Factor vs OEM alternator

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Biggles109

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Some quick advice please - I need a new alternator, and have a choice of factor versus OEM (VP) supplied units. OEM is about double the price of the factor part. Both have the same output, fit etc. Am I likely to see any difference in quality?
 
Try and get the same (e.g. Valeo A13N234 / 2541451 for KAD32) unit if you can, but not necessarily from VP.
Something with the right part number should have the correct spark protection, insulated return, dust proofing, etc.

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Have you looked into having yours repaired? Often cheaper than an aftermarket and you still have the VP original when its comes back.
 
There are several factors to consider. Dont buy through an engine retailer like Volvo or the same unit will cost a lot more than it should. Dont buy a very high output unit (say over 130amps) with the same frame size. It could overheat and die young. If you are looking for a direct equivalent though, like Prestolite from the USA they are very good indeed and much cheaper. You can also uprate say from 60 amps to 90 amps within reason and I have not had one die yet. Don't forget though that uprating may require a better drive belt. Unless you can be more specific regarding make model amperage and drive belt (single, twin or flat belt) I could not comment further. Your direct question regarding quality depends on which you are considering. More info would be helpful.
 
Thanks all. The factor part I have been offered is a Prestolite 70A, which matches the latest Volvo replacement part. The original was I think 55A. Good to hear that Prestolite are well respected, at the difference in price I was wondering if they were any good. The engines are AD41B's. Repair is also an option, but the price of the Prestolite is tempting, plus I am effectively upgrading.
 
Before you buy you must factor in that the alternator drives the tachometer, failure to match the windings exactly will give an incorrect reading ( myself and lanerboy have first hand experience of this ,but that's another story. I'd go for a genuine vp alternator or have yours repaired , that way you are safe in the fact it will work. When I say dealer I mean dealer.
 
Biggles109 said:
Some quick advice please - I need a new alternator, and have a choice of factor versus OEM (VP) supplied units. OEM is about double the price of the factor part. Both have the same output, fit etc. Am I likely to see any difference in quality?
Click to expand...

Try "Altenator Man" Portsmouth.


wwwaltenatorman.co.uk

07940050058

02392348920

Open 24/7
 
Hi Biggles. The 70amp Prestolite will be an excellent replacement for what I believe was probably a Valeo unit in the first place. You will probably need to keep the pulley off your old one to retrofit to the new one but it's easy to swap. If you can grip the pulley in a vice and remove the nut with a spanner to avoid stressing the shaft. If you do this (or by good fortune the new pulley is the same size as the old) the tacho signal will be exactly as it was. No worries. One characteristic of the Prestolites is that they often need a good "blip" on the throttle to energise them while the Valeo energises easily at a tickover. Other than this they are brilliant. I had a 90 amp one on a Vetus engine on my last boat and it did everything it said on the tin. I have 2 90 amp ones on my present boat as replacements for the Valeos on my TAMD41As and they work perfectly together balancing out the 90amp load through an inverter for my aircon when running with loads of capacity to spare for battery charging and other things so they work hard and have been great. Don't be put off by others. Go for it!
 
Thanks - I had read about the sort of issues VP mentions (thanks VP), so was cautious, interesting to get Mike's view too. As with all these things there is no right or wrong answer - such is the cost saving I will probably try the prestolite and if it doesn't work for me can always ebay it and buy the other one.
 
yep I was on the receiving end of buying a boat that had a cheap after market alternator and it was reading 500rpm low on the rev counter when VP did the sea trial, after a few different efforts at rectifying the fault I ended up removing the cheap alternator and having it rebuilt to vovlo standard and once re fitted it worked perfectly so please be care full when buying cheaper after market stuff as everyone tells me you get what you pay for
 
I have fitted a couple of Prestolites this year and the customers seem happy with them. Commercial users so boats running all day, everyday.
Can VP tachos not be re-calibrated? (Worked with a lot of TAMD's offshore on rescue craft but never played with tachos).
I had the joy of re-calibrating a VDO tacho on a retrofit panel this year. They must be the most complicated tachos to calibrate on Earth but once it was figured out it was a twenty minute job to adjust-check- refine the adjustment and set.
 
VP is correct in general terms and I would be cautious of some makes (especially Chinese copies) but speaking of Prestolite v Valeo (as fitted to Volvo) I can confirm that there are no recalibration issues providing that the pulley size is the same. The pulses per rev on Prestolite are the same as Valeo. If you contact Prestolite direct as I did you will find they will confirm this if you are still in doubt.
 
Thanks to all who contributed; I fitted the Prestolite today (only problem was one of the holes in the frame needed to be drilled out by 1mm to take the Volvo mounting bolt), and it works very well. Revs on the tacho are as they should be, and other gremlins on the warning panel have disappeared now it is charging properly. Price was £120 incl. VAT, from the Starter Motor and Alternator Company in Plymouth, who also swapped over the pulley for me.
 
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