Duratec alternator woes

[GreigM]

Hoping someone else has experience here and can point me in the correct direction.

I have a high-revving duratec which has eaten its alternator (probably due to the high-revvingness), so I contacted a reputable alternator specialist to procure a replacement. The original alternator was from Raceco (out of business) and had a ~63mm pulley wheel.

On contacting the alternator specialist, they got all the measurements for pulleys, photographs of the old alternator and identified the model and said they could supply a direct replacement. All good.

The alternator arrived with a 55mm pulley - don't know why, even the invoice specified a different pulley size (67mm).

On contacting the supplier they suggested taking the pulley off the old alternator - good idea. Did that, but the "offset" is different - i.e. the new alternator makes the pulley sit further out, meaning the belt is not aligned correctly (and ended up riding up onto the lip of the pulley and destroying the belt).

Contacted the supplier again, and they said they simply don't have a pulley of the correct size (knowing this I wouldn't have bought from them in the first place) and after a lot of back and forth found a 60mm wheel and sent this to me - but it has the same "offset" as the one I had, and different to the wheel they supplied on the alternator (which aligns correctly but is too small).

So I'm left with no working solution, and out the cost of an alternator which is useless, a shredded belt and £15 for delivery of a useless pulley wheel.

So I'm looking for any suggestion at this point - I could go down the road of having the alternator mounts and/or pulley wheel machined but would prefer to find an easier (and quicker) route!!

[DCL]

Been here (). The good news is that there will be a solution but first need to identify the alternator - can you post a picture of the new one. Also can you confirm the postion and idle arrangement?

David.

[GreigM]

The new alternator is here:


the old one in position under the manifold:


Not sure what the idler arrangement means.....but the rest of it I believe is standard duratec - 130mm crank pulley.

The new alternator has the pulley from the old alternator attached and as you can see it sticks out considerably.

[mic]

How old is that car? I have not supplied alternator brackets in black for years. You need the larger steel pulley that is fitted to R300 race cars and R500s. The alternator is a standard 40amp unit.

[DCL]

Ok, it's on the exhaust side - the idler is the little pully in the photo. Solution - use a smaller belt. Either buy one (SBD), or cut the standard 6v down to a 4v. This is more than enough for the alternator load and hopefully will be enough to accommodate the offset. Add washers to space the alternator more accurately if need be.

For regular 9000rpm get yourself a bigger pulley - you'll need 75mm + (or there abouts), but that'll cause charging problems at low RPM. If it is just a the occasional blast to 9k, then you may want to keep to the 63mm but 55 is too small.

etdit to add
|http://thumbsnap.com/k1CbTY6e[/url]

Edited by DCL on Wednesday 3rd December 20:01

[GreigM]

mic said:

How old is that car? I have not supplied alternator brackets in black for years.

The car isn't that old, but the engine block came from an old R300 race car (the internals were completely gutted and replaced), I imagine the brackets came with the block.

David - I'll try cutting down a belt, it would get me going in the short term - over the longer term I'll go for a larger pulley.

[bazzat]

Doubt position is the cause of failure. In my experience they fail if they over rev or subjected to unnecessary vibration. Presume the crank pulley is Ford standard? I'd doubt the pulley is the cause tbh, however I would not hesitate changing to the R500 72mm dia pulley CC supply. I have that with the standard Ford crank pulley, it happily charges at idle, no problem at all.
My failures have been due to vibration causing the inner shell barrel rotating inside the outer shell barrel (they shouldn't). My supplier (Brise)now tack weld the two barrels together, not had a failure in three years racing since.

[GreigM]

DCL - genius....the cut down belt works perfectly. I also subsequently found out that there is some sort of "spacer" fitted to the alternator nose which can be removed which will give me a permanent solution, but for this week the 4pk belt will do the job.

[DCL]

Glad it worked There are advantages to running a smaller belt - less power lost, and more tolerant of alignment. The 6v is really intended for power steering and air-conditioning type use.

[Ross_328i_sport]

Gents,

I had a similar problem and have recently purchased the very smallest alternator from SBD however wish to install the Alternator on the same side as the previous item (raceco alternator same as above) SBD only do the brackets to mount the small alternator on the exhaust side therefore wonder if there are any known solutions or drawings available for brackets to mount on the opposite side. I also have the Raecline dry sump system with internal chain driven pump.

Thanks.

[DCL]

Caterham do the bits - search under 'alternator' in their online store. There are various configurations for tensioners and belts, depending on what else is fitted, but the basic brackets are:

http://www.caterhamparts.co.uk/product.php?id_prod...
http://www.caterhamparts.co.uk/product.php?id_prod...

[bazzat]

Raceline do a mounting kit for either side. I have Raceline dry sump system same as you describe and their alternator kit which is on inlet side, retains standard water pump but requires different belt tensioner. If you run oversize water pump pulley your need to raise the tensioner

See here:

http://www.raceline.co.uk/products/part_section.as...

[Ross_328i_sport]

Just to confirm i currently have the race line alternator bracket installed on the car however i have not compared the alternator from that which failed (Raceco alternator failed) and the item i have bought see link below and it is the smaller of the 2 (ALT-SM2-B)

http://www.sbdev.co.uk/Duratec/Alternators.htm

Does the raceline or Caterham brackets linked above allow me to fit the SBD alternator to the car and utilise the same belt?

[DCL]

I've fitted the SBD kit with the Caterham alternator and it's in the right place (no offset) so their alternators matches the Caterham alternator. My understanding is mounting points and offset is standard for all the small alternators makes available for this set-up, so the SBD alternator is likely to fit the original Raceco, or Raceline, mountings. I think the issue above was really a pulley(perhaps a spacer) one.

Edit to add:

The belts for both sides are similar in length and your old belt should do. If not I'm afraid there are so many variations with pulley sizes and tensioners that you'll really need to measure it and and get one that works - there are various length available from Caterham, SBD, Raceline etc.

Edited by DCL on Wednesday 10th December 09:45