienced problems with keeping the battery charged you probably don't really need an alternator. 

You can get electronic regulators for the dynamo which fit inside the original regulator box.  

The drawback with those alternator-in-a-dynamo-case devices that Rod describes is a tendency to overheat through lack of ventilation if you actually use the extra output they can provide.  There is a reason alternators are built with plenty of ventilation slots and the dynamo casing is very restrictive in that regard.  Most alternators have the regulator electronics inside and do not like getting hot. 

Changes to the wiring for an alternator are fairly minimal though you do need the connector and wires to suit. There is no real need to alter the main loom.

If you go for an alternator you then have to decide whether to keep the original wide fan-belt or to swap to a modern narrow one. Alternators come with smaller diameter narrow pulleys so you would need a special pulley if you retain the wide belt. (It is possible to fit the old dynamo pulley on an alternator but then you lose most of the benefit of more charge at low speed, because the rotation is no faster.) 

Fitting a narrow belt entails removing the fan extension from the engine for which you need to take the radiator out which is a major dismantling job on a sidescreen car- most people take the front cowl off the car to do that. You need to replace the pulley on the water pump too.

There is even a choice to be made of which type of alternator to fit - either the Lucas ACR type or the Denso one like that  in Hamish's photo.  There are others available too.  

Edited by RobH
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I was referring to a high output Dynamo as used in the Commer type period Ice cream vans. I have 35amp output and can still use the original fitting, the company also provided a matching regulator. I have never had an issue with lack of power, charging , rattling loose bodged together brackets. All these I have seen with alternator conversions.

Go to London &Essex auto electrics Ltd and ask about uprated dynamo.

https://londonessexautoelectrics.co.uk/

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With a decent bracket to support an alternator, no reason whatsoever for it to fail.

I have published 2 articles in TR Action (both accessible via the Register's on-line system):

- TR Action 118, November 1994, repeated in Section J4 of the Technicalities CD

- TR Action 248, March 2011 (this in conjunction with James Christie).

If sticking with a dynamo, there are favourable reports on the Forum of an electronic version of the regulator unit - looks almost identical and works!

If changing to alternator, change to narrow belt as the original belt doesn't like following the smaller pulley used on the alternator.  And, should the narrow belt fail, it's much easier to fit a replacement (which also takes less room in the boot as it can be folded).

I would agree with the comments about alternator inside a dynamo casing.  Insufficient cooling and hence likely to fail at a very inconvenient time - very wet night, when headlights, wipers and heater (to demist the screen) in operation.

Ian Cornish

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17 minutes ago, ianc said:

change to narrow belt as the original belt doesn't like following the smaller pulley used on the alternator

You can use a flexible cogged 17mm raw-edge belt which works fine Ian. I agree that the standard rigid monstrosity won't do it. The cogged belt is shallower too so is much easier to change. 

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  • 2 weeks later...

I don't mean to take this in a different direction but what is the best way to shield the alternator?  Having experienced first hand the results of not shielding it I think that I need to get at this ASAP.

Should I use this with the ty-strap?

 

https://www.revingtontr.com/product/rtr2067/name/shield-heat-dynamo-tr2-4a

Edited by David Owen
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Given where you are David the postage may be as much as the part. 
I am no engineer and I made my own out of thin gauge aluminium it’s quite do-able.

and as they say if I can do it anyone can !!:lol:

as revington does the main fixing point is the front bottom exhaust manifold stud. 
 

I also managed to use the rear alternator bracket mount hole as I had fitted a smaller alternator.

i got a bit carried away and covered it in exhaust wrap !!

 

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1 hour ago, Hamish said:


I am no engineer and I made my own out of thin gauge aluminium it’s quite do-able.

and as they say if I can do it anyone can !!:lol:

as revington does the main fixing point is the front bottom exhaust manifold stud. 
 

 

+1 The rear of the shield is attached to a wrapped exhaust down pipe with a stainless steel tie.

Although I am now experiencing a feeling of 'heat shield inadequacy'!

DSC05502.thumb.jpg.d67ed95813282d16179b608fa75e37a2.jpg

 

Edited by MilesA
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Revington's heat shield is based on the shields which were fitted in 1962/3 to the Works' TR4 Rally cars to protect the dynamo.  Neil first met the shield when he re-built 4VC for me in the early 1990s (the car was back on the road in 1993, with an alternator replacing the dynamo).  4VC still has its original shield, a piece of bent tinware, but I have added a piece of soldering mat on one side for extra protection.

Ian Cornish

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4 minutes ago, Ian Vincent said:

My heat shield is two layers of aluminium with an air gap between them - formed by pop riveting through the middle of a slim nut used as a spacer in a couple of places.

