Alternator Conversion

[gwr]

Having given up trying to resolve my over-amping problem, I've decided to replace the existing dynamo with an ACR alternator - as supplied by Moss. I want to keep the wide fan belt, because I don't want the expense of fitting a narrow belt and electric fan etc.

 

The spindle diameter of the supplied alternator is significantly larger than that of my current dynamo. So, despite being advised that I could keep the dynamo pulley, it appears that it isn't going to fit. I've searched the forum for this topic but haven't found anything that address this particular problem.

 

Has anyone done this specific conversion? What pulley did you use to retain the wide fan belt? Is there a part number?Any other fitting tips?

[MikeF]

Having given up trying to resolve my over-amping problem, I've decided to replace the existing dynamo with an ACR alternator - as supplied by Moss. I want to keep the wide fan belt, because I don't want the expense of fitting a narrow belt and electric fan etc.

 

The spindle diameter of the supplied alternator is significantly larger than that of my current dynamo. So, despite being advised that I could keep the dynamo pulley, it appears that it isn't going to fit. I've searched the forum for this topic but haven't found anything that address this particular problem.

 

Has anyone done this specific conversion? What pulley did you use to retain the wide fan belt? Is there a part number?Any other fitting tips?

 

I can't find my Moss catalogue jsut now, but I think I recall from when I read it prior to my own conversion to alternator that one of the pulley options (rather dismissively ) offered enabled retention of wide fan belt, That part of the catalogue is written to confuse though as I also recall, so you could have missed it or I could have misread it.

 

Mike

[Tr4Tony]

Unfortunately the advice that you can retain the original pulley is just wrong in my experience - I tried about 3 years ago and ended up with a load of bits that I couldnt use. The only way to do so is to machine ithe pulley out (cant file as it needs to be circular so as not to vibrate and destroy the bearing) and refit ..... this does work, but hassle if you havent got a lathe. And not what you paid your money for. You can buy a wide belt alloy pulley (or you certainly could at the time) but I cant remember the source for the life of me.

 

Good luck.

 

Regards

 

Tony

[RAHTR4]

Gordon,

 

I am currently looking to do the same as you and fit an alternator using the original big fan belt on my TR4.

 

So far I have sourced a Lucas 15ACR alternator, which is the type fitted to TR7's and many other makes and this does have the same diameter shaft as the original TR dynamo, thus the original pulley can be used.

If the alternator mounting lugs are in the wrong position it is easy to remove the three clamping bolts, twist the top and bottom aluminium castings to achieve the required configuration

 

What make is the alternator that you have bought?

 

As the pulley that came with the alternator is a much smaller diameter, thus would spin the alternator faster to produce the current I have corresponded with Jeff Marks at Moss to see if they supply alternative pulleys.

Unfortunately they do not.

However Jeff does know of a number of cars that have been successfully fitted with alternators re-using the original size pulley - but he does not know what output has been achieved.

 

So I am considering getting a smaller pulley turned up to match the TR7 size and at the same time I can get the thickness made up to suit the final fan belt alignment of the alternator on the engine.

 

Still have to work out the detailed mod required to fit the alternator onto the original U shaped dynamo bracket bolted to the side of the engine, but an internally threaded solid spacer should work.

 

Regards, Richard

[Dale Moore]

Had the same problem when converting to an altenator some time ago, wanted to ditch the wide belt but not the expense of replacing the other pulleys. "Aquired" a regular "A" section pulley and had it bored to suit the alternator. Then used a standard A section industrial vee belt. Not sure of the size but could check on the car if anyone is interested. The belt runs low, but does'nt bottom out in the crank pulley and the same can be said for the waterpump. No problems for 5 or 6 years and the belt will just slip between the suspension brace if it needs changing

Regards

Dale

[ianc]

If you intend to fit a TR7-type alternator with the original wide belt, you are going to find it difficult to get the belt onto the pulley, even with the alternator rammed hard against the engine block (i.e. with the bolt in the adjuster arm completely removed). I managed to find a slightly longer, wide, belt, but it was old stock and I couldn't obtain a spare. Far better to do the job properly - convert to narrow pulleys and an internally notched belt. You'll be amazed how much extra space there seems to be at the front of the engine, and how easy it is to get the belt onto the pulleys.

Ian Cornish

[Mikell]

If you intend to fit a TR7-type alternator with the original wide belt, you are going to find it difficult to get the belt onto the pulley, even with the alternator rammed hard against the engine block (i.e. with the bolt in the adjuster arm completely removed). I managed to find a slightly longer, wide, belt, but it was old stock and I couldn't obtain a spare. Far better to do the job properly - convert to narrow pulleys and an internally notched belt. You'll be amazed how much extra space there seems to be at the front of the engine, and how easy it is to get the belt onto the pulleys.

