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Lucas C45 vs C39 Dynamo - Possible Fix for Charging System?


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Although this post is related to a recent topic concerning my charging system , see http://www.tr-register.co.uk/forums/index.php?/topic/52461-bloody-ignition-light/, I thought I better start a new topic. This is more related to the simple question of a C45 versus a C39 dynamo, and whether or not it would fit into a TR3A. The reason for these questions, there is a guy in the US who can take a Lucas dynamo and convert it to an alternator, using the original case. Unfortunately, his design will not fit into the C39 dynamo. The only dynamo that is compatible is the C45. Now, I realize the physical difference is mainly the diameter of the case, 3.9 vs 4.5 inches, but are there any other features of the C45 design that would prevent it from fitting a TR3A?

 

Thanks, Frank :)

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Those alternator conversions are readily available however they really dont like high underbonnet temperatures due to the lack of cooling through the solid case. Dynamos will happily live with high temperatures Alternators wont. I would go for an uprated Dynamo as per the original works rally cars that will fit anyway though you may be limited on adjustment so careful selection of belt length may be involved.

Stuart.

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Frank, I haven't fitted a C45 to a TR, only a Jag, but I don't think the larger diameter would make much difference, other than perhaps needing a different length belt. More important is mount detail. A C39 inside-inside lower mount spacing is 144.5mm, so perhaps your conversion shop can check if a C45 matches or not.

 

Also the C45 pulley has to align with your water pump and crank pulleys. To compare, you'd need a C45 measurement from the inside of the front lower mount to the flat outside of the pulley. That measurement on a C39 is 49.5mm.

 

There are a few variations of the C45 dynamo, so you'd need the one measured to be the one you receive.

 

Holdens in the UK sell a C39 dynamo converted to alternator, so I wonder why your shop's alternator insides have to go in a C45, other than Jags being a larger market ?.

 

Viv

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Hi Peter,

 

as far as I'm aware any dynamo requires a voltage regulator to match - something I learned the hard way rallying a 3A in my youth.

 

The replacement C45 dynamo fried the original C39 regulator box, probably RB106, and the solution was to replace with, I think, a RB340 unit.

 

Cheers

 

Alec

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When I bought 4VC in 1969, it had a Lucas RB340 regulator unit - this has both voltage and current sensing, so there were 3 coils inside the box. I believe this was because the Works' cars had uprated dynamos.

In the rebuild, I changed to alternator and have been running that for 22 years.

Ian Cornish

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You wont need a regulator for an Alternator as the sensing is built into the case but my reply above re overheating of the units still applies.

Stuart.

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You wont need a regulator for an Alternator as the sensing is built into the case but my reply above re overheating of the units still applies.

Stuart.

 

Update: I have found two firms in the UK who offer alternators designed to look like a dynamo. Both offer a Lucas range.

 

1. WOSP Performance Products

Product called Dynator - £375.00

C39/40 replica http://www.autoelectricsupplies.co.uk/product/1070

Output 50amps

This company will also convert your dynamo to an alternator. I have enquired about this service and awaiting a reply.

 

2. Powerlite - Product called Dynalite - £335.00

C39/40 replica http://www.holden.co.uk/displayproduct.asp?sg=1&pgCode=080&sgName=Electrical&pgName=Dynamos+%26+Starters&agCode=1551&agName=Dynalites&pCode=081.200

Output 40amps

post-772-0-84404600-1435694382_thumb.jpg

post-772-0-65473100-1435694412_thumb.jpg

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Hi Frank,

 

I've heard more than a few dissatisfied comments about the various 'dynamo lookalike' alternators, and the warranty/repair situations when they go wrong, over the past quite a few years - and rather less by way of comment from satisfied customers.

 

Not good at the best part of £350-400 a pop . . . . . not when I can buy a decent reconditioned Lucas alternator or a new budget version for £50-60.

 

They don't seem to fool many technical scrutineers in motor sport, and nor do they seem to fool concours judges either. No surprise on either count.

 

There is a much cheaper version, which from what I've heard doesn't seem to be any worse than it's competitors at three times the price.

 

http://www.accuspark.co.uk/dynamator.htm

 

Cheers

 

Alec

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Frank

 

I agree with Alec on this one. Reports back on the disguised alternators are variously average and the after sales service very poor.

 

I've tried running the C45's and the just will not tolerate heat. The only solution is to encase in a 'sarcophagus' and even then it needs to be air fed. Add water and it's an instant failure. A C39 with an RB340 is significantly more reliable if you don't need the additional current.

 

The only solution that I have been able to make work for any length of time that gives better capacity has been the little Nippon Denso device (and you must use a genuine one, not a copy) - the 65 amp version powers everything you could wish for on a TR. You can hide with a shield if that's important.

 

Regards

 

Tony

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Hi Frank,

 

I've heard more than a few dissatisfied comments about the various 'dynamo lookalike' alternators, and the warranty/repair situations when they go wrong, over the past quite a few years - and rather less by way of comment from satisfied customers.

 

Not good at the best part of £350-400 a pop . . . . . not when I can buy a decent reconditioned Lucas alternator or a new budget version for £50-60.

 

They don't seem to fool many technical scrutineers in motor sport, and nor do they seem to fool concours judges either. No surprise on either count.

 

There is a much cheaper version, which from what I've heard doesn't seem to be any worse than it's competitors at three times the price.

 

http://www.accuspark.co.uk/dynamator.htm

 

Cheers

 

Alec

They are **** end of ,do not waste your money .

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I agree. I bought one of the expensive ones during my rebuild in a flight of fancy. The regulator failed, I suspect due to heat soak. I have a standard exhaust manifold by the way. The internals look like a Denso copy and if you've seen a genuine Denso and the way they address cooling you can see why these Dynamo lookalikes are compromised. I would not have another and now use a 65A Denso.

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Here is the type you want at an ebay in your country.

 

http://www.ebay.com/itm/100211-4390-NIPPON-DENSO-ALTERNATOR-12V-45AMP-KUBOTA-17369-64010-/231395433520?hash=item35e03e1c30&vxp=mtr

 

Cheers

Peter W

 

PS I run mine with the wide belt still - you need to machine a touch off the orig TR dynamo pulley nut area to get it to fit.

Wiring is a doddle.

The ammeter is happy with it

Racetorations do a fitting kit for this type of alternator to go on your 4 cyl TR.

Edited by BlueTR3A-5EKT
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