In the summer of 2008, my car was having trouble starting, with the starter only occasionally engaging. With the usual suspects checked including the grounding strap and the switch connection to the starter, I decided to pick up a aftermarket Hi-Torque starter from Pelican Parts.
The starter I got was from IMI Performance Products and on Pelican's site it said it would fit '65-73 911s. At less than 4.5kg, this motor is significantly smaller and lighter than the stock unit, while offering higher cranking power for lower current drain.
While removing the starter motor from all 911s is known to be a difficult and messy job, as usual on a Sportomatic car, it is significantly harder. Removing the top nut (10mm allen head) to get the starter out is the hard bit. On manual 911s, the technique for getting to this bolt involves 'hugging' the transmission while on your back and reaching with your right hand around the top of the transmission with your head facing the front of the car. To make access easier, you can unbolt the inner CV joints and hang them out of the way with bungee cords. With the right extension (about 150mm) you should be able to reach the starter top nut. However on a 925-equipped car, your vacuum servo is in the way preventing you from accessing this top bolt from the right side. After many evenings of trying, I was able to remove the top bolt after buying a set of flex-head stubby ratchets and wobble bars. You, however, should learn from my mistake and do it the easy way - by partially dropping the engine.
While performing a partial engine drop sounds daunting if you have never done it before, it is quite simple and is pretty much the only way to do this job. First I removed the hard oil line that goes from the engine to the oil tank. This needs a 36mm spanner and if it hasn't moved in some time, you might want to coat the nut with penetrating oil and leave it for a while as it likes to rust in to place. Also remove the connection to the oil cooler, making sure you catch any drips. The next step is to disconnect the gear linkage which can be accessed by removing the cover from the transmission tunnel in front of the rear seats.
Using a good quality jack and some large blocks of wood, take the weight of the engine by jacking under the sump (a known strong point). Remove the rear engine mount bolts. Also use axle stands with some wood on under your heat exchangers for additional safety. At this point you can also remove the license plate panel for better access and view. Now slowly drop the jack down while watching for any snagged connections in the engine bay. You can lower the engine a surprising amount without doing any damage, but just lower it enough so you can get your hand through the firewall to access the starter area.
My Starter Doesn't Fit!
I foolishly came to this conclusion after installing the new starter in the car and hearing it spin away to itself without engaging the ring gear when I turned the key. After taking it out again and measuring it against the old starter it became clear. The mounting plate of the new starter is a full 10mm wider than the original Bosch starter. Why would this be so? Pelican must sell ton of these so they must fit most early cars – is the 925 mounting different? A quick look at the factory transmission press pictures shows you why.
925:
915:
The Bosch unit has a flat ‘edge’ which enables it to clear the plate directly to the right of the starter. After speaking to Pelican tech support, they confirmed it – these starters don’t fit the 925. I also emailed UK Porsche expert Mike Bainbridge of MB Engineering who confirmed there is a different part number for the Sportomatic starter motors. Things looked bleak.
Getting my Vernier Caliper out, I measured the old and new starters and realized that the new starter would have the same dimensions as the original if the ‘lip’ of the right side of the starter could be machined off.
I made a quick diagram in Visio and found a local machine shop to see if they could make my starter fit. This should be an easy job as the mounting plate can be removed from the starter and rotated to adjust the orientation of the starter in the car. For only £25 (about $40) my starter looked like it would fit.
Taking it home, I offered it up to the mounting bolts and I was happy to realise that it now fitted. I tightened the bolts and tried the key – the engine cranked with newfound vigour!
