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Rover V8 starter motors

Posted: Fri Jun 26, 2020 10:48 pm
by j.johnson23
Hi all, I have a couple of spare starter motors and wondered which was the most powerful in terms of rated Kw.
One is a lucas 25701A possibly SD1 or RR classic.
The other is a Bosch 0 001 110 120 which I suspect is for a P38 4.0/4.6
While on the subject does anyone know which is the most powerful of the standard starter motors? I am pretty certain that other than solenoid position issues they can be all used on any engine.

Re: Rover V8 starter motors

Posted: Sat Jun 27, 2020 8:40 am
by DaveEFI
I think that's the case too. If they fit - the SD1 has the solenoid moved to clear the exhaust. If it fits, it should work.
I found the Lucas a bit marginal on a very cold day - seemed to struggle a bit to turn the engine. I'd expect the later Bosch to be better, being a newer design.

Re: Rover V8 starter motors

Posted: Sun Jun 28, 2020 2:05 pm
by ChrisJC
The Range Rover P38 style ones (which have an epicyclic reduction gear in there) are superb. They spin the engine over at tremendous speed.

But like all starters, if you have bad connections anywhere, including engine earth, then even a good starter will struggle to spin the engine over.

Chris.

Re: Rover V8 starter motors

Posted: Mon Jun 29, 2020 9:44 am
by Rossco
I agree, a poor earth can cause havoc, my advice is to run a seperate negative lead from one of the starter mounting bolts straight to the battery.

Re: Rover V8 starter motors

Posted: Mon Jun 29, 2020 12:26 pm
by garrycol
The starter from my mid 70s low comp 3.5 now runs my hi comp 4.6 no issues - just bolted straight up and no issues turning the engine over.

Garry

Re: Rover V8 starter motors

Posted: Mon Jun 29, 2020 3:09 pm
by DaveEFI
There was a Lucas change during the 3.5 life - early starters were bigger than the later ones. Dunno if their torque was the same, though. I am a fan of reduction gear types, though. Gets the motor on a more efficient part of its curve, meaning the motor can be smaller and use less current.

Re: Rover V8 starter motors

Posted: Tue Jul 07, 2020 9:00 am
by SuperV8
The later smaller gear reduction Bosch one is a fair bit lighter is weight if important.

Tom.

Re: Rover V8 starter motors

Posted: Tue Jul 07, 2020 12:06 pm
by DaveEFI
Yes - the WOSP and others based on the Denso geared unit - weigh 1/3rd of the original Lucas.