Rgds Ian

Thanks Ian.  I was wondering about the heat transfer from the exhaust to the shield via the steel tie.  That looks like a decent way to deal with it.  I also think I need to put the same louvre pattern in my bonnet as Hamish has.  That's a combination of on summer days in the high 30s here there needs to be more air flow and the fact that I have louvre envy.

Edited by David Owen
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Here are some photos of my heat shield.  One bracket fits onto the exhaust manifold stud and the other bolts onto the bottom extension of my TR4a inlet manifold.  FWIW, the top bracket was originally made of aluminium and it snapped - presumably with fatigue over time.  It's now made from a strip of galvanised steel.

Rgds Ian

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17 hours ago, David Owen said:

Thanks Ian.  I was wondering about the heat transfer from the exhaust to the shield via the steel tie.  That looks like a decent way to deal with it.  I also think I need to put the same louvre pattern in my bonnet as Hamish has.  That's a combination of on summer days in the high 30s here there needs to be more air flow and the fact that I have louvre envy.

David

Louvres may help with expelling hot air (and also look cool!) but I have been convinced by the merits of getting more air into the engine bay in the first place, which you may wish to consider: 

Miles

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Coming back to the Dynamo question, I have fitted an electronic regulator and am very pleased with the increased output, even at lower revs. They are a bit expensive and I did already have an uprated dynamo, but for the time being, its all doing the job. A big improvement on the old mechanical one.

With regard to the overheating issues, I have a re-cored radiator and an electric fan on the back of the radiator which Guildford Radiators supplied and fitted when they did the re-core and I have removed the standard engine driven fan. In all normal use I have no problem, even on really hot days, but it does start to heat up pretty quickly when you get stationary in traffic. Once you start moving again the temperature comes down quickly, even without the electric fan on, so there is no problem with getting enough air through the radiator in normal use. I have ten louvres on the bonnet, carefully placed to avoid getting water on the electrics!  An impressive amount of heat comes out of them when you are stationary with the fan on. I have also fitted an alloy scoop under the radiator at the front to try and direct some additional air through the bottom quarter of the radiator which is below the actual air intake, I had thought of cutting holes or an intake in the bottom of the front apron, but that is where I've got my number plate at present. The only real way to manage temp in traffic is to turn the engine off, a bit like modern eco cars do. The battery doesn't seem to mind, or at least it hasn't up to now!

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On 10/7/2020 at 9:08 AM, MilesA said:

+1 The rear of the shield is attached to a wrapped exhaust down pipe with a stainless steel tie.

Although I am now experiencing a feeling of 'heat shield inadequacy'!

DSC05502.thumb.jpg.d67ed95813282d16179b608fa75e37a2.jpg

 

Hi Miles,

your simple bent metal shield will work more than inadequately. Very similar to mine that has worked well for 22 years.

It will stop the direct radiated heat. The secondary radiated heat from its underside is much reduced.

Roger

 

 

 

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Roger is correct, the piece of thin sheet steel which was installed in 4VC in 1962 is still working well.  Probably installed under Ray Henderson's instructions - Graham Robson has enormous respect for Ray, his righthand man, and so have I.  In a very few months, learning as they went (because Ken Richardson left no information and his team had been disbanded in 1961), the very small team, on a very tight budget, built TR4s which were conformant to the regulations and were challenging the Big Healeys.  Nowadays, a great many changes, such as billet cranks are permissible, which is why Tony Sheach, Jonathan Hancox and others are so much quicker.

As I mentioned above, I have added just a cut piece of solder mat to the sheet shield.

Ian Cornish

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 Here is my prototype alternator heat shield.  I am going to follow Hamish's example and attach it to the rear bracket as opposed to the exhaust.  I will smooth out the curves and grind the ugly parts for aesthetics when ready to install.  Now I must buy a grinder.  :P I folded the edges over for rigidity.  Any suggestions welcome. 

The only question I have atm is whether or not I should wrap it in heat wrap?

 

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Heat Shield back view.jpg

Edited by David Owen
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Work of art. That will do nicely as it is. 
 

 

oh and your work area is way to clean and clear.

H

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5 hours ago, Hamish said:

Work of art. That will do nicely as it is. 
 

 

oh and your work area is way to clean and clear.

H

 

 

Thanks to everyone. :)

 

So I took it for an hour run and it's running a little bit hotter. (It's cooler outside than it has been)  So I think I might have to cut away some of the back to allow air to flow through as opposed to being trapped in the "cup" of the shield.  Perhaps because it is a full sized alternator in this case? (with the rear of the shield attached to the bracket). I may just cut a slit and allow the rear right hand side of the shield  to point toward the rear of the engine bay;. I will try that tomorrow.

Edited by David Owen
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