wild bill Posted May 4, 2012 Share Posted May 4, 2012 Right, alternator has packed up again ( second time in three years) I have a new spare ready to fit. I may have access to next doors ramp tomorrow. I know it's straightforward to replace but it looks very tight to remove any pointers before I start getting grazed knuckles? I've got a nasty feeling someone will be along to say its an engine out job. The position of the alternator is not great and must lend itself towards making reliability an issue so any suggestions to help with this. In all my other vehicles I have never had to replace an alternator ( or dynamo for that matter) Advice gratefully received Link to comment Share on other sites More sharing options...
Racing Snake Posted May 4, 2012 Share Posted May 4, 2012 Is it on the exhaust side 🤔 Link to comment Share on other sites More sharing options...
wild bill Posted May 4, 2012 Author Share Posted May 4, 2012 No it's on the passenger side and another thought is could it be a shorted relay draining the battery and making the no charge light come on rather than a failed alternator Link to comment Share on other sites More sharing options...
Racing Snake Posted May 4, 2012 Share Posted May 4, 2012 Ah mine is on the other side but it should be not too tricky to swap out Swap out and check might be the easiest war forward What size pulley wheel are you running at the crank ? Does it look like this 🤔 http://inlinethumb34.webshots.com/11937/2044304500104067410S600x600Q85.jpg Link to comment Share on other sites More sharing options...
wild bill Posted May 4, 2012 Author Share Posted May 4, 2012 Not sure hatter as view hidden at mo until I get the nose off tomorrow. Link to comment Share on other sites More sharing options...
Racing Snake Posted May 4, 2012 Share Posted May 4, 2012 Ok, but if your pulley wheel is almost the same size as the trigger disc you will be over revving the alternator. You will need to replace with the Undergear Pulley as shown. If i can help more give me a shout Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted May 4, 2012 Share Posted May 4, 2012 Time for an SV - loads of room Link to comment Share on other sites More sharing options...
wild bill Posted May 4, 2012 Author Share Posted May 4, 2012 Hatter are you saying that the alternator may be failing because of the pulley wheel and trigger disc size? My replacement alternator is the same unit as is in there. My theory was that the position of the alt meant that it was to easily soaked when driving in wet weather. I'll check pulley sizes but the set up is tha same as Dave Jackson and rob walker run I think and they seem to run ok without problems, or maybe an alternator every three years is normal? Link to comment Share on other sites More sharing options...
mic Posted May 4, 2012 Share Posted May 4, 2012 You would have to be using an alternator pulley smaller than 64mm and and really high rpm to kill the alternator with high rpm. Link to comment Share on other sites More sharing options...
Racing Snake Posted May 4, 2012 Share Posted May 4, 2012 Knows what he is talking about, so does DJ I just know that if you have a standard size pulley (almost the same size as the trigger disc, it over revs the alternator) I think Jason, recently had an issue with this unless the J&B is clouding my memory Link to comment Share on other sites More sharing options...
wild bill Posted May 4, 2012 Author Share Posted May 4, 2012 Ok I'll check the pulley size tomorrow revs are set for soft cut at 7200 (I'm not a racer and wanted longevity) so I'd be surprised if over revving was the issue. Aside from this is the removal straightforward or are there any tricks I need to know such as engine mount removal or some such? Thanks for the info so far, it's like an online Haynes manual. Edited to say I realise that the pulley size will affect the revs received irrespective of engine revs so my first job is to check pulley sizes and come back Edited by - wild bill on 4 May 2012 19:52:41 Link to comment Share on other sites More sharing options...
Racing Snake Posted May 4, 2012 Share Posted May 4, 2012 I would of thought 7200 rpm won't over rev the alternator 8000 - 9000rpm will for sure I am sure Jason will be along in a mo with some input Link to comment Share on other sites More sharing options...
wild bill Posted May 4, 2012 Author Share Posted May 4, 2012 In response to Micks BM pulleys are 125 and 64 mm (actually more like 130) taking the wire out of its wrap will be a bigger pain as its wrapped with a few others ☹️ biggest obstacles to removal will be the lower wishbone bolt and the oil cooler pipes which run close by. A voltage check first then well see. Link to comment Share on other sites More sharing options...
