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#1 Fosseway V12 Alternator Kit

Posted: Sun Jun 14, 2015 3:49 pm
by 71 V12
Hi Guys,

The output from my original Butec alternator is deteriorating and now feeble. Engine running and nothing else on except the radio the voltmeter is just in the charge zone.

Just turning the heater on low speed will send the meter into discharge. Reliable electrics are essential.

Has anyone yet fitted the Fosseway kit? ... nator-kit/

Grateful for any feedback/ experience on ease of fit and performance.

Thank you,



Posted: Sun Jun 14, 2015 6:49 pm
by MarekH
Dear Kevin,

It'd probably be easier and cheaper to rebuild the Butec - it is more than capable of supplying power enough for the car. If you were closer to Guildford, you could just come around as I have a couple of reconditioned units with regulators in the loft.

kind regards

#3 Re: Fosseway V12 Alternator Kit

Posted: Fri Mar 13, 2020 10:35 pm
by 73ET
I fitted a Fosseway alternator and it functions perfectly.

#4 Re: Fosseway V12 Alternator Kit

Posted: Fri Mar 13, 2020 11:36 pm
by 42south
yep, I've got one on the V12, and had no problems. Mine came through SNG I think, might pay to compare prices.
It opens up the front of the engine nicely,

#5 Re: Fosseway V12 Alternator Kit

Posted: Sat Mar 14, 2020 6:11 am
by MarekH
Dear 73ET,

As yours is perfect, can you tell us what the voltage it outputs is at say, 3000rpm please?
Also, tell us where you measured this voltage from.

kind regards

#6 Re: Fosseway V12 Alternator Kit

Posted: Sat Mar 14, 2020 9:49 am
by angelw
Hello All,
Of all the Alternator alternatives to the B.U.T.E.C. I've seen, the components for mounting the Alternator to the Alternator/Air Pump bracket are satisfactory, but the Belt Tensioning Device is rubbish.

The Tensioning Bracket shown in the following picture as part of the fitting kit supplied by one of the usuals, is close to nothing on the engine without making some "Heath Robinson" component to bridge the gap.


The following picture shows an Alternator installed using the components I manufacture to replicate the original method used with the B.U.T.E.C. It uses the original Jaguar Part at the outboard end of the rod, with my part attached to the Alternator.


The following picture shows the detail of my part. Threaded Rod was used when prototyping the assembly. I now use a rod threaded at each end only; I think it looks more purpose built than using Threaded Rod.




#7 Re: Fosseway V12 Alternator Kit

Posted: Sat Mar 14, 2020 1:06 pm
by madjack4
Hi i fitted a fosseway conversion about 3 years ago the unit failed on me at the jersey motoring festival last year i had to buy a spare battery and charger and keep swapping battery's to get home the fosseway conversion that i have mounts in the original place as the original it has a design flaw in that heat from the cooling fans blow hot air into the back of the alternator the internal fan in alternator tries to blow air out of the back bingo it overheats the regulator in the back of it .And when i had mine repaired the alternator specialist said in there words it is Chinese crap and not a denso unit .I believe the conversion they do now fits in place of the air pump so that should be ok


#8 Re: Fosseway V12 Alternator Kit

Posted: Sat Mar 14, 2020 3:51 pm
by jagwit
Did you check the accuracy of the Battery gauge?

I also thought my Butec expired, fitted a 130A alternator from a Land Rover Discovery 2 (I have a thread on this here), only to find the Battery gauge was still not showing good voltage!!!

Long story short, the point at which the battery gauge measures the voltage is not a good place from an electrical engineering perspective (too many contact points each causing a small voltage drop. There are so many, they add up causing the gauge to offer very pessimistic readings).

Plan A is to add a wire (with a 1A inline fuse close to the alternator) directly from B+ on the alternator to the gauge via a relay which is energised by a green wire (fused, ignition switched).

Plan B, Not as good as Plan A, is to move the green wire of the battery gauge to F6, same terminal where the white and pink wire from the ignition switch terminates. This way you already eliminate many voltage dropping connections.

After all the above I concluded that there was nothing wrong with the Butec in the first place....