Ian Cornish

Hi,

Possibly a bit late, but I had much the same issue last summer when I severley cooked my dying 4A dynamo. I decided to go 'alternator' at that time, but was definite about wanting to keep the original fat belt. As part of loads of re-searching I spoke to Revington (very helpful), and I bought their alternator with separate conversion kit which my local 'man in the garage' fitted. Ok, it probably wasn't the cheapest route, but it was easy, and since then everything has been fine.

[RAHTR4]

Mike,

 

Ian's comments make sense, but I would still like to retain the thicker belt so it would mean finding a larger diameter fan belt, however as you have successfully done the complete mod, can you advise details on the following ;

 

What make and model alternator did you fit?

 

Did the alternator come with a smaller pulley to suit the original fan belt section size?

 

Did you use the original dynamo belt or was a new fan belt with a larger diameter required?

 

What was the bracketry that you obtained for mounting the alternator to the block?

 

Regards, Richard

[Mikell]

Mike,

 

Ian's comments make sense, but I would still like to retain the thicker belt so it would mean finding a larger diameter fan belt, however as you have successfully done the complete mod, can you advise details on the following ;

 

What make and model alternator did you fit?

 

Did the alternator come with a smaller pulley to suit the original fan belt section size?

 

Did you use the original dynamo belt or was a new fan belt with a larger diameter required?

 

What was the bracketry that you obtained for mounting the alternator to the block?

 

Regards, Richard

 

Richard,

The alternator itself is Revington part number RTR8168 which is 17ACR rating. I had no idea at all what rating to go for, but Revington got me to talk through on the 'phone what electrics I had on the car - and then told me which alternator I needed. They got their analysis right because it has served me a treat since being fitted.

Their fitting kit is a 'must', and I handed it together with the alternator to a local auto electrics firm to fit - with no problem at all. The alternator came without a new front pulley as it uses the dynamo transplanted 'old' front pulley. Instructions on how to transfer it from the dynamo to the alternator come with the alternator packaging. Similarly there are detailed fitting instructions for the full item. I've used the same belt thas was already on there - as I recall my local auto people said that to change the belt was going to be difficult due to lack of space between the bottom pulley and the cross strutt (not sure what its real name is, but it sits right beneath the fan pulley ?). If it would help I can fax the fitting instructions through to you ? (sad git I still have them on file !!).

The spacing between the back of this alternator and my exhaust manifold is about 2.5 or 3.0 inches at the closest point. I'm hoping that spacing will be sufficient to avoid cooking - but I'm contemplating using exhaust wrap just in case. One point to note is that Revington supply an aluminium sheet as a heat shield to fit to the manifold - however I've never figured out how to attach it - so I haven't !

 

Regards,

Mike.

[ianc]

The Works TR4 Rally cars had the heat shield to help protect the (then) dynamo from the SAH tubular exhaust. The shield was originally a piece of thin steel plate (you can see it on any of the VC cars), and Neil has replicated this in his offering. Well worth fitting this if you have a tubular (rather than the original cast iron) exhaust system, whether you have a dynamo or alternator.

Ian Cornish

[Mikell]

The Works TR4 Rally cars had the heat shield to help protect the (then) dynamo from the SAH tubular exhaust. The shield was originally a piece of thin steel plate (you can see it on any of the VC cars), and Neil has replicated this in his offering. Well worth fitting this if you have a tubular (rather than the original cast iron) exhaust system, whether you have a dynamo or alternator.

Ian Cornish

Thanks Ian,

My 4A is on the original cast 'front' end - I'll have another look at fitting the shield, but I suspect I've got something missing to attach it to. That being the case I'll get creative.

Mike.

[ianc]

My heat shield is fitted to:

(a) the foremost exhaust manifold stud (sandwich it between two plain washers, to prevent the torquing of the brass nut damaging it);

( the bracket which supports the underside of the alternator to the block. I've made a little adaptor to the bracket to make connecting the shiled somewhat easier, as it's quite a fiddle getting this into position, even with small hands.

 

To provide further protection, I have scewed and glued a sheet of insulating material to the shield - I used one of the black mats which DIY stores sell for protecting surfaces when making soldered joints.

 

Don't forget that the bolts which secure that lower bracket go into the crankcase space itself, so you need to apply red heremetite (or similar sealant) to the threads to prevent an oil leakage. In addition, it is worth drilling the bolt heads and wiring them once secured. Why? If one were to come loose and fall out, you would discharge an amazing amount of oil from that small hole (I know, it happened to my brother!).

Ian Cornish