Jason Plato Posted May 4, 2012 Share Posted May 4, 2012 Iv e had two alternators fail in 6 years, I have now changed to the cosworth alt pulley as recommended by Mic is a twat of a job to get the bolts undone but take your time and it's comes out in 15 minutes Link to comment Share on other sites More sharing options...
The Pikey Posted May 4, 2012 Share Posted May 4, 2012 After wrecking mine I did the maths and found that with a engine speed of 8500 rpm my alternator was doing about 23000 rpm when it's rated at 18000 max. Get a piece of string and run it round the crank pulley then do the same on the alternator and work out the alternator RPM at your max engine speed. All the alternators I have seen are 18k max. Caterham offer a larger pulley for this reason. Jason Edited by - Jason Fletcher on 4 May 2012 20:44:46 Link to comment Share on other sites More sharing options...
wild bill Posted May 4, 2012 Author Share Posted May 4, 2012 Ok Dave changing pulleys seems like a good option whatever the prob Is it a Cc part? What size is the cosworth pulley? Link to comment Share on other sites More sharing options...
Racing Snake Posted May 4, 2012 Share Posted May 4, 2012 Bill YHM Its the same for the water pump pulley too Edited by - Mad Hatter on 4 May 2012 21:43:14 Link to comment Share on other sites More sharing options...
Racing Snake Posted May 4, 2012 Share Posted May 4, 2012 Oh and change the pulley bolt as its a one torque bolt only or swap for an ARP item Link to comment Share on other sites More sharing options...
The Pikey Posted May 4, 2012 Share Posted May 4, 2012 just to be sure that we are talking about the alternator pulley here? If you change the crank pulley you will mess the trigger wheel and cam timing up for sure unless you have a keyway fitted. Jason Link to comment Share on other sites More sharing options...
Racing Snake Posted May 4, 2012 Share Posted May 4, 2012 Jason i was talking about the crank pulley But yes you could change just the Alternator pulley, but that leaves the water pump over geared and causing cavitation. I guess option 1) keywayed crank and Cosy Under Pulley for the ultimate fix 2) Change the Alternator Pulley Sorry Bill, just options to consider Either way a change of a pulley wheel will help no end Link to comment Share on other sites More sharing options...
wild bill Posted May 4, 2012 Author Share Posted May 4, 2012 The word worm and can spring to mind 😬 I will be leaving the crank pulley as is as I see no reason to change it. The answer would seem to be changing the alt pulley as per DJ suggestion I imagine a different size belt may be required but I assume I can change out the alternator this weekend then fit the newer pulley when it arrives. Tell you what though this conversation beats clubbing or the pub..........oh hang on Link to comment Share on other sites More sharing options...
The Pikey Posted May 4, 2012 Share Posted May 4, 2012 can't see the std water pump pulley being a problem as Bill engine is only doing 7200RPM. A new alternator pulley of the correct size should be smokey cool IMO J Edited by - Jason Fletcher on 4 May 2012 22:09:20 Link to comment Share on other sites More sharing options...
Racing Snake Posted May 4, 2012 Share Posted May 4, 2012 Link to comment Share on other sites More sharing options...
Rob Walker Posted May 5, 2012 Share Posted May 5, 2012 WB, According to my records your alternator had the cosworth 64mm pulley fitted. It should be black anodised ali and 64mm diameter. DO NOT loosen the crank pulley or you will loose the valve timing. I cannot help with the cause of the failure, apart from check thoughly all the connections. I have also had a failure my armature had gone open circuit. It is straightforward to remove just a bit of a struggle to loosen the cap allen holding the lower bracket to the block. Rob Link to comment Share on other sites More sharing options...
wild bill Posted May 5, 2012 Author Share Posted May 5, 2012 Thanks Rob I'll check, don't worry I will be leaving the crank pulley well alone. Hopefully it will all be straightforward. Hope all is good with you Link to comment Share on other sites More sharing options...
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